Study on Influence of Construction Process of Double-Line Shield Tunnels on Frame Structure

This paper presents a study of the influence on stress and deformation of the frame structure induced by double-line shield tunnels during tunneling. Using the finite element software MIDAS/GTS, the construction process of double-line shield tunnels passing through the adjacent frame structure with a strip foundation was simulated. By comparing the ground settlement monitoring data of a building passing through Changsha Metro Line 2 with the numerical simulation results, it is found that the Midas GTS/NX finite element analysis is reliable and can be used to predict the impact of shield tunneling on the frame. The location and construction sequence of double-line shield tunnels were varied to investigate the response of frame structure. The results of the analysis are as follows: (1) the position and value of the maximum stress of the frame structure are different in different excavation locations. Under the condition that the left tunnel passes under the frame structure and the right tunnel passes through from the side of the frame structure, the maximum stress of the frame structure has the minimum. (2) The frame structure inclined towards the tunnel when double-line tunnels pass-through from the side of the frame structure. Under the condition that the left tunnel passes under the frame structure and the right tunnel passes through from the side of the frame structure, the frame structure produced the longitudinal inclination. (3) The maximum settlement of the strip footings locates the-axis position when double-line tunnels pass-through from the side of the frame structure. The maximum settlement of the strip footings locates the-axis under the condition that the left tunnel passes under the frame structure and the right tunnel passes through from the side of the frame structure. The maximum settlement of the strip footings locates the-axis position when the double-line tunnels pass under the frame structure. (4) Under the condition that the double-line tunnels pass-through from the side of the frame structure, the impact of different construction sequences on the frame structure is slightly different. The construction sequence of the synchronous excavation of two lines in the opposite direction is more likely to cause that the frame structure inclines to the tunnel during tunneling.