巨厚松散层力学性质及其对地表下沉的影响

开采引起的地表下沉与上覆岩土层的性质与结构密切相关,巨厚松散层条件下开采下沉规律具有特殊性。采用土工试验、数值模拟等相结合的方法,对巨厚松散层的力学性质及其对地表下沉的影响进行了研究。通过三轴不固结不排水试验对焦作矿区地表黏性土的抗剪强度进行了研究,得到焦作矿区松散层土体的内摩擦角和内聚力范围。以巨厚松散层条件下某工作面为实例,结合三轴试验结果,研究了不同巨厚松散层厚度、松散层内摩擦角和内聚力对地表下沉的影响;并将数值模拟结果与实测结果进行了对比验证。结果表明:地表最大下沉值随松散层厚度的增加而增加,随着松散层内摩擦角、内聚力的增加而减小。将巨厚松散层力学性质土工试验结果与开采下沉结合起来,对开采下沉的研究具有一定的指导意义。

Study on the mechanical properties of super-thick alluvium and its influence on the surface subsidence

The surface subsidence caused by mining is closely related to the nature and structure of the overlying strata and soil layer, and the characteristics of mining subsidence under the condition of super-thick alluvium is special. By means of geotechnical test and numerical simulation, the mechanical properties of super-thick alluvium and its influence on the surface subsidence were studied. The shear strength of clayey soil in Jiaozuo mining area were studied through unconsolidated undrained triaxial test, and the range of internal friction angle and cohesion force of clayey soil in Jiaozuo mining area were presented. Taking a panel covered by super-thick alluvium as an example, combined with the triaxial shear test results, the influences of thickness, friction angle and cohesive force of alluvium on the surface subsidence were researched. The results of the numerical simulation were compared with the measured results. The results show that the maximum surface subsidence value increases with the increase of the thickness of alluvium, and decreases with the increase of the friction angle and cohesive force. This paper combines the geotechnical test results of super-thick alluvium mechanical property with the surface subsidence induced by mining, which has a certain guiding significance for the study of the mining subsidence.