In recent years, Interferometric Synthetic Aperture Radar (InSAR) data, which reflect surface deformation, have increasingly been integrated into landslide susceptibility assessments. However, previous studies have not adequately addressed the variability in SAR images, particularly in alpine and canyon regions where the imaging characteristics of InSAR ascending and descending passes differ significantly, leading to substantial errors in surface deformation measurements.

This study selected the reservoir area of Xiangbiling Hydropower Station as the research site. After conducting a correlation analysis of influencing factors, 11 influencing factors and InSAR deformation data pertinent to landslides in alpine and canyon areas were chosen for landslide susceptibility evaluation.

Comparisons between using different deformation datasets revealed that incorporating sparse ascending-pass data from sampling points decreases the accuracy of landslide susceptibility assessment. Conversely, utilizing descending-pass SAR data, which includes a higher density of sampling points, improved the accuracy by 2.7% (AUC = 0.9248).

The inclusion of InSAR deformation data as a influencing factor in landslide susceptibility assessment significantly influences the evaluation outcomes. Therefore, it is crucial to select appropriate InSAR deformation data to enhance the accuracy of susceptibility assessments.

Xianrendong National Nature Reserve in southern Liaoning Province and its adjacent areas have experienced numerous geological disasters, such as landslides, during periods of concentrated rainfall in recent years. However, the vulnerability and risk assessment of landslide disasters in this region under the influence of concentrated rainfall have been rarely explored. Therefore, it is urgent to conduct in-depth research, which is of great significance for effectively reducing the harm of geological disasters in the reserve and enhancing the capacity for emergency response and risk prevention and control.

Firstly, using the SMOTE-Tomek comprehensive sampling method coupled with an XGBoost model, 12 indices including topography, geology and lithology, hydrometeorology, and human engineering activities are deeply analyzed to obtain the evaluation results of landslide susceptibility. Secondly, focusing on the impact of short-term concentrated rainfall and continuous rainfall, daily rainfall data from four weather stations surrounding the study area are used to calculate annual average rainstorm intensity from 2018 to 2023 and three-day cumulative rainfall as risk assessment indicators, enabling the quantitative assessment of landslide hazards. On this basis, considering the vulnerability characteristics of the disaster-bearing body and regional disaster prevention and mitigation capabilities, a multi-factor landslide disaster risk assessment model suitable for the study area is constructed, resulting in a landslide disaster risk zoning map.

The results show that high-risk and above areas account for approximately 10% of the total study area, primarily distributed in the northeast of Xianrendong Town, the north of Buyunshan Town, the north of Changling Town, and the southwest of Hehuashan Town.

In the future, efforts should focus on high-risk areas such as Xianrendong Town, strengthening monitoring and early warning systems to provide decision support for the prevention and control of geological disasters across the entire study area.

The properties of provenance play a crucial role in controlling Paleogene deposition and reservoir development in China's offshore basins. However, due to the high costs of coring and the interpretation ambiguities associated with seismic data, there is a lack of visual evidence to support related understandings. The Weihe Graben is a Cenozoic rifting basin, and regional geological studies indicate significant differences in provenance system between the northern and southern of the Weihe Graben, These differences and the tectonic setting and provenance systems exhibit strong similarities with the offshore basins.

Based on outcrops and systematic sampling in Weihe Graben, zircon U-Pb dating, cast thin section, backscattering, and X-ray diffraction analysis are carried out to investigate the source system, deposition, and reservoir characteristics of the northern and southern sandbodies within the graben.

The findings reveal that the detrital zircons in the northern Huacheng section exhibit two prominent ancient peaks from the North China Craton, alongside a younger peak corresponding to Caledonian and Hercynian tectonic movements. The conglomerate gravel types at the base of the sequence predominantly consist of carbonate rocks, calcareouss clastic rocks, and metamorphic rocks, which reflect distinct characteristics of Paleozoic carbonate and clastic rocks from the Weibei Uplift in the north. In contrast, the southern profiles are dominated by detrital zircons from late Caledonian and Late Indosinian peaks, with gravel types primarily consisting of granites and metamorphic rocks, indicative of provenance from the southern Qinling Mountains. Observations of profiles demonstrate that these provenance differences result in significant disparities in the sedimentary system and reservoir characteristics. The carbonate provenance area of the Weibei Uplift corresponds to a small, mud-rich sedimentary body, where the bottom conglomerate transitions directly to silty sand and mudstone, resulting in high calcium content in the reservoir. Conversely, the southern Qinling orogenic belt features extensive sedimentary bodies, multi-cycle sand-rich deposits, and low calcium content.

The distinct types of provenance systems provide the material basis and prerequisite for reservoir development and subsequent diagenesis. The analysis of outcrop systems in the Weihe graben offers valuable reference on offshore basin research in China.

It is still unclear about the effects of redox fluctuations by Fe(Ⅱ)-containing clay minerals on the adsorption-desorption and valence transformation of Cr(Ⅲ).

In this work, Cr(Ⅲ) adsorption experiments were carried out by preparing montmorillonite in three different conditions (oxidized, reduced, and reduced-reoxidized) to determine the adsorption value, Fe(Ⅱ)/total Fe ratio, hydroxyl radical concentration, as well as valence changes. The montmorillonite solid materials before and after adsorption were characterized via X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier transform infrared (FTIR).

The results revealed that the adsorption rate of Cr(Ⅲ) by oxidized and reduced montmorillonite increased with elevated pH, and that reduced montmorillonite had the highest adsorption rate due to its highest Fe content, with no valence change occurring in these two states. The adsorption rate of reduced-reoxidized montmorillonite was the lowest, which was due to the rapid activation of oxygen by Fe(Ⅱ), producing hydroxyl radicals. Cr(Ⅲ) was rapidly oxidized to Cr(Ⅵ), and the lower the pH, the higher the oxidation rate. Cr(Ⅵ) was reduced back to Cr(Ⅲ) by the reducing substance Fe(Ⅱ) after 8 hours. The high correlation between the consumption rate of Fe(Ⅱ) and the generation rate of hydroxyl radicals was verified by changes in the Fe(Ⅱ)/total Fe ratio and hydroxyl radical concentration, which altered the redox environment.

Experiments have shown that hydroxyl radicals are generated after reduction and reoxidation, which affects the adsorption and desorption of Cr(Ⅲ), and strongly oxidizing hydroxyl radicals can oxidize Cr(Ⅲ) to toxic Cr(Ⅵ), supporting the hypothesis that chromium reverts to yellowish color after redox fluctuations in the underground environment.

Hydrodynamic resistance is one of the key factors influencing the velocity of landslides entering water. To quantify the resistance experienced by reservoir bank landslides upon water entry and provide experimental data and a theoretical basis for analyzing their entry velocity, this study designed an experiment to measure the water entry resistance coefficient.

Based on the dynamics and kinematics equations of submerged test blocks, a comprehensive calculation model for the water resistance coefficient was established. The experimental results were analyzed using dimensionless analysis methods to investigate the effects of various dimensionless factors on the water resistance coefficient. A multiple linear regression analysis was conducted to derive the comprehensive water resistance coefficient calculation model. Taking the Baige landslide of October 11, 2018, as a case study, the velocity of the Baige landslide was calculated using the theoretical formula for the water resistance coefficient, and the results were compared with those obtained from other methods.

The results indicate that as relative velocity increases, the comprehensive water resistance coefficient initially rises and then decreases. Additionally, as the relative cross-sectional area increases, the comprehensive water resistance coefficient decreases. The theoretical formula for the water resistance coefficient has a coefficient of determination (R²) of 0.77, demonstrating good accuracy. Compared to existing calculation results, considering hydrodynamic resistance, the maximum movement speed of the Baige landslide decreased by 23.5%, with a maximum speed difference of 8.5 m/s, and the time at which the maximum speed occurred was delayed by 7.7 seconds.

This study proposes a comprehensive calculation model for the water resistance coefficient, addressing the challenge of determining its value accurately. This model contributes to improving the prediction accuracy of the entry velocity of reservoir bank landslides, thereby enhancing risk assessment and mitigation efforts.

In order to study the dissolution damage and mechanical damage of carbonate rock by acidic filtration solution.

In this paper, through carrying out different flow conditions, different time length of phosphogypsum acidic leaching solution on the dissolution of limestone test research, analyze before and after the test of limestone specimens of the apparent characteristics, quality, porosity, uniaxial compressive strength, and acoustic emission counts and other indicators of the law of change, revealing the impact of the acidic leaching solution on the physical and mechanical properties of the carbonate rock.

The test results show that the dissolution rate and porosity increment of the rock samples are positively correlated with the dissolution time and the flow rate of filtration solution, and the mechanical strength is negatively correlated with the dissolution time and the flow rate of filtration solution. With the dissolution, the surface of the rock samples will be attached with thicker and thicker fluorite minerals, which makes the dissolution rate of the rock samples slower. The damage form of the uniaxial specimen gradually changed from shear damage to tensile damage. Under the acidic environment of phosphogypsum leachate dissolution, the internal mineral composition of limestone is dissolved, which causes changes in macro-mechanical parameters.

The research results can provide theoretical and experimental data for the stability analysis of karst media under the influence of acidic wastewater, acidic wastewater treatment, and tailing project safety design.

