水对岩石力学特性及边坡稳定的影响及其机理分析

Effects and Mechanism Analysis of Water on Mechanical Properties of Rocks and Slope Stability

采用MTS815.04电液三轴伺服试验系统,对安康至陕川界高速公路沿线的几处典型边坡岩石试样进行了室内试验分析,结果表明,几种不同岩性试样的物理力学性质(包括单轴抗压强度、弹性模量和泊松比)随含水量的增加呈现减小的趋势,其中石灰岩和板岩随含水量的增加力学性质变化较大,砂岩和闪长岩变化较小。试验结果证实孟召平等人提出的含水量与岩石力学性质拟合方程较为符合工程实际。降雨是引发滑坡灾害的重要因素之一,目前研究降雨对边坡稳定性影响的方法主要有两种:统计分析方法和数值模拟方法。对降雨引起的岩质边坡失稳现象的研究结果表明,其影响机理主要有:降雨软化坡体、地下水位的升高、降雨对边坡坡面的冲蚀、水-岩化学作用以及裂隙中的渗流等。

The rock samples from several typical slopes along the An-Kang to Shanxi-Sichuan Boundary Expressway have been tested using the MTS Electro hydraulic Tri-axial Servo Test System.The results showed that the mechanical properties of several different lithological samples,including the uniaxial compressive strength,elastic modulus,and Poisson ratio,decrease with the increasing of the moisture content.The mechanical properties of the limestone and slate had a higher variability than the sandstone and diorite with the increasing of the moisture content.The results of the test also confirmed that the fitted equation between the moisture content and the mechanical properties presented by Meng Zhao-Ping is realistic.Rainfall is one of the most important factors to trigger a landslide disaster.Statistical analysis method and numerical simulation method are two main research methods to study the influence of rainfall on the slope stability.The phenomenon of rock slope landslide induced by rainfall had been studied and the influence mechanisms were as follows： the softening of the slope caused by rainfall,the rising of groundwater level,the erosion of the faces of slope due to rainfall,the chemical water-rock interaction,and the seepage in the fractures.