不同变位模式下无黏性土非极限被动土压力计算分析

假定内摩擦角与位移呈非线性关系，采用所提出的土压力计算理论，结合室内模型试验结果，对墙体的平移（T模式）、绕墙体底采点转动（RBT模式）、绕墙顶采点转动（RTT模式）变位模式下考虑位移的被动土压力进行计算分析，分析表明：计算结果在土压力强度沿墙高度上的分布、土压力合力大小以及合力作用点位置均与实测值较为吻合，从而表明：（1）用该计算理论公式计算不同变位模式下被动土压力是可行的。（2）从土压力强度的计算值和实测值吻合情况来看：RBT变位模式下计算值与实测值符合最好，T变位模式下次之，RTT变位模式下相对最差。（3）从达到朗肯被动土压力合力所需位移量来看：T变位模式下最小，RTT变位模式下次之，RBT变位模式下相对最大。（4）土压力合力作用点位置：T变位模式下在离墙底1/3高度处，RBT模式下均位于离墙底1/3高度以上，RTT模式下均位于离墙底1/3高度以下，并且RBT和RTT模式下均随着转动点至挡土墙最近端点的距离与墙高的比值n的增大逐渐向T变位模式下的合力作用点位置靠拢（即离墙底1/3高度处），这一观点与事实情况完全相符。

Calculation and analysis of unlimited passive earth pressure of cohesionless soil in different movement modes

Assuming the internal friction angles of backfills and their displacements are in nonlinear, to adopt the calculation model that was put forward by the author, combined with the indoor mode experiment, the authors calculate and analyze the passive earth pressure acted on the retaining wall in different movement modes: translation (i.e. Mode T), rotation around a certain point under the wall-bottom (i.e. Mode RBT) and rotation around some point above the wall top (i.e. Mode RTT). The analysis results show that the calculated values and the test values can agree with each other very well in the three ways of the distribution of soil pressure strength along the wall height, the values of the total earth pressure and the location of the action point of the total earth pressure. It is shown that: (1) It is feasible to use the calculation model to calculate the passive earth pressure in different movement modes. (2) For the agreement degree between the calculated values and the test values of the soil pressure strength distribution, it is the best in Mode RBT; next is Mode T; it is relatively the worst in Mode RTT. (3) For the required displacement to reach the Rankine's passive earth pressure force, it is the minimum in Mode T; next is in Mode RTT; it is relatively the maximum in Mode RBT. (4) For the location of the action point of the total earth pressure, in Mode T, those are all at the 1/3 wall’s height from the wall bottom; in Mode RBT, those are all over the 1/3 wall’s height; in Mode RTT, those are all below the 1/3 wall’s height; and in RBT and RTT mode locations of the action point all gradually trend to the 1/3 height place from the wall bottom with the value of n (the ratio of the distance from rotation point to retaining wall proximal endpoint to wall's height) increasing gradually. These views are completely consistent with the fact.