排桩＋斜支撑在某大面积基坑开挖中的受力变形性状研究

Study of Force and Deformation of Piles and Oblique Bracing in Excavation of Large Pit

随着基坑工程开挖面积越来越大,出现了一种排桩+斜支撑的组合支护结构。本文基于两阶段分析方法,首先采用Winkler地基模型模拟排桩的桩土作用,运用有限差分法考虑土的分层特性,然后应用水平受荷桩简化Mindlin解,考虑该组合支护结构的桩-桩相互影响,计算其遮拦效应,从而得到开挖条件下支护结构桩水平反应的简化分析方法。最后,结合济南某基坑工程实例,通过有限差分的方法,研究了排桩+斜支撑组合支护结构的受力变形特性。结果表明,该组合支护结构能够通过支撑桩和排桩的合理布置,有效调动基坑内部土体抵抗荷载,协调基坑土体变形以及支护结构的变形。

With the continued increase in surface areas tures of piles and oblique bracing has been developed. of pit excavation, a type of combined support strue-Based on a two-stage method, the Winkler＇s model was adopted to simulate the effect of pile-soil interaction while the characteristics of multi-layered soils was taken into account with the finite difference method. Then, with the simplified Mindlin＇s solution for piles subject to lateral loadings, the pile-pile interaction of the combined support structure was considered to calculate the shielding effect of the structure, to develop a simplified analytical scheme for the investigation of the lateral response of piles of the support structure in the process of excavation. Finally, the characteristics of force and deformation of the combined support structure of piles and bracing was studied for a real project in Jinan city with the finite difference method. The study has shown that the combined support structure can effectively transfer external loads to the pit＇s soil, and balance well the deformations of the soil and the support structure through proper arrangement of piles and bracing.