Active Earth Pressure on the Rigid Support Structures of Excavations Parallel to Tunnel Construction.

The failure mode of the soil behind the rigid support structure of excavations parallel to tunneling was simulated using the adaptive finite-element limit analysis method. This study showed the effects of tunnel diameter, tunnel construction clear spacing, excavation insertion ratio, and soil strength on the failure mode of the soil. Based on the simulated results obtained from finite-element software, a stress field was constructed for the portion above the horizontal plane at the bottom of the excavation support structure. Three types of boundary value problems were solved based on different regional divisions. Eventually, the stress state at any point within the plastic zone was calculated, providing the active earth pressure on the support structure adjacent to the tunnel during its construction. A comparison between the stress characteristic method calculation results and the finite-element simulation results showed consistency, confirming the efficiency and accuracy of the stress characteristic method in calculating the earth pressure on the support structure of excavations parallel to tunneling. [ABSTRACT FROM AUTHOR]