full-scale experimental study on the effect of ground surcharge on the stress and deformation of shield tunnels

To explore the internal force and deformation response law of the hangzhou subway shield pipe structure under engineering perturbations such as overhead loading, a self-developed “shield segment hydraulic loading system” was used to carry out a full-size loading test on a three-ring staggered segment. the influences of the lateral earth pressure coefficient, different loads under symmetric loading, and deviated load distance on the internal force and deformation of the shield tunnel segment are analyzed. additionally, the transfer coefficient of the pipe sheet moment and the transverse stiffness were analyzed. the results show that the segment deformation and internal force decrease with the increasing lateral earth pressure coefficient. under symmetric working conditions, the internal force and the deformation of the pipe sheets show different degrees of increase with a continuously increasing pile load above the tunnel. the internal force and deformation of the tubular sheets decrease gradually with increasing deflection distance, and the maximum convergence values of the tubular sheets are centered at 30° and 90°. the distribution of the number of mismatches in the results and the sensitivity to affecting factors differ significantly between the internal force and deformation. the bending stiffness increases with the increasing lateral soil pressure coefficient and pile load but decreases with increasing eccentric pile distance. the moment transfer coefficient has an approximately inverse relationship with the bending stiffness effective rate.