Trajectory of rockfall on the uniform slope
-
摘要: 现有的落石运动轨迹研究均将斜坡视为半无限均匀的坡面,而实际的工况下,坡面由不均一材料组成。根据落石不同的运动模式,将坡面简化为多层岩土体材料的结构形式,在滚动阶段,基于Hertz接触理论得到落石在不同坡面条件下运动特征,并给出坡面分层条件下落石切向摩擦系数的计算公式,在碰撞阶段,基于能量守恒定理,采用准静态接触力学理论得到法向恢复系数公式,理论推导得到任意层厚岩土体材料坡面条件下落石法向和切向恢复系数的解析解,然后求解得到碰撞后落石运动参数,并根据碰撞后落石的速度及回弹量关系,给出碰撞后落石运动模式转换的判别条件,最后结合运动学定理,得到3种运动模式任意分层坡面条件落石的运动轨迹,将理论公式应用于某山区落石运动轨迹预测,验证了理论公式的适用性和有效性。Abstract: Existing studies on the trajectory of the rockfall all regard the slope as a semi-infinite and uniform slope, but in actual working conditions, the slope is composed of heterogeneous materials.According to the different motion modes of rockfall, the slope surface is simplified to the structure of multi-layer rocks and soil materials.In the rolling stage, based on Hertz contact theory, the movement characteristics of falling rocks under different slope conditions are obtained, and the calculation formula for the tangential friction coefficient of the rockfall under the condition of the slope layering is given.In the collision phase, based on the law of conservation of energy, the normal recovery coefficient formula obtained by the quasi-static contact mechanics theory is used.The analytical solutions of the normal and tangential recovery coefficients of the rockfall under the condition of the arbitrary rock and soil material structure slope are derived, and then the motion parameters of the rockfall after the collision are obtained, According to the relationship between the speed of the rockfall and the amount of rebound after the collision, the judgment conditions for the transition of the motion mode of the rockfall after the collision are given.Finally, combined with the kinematics theorem, the motion trajectory of the falling rock under any layered slope condition in three motion modes is obtained. The theoretical formula is applied to the prediction of the motion trajectory of a rolling rock in a mountainous area, which verifies the applicability and validity of the theoretical formula.
-
Key words:
- rockfall /
- layered slope /
- contact theory /
- recovery coefficient /
- motion trajectory
-
图 1 单一坡面条件下落石滚动模式[23]
Figure 1. Rockfall rolling mode under single slope
图 4 碰撞过程计算模型[23]
Figure 4. Calculation model of collision process
表 1 滚动摩擦系数[24]
Table 1. Rolling friction coefficient
坡面特征 滚动摩擦系数 光滑岩面、混凝土表面 0.40~0.60 块石堆积坡面 0.55~0.70 密实碎石堆积坡面、硬土坡面 0.55~0.85 松散碎石坡面、软土坡面 0.50~0.85 表 2 落石运动计算参数
Table 2. Calculation parameters of rockfall movement
材料 ρ/(g·cm-3) E/MPa υ μ 落石 2.05 22 000 0.22 - 堆积物 - 46 0.30 0.6 灰岩 - 280 0.28 0.5 表 3 落石运动碰撞点速度
Table 3. Rockfall velocity of the point
碰撞点 碰撞前速度/(m·s-1) 碰撞后速度/(m·s-1) q1 36.3 13.5 P1 36.3 13.6 P2 17.1 12.8 P3 13.9 10.9 P4 11.3 10.0 -
