改进的主动土压力计算方法

墙背土压力分布与挡土墙的位移大小和转动模式密切相关。针对绕墙底向外转动的刚性挡土墙，基于土压力形成机制的分析及已有的研究成果，建立挡土墙位移与墙背土体内摩擦角发挥值之间的关系式，反映了墙背土体内摩擦角随着挡土墙位移的增加而渐进发挥的过程。在此基础上，提出一种改进的考虑位移影响的主动土压力计算方法。计算结果表明，随着挡土墙位移的增大，墙背土压力由静止土压力逐步减小。当挡土墙位移达到临界值后，相应的墙背土压力均收敛于库仑主动土压力。墙底背面土压力也是随着挡土墙位移的增长而逐步收敛于库仑主动土压力。与模型试验结果对比表明，理论计算值与试验实测值基本吻合。

Modified computational method for active earth pressure

Distribution of earth pressure behind retaining wall is closely related with displacement of retaining wall and mode of rotation. For rigid retaining wall rotating outward around the base, based on analysis of forming mechanism of earth pressure and precious studies, a formulation of the relation between mobilized internal friction angle of soil behind the wall and displacement is developed, which reflects the process of progressive mobilization of soil internal friction angle as displacement of retaining wall increases. On the basis of it, a modified computational method for active earth pressure considering wall displacement of retaining wall is put forward. Computational results show that earth pressure behind retaining wall decreases gradually from at-rest earth pressure as the displacement increases; and when displacement of retaining wall reaches a critical value, all corresponding earth pressure values behind the wall converge to Coulomb’s active earth pressure values. Earth pressure behind the bottom of retaining wall also converges to Coulomb’s active earth pressure gradually as the movement of retaining wall increases. By comparing with model test results, it is shown that the value of theoretical computation is in good agreement with the measured experimental value.