悬挂法在大断面浅埋暗挖隧道施工沉降控制中的应用

Application of Suspension Method in Settlement Control During Construction of Large Cross Section Shallow Buried Tunnel

在大断面浅埋暗挖隧道施工中,地表沉降是保证施工安全及评价施工对环境影响的重要指标。针对哈尔滨地铁3号线浅埋暗挖隧道工程,提出了一种改进的有效控制沉降的施工方法——悬挂法。采用有限元法模拟分析了悬挂法施工过程中地表沉降、拱顶沉降及系杆轴力的变化规律,并与交叉中隔壁法和双侧壁导坑法的数值模拟结果进行了对比。结果表明:与交叉中隔壁法和双侧壁导坑法相比,采用悬挂法施工更能有效控制拱顶沉降和地表沉降,尤其在拆除中隔壁后地表沉降控制效果显著。经在哈尔滨地铁3号线进乡街站大断面隧道中试验,采用悬挂法施工地表最大沉降在15 mm以内。

In the construction of large cross section shallow buried tunnel,surface settlement is an important index to ensure construction safety and evaluate the impact of construction on the environment.Aiming at the shallow buried tunnel project of Harbin metro line 3,an improved construction method of effective settlement control was proposed,which is the suspension method.The finite element method was used to simulate and analyze the surface settlement,arch crown settlement and tie bar axial force during the construction process of suspension method,and the results were compared with the numerical simulation results of center cross diaphragm method and double sidewall heading method.The results show that compared with the center cross diaphragm method and double sidewall heading method,the suspension method is more effective in controlling the arch crown settlement and surface settlement,especially after the center cross diaphragm is removed.Through the test in the large section tunnel of Jinxiangjie station of Harbin metro line3,it is found that the maximum surface settlement is less than 15 mm by using the suspension method.