基于混合离散的砌石挡土墙边坡极限承载力下限分析  

Lower bound analysis of ultimate bearing capacity of stone masonry retaining wall slope using mixed numerical discretisation

作　　者：李泽[1] 刘毅 周宇[1] 王均星[2] LI Ze1, LIU Ni1, ZHOU Yu1, WANG Jun-xing2(1. Faculty of Civil Engineering and Mechanics of Kunming University of Science and Technology, Kunming, Yunnan 650500, China; 2. State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, Hubei 430072, Chin)

机构地区：[1]昆明理工大学建筑工程学院工程力学系,云南昆明650500 [2]武汉大学水资源与水电工程科学国家重点实验室,湖北武汉430072

出　　处：《岩土力学》2018年第3期1100-1108,1129,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.51564026)~~

摘　　要：将极限分析下限法理论、混合数值离散思想和线性规划结合起来研究砌石挡土墙边坡的极限承载力。采用三角形有限单元离散土体来模拟土体的连续介质力学特性,构建土体静力许可应力场的约束条件,采用块体单元离散砌石体来模拟砌石体的非连续介质力学特性,构建砌石挡土墙的静力许可应力场的约束条件;同时建立有限元单元和块体单元交界面的约束条件;然后以超载系数为目标函数建立求解砌石挡土墙极限承载力的下限法线性规划模型,并使用内点算法进行最优化求解,获得边坡的极限荷载(或安全系数)和对应的应力场。通过3个算例的分析验证了所提方法的正确性。所提方法是将混合数值离散思想引入极限分析领域的一次尝试。Stone retaining wall is constructed to resist the lateral earth pressure. Its characteristic is regarded as a discontinuous medium, whereas the characteristic of the soil behind the wall is a typical continuous medium. In this paper, the ultimate bearing capacity of masonry retaining wall was studied by combining the lower bound theory, the mixed numerical discretisation and linear programming. Firstly, soil mass was discretised by triangular finite elements to simulate its continuum mechanics characteristics, while the masonry wall was discretised by rigid block elements to simulate its non-continuum mechanics characteristics. Thus, constraint conditions of the statically admissible stress field were both proposed for soil and the masonry retaining wall. Meanwhile, constraint conditions were also proposed for interfaces between finite elements and block elements. By considering the overload coefficient as the objective function, the linear programming model was established for calculating the ultimate bearing capacity of masonry retaining wall. In addition, the interior point algorithm was employed to solve the problems of linear mathematical programming. At last, the ultimate load（or safety factor） of slope and its corresponding stress field were obtained directly. Moreover, three typical examples were conducted to validate the proposed method. Therefore, this study successfully introduced the mixed numerical discretisation into the limit analysis.

关 键 词：土质边坡 砌石挡土墙 极限分析 下限法 极限承载力 

分 类 号：TU470[建筑科学—结构工程]