滑带土抗剪强度参数的三维反分析

3D back analysis of shear strength parameters of slip soil

以滑面正应力修正模式的三维边坡稳定性分析方法为基础,建立了确定滑带土抗剪强度参数的三维反分析模型。先对滑坡体的稳定性进行调查评估,确定滑坡的安全系数与三维滑面的几何尺寸;然后,通过对滑面正应力进行合理假定与修正,建立了平衡方程,以强度参数为未知数,利用数学方法并结合试验、经验等手段求解出抗剪强度参数。该模型克服了二维反分析将会高估滑带土的抗剪强度参数的缺陷,而且计算过程简单,易于编程实现。两个简单算例表明,三维反分析模型可以考虑三维滑体的空间效应,得到的抗剪强度参数更真实、更符合实际情况,为滑坡治理提供参考。

Based on the slope stability analysis method of normal stresses modification over 3D slip surface,a 3D back analysis model for shear strength parameters of slip soil is established.Firstly,the stability of slope mass is investigated and assessed to identify the safety factor of landslide and the geometrical dimensions of 3D slip surface.Then,through reasonable assumption and modification of the normal stress of slip surface,the equilibrium equations on the strength parameters are obtained;and the parameters would be solved out by using mathematic methods combining experimentation and experience.The presented model overcomes the defect that the 2D back analysis often overestimates the shear strength parameters of slip soil;and its calculation process is simpler with the help of programming.Two simple case studies show that the 3D back analysis model can take the space effect of 3D landslide mass into account;thus the shear strength parameters calculated is more reasonable and could be the reference for slope treatment.