非对称基坑开挖对浅埋下卧地铁隧道的影响

Influence of Asymmetric Foundation Pit Excavation on Shallow-buried Subway Tunnel Structure

地铁隧道里程数越来越长,近接地面工程建设对其安全影响不可忽视。为了研究地面工程建设对下卧地铁隧道的影响,采用数值分析方法建立三维模型,以基坑未开挖作为初始状态,分析了基坑降水、非对称基坑开挖和桩基荷载施加等过程的地铁隧道空间位移特征及结构受力特征。结果表明:基坑降水过程对下卧地铁隧道位移影响不明显,非对称基坑开挖会导致下卧地铁隧道结构整体产生上浮及偏移,桩基荷载施加后隧道会产生相应的下沉现象,但仍有残余位移;隧道受力结果表明,基坑降水对隧道受力影响也不明显,基坑开挖过程隧道受力逐渐增大且整体受力均匀,桩基荷载施加后隧道顶部和底部受力进一步增大,两边墙受力变化相对较小,受力整体呈椭圆形。研究结果可为确保类似工程施工安全提供借鉴。

The mileage of subway tunnel is getting longer and longer,the influence of close-spaced ground square construction can＇t be ignored. In order to study the influence of ground square construction on subway tunnel,numerical analysis method was used to establish a 3 D model. the unexcavated condition of foundation pit is taken as original state,the space displacement and stress of subway tunnel are analyzed in progress of dewatering,foundation pit excavation and load application. The results show that the progress of dewatering had little influence on displacement,the foundation pit excavation could lead the subway tunnel to floating or excursion,the subway way may sink after foundation load application; the results of stress show that dewatering had little influence on stress of subway tunnel,the stress may increase with the progress of foundation pit excavation,the stress of the top and bottom increased further after the foundation load application,but the stress of both side changed little,the shape of global stress was oval. The results can provide references for construction safety of similar project.