[1] 连志鹏, 徐勇, 付圣, 等. 采用多模型融合方法评价滑坡灾害易发性: 以湖北省五峰县为例[J]. 地质科技通报, 2020, 39(3): 178-186. https://dzkjqb.cug.edu.cn/CN/abstract/abstract10035.shtmlLian Z P, Xu Y, Fu S, et al. Evaluation of landslide disaster vulnerability based on multi-model fusion method: A case study of Wufeng County, Hubei Province[J]. Bulletin of Geological Science and Technology, 2020, 39(3): 178-186(in Chinese with English abstract). https://dzkjqb.cug.edu.cn/CN/abstract/abstract10035.shtml [2] 胡燕, 李德营, 孟颂颂, 等. 基于证据权法的巴东县城滑坡灾害易发性评价[J]. 地质科技通报, 2020, 39(3): 187-194. https://dzkjqb.cug.edu.cn/CN/abstract/abstract10036.shtmlHu Y, Li D Y, Meng S S, et al. Landslide susceptibility evaluation of Badong County based on the right of evidence method[J]. Bulletin of Geological Science and Technology, 2020, 39(3): 187-194(in Chinese with English abstract). https://dzkjqb.cug.edu.cn/CN/abstract/abstract10036.shtml [3] 廖启鹏, 陈茹, 黄士真. 基于模糊综合评判与GIS方法的废弃矿区景观评价[J]. 地质科技情报, 2019, 38(6): 241-250. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201906029.htmLiao Q P, Chen R, Huang S Z. Landscape evaluation of abandoned mining area based on fuzzy comprehensive evaluation and GIS method[J]. Geological Science and Technology Information, 2019, 38(6): 241-250(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201906029.htm [4] 张俞, 殷坤龙, 郭子正, 等. 库水位变动联合降雨作用下麻柳林滑坡稳定性评价[J]. 地质科技情报, 2019, 38(6): 198-205. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201906024.htmZhang Y, Yin K L, Guo Z Z, et al. Evaluation on stability of Malulin landslide under the action of reservoir water level fluctuation combined with rainfall[J]. Geological Science and Technology Information, 2019, 38(6): 198-205(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201906024.htm [5] 向欣. 边坡落石运动特性及碰撞冲击作用研究[D]. 武汉: 中国地质大学(武汉), 2010.Xiang X. Research on motion characteristics and impact force of rockfall[D]. Wuhan: China University of Geosciences(Wuhan), 2010(in Chinese with English abstract). [6] Giani G, Giacomini A, Migliazza, et al. Experimental and theoretical studies to improve rockfall analysis and protection work design[J]. Rock Mechanics and Rock Engineering, 2004, 37(5): 369-389. doi: 10.1007/s00603-004-0027-2 [7] Bourrier F, Dorren L, Nicot F, et al. Toward objective rockfall trajectory simulation using a stochastic impact mode[J]. Geomorphology, 2009, 110: 68-79. doi: 10.1016/j.geomorph.2009.03.017 [8] Chau K, Wong R, Wu J. Coefficient of restitution and rotational motions of rockfall impacts[J]. International Journal of Rock Mechanics and Mining Science, 2002, 39(1): 69-77. doi: 10.1016/S1365-1609(02)00016-3 [9] Bourrier F, Berger F, Tardif P, et al. Rockfall rebound: Compasion of detailed field experiment and alternative modeling approaches[J]. Earth Surface Processes and Landforms, 2012, 37(6): 656-665. doi: 10.1002/esp.3202 [10] Sasaoka T, Shimada H, Sasaki T, et al. Study on control of rock fragmentation at limestone quarty[J]. Journal of Coal Science & Engineering(China), 2008, 14(3): 365-368. http://www.cnki.com.cn/Article/CJFDTotal-MCXB200803005.htm [11] 章广成, 向欣, 唐辉明. 落石碰撞恢复系数的现场试验与数值计算[J]. 岩石力学与工程学报, 2011, 30(6): 1266-1273. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201106026.htmZhang G C, Xiang X, Tang H M. Field test and Numerical calculation of the coefficient of rockfall impact[J]. Chinese Journal of Rock Mechanics and Engineering, 2011, 30(6): 1266-1273(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201106026.htm [12] 吴顺川, 高永涛, 杨占峰. 基于正交试验的露天矿高陡边坡落石随机预测[J]. 岩石力学与工程学报, 2006, 25(增刊1): 2826-2832. