Experiments on the seismic performance of Y-shape joints of subway stations built by enlarging two parallel shield tunnels

Abstract

To improve the seismic performance of subway stations built by enlarging two parallel shield tunnels, joints of special structures between prefabricated open-loop segments and cast-in-site main station structures were proposed. Experiments on the low-frequency cyclic loading of full-scale models of joints under different structural configurations werecarriedout. The seismic performance, such as the load–displacement hysteresis curves, skeleton curves, structural ductility, strength degradation, energy dissipation, strain of the cable-stayed bars and failure modes, were studied. The results showed that compared with the pre-embedded connector joint, the pre-embedded steel plate joint had advantages in terms of the mechanical stability, intensity, stiffness, energy dissipation capacity and ductility performance. However, the relative displacement between the segment and wall column of the pre-embedded steel plate joint was larger than that of the pre-embedded connector joint. Both types of joints had a full hysteretic circle, good ductility nature, energy dissipation ability, and stable elastic and elastic–plastic deformation. The cable-stayed bars did not yield in the stretch area when the joints failed. Both of the joints could meet the performance requirements of strong joints and weak components.