挡土墙被动土压力分布与被动侧压力系数

采用库仑土压力理论假设:挡土墙被动土压力是由墙后填土在被动极限平衡状态下出现的滑动楔体产生,在该滑动楔体上沿竖向取水平薄层作为微分单元体,通过作用在单元体上的水平力、竖向力和力矩平衡条件,建立挡土墙被动土压力强度的一阶微分方程,给出了被动侧压力系数、被动土压力强度、被动土压力合力和被动土压力合力作用点的理论公式,并分析了被动极限平衡状态下填土内摩擦角和墙背摩擦角对被动侧压力系数、被动土压力强度、被动土压力合力、被动土压力合力作用点和抗倾稳定性的影响。结果表明,随着填土同墙背间摩擦角增大,被动侧压力系数K值和被动土压力合力作用点高度减小,水平被动土压力合力增大,水平被动土压力合力对墙底的合力矩保持不变。

Passive Earth Pressure on a Retaining Wall and Coefficient of Passive Lateral Earth Pressure

On the basis of Coulomb's concept that the passive earth pressure against the back of a retaining wall is due to the thrust exerted by a sliding wedge of soil between the back of the wall and a plane which passes through the bottom edge of the wall and has an inclination of , the differential equations of first order are set up by considering the equi- librium of the forces and the moments on an element of the wedge. The lateral coefficient of passive earth pressure, the unit passive earth pressure,the resultant force of passive earth pressure and the application point of the resultant force are obtained. The effects of the internal frictional angle of backfill and the frictional angle between the wall back and the backfill on the lateral coefficient of passive earth pressure, the unit passive earth pressure, the resultant force of passive earth pressure, the application point of the resultant force and the overturning stability of a retaining wall are investigated. It is shown that the coefficient of passive lateral earth pressure K and the application height of the resultant force are reduced, the resultant force of passive earth pressure is increased, and the overturning moment induced by the resultant force of passive earth pressure remains a constant with the increase of the frictional angle between the wall back and the backfill.