基坑水泥搅拌桩桩身水平位移影响因素的颗粒流数值模拟  

Numerical simulation of granular flow on factors for the horizontal displacement of cement mixing pile in the foundation pit

作　　者：沈一帆[1] 胡敏云[1] 计国贤[1] 

机构地区：[1]浙江工业大学建筑工程学院,浙江杭州310032

出　　处：《浙江工业大学学报》2011年第3期273-278,共6页Journal of Zhejiang University of Technology

基　　金：国家自然科学基金资助项目(50978231)

摘　　要：采用基于散体介质理论建立的颗粒流细观力学方法,对基坑开挖过程中水泥搅拌桩支护的桩身水平位移特征及影响因素进行了计算分析.分析中主要考虑了5个影响因素:桩身埋置深度,桩径尺寸,土体内摩擦系数,颗粒刚度参数及施工进度.数值模拟结果表明,当桩身埋置深度较小时,增加桩身埋置深度可以明显减小基坑侧壁的水平位移变形量,但是,当桩身埋置深度超出基坑开挖深度后,对桩身水平位移的限制作用就不大了.桩径尺寸对基坑水泥搅拌桩桩身水平位移影响较为显著,能有效控制桩身水平位移大小.土体内摩擦系数的增大对桩身水平位移影响具有一定的影响,但其并不是起控制作用.颗粒刚度的变化体现了不同的土层性状的差异,其对桩身水平位移变化也比较明显.基坑开挖中分层施工进度的快慢对桩身最大水平位移影响也较大,随着基坑暴露时间的加长,桩身水平位移逐渐加大,反映了基坑开挖过程中水泥搅拌桩桩身水平位移具有时效性.Based on granular Media-based theory of micromechanics of particle flow method,horizontal displacement characteristics and influencing factors of the cement mixing pile in the excavation process were calculated and analyzed.Five main factors were considered in the analysis： pile embedded depth,pile diameter size,soil body friction coefficient,particle stiffness parameters and construction schedule.Numerical simulation results showed that when the pile embedded depth is small,increasing the depth of the pile can significantly reduce the laying of the horizontal displacement of foundation pit wall deformation,however,when the pile embedded depth is beyond the depth of excavation,the restrictions on the shaft the role of horizontal displacement bam be ignored.The pile diameter size of the pit of cement mixing pile horizontal displacement of the body affected more significantly,can effectively control the size of the horizontal displacement of the pile.Soil body increases the friction coefficient of the horizontal displacement effect on the shaft has a certain influence,but not for control purposes.A change of particle stiffness of different soil characteristics of the differences in the level of displacement on the shaft of its change is also more obvious.Excavation layered construction schedule on the shaft speed of the maximum horizontal displacement of a larger impact,with the excavation of the longer exposure time,the gradual increase in horizontal displacement of the pile,reflects excavation process of cement mixing pile horizontal displacement of the body has a time-sensitive.

关 键 词：水泥搅拌桩 颗粒流 数值模拟 基坑开挖 桩身水平位移 

分 类 号：TU473.1[建筑科学—结构工程]