To more comprehensively and accurately analyze the surface deformation information of the landslide,

this study employs the Stanford method for persistent scatterers-multi-temporal InSAR (StaMPS-MTI) and small baseline subset InSAR (SBAS-InSAR) technology, combined with Sentinel-1 data, to invert the deformation information of the Muyubao landslide from 2017 to 2022. The deformation information is compared with GNSS monitoring data, and a regional analysis of the spatio-temporal deformation characteristics of the landslide is conducted by integrating the advantages of both technologies through a combination of point and surface measurements.

The results confirm that the deformation information obtained by InSAR technology is reliable, and each time-series InSAR technology has its own strengths and limitations. Specifically, the deformation rate intervals are as follows: the eastern slope of the landslide (−30.6 to −46.2 mm/year) > the eastern side of the major slipping plane (−25.2 to −37.8 mm/year) > the western side of the major slipping plane (−21.5 to −31.5 mm/year).

Based on the InSAR deformation results and previous studies, the deformation mode of the Muyubao landslide can be summarized as follows: the landslide undergoes overall and local deformation influenced by rainfall and reservoir water levels. During high water level periods, buoyancy-induced weight loss causes overall deformation, with a critical water level threshold of approximately 168 m. Heavy rainfall infiltrates the rock mass, raising the groundwater level, which promotes overall deformation and triggers local deformation in shallow soil and fractured rock masses. During the reservoir water decline period, the landslide is influenced by both buoyancy-induced weight loss and hydrodynamic pressure, with buoyancy effects being dominant; the hydrodynamic pressure effect lags by about 36 days. During low water level and rising water periods, overall deformation ceases, and heavy rainfall primarily causes localized deformation. The results indicate that time-series InSAR technology can effectively identify and monitor landslides, providing technical support for geological disaster prevention and risk assessment.

The Mufushan area, in the central Jiangnan Orogen, South China, has become one of the most significant rare metals resource bases in China. The Duanfengshan pegmatite-type Nb-Ta deposit is the only large-sized deposit in the northwestern margin of the Mufushan granitic batholith. However, its genesis and physicochemical conditions are still unclear. Niobium-tantalite, garnet and tourmaline coexist in the newly discovered Nb-Ta mineralized microcline pegmatite veins. Therefore, the study of garnet genesis can provide significant constraints for the Nb-Ta mineralization.

This study focuses on garnets in the mineralized and unmineralized microcline pegmatite veins in the Duanfengshan area. Garnets were observed using cathodoluminescence (CL) and backscattered electron (BSE) imagery. The major and trace elements are determined by EPMA and LA-ICP-MS, and are used to discuss the genesis of garnet and the indication for Nb-Ta mineralization within microcline pegmatite veins.

These mineralogical and geochemical features suggest a magmatic origin for garnets within microcline pegmatite veins in the Duanfengshan area. Garnets from pegmatites in the Duanfengshan area formed in medium-high temperatures and medium-low pressures. Garnets in mineralized and unmineralized pegmatites both belong to the solid solution series of almandite-spssartite. Garnet in the mineralized pegmatites is dominated by almandite (Sps_42.56 Alm_54.63), whereas garnet in the unmineralized pegmatites is mainly characterized by spessartite (Sps_58.93 Alm_37.18).

Garnets in mineralized pegmatites mostly coexist with columbite-tantalite, and have low Mn, Nb and Ta contents, as well as a decrease in Mn content and an increase in Fe content from the core to the rim. This mineralogical result is resulted by the crystallization of Nb-Ta minerals. It shows that the evolution relationship of Nb, Ta, Fe, Mn elements in garnet can indicate the pegmatite-type Nb-Ta mineralization in the Mufushan area.

Reveal the relationship between the outbreak of debris flow in SangguValley and factors such as material source and rainfall,

A new method combining InSAR and RAMMS techniques is proposed to analyze the deformation process of debris flow before and during debris flow eruption. Based on SBAS-InSAR technology, the deformation of SangguValley debris flow during two outbreaks was analyzed, combined with satellite image, UAV image and field investigation, the deformation process inversion and disaster trend prediction were realized before SangguValley debris flow disaster. RAMMS debris flow numerical simulation software is used to simulate the movement process of SangguValley debris flow during the eruption,

The research shows that: (1) The LOS deformation of SangguValley debris flow was calculated by InSAR technology, and the slope was in a creep state for a long time; The maximum deformation rate in the source area is 139 mm/a, the maximum deformation rate in the flow area is 46 mm/a, and the maximum deformation rate in the accumulation area is 20 mm/a. Rainfall provides a lot of loose sources for debris flow development. (2) The evolution process of the study area is divided into three stages: initial motion, accelerated motion, deceleration and final motion according to the accumulation depth and velocity of debris flow under the state of asynchronism.

This method, combined with the historical analysis of glacier debris flow deformation and the simulation of movement process, provides a scientific basis for the development trend and prediction of debris flow, and provides a reference for engineering control design.

With the frequent occurrence of landslide disasters in China, it is crucial to enhance research on unstable rock masses and slopes. Traditional analysis methods have limitations in quantifying certain factors, necessitating improvements. This paper adopts a non-contact measurement method to obtain and analyze parameters of wedge-shaped unstable rock masses and assess their stability under different working conditions.

Taking the wedge-shaped unstable rock mass in the upper reservoir of a pumped storage power station as an example, this study reveals the basic features and stability-influencing factors of the unstable rock mass based on detailed engineering geological field investigations. A long-distance 3D laser scanning system was used to collect high-precision point cloud data of the slope. Through preprocessing, spatial parameters of the wedge-shaped unstable rock mass were obtained. The critical surface plane was determined using least-squares fitting to calculate the slope angle and height of the wedge-shaped body. Local point cloud data were fitted to determine the normal vector, which was then used to calculate discontinuity orientations. The Alpha shape method was employed to calculate the volume of the unstable rock mass, with the most suitable radius parameter determined by comparing it with the actual unstable rock mass. The stability of the unstable rock mass was evaluated using the limit equilibrium method.

The results show that under natural conditions, the stability coefficient of the wedge-shaped unstable rock mass is 1.131, indicating an essentially stable state; under rainstorm conditions, the stability coefficient drops to 0.896, indicating instability; and under seismic conditions, the stability coefficient is 0.917, also indicating instability.

This paper applies non-contact measurement and intelligent recognition techniques to the stability analysis of wedge-shaped unstable rock masses. The total analysis time was 102 minutes, significantly improving the efficiency of stability analysis and reducing risks associated with engineering construction. The proposed method provides a reliable alternative for assessing the stability of complex geological structures, enhancing safety and reliability in geotechnical engineering projects.

Landslide debris flows are common geological disasters characterized by large scale, long sliding distances, and high speeds. The terrain of hillside ravines and valleys significantly influences the trajectory of these flows, causing them to block, turn, pile up, and exhibit a series of complex behaviors. Therefore, the movement path of landslide debris flows is not a simple straight line but is influenced by various terrain factors, resulting in complex and varied trajectories.

This study focuses on the aggregation behavior of landslide debris flows along different motion trajectories. Using EDEM software, we analyzed the impact and accumulation characteristics of symmetrically aggregated landslide debris flows at various aggregation angles.

This study has reached results in three aspects. 1) Effect of the aggregation angle on movement velocity: Larger aggregation angles result in lower v_y values, higher degrees of separation of the landslide debris flow, and longer sliding times. 2) Effect of the aggregation angle on accumulation morphology: Larger aggregation angles cause the landslide to stabilize at the foot of the slope, with the accumulation zone lengthening on the slide side and decreasing in height at the blocking structure. 3) Effect on impact performance: Larger aggregation angles lead to lower and later peak impact forces on the barrier structure. Additionally, the residual impact force after the formation of a static accumulation area is lower and closer to the peak impact force.

These findings provide a fundamental basis for the in-depth study of the complex movement paths of landslide debris flows and offer theoretical references for optimizing landslide debris flow control structures.

To establish a prediction model for groundwater microbial toxicological indicators (total bacteria count [TBC] and total coliform count [TCC]) in alpine regions,

this work focuses on the microbial toxicity indicators (TBC and TCC) of groundwater from a specific water source in the western plateau region of China. By using an orthogonal experimental design combined with indoor soil column batch experiments, we varied environmental factors such as pH, temperature, and porosity to obtain the evolution results of TBC and TCC under different depths, pH values, oxidation-reduction potential (ORP) values, temperatures, porosities, and chemical oxygen demand (COD) conditions. On the MATLAB platform, a predictive model for microbial toxicity indicators in groundwater in frigid regions was subsequently established using the LM (Levenberg Marquardt)-optimized BPNN (neural network) algorithm.

These results indicate that the predictive results of the established TBC and TCC models align well with the experimental results. The maximum relative errors are less than 15% (meeting engineering requirements), yielding 11.52% and 14.55% for TBC, and TCC, respectively. Moreover, the evolutionary trends of TBC and TCC match the experimental results.

This model can be used for predicting microbial toxicity indicators in groundwater in plateau regions, and the results of this study provide new insights for predicting microbial toxicity indicators in groundwater in high-elevation areas.

With the increasing number of large engineering projects, geotechnical limit problems are becoming more common, often leading to extreme model deformation when numerical methods are employed. The traditional finite element method frequently encounters convergence issues, volume locking, and stress misalignment due to severe mesh distortion during the analysis of extreme model deformation, especially when low-order elements are used. Therefore, developing a new method for numerical analysis is of great importance.

The smooth finite element method is an effective approach to address the inherent defects of the traditional finite element method, enhancing both solution accuracy and convergence speed. Thus, based on the smooth finite element method combined with a modified Mohr-Coulomb yield criterion and a linear search optimization algorithm, an elastoplastic calculation model for rock and soil masses is developed in this study.

