考虑土拱效应的粘性填土平行挡土墙侧向土压力计算方法

Calculation Method for Lateral Earth Pressure on Parallel Retaining Walls with Clayey Backfill Considering Soil Arching Effect

考虑土拱效应的影响,采用圆弧形拱作为小主应力轨迹,以粘性填土平行挡土墙为研究对象进行了研究。充分考虑墙土摩擦角、填土内摩擦角、填土粘聚力、竖向均布荷载、平行挡土墙间的水平距离等多种影响因素,运用力学单元平衡方程和摩尔-库伦强度理论推导了平行挡土墙侧向土压力系数和侧向土压力计算公式。最后通过算例分析得出墙土摩擦角部分发挥和充分发挥,以及平行挡土墙间水平距离对墙侧向土压力的影响变化规律。结果表明:考虑土拱效应的侧向土压力系数和侧向土压力沿深度为非线性分布,并且其与墙土摩擦角、填土内摩擦角、填土粘聚力、竖向均布荷载、平行挡土墙间的水平距离有关;不考虑土拱效应的常规方法计算得到的土压力偏不安全。

With soil arching effect considered, circular arch form as the trajectory of minor principal stress and parallel retaining wall filled with clayey soil as object, both the coefficient and formula of lateral earth pressure on parallel retaining wall were derived with mechanical unit equilibrium equation and Mohr-Coulomb strength theory, with the effect of soil-wall friction angle, internal friction angle, cohesion of backfill, vertical uniform load and horizontal distance between parallel walls considered. The influence laws of the soil-wall friction angles with full and part effect and the horizontal distance between parallel walls on the lateral earth pressure were obtained through examples analysis. The results show that the coefficient of lateral earth pressure and lateral earth pressure itself are in nonlinear distribution along the depth with soil arching effect considered, and are related with soil-wall friction angle, internal friction angle of backfill, cohesion of backfill, vertical uniform load and the horizontal distance between parallel walls. The conventional met hod for earth pressure without consideration of soil arching effect is not safe.