非极限主动土压力计算方法初探

针对未达到极限位移的刚性挡土墙，提出了一种简单可行的主动土压力计算方法。根据反映墙后主动区土体应力-应变性状的卸荷应力路径试验确定的应力-应变关系，建立非极限状态摩擦角与墙体位移的关系。对于未达到极限位移的挡土墙，结合已取得的位移与摩擦角之间的关系，采用与滑裂面相平行的微条对墙后滑动楔体进行划分，对微条进行受力分析，建立平衡方程，推导了滑裂面的倾角，从而得到非极限主动土压力计算公式。随后与一例模型试验数据作了对比分析，计算值与实测值基本吻合，仅在墙下部1/3墙高范围内存在一定的差距。研究表明，所提出的计算方法能够用于计算处于非极限状态下挡土墙的土压力，具有一定的理论意义和工程参考价值。

Preliminary study of active earth pressure under nonlimit state

A reasonable and simple method is proposed to calculate the active earth pressure on rigid retaining wall under nonlimit state. Based on the unloading stress-strain relationship obtained from the unloading stress path experiment reflecting the stress-strain characters of soil in the active area behind the wall, the relationship between the friction angle and wall movement is established under nonlimit state. The sliding wedge, behind the retaining wall of not reaching the limit displacement, can be divided into numerous differential slices paralleling to the sliding plane. Then, with the force analysis of these differential slices and the relationship mentioned above, equations can be set up and the inclination of the sliding plane is also derived. Thereby, the calculation formula of the nonlimit active earth pressure is obtained. Subsequently, compared with one model test, the value of the calculated earth pressure has a satisfying agreement with the observed at the upper two-third of wall height and a certain deviation at the lower one-third of wall surface. The results show that the proposed method can provide a good prediction of active earth pressures for walls under nonlimit state and has some theoretical significance and engineering reference value.