The classical bearing capacity model for the strip foundation and slope model was tested, and the numerical results align well with the reference solutions. The findings indicate that the calculation accuracy of the smooth finite element method is clearly superior to that of the traditional finite element method, confirming the feasibility and practicality of the proposed algorithm.

In this work, the calculation model developed using the smooth finite element method significantly improves the calculation accuracy for rock and soil elastoplastic problems, while reducing the calculation error and stress misalignment caused by mesh distortion in traditional finite element methods.

The compression index C_c and swell index C_s of soil are critical parameters for calculating soil settlement and swelling. Utilizing machine learning algorithms to predict these indices quickly and efficiently can significantly reduce testing duration and costs.

In this study, we introduce Piezocone Penetration Test (CPTU) in-situ data and quantify soil layer information using the Soil Behaviour Type (SBT) index I_c. We then combine laboratory data with CPTU data to develop a multi-output genetic algorithm-optimized backpropagation neural network (GA-BPNN) model. The input parameters for the multi-output GA-BPNN model were determined through correlation analysis. Using the TC304 standard site database, the prediction results from the multi-output GA-BPNN model were compared with those from the multi-output BPNN model and the single-output GA-BPNN model, verifying the effectiveness of the multi-output GA-BPNN model and obtaining pre-trained model parameters. For sites with limited data in Nanjing, the superiority of the multi-output BPNN model was further evaluated by analyzing the impact of pre-training and in-situ test data on model performance. A sensitivity analysis was also conducted to assess the robustness of the model.

The results demonstrate that the pre-trained multi-output GA-BPNN model, derived from standard site data, can effectively predict the compression and swell indices under limited data conditions. When combined with in-situ test data, the multi-output GA-BPNN model exhibits high prediction accuracy for these indices, with predicted values closely matching measured data. The consistency of the predicted results aligns well with existing studies.

The pre-trained multi-output GA-BPNN model can efficiently predict the compression and swell indices of soft soil under limited data conditions. The proposed method shows significant potential for multi-parameter prediction in engineering practice, enhancing the efficiency and reliability of geotechnical engineering assessments.

Stability analysis of rock slopes is crucial for ensuring the normal construction and safe operation of engineering facilities. Instability of slopes can cause severe casualties and economic losses. The widespread presence of determining and random discontinuities within rock slopes leads to rock mass discontinuity and heterogeneity, significantly affecting slope stability, deformation characteristics, and failure modes. Therefore, studying the development characteristics of discontinuities and their influence on slope stability is vital for slope protection and disaster prevention. However, existing studies rarely consider both determining discontinuities and random discontinuity networks when constructing rock slope models for probabilistic stability analysis and failure mechanisms.

In this study, a three-dimensional numerical slope model was constructed using Rhino software. The discrete fracture network (DFN) model was applied to generate both determining and random discontinuity networks based on field discontinuity data. A coupling analysis model for random discontinuities was then developed by integrating the slope model and discontinuity networks via 3DEC software. A probabilistic stability analysis method was proposed to analyze the effects of random discontinuities on slope stability. Finally, the proposed method was demonstrated using a simplified rock slope model to assess the impact of random discontinuity networks on slope stability, along with a probabilistic stability analysis of the left bank shoulder slope of the Jinping I Hydropower Station under natural and excavated slope conditions.

The results indicate that (1) The proposed method effectively and accurately simulates both the deterministic and random discontinuity networks, as well as coupling the discontinuity network with the rock slope model. (2) The probabilistic distribution of the slope stability coefficient can be obtained, and the results are more comprehensive and aligned with engineering practice. (3) The random discontinuity network has a greater impact on slope stability under excavated slope conditions and alters the failure path and instability mechanism of the rock slope.

The research results provide references for excavation and support schemes for rock slopes in engineering practice and offer a theoretical basis for geological disaster prevention and control.

Disaster-causing environmental factors serve as input variables for landslide susceptibility prediction modeling, referring to various natural attribute factors influencing the occurrence, development, and distribution of landslides on slopes. A comprehensive and clearly-defined set of disaster-causing environmental factors is of vital importance for enhancing the accuracy and reliability of landslide susceptibility outcomes.

To further clarify the research status and future prospects of disaster-causing environmental factors, this paper conducted a literature search in the core collection database of Web of Science, with the titles containing "landslide susceptibility" and the publication date ranging from 01/01/2013 to 31/12/2023, collecting 767 English papers on landslide susceptibility to form a literature database. Firstly, information such as the quantity of disaster-causing environmental factors, acquisition methods, sources, importance, and acceptance in each paper was statistically analyzed. Then, the definitions and physical meanings of disaster-causing environmental factors were elaborated in detail. Subsequently, characteristics such as the optimization selection/combination methods of disaster-causing environmental factors, factor connection methods, factor errors, and suitability were discussed, providing a reference for the uncertainty research of selecting disaster-causing environmental factors when predicting landslide susceptibility.

The review results indicate that: (1) A total of 82 types of disaster-causing environmental factors were statistically analyzed in the literature database, with over 40 frequently used ones. Among them, slope, aspect, elevation, and lithology are the four most frequently used factors. The importance of factors such as slope, elevation, road density, lithology, and rainfall in landslide susceptibility prediction is the highest in sequence. (2) It was discovered that research on using comprehensive and physically meaningful disaster-causing environmental factors, constructing model input variables based on environmental factor connection methods, eliminating random errors in environmental factors, enhancing the suitability of environmental factors, and employing various explainable methods can effectively improve the performance of machine learning in predicting landslide susceptibility. Therefore, in future research on the disaster-causing environmental factors of landslides, it is necessary to focus on these key issues.

Seabed carbon dioxide (CO₂) geological sequestration technology has become a hot spot in carbon sequestration and carbon neutralization. There are favorable space and temperature and pressure conditions for the formation of CO₂ hydrate in the seabed sediments in the northern part of the South China Sea, and the formation of CO₂ hydrate in the cracks and pores can block the further upward migration of CO₂ and generate self-sealing capacity. However, the CO₂ leakage in the fracture and the effect of hydrate plugging and instability conditions are still unclear.

In this paper, the visualization experiment platform of hydrate growth and the instability process of water injection supercharging at high pressure and low temperature was used to observe the formation of CO₂ hydrate and experiment platform was used to simulate the conditions of seafloor sedimentary cover under the conditions of 2℃ and 3～4 MPa, and the hydrate instability condition and plugging effect were evaluated with the breakthrough pressure, breakthrough pressure difference, duration, permeability coefficient of initial instability stage and plugging rate as indicators.

The experimental results show that hydrate formation can be simplified into four processes: nucleation, expansion, forming and aggregation. Hydrate formed in cracks can efficiently block the migration of fluids such as water and CO₂, but the instability phenomenon begins when the fluid pressure gradually increases and reaches the critical breakthrough pressure. The instability process of hydrate can be simplified into two parts: particle size degradation and surface friction failure. The core of hydrate mass is unstable first, and the sealing state can be maintained before the surface of hydrate fails to friction fracture. The instability conditions of hydrate in the fracture are investigated experimentally. The breakthrough pressure is 6.414～6.966 MPa and the breakthrough pressure difference is 2.403～3.203 MPa. The instability rate of hydrate is mainly affected by the flow rate, followed by the saturation of hydrate, and the flow rate affects the instability rate through the interface effect. The key factors determining the breakthrough pressure of hydrate are temperature and pressure conditions, while the effect of flow rate is mainly reflected in regulating the specific time when hydrate enters the instability state. Under the condition of 3～4 MPa seafloor sedimentary cover, the sealing rate is 99.0～99.6% and the permeability coefficient of initial instability stage is 0.555～1.260 md.

The experimental results provide a reference for the risk assessment of the overlying layer under similar conditions in the South China Sea for CO₂ seabed geological sequestration. The difference between the pressure under the capped CO₂ hydrate layer and the actual pressure on the seabed should be ensured to be less than 2 MPa to maintain the sealing effect of the hydrate.

The seepage of fractured rock masses has non-uniformity and anisotropy, and its complexity is reflected in parameters such as density, orientation, and trace length of individual fractures, as well as the connectivity of fracture networks. The connectivity of fracture networks is a difficult problem in calculating the seepage parameters of three-dimensional fractured rock masses. At present, the calculation methods for seepage parameters of three-dimensional fractured rock masses have their own advantages and disadvantages due to different models. To analyze the hydraulic anisotropy and permeability coefficient of fractured rock masses, a new method for solving the permeability coefficient of three-dimensional fractured rock mass dense sections based on dimensionality reduction is proposed.

This method, founded on the simulation of three-dimensional fracture networks, approximates the fractured rock masses through dense sections in different directions, decomposing the three-dimensional fracture network into multiple continuous two-dimensional sectional fracture networks, using graph theory to analyze the hydraulic connectivity and permeability paths, and water head boundary conditions are set to calculate the permeability coefficient. Through the relationship between lines, surfaces, and volumes in space, the calculated permeability coefficient in two-dimensional space is expressed as the directionality in three-dimensional space, and the permeability tensor of the three-dimensional fractured rock mass network is constructed.

By treating the section permeability coefficient as a permeability ellipse, the new method calculates the equivalent permeability coefficient of the section and provides a solution formula for the equivalent permeability tensor of the rock mass. It also discusses the scale effect and the representation of anisotropy in the rock mass. By constructing three-dimensional and two-dimensional fracture networks, different sizes of unit cells were intercepted to calculate the permeability coefficient, and the side length of a typical unit cell was determined to be 20m. The feasibility of the method was verified through field drilling water pressure experiments.

