Inelastic dynamic analysis and damage assessment of a hydraulic arched tunnel under near-fault SV waves with arbitrary incoming angles

摘要

The incoming directions and incoming angles of near-fault (NF) seismic waves may play important roles in potential seismic-induced damage to hydraulic arched tunnels due to the uncertainty and randomness of NF ground motions. Moreover, the correlation between the seismological characteristics of NF ground motions and the seismic behaviour of underground structures, especially hydraulic arched tunnels, is not well understood. However, the current seismic dynamic analysis procedures and seismic designs of hydraulic arched tunnels generally ignore the abovementioned key factors. For this reason, the focus of this paper is to evaluate the seismic behaviour and damage degree of a hydraulic arched tunnel under NF SV waves with arbitrary incoming angles. Based on the elasticity and wave theory, an obliquely incoming method of SV waves that considers the incoming angle and direction is first developed by the equivalent nodal force method and verified through two examples. Ten as-recorded NF seismic events that display ground motion with a high frequency content are selected to reflect the seismological characteristics of NF ground motions. In addition, a hydraulic arched tunnel is built using the commercial software ABAQUS, and it considers fluid-structure-rock interaction systems based on the coupled Eulerian-Lagrangian method to approximate the environmental conditions experienced by hydraulic arched tunnels when a real earthquake event occurs. Subsequently, an inelastic dynamic analysis of hydraulic ached tunnels under NF SV waves with arbitrary incoming angles are conducted. The numerical results indicated that the propagation directions and incoming angles of SV waves have notably different impacts on the inelastic dynamic responses and damage degrees of hydraulic arched tunnels. In addition, by comparison with our team's previous work, it can be found that obliquely incident SV waves may be more likely to cause severe damage to hydraulic ached tunnels compared to obliquely incident P waves. On the other hand, significant durations and velocity-related intensity measures present strong correlations with the global tensile damage index of the linings of hydraulic arched tunnels. Therefore, both the incoming angles of SV waves and the seismological characteristics should be considered when evaluating the seismic performance and design of hydraulic arched tunnels.