大型地下结构下修建盾构隧道模型试验

Model Test of Constructing Shield Tunnel under Large Underground Structure

采用三维相似模型试验,研究了在南京玄武湖公路隧道下新建地铁盾构隧道时,两重叠隧道间的相互影响.试验结果表明:盾构隧道施工对玄武湖隧道周围土体的扰动十分有限,不会产生因下方土体变形过大导致玄武湖隧道出现“漂移”现象;对玄武湖隧道下方土体进行加固和加设抗拔桩后,结构附加内力和变形值明显减小;地表下沉很小,不会造成路面结构破坏.最后,用有限元计算进行了对比分析,表明盾构隧道施工中,玄武湖隧道和盾构隧道是安全的,不需进行特殊处理.

A 3D model test was carried out to investigate the interference when a metro tunnel is excavated with the shield method under an existing underground structure, the Xuanwuhu tunnel in Nanjing City. The experimental results show that the construction of the shield tunnel has a slight effect on the Xuanwuhu tunnel is and large deformation to lead to the “excursion” of the Xuanwuhu tunnel does not occur. Under the conditions of setting uplife piles and reinforcing the ground below the Xuanwuhu tunnel, the additional deformations and internal forces are obviously reduced. In addition, the settlement of ground is small, so pavement structures can not be destroyed. Finally, to compare with the experimental result FEM （finite element method） was used. The numerical simulation result shows that both the Xuanwuhu tunnel and the shield tunnel are safe during the construction of the shield tunnel, and special measures are needed.