This method offers a reference for solving the permeability coefficients in different directions of heterogeneous fractured rock masses of various scales.

In response to the problems of strong reservoir heterogeneity, low signal-to-noise ratio of seismic data, insufficient prediction accuracy of post stack reservoirs, and difficulty in identifying fractures in the ultra deep carbonate reservoirs in Shunbei, a new method for improving the prediction accuracy of fractured reservoirs is explored based on five dimensional seismic data.

Based on the study of the reservoir development characteristics of the Shunbei fault controlled fracture cave type oil and gas reservoir, this article conducts five dimensional seismic anisotropic forward simulation, establishes the relationship between seismic amplitude and fracture parameters, and optimizes the sensitive parameters for fracture prediction; Based on this, derive the Fourier series form of the directional elastic impedance equation, carry out fracture type reservoir prediction, and apply it in the Shunbei X well area.

Through research, the AVAZ seismic response characteristics of ultra deep carbonate rock fault controlled reservoirs have been clarified, and it is pointed out that fracture density is a sensitive parameter indicating fractured reservoirs; Meanwhile, by utilizing second-order Fourier coefficients to characterize the density of fracture development, a precise characterization of fracture type reservoirs was achieved in the Shunbei X well area, with a high prediction accuracy.

The five dimensional sesmic prediction technology based on amplitude attributes enriches the prediction of fracture development density and direction by mining amplitude and orientation information of wide azimuth seismic data. The established Fourier coefficient fracture density mapping relationship provides a quantitative prediction tool for fracture controlled fracture cave reservoirs, and offers new ideas for fracture prediction and target evaluation in fracture controlled fracture cave reservoirs.

Carrying out land surveys and evaluations and developing special industries is a very important task for China to realize rural revitalization and consolidate the results of poverty alleviation. In order to more accurately and effectively guide regional agricultural production layout and specialty industry development, a selenium-rich land survey and evaluation was conducted in Tunliu District, Changzhi City, Shanxi Province, China.

Therefore, the indicators of selenium-rich industry quality, ecological environment and arable land strength were selected to construct a comprehensive quality evaluation system for selenium-rich land, and then fuzzy mathematical method, entropy weighting method, and composite index method were applied to evaluate and grade the land in the study area, and ArcGIS was used to implement the results.

The results show that: ① the land with soil selenium content grades of high selenium and moderate selenium in Tunliu District accounted for 54.47% of the statistical area, and these soils were concentrated in the eastern part of the district; the distribution of cultivated land strength grades in Tunliu District was uneven, and the overall characteristics showed that it was low in the western part and high in the eastern part; the results of the evaluation of ecological environment grades were clean in the whole district. ② There are 299.33 square kilometers of selenium-enriched land in Tunliu District with comprehensive quality grade of first class, accounting for 26.61% of the statistical area, and concentrating in the plain area in the east. ③ Wheat, sharp peppers and green peppers in Tunliu have reached the standard of selenium enrichment of crops. Among them, the selenium enrichment rate of sharp peppers is 100%. In addition, the results of heavy metal element testing show that the crops in the district are in good clean condition.

Based on the evaluation results of land and crops, and in conjunction with the spatial planning of land in Tunliu District, the land is divided into three types: A, B and C. Among them, type A land is characterized by high soil selenium content, rich nutrients and clean environment, so it is recommended to build selenium-enriched wheat and green vegetable planting bases in the area where this type of land is concentrated and develop tourism agriculture at the same time. Class C land is characterized by low soil selenium and nutrient content, which is unsuitable for planting crops, so it is recommended to build deep-processing factories for agricultural products in the areas where this type of land is concentrated, and to develop agricultural trade and tourism at the same time. It provides theoretical support and scientific suggestions for the planning of selenium-rich agriculture industry in Tunliu District and the synergistic development of the region.

In tunnel engineering, the prerequisite for tunnel design and construction safety is to accurately assess the amount of deformation of tunnel surrounding rock.

In this paper, the Firefly Algorithm (FA), Whale Optimization Algorithm (WOA) and Gray Wolf Optimization Algorithm (GWO) are combined with optimized Support Vector Regression (SVR), and based on which three hybrid swarm intelligent optimization prediction models are constructed to predict deformation of extruding surrounding rock tunnels. A database containing 62 samples was constructed, and seven initial parameters of tunnels and surrounding rocks were selected as the input parameters of the prediction models, and the radial deformation of tunnels as the output quantities. The coefficient of determination (R²), root-mean-square error (RMSE), and mean absolute error (MAE) were selected as the evaluation indexes of the model prediction effect. Finally, the effects of different input parameters on the prediction results of tunnel rock deformation were evaluated using normalized mutual information values.

The FA-SVR model demonstrated superior predictive performance during both the training and testing phases compared to the GWO-SVR and WOA-SVR models. For the training set, the corresponding R² values were 0.9634 and 0.9648, respectively, while the RMSE values were 18.786 and 14.699, and the MAE values were 9.460 and 11.170. The ranking of predictive capability was as follows: FA-SVR > WOA-SVR > GWO-SVR.

The results show that the firefly algorithm, the whale optimization algorithm and the gray wolf optimization algorithm can improve the prediction performance of the support vector regression model, the FA-SVR model has the best prediction effect, and the optimized hybrid prediction model performs significantly better than the classical models. The sensitivity analysis shows that joint frequency is the most important parameter that affects the predicted value of deformation of tunnel surrounding rock.

The distribution of structural planes plays a significant role in determining the engineering and mechanical properties of rock masses. Accurately obtaining information about structural planes is crucial for analyzing the characteristics and stability of rock masses.

Three-dimensional point cloud data of a steep rock slope was acquired using 3D laser scanning technology. After the filtering preprocessing of the point cloud data, the open-source program Discontinuity Set Extractor (DSE) was then used to semi-automatically recognize and classify the point cloud data, obtaining key parameters and clustering information of the slope rock mass structural planes, such as attitude, trace length, and spacing. By fitting the point cloud clustering information, a probability distribution model was created, and a Discrete Fracture Network (DFN) model was established. Furthermore, a three-dimensional block discrete element model of the steep slope was developed using the "Rhino-Griddle-3DEC" integrated modeling method based on the point cloud data. The model investigated the stability of slope and potential failure area.

The results show that under the gravity condition, the safety factor of the whole slope is about 1.5 and the potential unstable area is the dangerous rock mass located on the top of the slope.

Therefore, the structural plane parameters identified by this method can better reflect the engineering properties of the rock mass, providing important guidance for the analysis and evaluation of the stability of steep rock slopes.

Thermal structure analyses in the Songliao Basin are mostly confined to the sedimentary scale in the north-south zoning, and the lack of basin-wide thermal structure portrayal at the lithospheric scale constrains the genesis analysis in a geodynamic background.

Based on the published parameters of surface heat flow, geothermal gradient and thermophysical properties, this paper supplements the thermophysical properties of Yaojia Formation, Qingshankou Formation and Quantou Formation, and adds several geothermal field data to comprehensively characterize the geothermal field of the whole Songliao Basin, and analyze the characteristics of the present-day lithospheric thermal structure.

The results show that the geothermal gradient in Songliao Basin ranges from 21.10 to 63.45℃/km, with an average value of 41.41℃/km, which is higher than the global average value of 30℃/km; the distribution of surface heat flow values ranges from 30.38 to 106.58 mW/m², with an average value of 71.85 mW/m², which is higher than the global average value of 60 mW/m² and belongs to a typical "hot" basin. Under the influence of the Pacific plate subduction, the delamination and thermal erosion made the thinned thickness of the thermal lithosphere of 58.59 km. The heat flow contribution by radioactive elements in the thinned crust is only 16.40 mW/m², accounting for 22.83% of the surface heat flow; and under the influence of the dehydration of the stagnant plate, part of the molten mantle heat material is upwelled, the mantle heat flow contributes as high as 55.45 mW/m², accounting for 77.17% of the surface heat flow.

Therefore, controlled by lithospheric thinning and mantle upwelling, the Songliao Basin has "hot" basin properties and "hot mantle and cold crust" lithospheric thermal structure characteristics.

In order to clarify the development characteristics of such reservoirs and reduce the risks associated with deep-ultra-deep oil and gas exploration.

Based on the experimental analyses of well logging, thin section petrography, high pressure mercury injection and PVT phase diagrams, the characteristics of tight sandstone reservoirs and the causes of physical property differences were discussed.

The rock types of Bashijiqike Formation reservoir in Bozi area which the study highlights are medium-fine grained lithic feldspar sandstone and feldspar lithic sandstone. Notable differences exist in the spatial distribution of carbonate cement content. Original porosity in the medium-fine sandstone reservoirs that ranges from 32.4% to 38.1%, exhibiting comparable intergranular compaction strength primarily reliant on point-line contacts. Southern reservoirs maintain an average porosity of 8.6% and an average permeability of 3.4mD. Central reservoirs present an average porosity of 6.53% and an average permeability of 0.65mD. The average porosity and permeability of the northern reservoir are 4.9% and 0.62mD respectively. Primary intergranular pores dominate the southern reservoir space, whereas residual intergranular pores and dissolution porosity prevail in the northern and central zones. Furthermore, superior pore-throat structures characterize the southern region compared to the northern and central sectors.

