SEISMIC ANALYSIS AND PERFORMANCE EVALUATION OF SHIELD TUNNELS IN TRANSVERSE DIRECTION

This paper deals with several key issues in seismic analysis and seismic performance evaluation of shield tunnels by means of response displacement method. The rationality of the existing computation method for site soil parameters is verified. The formulation of soil spring stiffness is proposed, which accounts for the depth of tunnels. According to the soil-structure interaction principle, the way to apply seismic displacement and shear loading of soil is presented. Based on the above research results, seismic analysis of shield tunnel in different site soils is conducted, using a beam-spring model which takes the tensile, shearing and flexural performance of joints into account. According to the characteristic of seismic response of shield tunnels, it is suggested that segment stress, joint deformation and flexural bearing capacity, are key performance indexes to evaluate the endurance, serviceability, and seismic safety of a shield tunnel. It is also benefit in improving the response displacement method and promoting the application of this method in seismic design and evaluation of shield tunnels in the frame of performance-based design philosophy.