放坡状态有限土体刚性挡土墙主动土压力研究  

Active earth pressures against rigid retaining walls for finite soil under the grading condition

作　　者：胡卫东[1] 曾律弦[1] 刘晓红[1] 廖嘉 HU Weidong;ZENG Lyuxian;LIU Xiaohong;LIAO Jia(College of Civil Engineering and Architecture,Hunan Institute of Science and Technology,Yueyang,Hunan 414006,China)

机构地区：[1]湖南理工学院土木建筑工程学院,湖南岳阳414006

出　　处：《水文地质工程地质》2018年第6期63-70,共8页Hydrogeology & Engineering Geology

基　　金：湖南省自然科学基金项目资助(2017JJ2110)

摘　　要：针对现有有限土体刚性挡土墙主动土压力研究大都集中于临近建筑物墙体或地下室外墙的狭窄土体,相邻基坑、路堤与切坡挡土墙形成放坡状态有限土体研究甚少,本文考虑填土黏聚力及墙土间黏结力、墙土间摩擦作用、墙背倾角及填土顶面竖向荷载等的影响,利用刚体极限平衡理论进行研究。根据相邻基坑与边坡挡土墙放坡状有限土体的工程特性,分析挡土墙平动位移模式下平面滑动破裂面的形成特征,建立放坡状态有限土体主动土压力计算模型,并利用数值计算方法可以求解。通过对放坡状有限土体主动土压力进行算例分析与参数分析,表明极限破裂角与宽高比、黏聚力、墙背倾角及墙土间外摩擦角为负相关,不同黏聚力下随着宽高比增大,极限破裂角趋近于考虑黏聚力作用库伦方法得到的极限破裂角值,不同黏聚力下有限土体宽度临界值亦是变化的;主动土压力随黏聚力、墙背倾角及墙土外摩擦角增大而减小,随着宽高比增大而增大并逐步趋近于库伦方法计算的土压力值。最后,通过模型试验验证表明按本文方法计算的极限破裂角与实测破裂角吻合,PIV系统测试得到的临界宽高比与库伦方法的结果一致。The active earth pressme against rigid retaining walls with narrow backfill adjacent existing smTounding buildings or basements has widely been studied. However, the finite soil under the grading condition behind the letaining walls of excavations, embankments and cutting slopes is seldom examined. In this paper, the rigid body limit equilibrium theory is introduced. The influence parameters, such as the soil cohesion, the cohesive force between soil and wall, the wall friction, the inclination angle of walls, and the surcharge on top of the backfill ale considered in this study. The plane sliding failure surface is analyzed under the translation mode, combining with the characteristics of tile finite soil under the grading condition behind the retaining walls. The formulae for calculating the active pressure for the finite soil is plesented, which can easily be solved by using the numerical calculation method. The calculation example analysis and parameter analysis about the active earth plessure for the finite soil under the grading condition are put forward. The results show that the limit ruptme angle is not constant and it will decrease with the incleasing ratios of the width to height, the soil cohesion, the inclination angle of walls, and the wall friction. The limit rupture angle will tend to the value based on the Coulomb＇ s active earth pressure formulae considering the soil cohesion with the incleasing ratios under different soil cohesions. The threshold of the limited width varies with soil cohesion. Meanwhile, the active earth pressure will decrease with the incleasing soil cohesion, the inclination angle of wall, the wall friction. It will increase with the value with the Coulomb＇ s method. The calculated rupture test, and the threshold of the ratios of the width to height with the Coulomb＇ s method. increasing ratios, which will gradually tend to the angle approaches the tested angle through the model tested by the PIV test system approaches the value

关 键 词：有限土体 主动土压力 放坡 极限破裂角 极限平衡 

分 类 号：TU432[建筑科学—岩土工程]