Experimental study of the coupling effect on segmental shield tunnel lining under surcharge loading and excavation unloading

摘要

? 2023 Elsevier LtdSurcharge loading and excavation unloading are two common engineering disturbances affecting the adjacent tunnel in congested urban areas. The coupling effect on segmental shield tunnel lining under loading and unloading conditions is still unclear. In this paper, physical model tests conducted in 1-g plane strain conditions were designed and performed to study the coupling effect of loading and unloading on shield tunnel. The results show that the response of segmental shield tunnel linings will be significantly amplified under the coupling conditions compared with the individual disturbance. A coupling effect index was proposed to evaluate the coupling degree of different disturbances. The classification was also presented, divided into favourable, zero, and unfavourable coupling effects. The tunnel response has a more significant coupling effect in the case of loading first and unloading later. There is a coupling amplification effect of 128% and 144% for the tunnel horizontal convergence and the springline near the excavation.