Experimental study of dissolution damage to carbonate rocks by acidic leachate
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摘要: 强酸性废水对碳酸盐岩有很强的腐蚀性,可以导致碳酸盐岩的物理力学性质发生重大改变。本文通过开展不同流速条件下,不同时长磷石膏酸性淋滤液对灰岩的溶蚀试验研究,分析试验前后灰岩试样的表观特征、质量、孔隙度、单轴抗压强度以及声发射计数等指标的变化规律,探讨了酸性淋滤液对碳酸盐岩的溶蚀损伤和力学损伤,揭示了酸性淋滤液对碳酸盐岩物理力学特性的影响。试验结果表明:岩样的溶蚀率、孔隙度增量与溶蚀时间及淋滤液流速均成正相关关系,力学强度与溶蚀时间及淋滤液流速均成负相关关系。随着溶蚀的进行,岩样表面会附着越来越厚的萤石矿物,使得岩样的溶蚀速率变慢。单轴试样的破坏形式由剪切破坏向张拉破坏逐渐转变。在磷石膏淋滤液溶蚀的酸性环境下,灰岩内部矿物成分被溶解,从而引起宏观力学参数的变化,研究结果可为酸性废水影响条件下岩溶介质稳定性分析、酸性废水处理、尾矿工程安全设计等方面提供理论与试验数据依据。Abstract: Strongly acidic wastewater is highly corrosive to carbonate rocks, which can lead to significant changes in the physical and mechanical properties of carbonate rocks. 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, to discuss the dissolution damage of acidic leaching solution to carbonate rock and mechanical damage, 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, and the results of the study 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.
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Key words:
- Limestone /
- Acidic dissolution /
- Dissolution rate /
- Mechanical damage /
- Acoustic emission
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