论文部分内容阅读
节理岩体的剪切特性是主导岩体工程稳定性的关键因素。基于PFC~(2D)离散元颗粒流程序,结合室内试验结果对比分析,选取合理的细观参数进行数值模拟,分别从细观角度研究了节理岩石的裂纹发展、能量转化及声发射现象等特性,从宏观角度研究了节理岩石的强度模型和破坏形态。结果表明:节理岩体主要呈现磨损和剪断两种破坏形态,不同的破坏形态对应不同的强度模型;随着剪切变形增加,岩体沿节理面发生破坏,弹性阶段以法向裂纹为主,而塑性阶段切向裂纹起主导作用,滑移区R、P裂纹贯通形成破碎带,节理面产生较大滑移;在应力达到峰值强度前,边界能主要转化为应变能,法向裂纹生成较多;越过峰值强度后,摩擦能快速增长,并伴随大量切向裂纹产生。与室内试验结果相比,PFC~(2D)较好地模拟了节理岩体剪切力学特性,弥补了室内试验中无法进行细观特性研究的缺陷,对于节理岩体后期研究提供了一些参考。
The shear characteristics of jointed rock mass are the key factors leading the stability of rock mass engineering. Based on PFC ~ (2D) discrete element particle flow program and the comparative analysis of laboratory test results, reasonable numerical parameters were selected for numerical simulation. The crack propagation, energy conversion and acoustic emission phenomena of jointed rock The strength model and failure mode of jointed rock are studied from a macroscopic perspective. The results show that the jointed rock mass mainly exhibits two kinds of failure modes: wear and shear, and the different failure modes correspond to different strength models. With the increase of shear deformation, the rock mass breaks along the joint surface and the normal crack is the main part in the elastic phase. However, the tangential cracks in the ductile stage play a leading role. The R and P cracks in the slip zone lead to the formation of the crushing zone, and the joint surface produces a large slip. Before the peak stress is reached, the boundary can mainly be transformed into the strain energy, More; After the peak strength, the friction can rapidly increase, accompanied by a large number of tangential cracks. Compared with the experimental results in the laboratory, PFC 2D simulates well the shear mechanics characteristics of jointed rock mass, and makes up for the defects of inability to study mesoscopic characteristics in laboratory tests. It provides some references for the later study of jointed rock mass.