Seismic Fragility Analysis of Submarine Immersed Tunnel Based on Vector-valued Intensity Measure

In order to reasonably evaluate the seismic performance of the submarine immersed tunnel,the seismic fragility analysis of immersed tunnel based on vector-valued intensity measure is carried out,and fragility surfaces of immersed tunnel are established with the maximum inter-story drift ratio and energy ratio as damage measures.Taking the Hong Kong-Zhuhai-Macao immersed tunnel as the research object,and 4 typical intensity measures are comprehensively evaluated by using three methods:efficiency,practicability and proficiency.Considering the uncertainty of earthquake,the incremental dynamic analysis of immersed tunnel is carried out.The probabilistic seismic demand model is obtained by using regression analysis method,and then the seismic fragility surfaces of immersed tunnel with different damage measures are established.The efficiency of vector-valued intensity measures and scalar-valued intensity measures are compared and analyzed.The results show that the seismic fragility analysis based on vector-valued intensity measures can reasonably reflect the influence of two intensity measures on the failure probability of immersed tunnel.The efficiency of seismic fragility analysis based on vector-valued intensity measures is higher.Vector-valued intensity measures can better reduce the dispersion of response prediction of immersed tunnel and improve the prediction accuracy of seismic performance of immersed tunnel.