基于混合粒子群算法和能量法主动土压力计算

假定挡土墙后填土滑动面为通过墙踵的对数螺线滑动面，基于能量法，推导出了墙背倾斜、粗糙、墙后填土向上倾斜，适用于砂性土与黏性土的主动土压力上限解。以对数螺线通过斜坡的旋入角? 0和旋出角? h为变量，使用基于自然选择的混合粒子群优化算法对最危险滑动面进行全局搜索，从而获得主动土压力最优解。对于砂性土，将土压力系数与经典的极限分析上限解相比，发现在墙面倾角较小时两者基本一致，但当墙面倾角大于30°时，经典解明显偏小，而文中解与基于最优性原理的极限平衡解较接近。至于黏性土，对一工程实例进行计算，计算结果与实测值的相对误差为5.4%。

Calculation of active earth pressure based on hybrid particle swarm algorithm and energy method

Assuming a log-spiral sliding surface passing through the toe of retaining wall,based on energy method,the upper bound of active earth pressure for rough walls with inclined backfill is formulated.The formula can be applied to sandy soil and cohesive soil.Extracting the screw-in angle 0and screw-out angle h through the slope as variables,hybrid particle swarm optimization is used to search the most dangerous sliding surface globally.Hence,the optimal solution of active earth pressure is obtained.For sandy soil,the earth pressure coefficients in this work agree with the classical upper bound solutions of limit analysis when the inclination of wall is small,but obviously bigger than the classical solutions while the wall angle is larger than 30°.Compared to other well-known solutions obtained by limit equilibrium based on optimum principle,the solution herein is more approximate than that of the classical upper bound solution.For cohesive soil,employing the formula developed by this work to calculate the active earth pressure in an engineering practice,it is found that the relative error between calculation results and measured data is 5.4%.