In order to investigate the influencing laws of shield construction on the structure and stratum deformation of the existing tunnels,this paper took the proposed Shijiazhuang Metro Line 5 undercrossing the existing six-line tunnel of Beijing-Shijiazhuang Expressway as the engineering background,formulated the stratum and structure model test materials based on the geometric similarity ratio,and designed the test monitoring system.The construction process of shield tunnel undercrossing the existing six-line tunnel at different depths was experimentally simulated using a small shield tunneling machine with the diameter of 1,200 mm.The settlement and deformation laws of the existing six-line tunnel and the soil layer during the undercrossing process was also analyzed.The results show that the settlement of the stratum decreases with the increase of the distance between the bottom strata of the existing tunnel and the shield tunnel vault.The influence range of shield construction on the stratum is about 1.5 times of the tunnel diameter,and the significant impact area is 1 time of the tunnel diameter.With the increase of the burial depth,the settlement of the stratum below the structure caused by the shield construction decreases.The maximum difference in settlement when the distance from the shield tunnel vault is 1 and 1.5 times of the tunnel diameter is 31.25％.The existing six-line tunnel and the stratum underneath the structure are decoupled,and the settlement of the stratum in the stage of the shield tail decoupling is greater than 80％.
关键词
地铁/盾构施工/下穿既有隧道/模型试验/沉降规律/埋深
Key words
Shield tunnel construction for metro/Undercrossing existing tunnel/Model test/Settlement law/Buried depth
维普
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