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX2006S1034.htmWu S C, Gao Y T, Yang Z F. Random prediction of rockfall in high and steep slope of open-pit mine based on orthogonal test[J]. Chinese Journal of Rock Mechanics and Engineering, 2006, 25(S1): 2826-2832(in Chinese with English abstract). https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX2006S1034.htm [13] Ueno S, Odagiri X, Ma G C. An example of the DDA analysis focused on difference of the vegetation[C]//Anon. Proceedings of the 36th symposium on rock mechanics, Tokushima, 2001. [14] Yang M, Fukawa T, Ohnishi Y, et al. The application of 3-dimensional DDA with a spherical rigid block for rockfall simulation[J]. International Journal of Rock Mechanics and Mining Science, 2004, 41: 1-6. http://www.sciencedirect.com/science/article/pii/S1365160904001558 [15] Guzzetti F, Crosta G, Detti R. STONE: A computer program for the three-dimensional simulation of rock-falls[J]. Computers and Geosciences, 2002, 28(9): 1079-1093. doi: 10.1016/S0098-3004(02)00025-0 [16] Lan H, Martin D, Lim C. Rock fall analyst: A GIS extension for three-dimensional and spatially distributed rockfall hazard modeling[J]. Computers Geosciences, 2007, 33: 262-279. doi: 10.1016/j.cageo.2006.05.013 [17] Thornton C, Ning Z, Wu C Y, et al. Contactmechanics and coefficients of restitution[M]. Berlin Heidelberg: Springer, 2001. [18] Mangwandi C, Cheong Y S, Adams M J, et al. The coefficient of restitution of different representative types of granules[J]. Chemical Engineering Science, 2007, 62(1): 437-450. http://www.sciencedirect.com/science/article/pii/S0009250906005549 [19] 杨海清, 周小平. 边坡落石运动轨迹计算新方法[J]. 岩土力学, 2009, 30(11): 3411-3416. doi: 10.3969/j.issn.1000-7598.2009.11.032Yang H Q, Zhou X Q. A new method for calculating rockfall trajectory of slope[J]. Rock and Soil Mechanics, 2009, 30(11): 3411-3416(in Chinese with English abstract). doi: 10.3969/j.issn.1000-7598.2009.11.032 [20] Ritchie A. Evaluation of rockfall and its control[J]. Highway Research Record, 1963, 17: 13-28. http://www.researchgate.net/publication/284329257_Evaluation_of_rockfall_and_its_control [21] Stevens W D. Rockfall: A tool for probalistic analysis, design of remedial measures and prediction of rockfalls[D]. Toronto: Department of Civil Engineering, University of Toronto, 1998. [22] Hertz H. Über die berührung fester elastischer körper(On the contact of elastic solids)[J]. Journal fur die Reine und Andgewandte Mathematik, 1882, 92: 156-171. [23] 吕庆, 孙红月, 翟三扣, 等. 边坡滚石运动的计算模型[J]. 自然灾害学报, 2003, 12(2): 79-84. doi: 10.3969/j.issn.1004-4574.2003.02.014Lü Q, Sun H Y, Zhai S K, et al. Calculation model of rock motion of slope[J]. Journal of Natural Disasters, 2003, 12(2): 79-84(in Chinese with English abstract). doi: 10.3969/j.issn.1004-4574.2003.02.014 [24] 陈洪凯, 唐红梅, 王林峰, 等. 危岩崩塌演化理论及应用[M]. 北京: 科学出版社, 2008.Chen H K, Tang H M, Wang L F, et al. Theory and application of collapse evolution of dangerous rocks[M]. Beijing: Science Press, 2008(in Chinese). [25] 刘涌江. 大型高速岩质滑坡流体化研究[D]. 成都: 西南交通大学, 2002.Liu Y J. Study on fluidization of large high speed rock landslide[D]. Chengdu: Southwest Jiaotong University, 2002(in Chinese with English abstract).