RESEARCH ON CONSTRUCTION MECHANICS OF OVERLAPPING TUNNELS
重叠隧道的施工力学研究

Overlapping tunnels have emerged in facilitating the underground space utilization. The initial stresses in ground will be changed by the first excavation, and the ground stiffness is no longer symmetrical to the vertical single tunnel axis because of the adjacent lined tunnel in the ground. The construction of the second tunnel has effect on the first constructed tunnel. ANSYS program is used to analyze three typical sections of overlapping tunnels of the first-phase of the project of Shenzhen metro. Analysis results show that the settlement of surface and arch and the stability of soil between two tunnels are difficult to control, and the settlement of upper tunnel occurs easily.