The physical properties of sandstone reservoirs in Bozi area are controlled by sedimentation, diagenesis and tectonic processes (fissures), among which carbonate cementation emerging as the principal factor of the late reservoir physical properties alterations. Overpressure, hydrocarbon fluid charging, and fracture development significantly affect carbonate cementation, subsequently causing variations in reservoir physical properties. Stronger overpressure, earlier oil and gas charging time and limited fracture filling result in better reservoir properties in southern Bozi than those in northern and central areas.

The development of karst reservoirs in the Maokou Formation of the Lower Permian in southern Sichuan is a key formation for conventional oil and gas exploration in southern Sichuan. The development level of supergene karst reservoirs is directly controlled by the rich and varied karst microgeomorphology, resulting in strong lateral heterogeneity of karst reservoirs.

This paper uses 3-D seismic data, combined with strata thickness, gradient structure tensor attributes, and geological body carving techniques, to characterize the microgeomorphic characteristics of Dongwu karst in the Yunjin area. Predicting favorable zones for surface karst reservoirs through model forward modeling and amplitude attributes.

Research suggests that:①The Yunjin area had significant differences in karst micro- geomorphology during the Dongwu period, with a series of karst caves developed, which exhibited a seismic feature of "pull-down" of the seismic event event axis at the top boundary of the Maokou Formation;②Effectively characterizing the distribution pattern of karst collapse bodies in Yunjin syncline area using gradient structure tensor attributes combined with geological body carving technology. There are three distribution patterns of karst collapse bodies on the plane: isolated, linear, or contiguous;③The seismic amplitude on both sides of the edge of the karst collapse body is weakened, and the karst process is strong, with the development of karst caves, which is a favorable zone for reservoir development.

This research result has guiding significance for the subsequent prediction of Maokou Formation reservoirs.

Concentrated recharge conditions often significantly impact the water quantity and quality of karst underground rivers. Therefore, it is of great importance to clarify the effects of different concentrated recharge conditions on these aspects.

Based on hydrogeochemical surveys, this study simultaneously monitored the hydrological and hydrochemical dynamics at the sinkhole entrance and underground river outlet of the QLK underground river system in western Hubei, to explore the impacts of different recharge conditions on the water quantity and quality of the underground river.

The results show that recharge intensity and soil moisture content directly control the generation and convergence processes of flow within the sinkhole, as well as the flow response of the karst underground river system. Rainfall events that do not reach a threshold will not trigger a flow response in the underground river.As concentrated runoff converges towards the sinkhole entrance, the concentrations of various hydrochemical ions increase significantly.The hydrochemical response observed at the outlet of the QLK underground river system is influenced by the intensity of recharge. Under heavy rainfall conditions, this response is further intensified due to the enrichment of hydrochemical ion concentrations at the sinkhole entrance.Following heavy rainfall, TIN (Total Inorganic Nitrogen) and phosphates accumulate at the sinkhole entrance, leading to concentrations that are 2 to 3 times higher than the natural background levels. Pollutants introduced through concentrated recharge directly contaminate the underground river. In the hydrochemical response, N-${\mathrm{NH}}_4^+ $ enters the karst water cycle prior to N-${\mathrm{NO}}_3^- $, and the fluxes of nitrate and TIN increase at the outlet of the underground river system relative to the inlet. Meanwhile, the flux of ammonium N-${\mathrm{NH}}_4^+ $ gradually decreases over time as recharge occurs, suggesting nitrification reactions within the conduits.

The results of this study can provide a scientific basis for pollution prevention and control, as well as water environmental management of karst underground rivers.

There are many factors affecting the bonding performance of the anchor-mortar interface, and the current research on the bonding performance of the interface focuses on the influence of a single factor, while the research on the bonding performance of the interface under the action of multiple factors still leaves a gap.

In this paper, we take the anchor-mortar as the research object, using electrochemical impedance spectroscopy to obtain the state of the anchor-mortar interface and electrochemical parameters under different influencing factors, obtain the bond strength of the anchor-mortar interface through the pullout test, and combines the electrochemical parameters to investigate the relationship between the electrochemical parameters and the pullout load when the specimen maintenance is completed and analyses the influence of the three factors on the bonding performance of the interface between the anchor-mortar.

The sensitivity analysis of orthogonal test shows that the pull-out load of the specimen is mainly controlled by the diameter of the anchor rod, the pore solution resistance (R_s) is mainly controlled by the water-cement ratio, and there is no obvious controlling factor for the charge transfer resistance (R_ct); at the early stage of specimen maintenance, under the influence of the three factors, there will be two kinds of states of the anchor-mortar interface, namely, complete passivation film and incomplete passivation film. The results of the study show that, within the range chosen for the test, the pullout load increases with the increase of fine sand particle size and the decrease of water-cement ratio, and the pullout load of the specimen is positively correlated with the pore solution resistance (R_s) and charge transfer resistance (R_ct).

The research results are of great significance for the validation of the effectiveness of anchored structural mortar proportioning and application.

Studying the spatial distribution law of earthquake-induced landslides can not only provide an important basis for the investigation of hidden dangers of geological disasters in disaster areas, but also be of great significance for post-disaster reconstruction, post-disaster resettlement and site selection, and geological disaster prevention and control.

Taking the earthquake with M_s6.8 in Luding County, Ganzi, Sichuan Province on September 5, 2022 as an example, firstly, based on the optical image (DOM) with 0.2m resolution and the digital elevation model (DEM) with 0.5 m resolution obtained after the earthquake, the earthquake-induced landslides were interpreted by artificial visual three-dimensional remote sensing, and then combined with field investigation and correction, the final number of earthquake-induced landslides was determined. On this basis, the relationship between the geological background such as topography, geological structure and seismic factors and the distribution of earthquake-induced landslides was analyzed.

①The Luding earthquake event triggered 9248 landslides in the study area of about 680km², mainly small and medium-sized landslides, and the highest area density of landslides was concentrated in the intersection of Xianshuihe fault, Daduhe fault and Jinping mountain fault. The total landslide area is about 45.57 km², and the average landslide area can reach 4941m²; ②The distribution of landslides in this earthquake is mainly influenced by PGA and fault structures, and most of them are distributed within the range of PGA> 0.6 g and 1km from both sides of the seismogenic fault; In addition, the development of landslide is negatively related to the distance from water system and road; Locally influenced by topographic factors, it mainly develops at the elevation of 1200-2400 m, the slope is 30-60, and the slope is eastward and southeast, and the stratum lithology is mostly hard rock; ③The relationship between the number and area of landslides and magnitude of Luding earthquake also follows exponential distribution; At the same time, due to the high accuracy of the basic data of this interpretation, the number of earthquake landslides obtained by interpretation is more than that of other documents, with a smaller minimum area and a larger total area.

The results obtained in this study have been applied to the post-disaster recovery and reconstruction in Luding earthquake-stricken area.

This study addresses the threat of potential karst geological disasters to the core cities of the Guangdong-Hong Kong-Macao Greater Bay Area, such as Guangzhou and Shenzhen, impacting the safety and development of their underground spaces. Standard penetration testing, a crucial method for investigating karst strata, plays a vital role in soil layer classification, load-bearing capacity evaluation, and foundation selection. However, traditional standard penetration tests can escalate project costs and are significantly influenced by the skill level of the operators.

To deal with these challenges, this paper introduces a new method for rapidly and accurately obtaining standard penetration test data in karst areas. Focusing on the karst regions of Shenzhen, we collected 1006 sets of soil penetration data and developed a single hidden layer neural network model with an 11-5-1 structure; this model is featured by only five neurons and has an analytical form that enables easy computation.

The research findings reveal that this neural network model has a high determination coefficient of 0.93, indicating its high accuracy in prediction. The model factor has a mean value of 1.04, with a coefficient of variation (COV) ranging between 9% and 23%. Overall, the model demonstrates high precision and low predictive dispersion. The paper thoroughly examines various factors affecting the model's stability and predictive performance, including the number of neurons in the hidden layer, data normalization methods, choice of activation functions, data splitting ratios, and the impact of random sampling. The practical applicability of this neural network model has been validated through its implementation in two independent engineering projects in the Longgang District of Shenzhen.

This study offers significant insights for the advancement of engineering survey methods in karst regions.

In order to analyze the mechanical behavior of the pipe roof during tunnel excavation,

an analytical model of the support pipe at the bottom of the pipe jacking roof is constructed based on the Pasternak elastic foundation beam theory, making full use of the displacement, rotation, bending moment, and shear continuity conditions to derive the displacement and internal force equations of the support pipe.

The calculation results are in close agreement with the measured strain from the project, proving the applicability of the model. Moreover, by analyzing the maximum strain change law of the support pipe, the reasonable pipe roof diameter was selected, using the pipe jacking roof of the Qinhuai New River section as an example.

The research shows that the initial pipe diameter significantly influences the support performance of the bottom support pipe, with this influence gradually decreasing as the pipe diameter increases. The excavation step length and pipe spacing positively impact the support performance, with a more pronounced effect on the maximum strain of the support pipe when the pipe diameter is small. Pipe spacing has minimal effect on the longitudinal strain of the support pipe. The unloading lever of the pipe jacking roof can effectively transfer the unloading value from the excavation area to the unexcavated area, thus ensuring the stability of the excavation surface of the pipe jacking roof.

