滑移线法求解挡土墙主动土压力  

Active Earth Pressure on Retaining Walls Using Slip-line Method

作　　者：彭明祥 PENG Mingxiang(China Energy Engineering Group Guangdong Electric Power Design Institute Co.,Ltd.,Guangzhou 510663,China)

机构地区：[1]中国能源建设集团广东省电力设计研究院有限公司,广州510663

出　　处：《南方能源建设》2018年第1期1-13,共13页Southern Energy Construction

摘　　要：滑移线法常用来求解挡土墙极限土压力,但至今仍有一些问题尚未得到解决。基于极限平衡理论,视墙后填土为服从Mohr-Coulomb屈服准则的理想弹塑性材料,并且假定它是各向同性的、均匀的以及不可压缩(膨胀)的理想连续介质,计算模型中考虑各种影响因素,提出弹性覆盖层替代传统的张拉裂缝,引进一个新概念"应力奇点"及其应力边界条件,建立静定可解的极限平衡问题数学模型而没有考虑土的应力-应变关系,采用滑移线法求解墙后塑性区的滑移线应力场,进而求解挡土墙主动土压力和滑裂面土反力,并且通过无量纲分析首次提出几何力学相似原理。研究结果表明,主动土压力的滑移线解一般总是大于或等于库仑解,朗肯解或满足非奇异条件的经典库仑解与滑移线解一致,Hencky第一定理和第二定理不具有普遍适用性。The slip-line method is commonly used to solve the limit earth pressure on retaining walls,but to date,there are still a number of problems which have not yet been solved.Based on the limit equilibrium theory,the backfill is considered to be an ideal elastic-plastic material,which obeys the Mohr-Coulomb yield criterion,and is assumed to be an ideal continuous medium which is isotropic,homogeneous and incompressible(or non-expansive).Various factors of influence are considered in the calculation model.An elastic overburden is proposed as a replacement for traditional tension cracks.A new concept“stress singularity”and its stress boundary conditions are introduced,and a statically determinate and solvable mathematical model for the limit equilibrium problem is established without considering the stress-strain relationship of soil.The slip-line stress field in the plastic zone of the backfill is solved by using the slip-line method,following which the active earth pressure on retaining walls and the soil reaction on slip surface are derived.The geometric and mechanical similarity principle is first proposed by dimensionless analysis.The results show that the slip-line solution to active earth pressure is generally always greater than or equal to Coulomb′s solution and coincides with Rankine′s solution or the classical Coulomb′s solution that satisfies the non-singularity conditions.Hencky′s first and second theorems are not generally applicable.

关 键 词：挡土墙 主动土压力 滑移线法 应力奇点 

分 类 号：TU432[建筑科学—岩土工程]