强降雨作用下的浅层滑坡稳定性分析

根据实测和室内物理力学试验结果以及工程实践,研究强降雨作用下浅层滑坡稳定性系数与滑面带抗剪强度指标及滑体饱水面积比三者的关系,建立其数理统计相关式。依据建立的数理统计相关式,对采用不分离接触弹塑性有限元强度折减算法分析强降雨作用下浅层滑坡稳定性的难处进行初步探讨。结果表明:首先,可以利用建立的数理统计相关式,选择不同滑体饱水面积比求出强降雨时滑面带的等效抗剪强度指标,作为不分离接触弹塑性有限元强度折减算法中滑面带上接触单元的抗剪强度指标;然后,采用该算法分析强降雨作用下的浅层滑坡稳定性,通过建立的数理统计相关式计算滑坡的稳定性系数,为该类型浅层滑坡稳定性分析和较准确地预报提供更加可靠和充分的依据。研究结果揭示了强降雨对浅层滑坡变形解体和破坏的作用机理,表明强降雨是诱发浅层滑坡的最关键因素。

基于有限元滑坡的稳定性分析

为准确分析评价西宁市泥岩滑坡稳定性,确定其失稳破坏及其模式,通过查阅西宁详细勘察报告并现场地质调研与勘察,以张家湾砖厂滑坡工程为例,建立地质模型。基于FLAC3D强度折减法及SLIDE极限平衡法对比分析,论证其破坏失稳模式。结果表明:张家湾砖厂滑坡总体的稳定性系数为1.290,整体处于稳定状态,滑体不产生滑动,但局部(3个监测点)具有不同程度的失稳破坏;与初步判断3个监测点失稳破坏模式倾倒—崩落、平面滑动、崩滑破坏一致,其中倾倒—崩落破坏变形最为明显,位移最大,达到3.70 m。经过对比分析,充分验证滑坡体失稳破坏模式的准确性,为西宁地区泥岩滑坡失稳破坏模式提供了理论依据。

Research on the stability analysis and design of soil tunnel surrounding rock

The paper first analyzes the failure mechanism and mode of tunnel according to model experiments and mechanical calculation and then discusses the deficiency of taking the limit value of displacement around the tunnel and the size of the plastic zone of surrounding rock as the criterion of stability. So the writers put forward the idea that the safety factor of surrounding rock calculated through strength reduction FEM(finit element method) should be regarded as the criterion of stability,which has strict mechanical basis and unified standard and would not be influenced by other factors. The paper also studies the safety factors of tunnel surrounding rock (safety factors of shear and tension failure) and lining and some methods of designing and calculating tunnels. At last,the writers take the loess tunnel for instance and show the design and calculation results of two-lane railway tunnel.