土拱效应和渗流作用刚性挡墙主动水土压力研究

 假定小主应力迹线为抛物线，分析刚性挡墙后土拱效应，推导土拱效应作用下刚性挡墙主动水土压力系数和水平微分单元层间系数。建立二维Laplace方程分析墙后持续暴雨作用形成的稳定渗流场。在土拱效应和渗流作用分析基础上，提出土拱效应和渗流作用下主动水土压力计算模型，推导主动水土合力、合力作用点计算公式，给出实用主动水土压力系数。研究分析表明：理论计算结果与实测结果吻合较好；土拱效应和稳定渗流作用下水土压力成非线性分布，合力增大，合力作用点位置上移。工程实践中，应当重视持续暴雨期间的土拱效应和渗流作用对刚性挡墙的稳定不利影响。实用主动水土压力系数方法为持续暴雨作用下挡墙主动水土压力计算提供简化实用方法。

STUDY OF ACTIVE EARTH AND WATER PRESSURE OF RIGID RETAINING WALL CONSIDERING SOIL ARCHING AND SEEPAGE

On the basis of the assumption that minor principal stress trace is parabola，the soil arching behind rigid retaining wall is analyzed. The coefficients of active earth and water pressure(AWP) and the horizontal differential element interlayer are obtained. The two-dimensional Laplace equation of the stable seepage field behind rigid retaining wall is also established during continuous rainfall. Based on the analysis of considering，the calculating model of AWP is presented. The formulas of the resultant force，the point of resultant force and the practical coefficient of AWP are proposed. The result of theory analysis shows that the theory value is consisted with the experimental value. When the soil arching and the stable seepage are considered，the distribution of AWP is nonlinear，and the resultant force increases，and the point of resultant force is higher. Therefore，the adverse effect of the soil arching and seepage on the safety of rigid retaining wall should be highly emphasized in the engineering practice. The practical coefficient method of AWP is available for the simplified and practical calculating method of AWP during continuous rainfall.