软弱地层基坑开挖对下卧集群隧道影响分析

Analysis of the Impact of Excavation in Weak Strata on the Underlying Cluster Tunnel

基坑开挖引起土层应力重分配,尤其是软弱地层基坑开挖引起的土体卸荷会导致下卧隧道发生隆起变形。依托工程实例,通过有限元分析研究软弱地层基坑开挖对下卧集群隧道的影响,确定隧道上方软弱地层基坑开挖关键技术方案。通过对比分析,对区间隧道上方地层进行预处理后,通过严格遵循分区、分块、分层、对称、限时的开挖原则,能有效保障下卧集群隧道的安全。

Excavation of foundation pits causes stress redistribution in soil layers,especially in soft and weak strata where soil unloading can lead to uplift and deformation of the underlying tunnel.Based on engineering examples,this study uses finite element analysis to investigate the impact of excavation of weak foundation pits on the underlying cluster tunnel,and determines the key technical solutions for excavation of weak foundation pits above the tunnel,providing reference for similar projects.Through comparative analysis,it can be concluded that after preprocessing the strata above the interval tunnel,strict adherence to the excavation principles of zoning,blocking,layering,symmetry,and time limit can effectively ensure the safety of the underlying cluster tunnel.