地铁明挖基坑内撑失效分析及基坑抢修恢复方法  

Failure Analysis of Internal Support in Subway Open Cut Foundation Pits and Methods for Pit Repair and Restoration

作　　者：周朋 ZHOU Peng(China Railway 25th Bureau Group Fifth Engineering Co.,Ltd.,Qingdao 266000,China)

机构地区：[1]中铁二十五局集团第五工程有限公司,青岛266000

出　　处：《价值工程》2024年第16期14-17,共4页Value Engineering

摘　　要：某地铁车站基坑为三层明挖形式,夏季某日由于两天大范围降雨及给水管线大量渗水,基坑内产生了涌水涌泥现象,围护结构产生大量变形导致北端头井角撑脱落、端头墙折断、侧滑。本文首先采用有限元模拟对内撑失效的原因进行分析,详细了解了内撑及围护结构在基坑土体强度较小的条件下的工作状态,发现内撑安全系数较小,围护桩发生了极大地变形是失效的力学原因。然后详细描述了基坑抢险的经过,并对恢复工作进行了探讨,并给出了加固基坑外地层→建立新的围护桩→开挖已坍塌基坑土方→建立新的内撑结构及车站结构→回填加固基坑外放坡土体的基坑恢复施工技术方案,希望对类似条件下的工程提供一定的参考。The foundation pit of a certain subway station is a three-layer open excavation form.On a certain day in summer,due to two days of large-scale rainfall and a large amount of water seepage in the water supply pipeline,there was a phenomenon of water and mud surging in the foundation pit.The surrounding structure underwent a large amount of deformation,resulting in the detachment of the angle brace of the northern end well,the breaking of the end wall,and lateral sliding.This article first uses finite element simulation to analyze the reasons for the failure of internal braces,and provides a detailed understanding of the working state of internal braces and retaining structures under the condition of low soil strength in the foundation pit.It is found that the safety factor of internal braces is relatively small,and the mechanical reasons for the failure are the significant deformation of the retaining piles.Then,a detailed description was given of the process of foundation pit rescue,and the restoration work was discussed.A technical plan for foundation pit restoration was proposed,which included reinforcing the outer layer of the foundation pit,establishing new retaining piles,excavating collapsed foundation pit soil,establishing new internal support structures and station structures,backfilling and reinforcing the slope soil outside the foundation pit.It is hoped that this plan can provide some reference for similar projects under similar conditions.

关 键 词：地铁基坑 内撑失效 强降雨 基坑修复 

分 类 号：TU753[建筑科学—建筑技术科学]