盾构隧道上覆溶洞对地表沉降的影响

Influence of overlying karst cave on ground settlement of shield tunnel

岩溶地层盾构隧道施工过程中,受溶洞影响,地层稳定性降低,地表沉降较大。通过数值模拟与现场实测等方法分析了岩溶分布、形态对地表沉降的影响规律。研究得出:上覆溶洞会增大对周边土体的扰动范围,且溶洞越长、越高,溶洞与隧道间距越小,地表沉降越大,溶洞长度对地表沉降影响最大;同时,济南地铁R4线工程监测结果表明,当地表沉降过大时,注浆加固可减小岩溶地层的沉降。研究成果可以为岩溶地层盾构施工地表变形预测、风险评估及处理提供依据。

In the construction process of shield tunnels in karst formations,the stability of the strata is compromised,resulting in significant surface settlement due to the influence of solution caves.This study utilized methods such as numerical simulation and on-site measurements to analyze the impact of karst distribution and morphology on surface settlement.The research concludes that overlying solution caves increase the disturbance range on surrounding soil.Furthermore,as the caves become longer and higher with smaller spacing from the tunnel,surface settlement increases,with cave length having the greatest impact.Simultaneously,monitoring results from the Jinan Metro R4 Line project indicate that,in cases of excessive surface settlement,grouting reinforcement can reduce the settlement of karst formations.The research findings can serve as a basis for predicting surface deformation,risk assessment,and treatment in shield tunnel construction in karst formations.