双排桩支护软粘土基坑开挖的有限元分析

双排桩支护结构是基坑围护结构的一种形式,但目前的分析方法无法考虑其与土体的共同作用。采用平面应变有限元方法研究了软粘土地基基坑开挖双排桩支护结构的性状,重点分析了桩土界面特性、前后排桩间距等因素对支护结构的内力和变形的影响。分析表明,当双排桩排距过小时,围护结构类似于悬臂式单排桩性质;当排距过大时,后排桩对前排桩起到类似拉锚桩的作用;只有当排间距为4d左右时,双排桩围护结构才能达到最好的效果。

Numerical Analysis on Deep Excavation Supported by Structure of Double-row Piles in Soft Clay

Double-row pile is one type of bracing structure of foundation pit,but it can't be taken into consideration for the interaction between pile and soil by existing analytical method.With plain strain finite element method,the characteristic of double-row pile of excavation of foundation pit in soil clay is studied. It is emphasized on the influencing factors on the stress and displacement of bracing structure,the characteristic of interface of pile-soil and the spacing between two rows of pile.It is presented that the bracing structure of double-row pile is as the cantilever one-row pile while the spacing of two rows is too close.While when the spacing of two rows is too large,the back pile is just as the anchor pile for the front pile.The double-row pile is the most effective as a bracing structure while the spacing of two piles is about 4d.