考虑条间剪力的刚性挡墙静力与地震主动土压力水平条分法  

Static and seismic active earth pressure on rigid retaining walls based on horizontal slice method considering shear forces on interslice

作　　者：陈柏吉 肖世国[2] CHEN Bai-ji;XIAO Shi-guo(Department of Geological Engineering,Southwest Jiaotong University,Chengdu,Sichuan 610031,China;Key Laboratory of High-speed Railway Engineering of Ministry of Education,Southwest Jiaotong University,Chengdu,Sichuan 610031,China;Dayi Archives Bureau,Chengdu,Sichuan 611330,China)

机构地区：[1]西南交通大学地质工程系,四川成都610031 [2]西南交通大学高速铁路线路工程教育部重点实验室,四川成都610031 [3]成都市大邑县档案馆,四川成都611330

出　　处：《岩土力学》2022年第8期2263-2276,共14页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.51578466);四川省交通运输科技项目(No.2020-A-01)。

摘　　要：针对以往对刚性挡土墙墙背主动土压力采用水平条分法时条间剪力处理不合理的问题,引入条间抗剪强度发挥系数,提出该发挥系数随深度变化的正弦、线性、双曲3种函数模式,并基于大量土压力的模型试验与现场监测结果统计,给出了该发挥系数的取值方法;在此基础上,通过水平条分极限平衡法及拟静力法,建立了充分考虑条间剪力的刚性挡土墙静力与地震主动土压力计算方法,考虑了墙后土体中平面、对数螺旋曲面两种可能的滑裂面形态,且集挡土墙结构型式、墙后填土性质、外荷载等多因素于一体。当墙-土摩擦角等于内摩擦角或其一半时,条间抗剪强度发挥系数一般不为0,墙-土摩擦角对其影响显著;引入条间抗剪强度发挥系数会使土压力合力作用点更接近实测值,建议墙体平动时采用双曲模式、墙体绕踵转动时可采取正弦模式。土体内摩擦角、墙-土黏聚力、竖向地震影响系数等对土压力合力作用点影响较小,但土体黏聚力、土体顶面倾角、墙背倾角、墙-土摩擦角、水平地震影响系数等对其影响较大。实例分析表明,该方法可定量确定主动土压力分布,所计算的主动土压力与实测值吻合良好,合力及其作用点处最大误差分别约为10%和7%。In view of the existing unreasonable assumption on interslice shear forces involved in the horizontal slice limit equilibrium method for active earth pressure on rigid retaining walls,a mobilized coefficient of the interslice shear strength of the soil is proposed and its development mode is assumed to be 3 types of function including sine,linear,and hyperbolic patterns.A series of statistical values of the coefficient is given based on a great number of model test and in-situ observed results of the earth pressure.Further,static and seismic active earth pressure on rigid retaining walls can be determined using the horizontal slice method and pseudo-static approach with rationally considering the shear forces on interslice.Planar and log-spiral modes of potential slip surfaces of the retained soil are involved in the proposed method,which takes into account wall configuration,soil properties as well as external loads.It is found that the mobilized coefficient is not usually zero in the condition that wall-soil friction angle is equal to soil internal frictional angle or half of it,and the coefficient is greatly influenced by the wall-soil friction angle.The hyperbolic profile of the mobilized coefficient for wall translation and the sine mode for wall rotation about its heel are recommended because that the introduction of the mobilized coefficient can make the application points of the resultant of the active earth pressure relatively approach to the measured values.Internal friction angle of the soil,wall-soil cohesion,and vertical seismic factor have little effect on the application point of the resultant,while the soil cohesion,dip angle of the soil top surface,wall back inclination,wall-soil friction angle,and horizontal seismic factor have a greater influence.Some examples show that calculation results including the resultant and its application point of the active earth pressure using the proposed method are in good agreement with those monitored,and the maximum errors are less than about 10%and 7%,respect

关 键 词：刚性挡土墙 主动土压力 水平条分法 条间剪力 分布模式 

分 类 号：TU431[建筑科学—岩土工程]