Nonlinear Seismic Damage Response Of Tunnel Structure Across Fault

A systematic study on the seismic theory and its application of tunnels across faults are presented in the dissertation. A numerical joint analysis model for dynamic interaction between surrounding rock and tunnel structure is proposed, which can take the influence of static loads into consideration. Nonlinear seismic damage responses of tunnels across faults in high-intensity earthquake zones are analyzed, and large-scale shaking table tests are conducted to study the damage mechanism and control of tunnels across faults under strong earthquake.Combined with computer simulation and shaking table tests, the main work of the dissertation is described as follows:(1) Damage information of tunnels in Dujiangyan-wenchuan highway after the Wenchuan earthquake are investigated completely. Furthermore, damage degree on tunnels across faults, including Jiujiaya Tunnel, Zipingpu Tunnel, Longdongzi Tunnel and Longxi Tunnel, are evaluated and lessons learnt from seismic damage are presented at last.(2) A unified infinite element boundary method for static and dynamic analysis is proposed based on the infinite element theory and corresponding subroutine is implemented based on the ABAQUS platform.(3) Subroutine of Lee's rate-dependent damage model based on the ABAQUS platform is implemented, which takes into consideration the dynamic effect (the strengthening effect of strain rate & the weakening effect of damage). Nonlinear seismic damage analysis of tunnels across faults are performed based on the subroutines of unified infinite element boundary and Lee's rate-dependent damage model. Damage distribution and development of tunnels under strong earthquake are hereby presented. Moreover, energy time-histories of input waves are analyzed using Hilbert-Huang Transform spectrum technology.(4) Damage index and energy index for seismic assessment of tunnels are proposed, by whcih the seismic vulnerable area and progressively damage process of tunnels can be obtained. And more, Seismic layer is proposed based on the concept of flexibility ratio and validated effective. Seismic layer is hereby applied to practice. (5) Dynamic response and damage configuration of tunnels across faults under strong earthquake action are conducted by shaking table tests. The effectiveness of seismic layer are also analyzed.