岩体应力应变曲线的围压及孔压效应和降雨触发滑坡的机制分析

从宏观分析与微观机制方面探讨了围压、孔隙水压力对岩体应力应变曲线峰后特性即脆－延性转变的影响。定义了一个峰后破坏割线模量 来表征孔隙水压力对岩体应力应变曲线转型的影响，并结合斜坡失稳的刚度判据，进一步分析了孔隙水压力对应力应变曲线峰后斜率的影响，随孔隙水压力的增加，峰后曲线斜率变陡，峰后刚度增大，即材料的均匀性、脆性增大与刚度比k减小。因此在围压等外界环境因素及系统内部条件不变时，刚度比 时就存在一个临界孔隙水压力 ，也就是说降雨等涨落因素引起滑面介质中的孔隙水压力大于这个临界值时斜坡就易于发生突变失稳。从而进一步加深认识了降雨等外部涨落因素对斜坡系统失稳的重要触发作用。

Analysis on the effects of the confining pressure and pore pressure on the stress-strain curve of rock mass and the mechanism of the rainfall-induced Landslides

The effects of the confining pressure and pore pressure on the post-peak characteristics of the stress-strain curve of rock mass are analyzed in this paper. The apex post modulus is define to indicate the effect of the pore pressure transition of the stress-strain curves, the stiffness criterion of the landslide, the effect of the post-peak slope of the stress-strain curves is further analyzed. With the pore pressure increasing, the post-peak curve becomes steep, and the post-peak stiffness augments, that is , the homogeneity and brittleness of the material increases and the stiffness ratio k decreases. Therefore, under the same environmental and systematic conditions, there is a critical value for the stiffness ratio of 1. When the pore pressure surpasses the value , the landslide is inclined to be induced by rainfall. Rainfall is an important triggering factor of landslides.