Abstract: The damage evolution laws and the envelope characteristics of seismic response of tunnel crossing rock-soil interface under strong earthquake were studied with the large-diameter river-crossing highway-and-subway-combined shield tunnel built in Sanyang road, Wuhan city as research background. A model composing twin tunnels (containing inner components: horizontal highway plate and vertical partition plate) and soil was established using the dynamic finite element numerical platform in ABAQUS. The dynamic viscoelastic model, modified Davidenkov model, was employed to model the characteristics of soil, while the concrete damage plasticity model was adopted to model the fracture and damage of tunnels. Results revealed abrupt changes in the acceleration, displacement, and stress response of shield tunnel lining in the vicinity of rock-soil interface. Due to the existence of rock-soil interface, the haunch of tunnel is destroyed first, and then the joints of inner components and at last the spandrel. The seismic damage of haunch mainly occurred in the soft soil part. The inner components reduced the horizontal shear stress at both sides of the large-diameter tunnel.

Key words: shield tunnel, rock-soil interface, damage evolution law, seismic response envelope, strong earthquake