Seismic damage mechanics and vulnerability analysis for the immersed tunnel subjected transverse earthquake records

For evaluating the post-earthquake failure probability of the immersed tunnel of Hong Kong-Zhuhai-Macao Bridge subjected transverse earthquake loading. A two-dimensional (2-D) finite element model considering the water-soil-tunnel interaction has been built based on the Abaqus software platform, and a more refined threedimensional(3-D) model was built to examine the preciseness of the 2-D model in calculating the displacement response of immersed tunnel. The seismic damage evaluation of immersed tunnel was presented based the numerical analysis results of 3-D model, and it indicated the IDR is significant related to the damage level of tunnel. The inter-story drift ratio limits of immersed tunnel were defined based on the seismic performance curve obtained from the Pushover analysis. The non-linear dynamic analysis was performed for the 2-D model subjected different amplitude-modulated earthquake records according to the incremental dynamical analysis (IDA) procedure. The IDA curve cluster and corresponding 16 %, 50 %, 84 % percentile lines were plotted by defining the damage measure as the inter-story drift ratio, and employing the PGA to describe the intensity measures. The probability of the immersed tunnel exceeding different seismic performance level subjected different earthquake intensity have been given, and the finding shown the immersed tunnel perform enjoying good seismic performance.