盾构隧道穿越河流最小覆土厚度及沉降研究

Study on Thickness and Settlement of Minimum Covering Soil of Shield Tunnel Crossing River

为解决盾构隧道穿越河流由于浅覆土层引起的施工地层扰动的问题,以及由于同步注浆量、掘进压力导致地层沉降的问题,基于常州地铁二号线一期工程实际情况,结合抗浮稳定的方法求解盾构隧道下穿河流所需最小覆土厚度,同时运用ABAQUS建立三维有限元分析模型,验证计算结果的正确性。基于最小覆土厚度计算结果,通过对不同注浆量、不同掘进压力下的沉降情况对比,提出有效的控制方法。结果表明,该区间所需最小覆土厚度为9.13 m,且同步注浆量越大,地表沉降越大,掘进压力越大,地表沉降越小。所得结论可为盾构隧道穿越河流施工提供一定的参考。

In order to solve the problem of construction stratum disturbance caused by shallow overburden layer of shield tunnel crossing river,and the problem of stratum settlement caused by synchronous grouting volume and tunneling pressure,this paper is based on the actual situation of Changzhou Metro Line 2 Phase I project,combined with the method of anti-floating stability,this paper solves the minimum soil thickness required for the shield tunnel to pass through the river.At the same time,ABAQUS is used to establish a three-dimensional finite element analysis model to verify the correctness of the calculation results.Calculation based on minimum soil thickness,an effective control method is proposed by comparing the settlement conditions under different grouting volumes and different tunneling pressures.The results show that the minimum required soil thickness of this interval is 9.13 m,and the larger the synchronous grouting amount,the larger the ground settlement,the larger the tunneling pressure and the smaller the ground settlement.The conclusions obtained can give a certain reference for the construction of shield tunnels crossing rivers.