考虑土体硬化的基坑开挖性状及隆起稳定性分析  

Investigation of excavation characters and basal stability with considering soil hardening behavior

作　　者：张飞[1,2] 李镜培[1,2] 唐耀[1,2] 

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学岩土及地下工程教育部重点试验室,上海200092

出　　处：《水文地质工程地质》2012年第2期79-84,共6页Hydrogeology & Engineering Geology

基　　金：上海市科委科技攻关计划(09231200900)

摘　　要：基坑开挖过程中,土体应力路径、卸载回弹再压缩特性与简单加载或卸载不同,采用常规的理想弹塑性模型模拟基坑开挖,得到的围护墙位移、坑内土体回弹以及坑外沉降较大。分析了基坑开挖不同区域土体的性状,采用土体硬化模型模拟基坑开挖的卸载与土体硬化行为,结合工程算例,对比土体硬化模型和理想弹塑性模拟以及实测的围护结构土压力、围护墙水平位移和坑外土体沉降,并利用强度折减法分析基坑的稳定性。计算结果表明,考虑土体硬化的HS模型有限元方法能体现土体卸载再加载与开挖的特性,所得土压力、围护结构水平位移以及基坑抗隆起稳定性符合软土地区基坑工程的实践。The stress path of soil in excavation is different from that of loading and unloading. The computed retaining wall displacement and basal heave and peripheral ground settlement may be inaccurate with adopting normal ideal elastoplastic model of soil. The soil properties in different excavation zones were analyzed, and the hardening soil model was adopted to simulate the influence of excavation unloading and soil hardening. An actual excavation was numerically analyzed using finite element method, the earth pressure on retaining wall and lateral displacements of retaining wall were computed and compared with measured data. In addition, the stability of excavation was analyzed with adopting strength reduction FEM. The results show that the numerical analysis with adopting hardening soil model can reflect unloading/reloading and hardening characters of soil, the computed results of earth pressure on retaining wall, lateral retaining wall displacements and basal stability factors coincide with experiential results of excavation in soft ground.

关 键 词：基坑工程 土体硬化模型 开挖卸载 土体性状 有限元强度折减法 

分 类 号：TU463[建筑科学—结构工程]