黏性土坡地震失稳机制及其在黄土斜坡地震稳定性分析中的应用

Earthquake Instability Mechanism of Cohesive Soil Slope and Its Application in Seismic Stability Analysis of Loess Slope

摘要:

基于地震作用下黏性土坡失稳滑动特点,以土体应力状态及其变化分析边坡失稳过程。通过分析地震作用下边坡不同部位土体应力状态和剪应力变化,结合实际地震边坡失稳破坏特征,提出黏性土坡地震三段式滑动失稳机制。在分析该滑动失稳机制与有限元强度折减法之间应力关联的基础上,将两者结合应用于实际黄土地震滑坡动力稳定性分析。依据此考虑得到的动力安全系数相比较其他方法,与极限平衡法得到的结果更为接近。

Abstract:

Based on the earthquake instability characteristics of cohesive soil slopes, in this study, we used the stress analysis method to analyze the process of slope instability. By analyzing the stress state and shear stress variation features of soil in different parts of the slope during earthquakes, combined with the failure characteristics of actual slopes during earthquakes, we developed our proposed three-segment sliding instability mechanism of cohesive soil slopes. From our analysis results of the stress correlation between the above-mentioned mechanism combined with the strength reduction finite element method (FEM), we carried out a dynamic stability analysis of an actual loess seismic landslide. A comparison of our results with those of other methods reveals that the dynamic safety factor obtained by the strength reduction FEM, which considers the three-segment sliding instability mechanism of cohesive soil slopes, was very close to that determined by the limit equilibrium method.