中文摘要：

朗肯土压力理论至今仍是计算土压力的重要方法。由于朗肯主动土压力分布是根据墙后土体应力达到极限状态而得到的,根据极限应力状态认为墙后极限土体的滑动面为一簇平面,由此计算墙后极限土体与土压力的力学平衡不能满足。从极限平衡理论出发,针对朗肯主动土压力下墙后土体极限滑动面问题,明确提出墙后极限土体边界为滑动平面和开裂面的组合,提出的滑裂面（包含滑动面和开裂段）从力学平衡、土压力分布、土压力合力大小等方面完全符合朗肯主动土压力的理论解,可认为是朗肯主动土压力所对应的墙后土体真实滑裂面。同时对朗肯理论的墙后拉应力问题也作出了相应解释,并论证了被动土压力的墙后土体滑动面为一簇平面。研究结论对朗肯土压力理论是一个补充和完善。

英文摘要：

Nowadays,Rankine＇s earth pressure theory is still playing an important role on calculating soil earth pressure.Based on Rankine＇s theory,active earth pressure behind the wall is distributed to reach a limit equilibrium state in which the sliding surface of limit soil mass is considered as a cluster of planes.Proceeding from limit equilibrium theory,it is pointed out that the boundary of limit soil mass is a combination of sliding surface and crack section.This proposed sliding-cracking surface,which is in full compliance with Rankine＇s theory with regards to active earth pressure distribution and resulting force,can be considered as an actual sliding surface when the soil failure occurs under active earth pressure.On the other hand,Rankine＇s theory is applied to evaluate the soil tensile stress behind the wall under passive earth pressure,verifying that the sliding surface of limit soil mass can also be considered as a cluster of planes under passive earth pressure.The study result enhances the application of the Rankine＇s earth pressure theory.