土体滑裂面形状对挡土墙主动土压力有重要影响。以无黏性填土挡墙为研究对象，假设在考虑土拱效应时，极限状态下墙后土体的滑裂面为曲线，基于水平微分单元法推导出平动模式下挡土墙主动土压力的分布。首先将计算与模型试验结果及已有理论研究成果进行对比分析，验证了方法的可靠性；其次，研究土体内摩擦角和墙-土摩擦角对主动土压力分布、合力大小和作用点高度的影响。结果表明：基于曲线滑裂面假设得到的滑动楔体范围略大于采用直线滑裂面的假设；对于不同高度的挡土墙，建议的计算结果与模型试验结果更为符合；对于不同的土体内摩擦角和墙-土摩擦角，土压力的分布形式和合力作用点与Paik解较为接近，但合力略大于Paik解。

The shape of sliding surface has important influence on the active earth pressure of retaining wall. A new active earth pressure formulation is proposed based on horizontal differential element method assuming retaining wall backfilled with cohesionless soils is under horizontal translation model. The assumption of formulation is that the sliding surface is curved when backfill behind a retaining wall reaches limit equilibrium and that the soil arching is considered. First, the reliability of the formulation is verified based on the compared calculation results of the formulation, model test and classical theory. Second, the influences of the different internal frictional angles of soil and wall-soil friction angles on the distribution, resultant and loading position of active earth pressure are analyzed. The results show the regions of sliding wedge obtained from curved sliding surface assumption are slightly bigger than the regions of plane assumption. The results by the proposed formulation are more consistent with model test results for retaining walls of different heights. The distribution form and loading position of active earth pressure are close to Paik’s solutions in different inner friction angles and friction angles on the soil-wall interface. However, the magnitudes of active earth pressure are greater than Paik’s solutions slightly.