The mutual conversion between river water and groundwater plays a crucial role in influencing the composition and evolution of hydrochemical components, and thus, has a significant impact on the water ecological environment. Hence, it is critical to gain a comprehensive understanding of the sources and evolution mechanisms of its hydrochemical components. The complex interactions between river water and groundwater can lead to alterations in the chemical constituents, which may have far-reaching consequences for the overall health and stability of the aquatic ecosystem.

This work focused on the Manas River Basin, which is located in a typical arid area of China, as the research area. A series of advanced methods were involved in this work, including hydrochemical diagrams (provide a visual representation of the chemical characteristics); ion ratio coefficient analysis (helps in determining the relative proportions of different ions); and inverse hydrogeochemical evolution (allows for a detailed exploration of the historical changes in the water chemistry). Through these methods, an in-depth study is carried out on the hydrochemical characteristics of river water and groundwater in different landforms within the basin, as well as the sources of major ion components and the evolution laws.

These results obtained from the research are highly revealing. It is found that with the changes in landforms and the conversion relationship between river water and groundwater, the hydrochemical types of river water and groundwater experience a progressive evolution. Initially, they are mainly of the HCO₃·SO₄-Ca type, but gradually transform into the Cl-Na type. The natural driving factor responsible for these hydrochemical changes also shifts. In the disconnected segment, the hydrochemical type of water bodies is predominantly HCO₃·SO₄-Ca, and the main influencing factor is diafiltration. In the upper reaches of the river-groundwater exchange section, it is mainly SO₄·Cl-Na type water, where leaching and mixing are the dominant processes. In the lower reaches of the interaction section, the hydrochemical type is mainly Cl-Na, which is dominantly affected by evaporation. The results of inverse evolution further quantitatively analyze the influence of water-rock interaction in the research area. Along the direction of groundwater flow, specific chemical reactions occur. For example, the precipitation of albite and anorthite takes place, while the dissolution of dolomite, gypsum, Ca-montmorillonite and rock salt is observed. Additionally, positive cation exchanges of Na-Mg and Ca-Mg are also detected.

The results of the study can provide a scientific basis for water environment protection and sustainable management in arid and semi-arid regions.

The gas-rich Wufeng-Longmaxi shale of the southern Sichuan Basin exhibits low-resistance anomalies in multiple areas. Statistical analysis reveals that the low-resistivity zone (<10 Ω·m) in the Wufeng-Longmaxi shale is spatially associated with tectonic faults. This study aims to reveal the coupling mechanism between shale resistivity and tectonic faults.

This study determines the petrological and geochemical characteristics of outcrop samples obtained from the Wufeng-Longmaxi shale in the southern Sichuan Basin through thin-section identification, X-ray diffraction, laser Raman spectroscopy, whole-rock asphalt reflectance, and conventional physical property analyses. The characteristics of resistivity change in the shale during deformation were analyzed through triaxial compression tests. The impacts of fracture system generation and conductive fluid intrusion on low-resistivity shale were also clarified.

The results show that the resistivity of shale samples, which have similar characteristics of clay minerals, pyrite, organic matter content, and thermal maturity level, significantly decreased after saturation with brines of various salinities. A positive correlation was observed between the resistivity reduction (95.07%-98.70%) and brine salinity. After reaching the compressive strength, the resistivity reduction of the brine-saturated samples varies from 5.7 Ω·m to 25.7 Ω·m (average: 13.3 Ω·m). This reduction shows a linearly positive correlation with the resistivity observed post cracking. The intrusion of conductive fluid and the generation of the fracture system in shale are the primary controlling factors for resistivity reduction. The resistivity after cracking is influenced by both the intruded saltwater salinity and fracture density.

This research elucidates the influence mechanism of tectonic fault zones on shale resistivity and enhances the theoretical framework for understanding the genesis of low-resistivity shale, with significant implications for the exploration and development of low-resistivity shale formations.

The ore bodies in porphyry copper deposits are primarily low-grade metal sulfides, and further research is needed to determine the depth and extent of these deposits via gas geochemistry.

Preliminary experiments were conducted in this study using a portable gas analyzer for H₂S and SO₂ geochemical measurements at the Pulang porphyry copper deposit.

The results indicate significant H₂S and SO₂ geochemical anomalies above copper mineralization, suggesting the method's efficacy in revealing hidden ore bodies and predicting their strike and dip extensions.

Areas showing good synergistic behavior, continuous anomalous concentration distributions, and potential for mineralization are promising targets for exploration. This approach represents an effective method for mineral exploration in covered porphyry copper deposits, offering new insights into prospecting concealed mineral resources.

In this paper, in order to study the evolution process, toppling mode, toppling deformation and failure mechanism of steep bedding rock slope,

we used the slightly weathered slate on the left bank of the reservoir as a reference prototype for the similar material material, then we choose to use the bottom friction test method to analyze the deformation and failure characteristics of slope under different condition of slope angles, plane inclination angles and structural plane occurrences.

The results show that: ①The main toppling failure mode of the steep bedding rock slope is the tensile-toppling type. In the early stage of evolution, the rock mass at the foot of the slope is the first to topple due to stress concentration, and gradually develops from the front edge of the slope body to the middle and back. The rock mass in the middle of the slope surface also gradually changes from the forward dip to the upright to the reverse dip state, and accelerates to bend and topple towards the free surface under the action of gravity. When the deformation of rock mass reaches a certain extent, it will fracture along the maximum bending part or structural plane, and eventually slip along the tensile fracture plane or even collapse directly. ②By comparing the slope parameters and deformation characteristics of the test models, the 7 groups of model slopes are roughly divided into 3 categories: near-vertical bedding rock gentle slope, steep dip bedding rock steep slope, near-vertical bedding rock steep slope. Compared with slope Angle, the rock layer dip Angle has more influence on the toppling deformation and failure of the steep bedding rock slope. The gently inclined structural plane that is not perpendicular to the plane is more likely to cause the toppling deformation and failure of the steep bedding slope than the one perpendicular to the plane, and the scale of toppling deformation and failure is larger when the slope body develops the inward structural plane compared with the outward inclined structural plane. ③From the perspective of deformation stage, the deformation evolution process of slope is divided into initial deformation stage, toppling deformation stage and toppling failure stage. ④The toppling deformation and failure process of steep bedding rock slope is divided into stress adjustment stage, flexural-creep stage, flexural-sliding stage and toppling-sliding-collapse fracture stage from the mechanism. According to the deformation degree of the toppling area, the deformed slope can be divided into three zones: a strong toppled zone, a weak toppled zone, and a stable zone.

The research results can provide reference for the research of the evolution process, toppling mode, toppling deformation and failure mechanism of steep bedding rock slope.

The extreme gradient boosting (XGBoost) algorithm is introduced to establish a model to improve the identification accuracy of the three characteristic zones within strike-slip faults.

The logging response characteristics of the three characteristic zones within strike-slip faults are analyzed, and the sensitive logging curves are selected to construct a feature vector space set based on the mean and variance. The XGBoost algorithm is applied to establish XGBoost regression prediction models for the dissolution, breccias, and damage zones of strike-slip faults. The key parameters of the XGBoost model are optimized through multiclass evaluation indicators to improve the identification accuracy of the characteristic zones within strike-slip faults.

The constructed XGBoost model was used to identify the internal characteristic zones of strike-slip faults in the study area, with a total of 234 samples; 208 samples were correctly identified, resulting in an identification accuracy of 88.89%. The prediction results reveal that, within the internal characteristic zones of strike-slip faults, the damage zone has the widest distribution, followed by the breccias zone, and the dissolution zone is the narrowest, which is consistent with the actual distribution of the internal characteristic zones of strike-slip faults.

The identification model of internal characteristic zones within strike-slip faults based on the XGBoost algorithm can be used to effectively identify the damage, breccias, and dissolution zones, thereby supporting more effective analysis of the distribution of small-scale dissolution cavities and fracture reservoir spaces inside strike-slip faults, and providing reference information for the accurate characterization of the internal structure of strike-slip faults.

Three sets of black organic-rich shales found in the Permian Dalong Formation, Wujiaping Formation, and Maokou Formation in northeastern Sichuan have yielded significant discoveries in shale gas exploration, presenting new opportunities beyond the established Wufeng-Longmaxi marine shale gas plays.

This study investigated the lithological characteristics and paleoenvironmental evolution of these formations through petrological and geochemical analyses. A comprehensive examination of the depositional environments and the key controlling factors for organic matter enrichment during the deposition of these organic-rich black shales from the Middle to Late Permian in northeastern Sichuan has been performed.

The findings demonstrate that the three organic-rich shales exhibit considerable heterogeneity, with distinct controlling factors influencing their development. The sedimentary period of the third member of the Maomao Formation was characterized by strong upwelling, weak volcanic activity, and limited hydrothermal activities. This environment featured a warm and humid climate, extremely high primary productivity, low terrestrial input, and anoxic sulfide water conditions. In contrast, the sedimentary environment of the second member of the Wujiaping Formation was marked by high productivity, low continental source input, seasonal upwelling, weak hydrothermal activity, and interstitial sulfidation-sulfidation conditions and driven by strong hydrothermal fluid, upwelling, and island arc volcanic activity. The sedimentary environment of the Dalong Formation also exhibited high primary productivity, low terrestrial input, and interstitial sulfidation-sulfidation conditions.

The research highlights the complex interactions of multiple geological events on organic-rich shales and constructs a genetic model for these shales influenced by various geological factors. This model provides a theoretical basis and supports the identification of favorable areas for marine shale gas exploration.

