基于流固耦合理论的饱和-非饱和土开挖边坡稳定性分析

现有开挖边坡稳定分析的研究中，综合考虑开挖效应与应力-渗流耦合作用对边坡稳定性影响的分析很少。为此，根据饱和-非饱和土渗流及抗剪强度特性，推导了饱和-非饱和土在应力-渗流耦合作用下的有限元求解方程，介绍了计算饱和-非饱和土开挖边坡稳定性的有限元强度折减技术。建立了一开挖边坡算例进行应力-渗流耦合分析，结果表明，相对于非开挖模式下的计算，开挖卸荷效应对开挖边坡稳定性有一定提高作用，但这一作用随着时间的延长会逐渐减弱直至消失。对影响开挖边坡稳定的各种因素进行了计算分析，开挖速度、初始水位高度、渗透系数以及弹性模量、泊松比等影响因素对应力-渗流耦合作用下的开挖边坡稳定性影响较大，影响规律和以往的研究结论有所不同。

Stability analysis of slopes excavated in saturated and unsaturated soils based on coupled consolidation theories

Among the current researches about the stability analysis of excavation slope, there are few analyses of the impacts on the stability of slope considering the factors of excavation and coupled state of stress-seepage. Therefore, according to the characteristics of seepage and shear strength in the saturated and unsaturated soils, a finite element equation is deduced for the saturated and unsaturated soils considering the coupled effect of the stress-seepage and a strength reduction finite element method is propsed to calculate the excavated slope stability. And a coupled stress-seepage analysis of an excavated slope example has been made in this study. Analysis results show that the unloading effects caused by slope excavation, to some extent, can improve the safety factors of slope calculated in the non-excavation mode. But this improvement would gradually fade and even vanish. Calculations and analysis are also made of various factors which can affect the excavated slope stability. Research results indicate that factors, such as slope excavation speed, initial water level, permeability coefficients and elastic modulus and Poisson ratio, have relatively great influences on the excavated slope stability under the coupled effect of stress-seepage and their effect patterns would be different from the conclusions made by the previous research cases.