STUDY ON THE STRESS OF TUNNEL PORTAL LININGS UNDER FAULT RUPTURE SEISMIC LOADING
Near-fault seismic motions have a significant impact on the seismic response and failure of engineering structures.To study the effects of near-fault seismic motions on the seismic response of tunnel portal linings,this re-search uses an experimental highway tunnel in the western region as a case study.The study employs extended finite element technology and dynamic implicit solving methods to simulate the cracking process of tunnel portal linings under near-fault seismic motions.The results indicate that under the action of vertically propagating shear seismic waves,the tunnel lining primarily experiences bottom bulging and inward deformation at the arch shoulders.Crack-ing first occurs at the arch shoulders where the tensile limit is reached,leading to a reduction in the load-bearing ra-tio of the arch shoulders and an increase in the load-bearing ratio of the arch bottom.Subsequently,the arch bottom also reaches its tensile limit and experiences cracking.The findings provide a foundation for the rational design of tunnel portal linings under near-fault seismic conditions.
tunnel portal liningnear-fault ground motionseismic responsecracking of lining