基于强度折减法的牵引式滑坡稳定性分析及防治对策研究

牵引式变形破坏是滑坡失稳的一种重要模式。基于某牵引式工程滑坡的地质成因和失稳机理，利用有限元软件建立滑坡三阶段数值分析模型，采用土工强度参数按步长进行场变量折减的方法，以弹塑性迭代计算发生不收敛，并结合坡面特征点产生位移突变作为失稳临界判据，分析了滑坡处于原始状态以及后继开挖和工程支护三阶段模型分别在天然和暴雨两种工况下的稳定性安全系数。针对工程支护后是否会发生越顶剪出或局部失稳的可能性问题，根据强度折减计算终止的坡体塑性应变场，提取塑性贯通区以确定局部失稳的最危险滑面，进行了可靠度评价。根据分析结果，提

Analysis on Stability of Retrogressive Landslide Based on Strength Reduction Method and the Countermeasures Study

Pull-type deformation and failure is an important mode of landslide instability. Based on geological genesis and failure mechanism of a retrogressive landslide, the three-stage numerical analysis model for the landslide was established by use of finite element software, with which, in a way that geotechnical strength parameter was used to carry out field variable reduction in steps, as well as non-convergence calculated by means of iteration of elastoplasticity combining with displacement saltation arose at the characteristic point on the slope surface were taken as the instability criterion, the stability coefficient of the landslide under natural and rainstorm conditions in the three-stage model of initial condition, subsequent excavation and structure support were analyzed. With regard to the probability of shearing out by overtopping or local instability, the reliability was evaluated in such manner that the stopped plastic strain field of the slope body was calculated by strength reduction method and the plastic penetration area was taken to define the most dangerous sliding face with local instability. Depending on the results of analysis, the advice on engineering control was proposed.