潮汐对海底隧道工作面稳定性的影响研究

Research on the Influence of Tide on the Stability of Subsea Tunnel Face

潮汐作用下水位变化触发海床地层应力的重分布,影响海底隧道施工中工作面围岩的稳定性。以青岛胶州湾第二海底隧道为工程背景,采用多相大变形数值计算方法—物质点法,分析了潮汐作用下水位变化对隧道开挖工作面围岩的破坏响应。通过数值模拟与现场监测数据的对比,验证了物质点法数值模拟方法的可行性。通过模拟196组不同围岩等级下的水位变化,探究海床沉降、围岩变形、塑性破坏区的分布和特征。结果表明:水位降低会增大施工期间隧道工作面的变形;水位变化与不良围岩参数的组合是隧道工作面失稳的关键,并得到了16组诱发工作面大变形失稳的参数组合。

Tidal induced variations in water levels trigger the redistribution of stress in the seabed strata,impacting the stability of the surrounding rock mass during subsea tunnel excavation.Set the Second Subsea Tunnel in Jiaozhou Bay,Qingdao as engineering background,a multiphase large deformation numerical calculation method,Material Point Method,is employed to analyze the destructive response of the tunnel face's surrounding rock mass under tidal influences.Through a comparison between numerical simulations and on-site monitoring data,the feasibility of the Material Point Method for numerical simulation is validated.By simulating water level changes for 196 groups with varying rock mass grades,the study investigates the distribution and characteristics of seabed settlement,rock mass deformation,and the plastic failure zone.The results indicate that:A decrease in water level amplifies the deformation of the subsea tunnel face during the construction period.The combination of water level changes and unfavorable rock mass parameters is identified as a critical factor leading to instability in the subsea tunnel face,revealing 16 sets of parameter combinations that induce significant deformation instability in the tunnel face.