深基坑h型双排桩的变形计算及优化分析

Deformation calculation and optimization analysis of h-type double-row piles in deep foundation pit

针对目前深基坑工程中h型双排桩理论的不足,在考虑桩土非线性共同作用弹性反力法的基础上引入考虑非极限状态的土压力理论,得到一种可同时考虑非极限土压力理论和支护桩与土相互作用的支护结构水平位移计算方法。推导支护结构水平位移和地面沉降公式,研究深基坑开挖中h型桩支护结构的受力特性和变形规律。将理论成果应用于工程实例,与实测结果进行对比分析,并建立二维有限元模型,优化h型双排桩的设计参数。研究结果表明:支护结构水平位移与坡顶沉降均呈“匙”分布,桩间距为2倍桩径,排间距为5倍桩径,后排桩桩底标高略低于基底为较合理的设计参数。

This paper aims at the theoretical defects of h-type double-row piles in deep foundation pit,the theory of soil pressure considering non-limit state was introduced on the basis of the elastic reaction method considering the nonlinear interaction.A method for calculating the horizontal displacement of supporting structure considering the non-limit soil pressure theory and the interaction between supporting pile and soil was proposed.The formulas of horizontal displacement and ground subsidence of the supporting structure were derived.Finally,the theoretical results were applied to engineering practice and compared with the measured results.A two-dimensional finite element model was established to optimize the design parameters of h-type double-row piles.The results show that the horizontal displacement of the supporting structure and the settlement of the top of the slope are distributed in a spoon distribution.The pile spacing is 2 times the pile diameter,and the row spacing is 5 times the pile diameter.The reasonable design is that the bottom elevation of the backrow pile is slightly lower than that of the base.