地铁近距离平行隧道有限元数值模拟

对近距离双孔平行隧道，不同的开挖顺序会有不同的结果，第二孔隙道是在第一孔隧道扰动之后的地层中修建的，地层刚度条件不再对称，第二孔隧道的修建又对已建的第一孔隧道有影响，这一影响又与围岩类别，隧道间的间距，开挖和支护方式等因素有关，应用ANSYS程序对这些因素进行了分析，揭示了这类隧道在开挖之后地表和拱顶下沉的规律。分析表明，第二孔隧道的掘进对已修建的第一孔隧道有较大的影响，这时的分析即不同于单孔隧道，也不同于交错重叠隧道。

2D FEM NUMERICAL SIMULATION FOR CLOSELY-SPACED PARALLEL TUNNELS IN METRO

For the utility of underground space,the number of closely spaced two-tube tunnels gets more and more. Different excavation sequence makes the results different. The second tunnel is constructed in the ground disturbed by the first one,so that the ground stiffness is unsymmetrical. The construction of the second tunnel has effect on the first excavated one,which is related to the distance between two tunnels and the method of excavation and lining. The ANSYS program is used to analyze the laws of the settlements of the surface and arch,under the conditions of different distances between tunnels and different methods of excavation and lining. The results show that the excavation of second tunnel has significant effect on the first tunnel.