一种改进的斜支撑体系支护某超大深基坑的变形分析

济南某商业广场超过50000 m^2的基坑采用一种改进的斜支撑支护体系进行支护,与普通斜支撑支护型式不同,该支护体系包括支护桩、斜撑、立柱与支撑桩。本文采用FLAC^3D显式有限差分数值计算分析方法,并结合支护桩水平位移测斜数据,对该支护体系的变形特性进行分析研究,从中论证各支护单元在3个开挖阶段的运动学效应。研究结果表明,该斜支撑支护体系可以把各支护单元以及它们之间的土体充分调动起来,相互之间积极协调,以抵挡基坑开挖带来的土压力,从而减小基坑周围土体位移,保障周围道路、地下设施及周边建筑的正常运行。

Practical Study on Displacements of Oblique Bracing Supporting System in Excavation of Large Pit

A modified oblique bracing supporting system was used in supporting construction of foundation pit for a shopping mall in Jinan city,which occupies more than 50000 m~2.The oblique bracing supporting system,which is different from normal pattern,includes supporting piles,oblique bracing constructions, vertical pillars and struts.Through the analysis of explicit finite difference numerical calculation with FLAC~（3D） program,considering the results of in-situ monitoring of supporting piles,some conclusions are drawn on the displacements of the supporting system,and the effects of supporting constuctions.It indicates that the supporting constructions in the system are fully utilized to work with the soil at the bottom of pit to resist the soil pressures caused by foundation pit excavation,and that the displacements of soil around the pit are reduced.Furthermore,the normal operation of roads,underground lines,and buildings surrounding the pit are ensured under the effective support of the system.