不规则基坑开挖导致紧邻地铁隧道附加应力的计算

Calculation of Additional Stress of Metro Tunnel Caused by Adjacent Irregular Foundation Pit Excavation

对于城市运营地铁线上方新建建筑物的工程,基坑开挖导致隧道受到卸载附加应力,严重的将影响隧道的安全。基于Mindlin解,借助Mathematica数学软件,首先计算矩形基坑坑底竖直卸载和坑壁水平卸载引起紧邻地铁隧道的附加应力值,进而分析隧道走向、隧道-基坑夹角、基坑开挖深度对隧道附加应力场的影响规律;最后以运营重庆地铁一号线七星岗地铁车站上方开挖罗宾森广场基坑为工程背景,计算了不规则形状基坑开挖作用下地铁隧道轴线上附加应力分布。本研究成果是进一步研究不规则形状基坑开挖导致隧道结构内力和变形的基础。

New buildings often located above the urban metro tunnel in operation,the unload additional stress caused by foundation pit excavation may damage the safety of tunnel. With the help of Mathematica software,firstly,additional stresses of metro tunnel caused by vertical and horizontal unloading of adjacent foundation pit excavation were respectively calculated by Mindlin solutions. Then,the law of factors influencing the additional stress field was analyzed; and the factors were considered including ordination of tunnel,angle between tunnel and foundation pit,excavation depth of foundation pit. Finally,taking the excavation of Chongqing Luobinsen square foundation pit above metro line 1 in operation as an engineering background,the distribution of additional stress along tunnel axis caused by the irregular foundation pit excavation was calculated out. The above research results provide certain basis for further research on the internal forces and deformation of tunnel caused by the irregular foundation pit excavation.