砂土中挡墙不同变位模式主动土压力模型试验

Model Test on Active Earth Pressure in Sand Induced by the Movement of Retaining Wall

针对刚性挡墙不同变位模式,对基坑开挖过程中土体作用于墙上的主动土压力进行模型试验研究。试验模拟了在平移(T模式)、绕墙趾转动(RB模式)和绕墙顶转动(RT模式)3种基本刚性变位模式下挡墙土压力的变化,得到了墙背主动土压力的基本规律。试验观察发现,挡墙平移时,主动土压力呈重心下移的抛物线形,挡墙变位最大位移约0.002H时达到极限平衡状态;挡墙绕墙趾转动时,主动土压力近似呈三角形分布,约0.0035H时达到极限平衡状态;挡墙绕墙顶转动时,主动土压力呈上部大而下部小的抛物线形,约0.0025H时达到极限平衡状态。本文还将得到的主动土压力规律进行简化,得到了3种基本变位模式下的主动土压力简化图,对工程实践具有指导意义。

This paper performs a series of model tests to explore the characteristic of active earth pressure induced by rigid wall with various movement modes,i. e.,translation mode（ T mode）,rotate about toe mode（ RB mode） or rotate about top mode（ RT mode）. The different active earth pressure curves are found relevant to three basic movement modes. It has been found that the T mode movement tends to cause a barycenter lower parabola-type earth pressure profile when the retaining wall movement attains to 0. 002 H,and RB mode will produce the triangleshape profile with the movement of the retaining wall reach to 0.0035 H,and RT mode movement will result in a upper big and lower small parabola-type profile when the retaining wall movement attains to 0.0025 H. In addition,this paper simplifies the regularity of active earth pressure,getting the simplified diagram of the active earth pressure in different movement mode. This work is significance for engineering practice.