The variogram quantifies the variability of geological attributes between two points in space, which is crucial for geological statistical analysis. When geological data exhibit trend changes with spatial coordinates, correctly selecting and estimating the variogram becomes particularly challenging.

To achieve model selection and parameter estimation for the variogram, a Bayesian theory-based variogram selection method is proposed. This method uses the Laplace approximation to approximate the posterior probability distribution as a Gaussian distribution. The method first calculates the posterior probability distribution of parameters and then computes the Bayesian model evidence for each alternative variogram, determining the optimal model. Additionally, this paper explores the applicability of three model selection methods in variogram selection, including Bayesian model evidence (BME), the Akaike Information Criterion (AIC), and the Bayesian Information Criterion (BIC).

The proposed method is demonstrated using cone penetration test data from measured static probe resistance. Differences in variogram model selection are compared among the three methods: BME, AIC, and BIC. In comparison, both the goodness-of-fit and complexity penalty of different variogram models are considered.

The research indicates that, under the given experimental data conditions, BME can reasonably consider both the fit and complexity of the variogram function, while the model selection results of the AIC and BIC identification criteria are identical. When the number of model parameters for variogram functions is the same, the AIC and BIC criteria only reflect differences in the fit of various variogram functions. In such cases, it is recommended to use BME for variogram selection.

Conglomerates are unique petroleum reservoirs, and understanding their sedimentary origin and evolution is crucial for accurately predicting the distribution of high-quality reservoirs.

Based on core logging, petrologic identification, heavy mineral and grain size analysis, and well logging data, the sedimentary characteristics, spatial distribution, and sedimentary provenance of the Lower Triassic Baikouquan Formation conglomerate in the Madong slope area are defined. Meanwhile, the sedimentary mechanism of the formation is clarified, and a sedimentary model is established.

The Baikouquan Formation was deposited as a shallow-water fan delta, and the fan body consists of three subfacies: the fan delta plain, fan delta front, and pro-fan delta, and can be divided into nine microfacies: debris flow, braided channel, flood deposit, subaqueous debris flow, subaqueous main channel, subaqueous branch channel, sandy clastic flow, far sand bar, and pro-fan delta mudstone deposits. Summarily, it contains 10 lithofacies types. The conglomerate was a sedimentary product of flood-induced gravity flow, reflecting complex lithofacies associations, significant evidence of event deposition, a sedimentary model dominated by paleoclimate, and a clear transformation of lake waves. Spatially, the grain size of the Baikouquan Formation conglomerate in the Madong slope region becomes finer from bottom to top, indicating a sedimentary sequence of lake transgression and a multi-period superposition of debris flows, underwater debris flows, and subaqueous channel deposits.

The three-dimensional simulation of kinematics, which considers the characteristics of slope topography, serves as a crucial foundation for assessing the risk of rockfall in mountainous highways. Additionally, its computational outcomes can bolster the management strategies for rockfall mitigation.

Leveraging field investigations and Unmanned Aerial Vehicle (UAV) aerial surveys, we have meticulously analyzed the distribution, material composition, and disaster characteristics of hazardous rocks within the study area. The RocPro3D software was employed to simulate the three-dimensional kinematics of rockfall, thereby enabling an evaluation of the disaster's impact and calculating the effectiveness of engineering interventions for rockfall of various particle sizes, complemented by protective measures.

Our findings indicate that the combination of joints, formed due to tectonic compression and stress relief from unloading, segment the precarious rock masses, while the weathering cavities at their bases diminish their stability. The hydrostatic thrust exerted by the trailing edge cracks, along with water seepage through these fractures, are identified as typical triggers of rockfall events. Post-collapse, the velocity and impact energy of the falling rocks initially surge and then decline, whereas the bounce height varies before a decreasing trend becomes apparent. The hazardous rock zones within the study area pose a significant threat to the management facilities situated at the foot of the slope. An effective remedial measure involves clearing the area adjacent to the dangerous rocks with diameters less than 0.8 meters and implementing a passive protection net measuring 6.0 meters in height, designed to withstand an energy level of 1000 kJ. The localized concentration areas within the spatial distribution of rockfall movement traces should be appropriately reinforced.

The three-dimensional kinematic simulation enables the acquisition of detailed information regarding movement traces, velocity, energy, bounce height, and unit density of rockfall. This approach transcends the spatial limitations inherent in two-dimensional cross-sectional analyses, proving to be immensely valuable for evaluating disaster damage and enhancing geological disaster prevention efforts.

An intensive Early Cretaceous magmatic-hydrothermal metallogenic system developed in the Mufushan area of the central Jingnan Orogen. This orogenic belt in the South China Block formed through the accretion and subsequent collision of the Yangtze and Cathaysia blocks during the early Neoproterozoic, resulting in the formation of rare metal deposits (Li-Be-Cs-Nb-Ta) and nonferrous metal deposits (Pb-Zn-Cu-Au-Sb).

This study investigates the structural control of polymetallic deposits in southern Hubei Province utilizing structural analysis, paleostress inversions of fault-slip data, and the spatial distribution of polymetallic ore deposits.

Structural analysis revealed that the Jiangnan fault, striking E-W and originating in the Neoproterozoic, exhibits Triassic top-to-the-north thrusting, Late Cretaceous oblique normal faulting, and Paleogene left-lateral strike-slip motion. The NE-striking Changping fault, formed during the Middle Jurassic Yanshanian orogeny, shows evidence of late Early Cretaceous left-lateral strike-slip motion, late Cretaceous normal faulting, and late Paleogene right-lateral strike-slip motion. Paleostress inversions indicate that southern Hubei Province experienced a series of paleostress fields, including a strike-slip stress field (with maximum principal stress oriented N-S and minimum principal stress oriented N-S) during the late Early Cretaceous, an NW-SE extensional stress field during the late Cretaceous, another strike-slip stress field (with maximum principal stress oriented NE-SW and minimum principal stress oriented N-S) during the early Paleogene, and a NE-SW extensional stress field during the late Paleogene.

Based on the polymetallic deposits in the study area, we conclude that secondary faults subparallel to the primary NE-SW trending fault, along with NW-SE and E-W trending faults intersecting with the primary NE-SW fault, present substantial potential for polymetallic mineral exploration.

Natural gas heterogeneity controlled by gypsum-salt layers is a significant model for enrichment and accumulation. While previous studies have primarily focused on experimental testing and qualitative descriptions, they have lacked three-dimensional characterization of the gypsum-salt layers distribution. This study proposes a novel three-dimensional modeling technique that integrates well-seismic data with sedimentary microfacies control in both the gypsum-salt layer and the gas-water layer.

The proposed technique encompasses five key technical aspects: (1) logging interpretation and 3D modeling of the gypsum-salt layer controlled by sedimentary microfacies, (2) seismic genetic inversion-based 3D modeling of the gypsum-salt layer guided by sedimentary microfacies, (3) well-seismically integrated 3D modeling of the gypsum-salt layer, (4) 3D modeling of gas-water distribution influenced by sedimentary microfacies, and (5) fusion-based 3D modeling of both the gypsum-salt and gas-water layers.

This method was applied to assess the influence of the gypsum-salt layer within the Feixianguan Formation in the Tieshanpo gas field of the Sichuan Basin on gas accumulation characteristics. Accurate 3D geological models were constructed that integrate well-seismic data with sedimentary microfacies control for both the gypsum-salt and gas-water layers. The results indicated that, except for some localized areas, a continuous distribution was observed across most regions of the Feixianguan Formation in the Tieshanpo area. Additionally, the formation exhibited multilayered characteristics with significant longitudinal thickness heterogeneity. Three distinct models were developed to illustrate the effects of gas capping, reduced gas storage capacity, and complex reservoir conditions resulting from the heterogeneous influence of the gypsum-salt layer.

These findings provide essential geological insights that can inform the development of effective strategies targeting natural gas reserves at non-equilibrium scales.

Particle size analysis is important for the evaluation of clastic petroleum reservoirs because it can identify the stratigraphic depositional environment and assess the permeability of reservoirs.

Using the dense sandstone reservoir of the Shaximiao Formation in the Tianfu Gas Field in the Sichuan Basin as the research object, we first analyzed the influence of the particle size and shape on the permeability of the clastic rock reservoir. Next, we combined the median and C values of the particle size and the sorting coefficient to perform a comprehensive characterization of the particle size indicator parameter (PI). Additionally, we carried out a principal component analysis on the natural gamma-ray logging value, photoelectric absorption cross-section index, and neutron porosity, which are more sensitive to particle size. An exponential relationship model between the PI and the principal component parameter was established. Finally, the correlation between PI and reservoir production capacity was analyzed by combining the Oil test and logging data.

The statistics of 8 test gas sections from 7 wells in the Shaximiao Formation of Tianfu Gas Field were collected, and the PI values of 7 wells were calculated using the above method. The response relationship between the unimpeded flow rate and the PI was analyzed in the test sections, and the results revealed that the unimpeded flow rate and the cumulative PI values in the Shaximiao Formation exhibited an exponential relationship, with a correlation coefficient of 0.85.

This study reveals that, for reservoirs whose lithology is dominated by medium- to fine-grained sandstone, with large variations in grain size, and with storage space dominated by residual intergranular pores, the PI can, to some extent, serve as an indicator of the production capacity of this type of reservoir.

The Paishanlou gold deposit is a large gold deposit on the northern margin of the North China Craton, containing more than 60 tonnes of gold resources. It is mainly hosted in Archean metamorphic rocks of the Jianping Group, structurally controlled by EW and NE ductile shear zones, and closely related to the Yanshanian granites. For many years, the genetic type of the Paishanlou gold deposit has been controversial.

