基于滑坡破坏渐进特征的新不平衡推力法及其应用

A New Unbalanced Thrust Method Based on Progressive Characteristics of Landslide Failure and Its Application

为了克服不平衡推力法不能体现滑坡破坏渐进性的缺点,在其基本计算方法的基础上,考虑到岩土体的软化特征,提出一种关于滑坡稳定性的简明计算方法。此方法主要从以下3点对传统不平衡推力法进行了革新:第一,考虑滑体变形;第二,引入节理本构模型,考虑滑体强度衰减及应力应变之间关系的转化;第三,考虑部分失稳对于整体稳定性的作用,基于条分法提出条块稳定系数与条块破坏概率的定义,进而定义滑坡整体稳定系数与整体破坏概率。给出了所提方法的计算公式,并阐述了计算的基本原理。改进方法与原方法共同应用于推移式滑坡实例的分析,分析结果表明:改进的不平衡推力法比改进前具有更低的稳定系数,并且在工程应用中更安全;同时,新方法可以体现部分失稳对于整体失稳的推动作用,能够计算出滑坡发生整体破坏的概率,从而较直观地评价滑坡的整体稳定性。

In order to overcome the shortcoming that the unbalanced thrust method cannot reflect the gradualness of landslide failure,based on the basic calculation method of it,a concise calculation method about stability coefficient of landslide was proposed with strain softening characteristics of rock-soil mass taken into consideration.This method innovated traditional unbalanced thrust method from the following three aspects.Firstly,the deformation of sliding body was considered.Secondly,the joint constitutive model was applied to consider the strength attenuation of the sliding body and the transformation of the relationship between stress and strain.Thirdly,considering the effect of partial instability on the overall stability,the definition of sliver stability coefficient and failure probability was proposed on the strip method,and then the overall stability coefficient and failure probability were defined.The calculation formula of the proposed method was given,and the basic principle of calculation was clarified.The improved method and the original method were applied to the analysis of bedded landslide.The analysis results show that the stability coefficient of the improved unbalanced thrust method is smaller than that before the improvement,and the improved method is safer in engineering application.At the same time,the new method can reflect the promoting effect of partial instability on the overall instability,and can calculate the probability value of the overall failure of landslide,so as to evaluate the overall stability of the landslide intuitively.