基于遍布节理模型的顺层边坡稳定性影响因素分析

在应力作用下,层状岩体表现出相对于均质各向同性的岩体更为复杂的力学行为,针对该种岩层采用目前广泛使用的各向同性本构模型在受力行为及变形破坏的机理上会造成较大的误差,以成都至兰州高速铁路某隧道洞口段边坡工程为研究背景,采用FLAC~(3D)自带遍布节理模型(ubiquitous-joint模型)描述层状岩体的各向异性特征,对岩体及节理面的稳定性影响参数进行强度折减并分析其与边坡安全系数的关系。结果表明:边坡的整体安全系数F随节理面倾角呈先减小后增大再减小的趋势;岩体与节理面的黏聚力、内摩擦角的相对值大小影响边坡安全系数的变化规律,而与绝对值大小无关,并且均在安全系数最低的30°倾角表现更高的敏感性,层状岩体的剪胀性对边坡安全系数的影响与节理模型的范围和岩体与节理面的内摩擦角相对值有关。

Analysis of Influence Factors on the Stability of Bedding Slope Based on Joint Model

Under stress,the layered rock mass exhibits more complicated mechanical behavior with respect to isotropic rock mass. In the light of the destruction errors in stress behavior and deformation mechanism due to the widely used isotropic constitutive model,and with reference to a tunnel entrance slope protection on Chengdu-Lanzhou high speed railway,the ubiquitous-joint mode is employed to describe the anisotropic characteristics of stratified rock mass,and strength reduction is performed on the rock mass and the joint surface stability parameter,and the relationship with the slope safety factor is analyzed. The results show that the slope safety factor decreases first and then increases and again decreases in corresponding to the stratification dip angle; the variation law of slope safety factor is influenced by the relative size of cohesive force and internal friction angle of rock mass and joint surface,and has nothing to do with the absolute value size with higher sensitivity at the lowest 30 degree inclination of the safety factor; the shear dilation of rock mass is related to the range of joint model and the relative value of internal friction angle of rock mass and joint surface