考虑墙体位移模式的成层土动主动土压力研究

Research on dynamic active earth pressure of layered soil with different wall movement modes

为了分析墙体位移模式对成层土动主动土压力的影响,本文基于水平层法,提出一种考虑墙体位移模式影响的成层土动主动土压力计算方法。借助矩阵方程的求解方法,简化了繁复的土压力强度计算式推导工作。利用Fortran语言编制计算机程序,实现了复杂情况下动主动土压力的快速计算。分析了不同位移模式下动主动土压力强度分布、土层微段单元顶底面上的等效黏聚力和等效内摩擦角对不同位移模式下动主动土压力强度分布、土压力对墙踵力矩最大值的影响等问题。分析结果表明:绕墙顶转动(RT)模式下动主动土压力强度分布呈向内收敛的趋势,应力集中于墙体偏上部,绕墙底转动(RB)模式下动主动土压力强度分布呈向外发散的趋势,应力集中于墙体偏下部;等效内摩擦角对动主动土压力强度分布的影响较大;动土压力对墙踵产生最大力矩时的破裂面并非产生动主动土压力时的破裂面。

In order to verify the effects of wall movement models on the active earth pressure of layered soil under seismic loading,a method for estimating the dynamic active earth pressure of layered soils is proposed based on the horizontal layer method considering the effect of wall movement model in this paper.The complicated derivation of earth pressure stress expression is simplified by introducing matrix equation,and the rapid calculation of dynamic active earth pressure in complex cases can be achieved by using a computer program compiled with Fortran language.The distributions of dynamic active earth pressure in different movement modes,the effects of equivalent cohesion and equivalent internal friction angle at the bottom and top surfaces of soil micro-section onthe distribution of dynamic active earth pressure in different movement modes,and the effect of earth pressure on the maximum moment at wall heel,are investigated in this paper.Results indicate that the distribution of dynamic active earth pressure stress in the rotation about top(RT)mode tends to converge inward,and the stress concentrates on the upper part of the wall;but in the rotation about bottom(RB)mode,the distribution of dynamic active earth pressure stress is divergent,and the stress concentrates on the lower part of the wall.And the equivalent internal friction angle has significant effects on the distribution of dynamic active earth stress.The rupture surface corresponding to the maximum moment at wall heel generated by dynamic earth pressure is not the rupture surface when active earth pressure generated.