In this study, we present new field geology and C-O-S-Pb isotope data for the T4 orebody in the Paishanlou deposit, in order to identify the ore-forming material sources and its genesis.

The δ¹³C_V-PDB and the δ¹⁸O_V-SMOW values of hydrothermal carbonate minerals from ores range from −7.0‰ to −2.1‰ and 12.2‰ to 16.7‰ respectively. Compared with the Gaoyuzhuang Formation dolomitic marble, the δ¹⁸O_V-SMOW values are lower while the δ¹³C_V-PDB values are almost identical, indicating that the C isotope in the ore-forming fluid was derived from the dissolution of the Gaoyuzhuang Formation dolomitic marble. The δ³⁴S values of pyrites from ores vary from 0.5‰ to 7.5‰ with two peak values (2.9‰ and 6.7‰), which correspond to δ³⁴S values of the metamorphic rocks of Jianping Group and the Yanshanian granitoids, indicating the sulfurs were mainly derived from a mixed source of the metamorphic rocks of Jianping Group and the Yanshanian magmatic sulfate. The Pb isotopic compositions of the pyrites from ores vary from 16.585 to 18.432, 15.299 to 15.698 and 37.159 to 38.982 for ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios respectively, which plot between the mantle and lower crust fields in the ²⁰⁷Pb/ ²⁰⁴ Pb versus ²⁰⁶Pb/ ²⁰⁴ Pb discrimination diagrams, indicating a mixed source of crust and mantle. Thus, we suggest the ore-forming metals were derived from a mixed source of metamorphic rock of Jianping Group and the Yanshanian granitoids.

Combined with the regional tectono-magmatic evolution history during the Mesozoic, we propose that the NE ductile shearing in the Paishanlou district resulted in dynamic metamorphism of Precambrian country rocks to form ore-bearing metamorphic fluid under the background of the regional extensional tectonism and lithosphere thinning during the late Cretaceous. During the migration of the ore-forming fluid along the ductile shear zone, the meteoric water, magmatic hydrothermal fluid and ore-forming materials from the country rocks were involved in it, resulting in the characteristics of crust-mantle mixing. Finally, in the favorable environment such as tectonic intersection or roof dolomitic marble interface, the ore-forming fluid reacted with the wall rock, leading to the rapid precipitation of ore-forming materials. The Paishanlou gold deposit is an orogenic gold deposit.

In recent years, significant progress has been made in the exploration of conventional sandstone reservoirs in Jingjingzigou Formation, Jinan Depression, Junggar Basin, with tertiary reserves exceeding 100 million tons and excellent exploration prospect. Although the main source rock as Lucaogou Formation of Middle Permian in Jinan Depression has been realized based on former research, the study on geochemical characteristics of source rocks and oil source correlation have been rarely reported.

Based on comprehensive utilization of test data such as total organic carbon, rock pyrolysis and characteristics of biomarkers,The geochemical characteristics of source rocks in different intervals of Lucaogou Formation and oils source correlation of Middle Permian have been studied in this paper.

The results show that:①Lucaogou Formation can be divided into three sections according to the characteristics of logging curves. P₂l₁ and P₂l₂ are excellent with high organic carbon content, hydrocarbon generation potential and soluble organic matter content, organic matter type asⅠ-Ⅱ₁ and maturity as early to peak, while P₂l₂ is better. The main of P₂l₃ is "non-general" source rock withⅠ-Ⅱ₁ organic matter type and high maturity affected by overlying.②General reduced environments with P₂l₁ as stratified saline water and P₂l₂ as fresh-brackish water, P₂l₃ is somewhere in between.beneficial to the preservation of organic matter are indicated by the molecular geochemical characteristics of source rocks. In terms of biological composition, it is proved that there are two characteristic hydrocarbon-generating parent materials in Lucaogou Formation, namely, green algae and cyanobacteria. The former evidence is a biomarker (C₂₈ sterane) related to age, while the latter is the detection of β -carotene and medium-chain monomethyl alkane, Hydrocarbon-generating organisms in different intervals are different with P₂l₁ and P₂l₃ mainly composed of aquatic organisms such as bacteria and algae, and cyanobacteria dominate, while P₂l₂ of high input of aquatic plants(green algae) and terrestrial plants. Differences in water salinity in lake basins are the key factors that affect the bloom of cyanobacteria and green algae in different layers of source rocks.③C₃₀αα- hopane was abundant in P₂l₁ and P₂l₂, but is lacking in the source rocks of P₂l₃, Based on the analysis of different isomerization parameters of sterane and hopane,C₃₀αα/αβ may be a possibe maturity parameter.④the Permian crude oil in Jinan Depression can be divided into three types. Type Ⅰ and Ⅱcrude oils were correspond to the source rocks of P₂l₁ and P₂l₂ respectively, and Type Ⅲ crude oil is different to P₂l source rocks, possibly correlated tomudstone of Jingjingzigou formation.

The research has reference significance for future oil and gas exploration and development in Jinan sag.

Currently, the understanding of the vertical and horizontal zonation of this volcanic weathering crust reservoir and the distribution patterns of favorable reservoirs remains unclear, hindering further exploration of volcanic oil and gas in the area. Therefore, an in-depth analysis of this unique volcanic weathering crust reservoir is necessary.

This study, based on data from well logging, drilling, lithology, and field geological profiles, analyzed the formation process of the volcanic weathering crust, its vertical and horizontal zonation, and favorable exploration directions.

The evolution of the Carboniferous volcanic weathering crust paleo-buried hill in the study area can be divided into four stages: the initial fissure-type volcanic eruption stage, the intermittent stage of volcanic eruptions, the stage of renewed volcanic activity, and the formation stage of the Carboniferous volcanic top weathering crust. The volcanic weathering crust reservoir mainly formed during the intermittent stages of volcanic eruptions, with the weathering materials consisting of volcanic rocks formed during the eruption periods and sedimentary rocks associated with volcanic activity. Multiple episodes of volcanic eruptions and weathering resulted in the formation of multi-layered weathering crusts within the volcanic rocks.

Each episode of the weathering crust can be divided, from bottom to top, into the bedrock layer, fracture layer, sandy layer, and sedimentary layer. Among these, the fracture layer and sandy layer have better reservoir properties and are the main oil and gas reservoirs. Horizontally, the weathering crust is divided into the dissolution platform area, dissolution slope area, and dissolution depression area. The dissolution slope area, where fractures and dissolution pores are most developed, is the most favorable exploration target. In contrast, the dissolution depression area suffers from severe cementation, resulting in the poorest reservoir properties.

Three-dimensional (3D) geological modeling is a technology which comprehensively uses computer technology, spatial information, scientific visualization, mathematical statistics and other cutting-edge technologies and methods to perform 3D digital representation, characterization and reconstruction of geological phenomena and processes. Its purpose is to provide a visualization platform that integrates scientific research, aided design and decision support for geoscientists, so as to understand and use the essential meanings and laws hidden behind geological phenomena and processes more deeply. [Progress] 3D geological models inferred from field data has become a necessary task for geological research and surveys involving basic geological survey, natural resource exploration and development, and geological disaster prediction and evaluation. This paper takes a comprehensive summarization for the recent progress of 3D geological modeling technology from research objects, data sources, spatial data models, and 3D geological modeling methods from three different perspectives. This paper also provides practical cases of 3D geological modeling technology in the fields of mineral exploration, geological disaster warning, urban underground space planning, oil and gas reservoir characterization, etc. [Prospect] In addition, the future trends of 3D geological modeling and related technologies are discussed.

However, the study on the genesis of threshold-value elements and the related hydrochemical evolution processes are rare. In addition, some sampling points have exceeded the threshold value, which directly affects the development and utilization of mineral water and is an urgent problem that needs to be solved.

In this study, the Huangshui River Catchment was considered as a target area. Hydrogeochemical and modeling methods were employed to uncover the hydrochemical features and genesis of mineral water by collecting spring samples from the catchment, which can play an important role in understanding the hydrogeochemical processes within the groundwater system in the Huangshui River Catchment.

Most of the groundwater samples in this study area reach the standards of the National Drinking Natural Mineral Water, and all the strontium concentration is higher than 0.2 mg/L with a few samples being rich in lithium and metasilicic acid. The Hydrogeological result shows that the groundwater moving from recharge area to discharge area has a transition of hydrochemical type from HCO₃-Ca·Mg to SO₄-Na, which is the result of gypsum dissolving in groundwater. The relationships between Sr and the major anions such as HCO₃⁻、SO₄²⁻ and Cl⁻ show that carbonates have a limited contribution on Sr concentration in groundwater. Instead, the gypsum layers may contain a certain number of Sr-bearing minerals because of the atom exchange between Ca and Sr. Those Sr-bearing minerals are responsible for the high concentration of Sr in groundwater. In terms of the genesis of Li and Si in groundwater, the ancient salt lake sedimental environment may explain the former one and the dissolving of aluminumsilicate minerals may explain the latter. The inverse modeling shows that the groundwater mainly dissolves gypsum, rock salt and illite, while the dissolution of azurite and lithium pyroxene contributes strontium and lithium in the northern catchment. The dissolution of gypsum and halite leads to the high TDS of groundwater in the southern catchment, combined with the dedolomitization process.

The whole research findings can serve as scientific basis for exploration and preservation of mineral waters.