考虑土拱效应刚性挡墙土压力研究

Research on earth pressure of rigid retaining wall considering soil arching

基于库仑土压力理论,假定刚性挡墙后主应力拱迹线为抛物线,推导了主、被侧土压力系数和水平微分单元间摩擦系数的理论公式,得到改进的主、被动土压力计算公式。研究表明:考虑土拱效应计算结果与模型试验结果吻合比较好。主动极限状态下,土体内摩擦角越小,墙土接触面上外摩擦角越大,土拱效应越明显,主动土压力合力作用点越上移;被动极限状态下,土体内摩擦角和墙土接触面上外摩擦角越大,土拱效应越明显,被动土压力合力点越往下移。

Based on Coulomb＇s earth pressure theory, assuming the trace of the principal stress arching in the back of rigid retaining wall as parabola, the theory formulae are obtained including the lateral coefficients of active and passive earth pressures and the friction coefficients of horizontal differential elements; then improved formulae of active and passive earth pressures are presented. The results show that the calculation results considering soil arching are consistent with the ones of model tests. Being in active limit state, the inner friction angles become smaller, the outer friction angles on the soil-wall interface become larger; the effect of soil arching becomes more distinct; as a result, the application point of resultant active earth pressure is higher. Being in passive limit state, the inner friction angles and the outer friction angles on the soil-wall interface are larger, the effect of soil arching becomes more distinct; and the application point of resultant passive pressures is lower.