奥林匹克公园某基坑围护结构受力和变形特性分析

Behavior of stress and deformation of supporting structure in deep foundation pit engineering

以北京奥林匹克公园某基坑工程为背景,采用基于杆系有限元法的专业软件对基坑开挖过程、支护施工进行了数值模拟。杆系有限元法可有效的反应基坑开挖过程中的各种因素及施工工况对支护结构内力和变形的影响,根据计算结果分析了在深基坑施工过程中围护结构的受力和变形特性,得出了采用桩锚复合支护体系作为围护结构的桩身水平位移、弯矩、剪力以及锚杆水平最大拉力等指标随开挖工况而变化的分布规律。结果表明这种围护结构对于控制基坑周边地层位移和围护桩的合理受力是有效的,为工程的顺利开展提供了理论依据。

For a certain deep foundation pit of Beijing Olympic Park,the beam calculation model was used for excavation and supporting of the deep foundation pit.In the pit,the piles and earth anchors were used as the supporting structure.The principle of bar system finite element method could effectively take into account the influences of various factors and complex situation during the course of excavation on interval force and deformation of supporting structure.According to the calculated results, for the horizontal displacements,bending moments and shear forces of the fence piles as well as the horizontal pull forces of the earth anchors,the analytic results were given with the increasing depth of excavation on earth change.It is shown that the supporting structure is effective in controlling the displacement of strata around the foundation pit and the proper stress of piles.