L型挡土墙主动土压力计算的基底摩擦系数折减有限元法  

Finite element method for computations of active earth pressures acting on L-shaped retaining walls with reduced friction coefficients of base bottoms

作　　者：戴自航[1] 林智勇[2] 郑也平 卢才金 

机构地区：[1]福州大学岩土工程研究所,福建福州350108 [2]福建工程学院土木工程系,福建福州350007 [3]福建省交通规划设计院,福建福州350004

出　　处：《岩土工程学报》2009年第4期508-514,共7页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(50678038);福建省自然科学基金重点项目(D0720001);福建省高等学校新世纪优秀人才支持计划项目(TM2006-30)

摘　　要：提出了通过将基底摩擦系数进行折减,按与传统刚塑性体极限平衡理论相对应的变形体极限平衡理论,采用有限元接触模拟算法进行L型挡土墙主动土压力计算的方法。按照该方法,利用著名非线性有限元分析软件ABAQUS进行了实例计算,以数值模拟手段揭示了坦墙后第二滑裂面的存在,证实了理论上的假设。真实揭示了符合坦墙条件的L型挡土墙后填土中第一和第二滑裂面的位置,且揭示对不严格符合坦墙条件的L型挡土墙,其填土中可能出现第三滑裂面。该方法具有理论上的严密性,而且算例计算比较表明,可更为准确合理地计算出L型挡土墙立板上主动土压力的分布形式及大小,较朗肯土压力理论更加可靠,现行朗肯理论计算的抗滑移稳定安全系数偏于保守,而抗倾覆稳定安全系数偏于危险。同时,该方法计算效率较高,因而具有良好的应用前景。Based on the theory of limit equilibrium of deformed body corresponding to the traditional theory of limit equilibrium of rigid-plastic body, the finite dement contact simulation method is presented for computations of active earth pressures acting on L-shaped retaining walls with reduced friction coefficients of base bottoms. According to this method, the computations of the engineering cases by using the commercial non-linear finite element analysis program, i.e., ABAQUS are performed. The existence of the second sliding surfaces behind substantially planar retaining walls, which is once a theoretical supposition, is discovered and proven by the numerical simulation method. The positions of the first and second sliding surfaces behind L-shaped retaining walls that accord with the conditions of substantially planar retaining walls are revealed truly. The potential third sliding surfaces in backfills behind L-shaped retaining walls which do not strictly accord with the conditions of substantially planar retaining wall are also discovered. The present method is rigorous in theory, and it is shown by its comparisons with practical engineering cases that the distributions and magnitudes of active earth pressures acting on backs of L-shaped retaining walls can be obtained more accurately and reasonably by this method. It is more reliable than Rankine earth pressure theory which was conservative or unsafe for the calculations of the factors of safety against sliding and the factors of safety against overturning, respectively. Meanwhile, the present method is of high efficiency, so it will have a bright application prospect.

关 键 词：有限元法 接触模拟 L型挡土墙 主动土压力 滑裂面 

分 类 号：TU432[建筑科学—岩土工程]