大直径盾构隧道下穿浅基础砖混房屋结构安全性影响研究  

Research on the safety impact of large diameter shield tunnels underpassing shallow foundation buildings

作　　者：吴奇帆 曾灿军 WU Qifan;ZENG Canjun(China Construction Infrastructure Co.,Ltd.,Shenzhen Guangdong 518000,China)

机构地区：[1]中国建设基础设施有限公司,广东深圳518000

出　　处：《现代城市轨道交通》2024年第10期100-106,共7页Modern Urban Transit

基　　金：中国建设基础设施有限公司基础课题(CSCIC2022KT(01));广州市科技计划项目市校联合资助项目(202102010456)。

摘　　要：地铁盾构不可避免地穿越城市建(构)筑物,施工扰动对既有结构影响重大,尤其对浅基础砖混房屋结构,一定程度上改变房屋内部应力分布,影响结构安全,需重点关注。文章以深圳地铁穿越浅基础砖混房屋为研究背景,采用数值模拟与现场实测对比分析的方法,探究大直径盾构穿越施工对土体沉降规律及由此引发的房屋应力重分布的现象。研究发现,左、右线穿越时,房屋监测点均呈阶梯式变化;左线掘进时,靠近隧道中线的左侧房屋沉降最大;右线掘进时,最大沉降集中在右侧房屋。房屋基础不均匀沉降导致靠近隧道中线侧的房屋中隔墙、外墙出现应力集中。受到左线盾构掘进影响,房屋承载中心向隧道侧偏移,而右线掘进时应力集中出现在靠近双线叠加区外墙侧。基于沉降和应力2项控制指标,提出房屋安全系数评价方法,发现右线掘进对房屋安全系数影响较大,将降低房屋安全系数,需加强监测和及时加固。The metro shield inevitably passes through urban buildings,and the construction disturbance has a significant impact on existing structures,especially on shallow foundation brick and concrete building structures,changes the internal stress distribution of the building to a certain extent,and affects structural safety,requiring special attention.This article takes the crossing of shallow foundation brick and concrete houses by Shenzhen metro as the research background,and uses numerical simulation and on-site measurement comparison analysis methods to explore the settlement principle of soil and the phenomenon of stress redistribution caused by large diameter shield construction.Research has found that when the left and right lines cross,the monitoring points of the houses change in a stepped manner;when excavating on the left side,the houses on the left side near the centerline of the tunnel would experience the largest settlement;when excavating on the right side,the maximum settlement is concentrated in the houses on the right side.Uneven settlement of the building foundation leads to stress concentration on the partition walls and exterior walls near the centerline of the tunnel.Affected by the left line shield tunneling,the center of the building's load-bearing capacity is offset towards the tunnel side,while stress concentration occurs near the outer wall of the double line overlay area during the right line tunneling.Based on the two control indicators of settlement and stress,a method for evaluating the building safety factor is proposed.It is found that the excavation on the right side has a significant impact on the building safety factor,which will reduce the building safety factor.Therefore,it is necessary to strengthen monitoring and carry out timely reinforcement.

关 键 词：大直径盾构 穿越房屋 数值模拟 沉降变形 房屋安全系数 

分 类 号：TU455.43[建筑科学—岩土工程]