Dynamic response study of tunnels with seismic isolation layers under random earthquake excitations
An updated spectral representation method was utilized to generate random ground motions,and tunnel models incorporating various seismic isolation layers were established for dynamic response analysis.The variations in two deformation indicators,the inclination angle and the diameter deformation rate of the tun-nel,under typical seismic motion were compared with those under random seismic motion.By developing a probability density evolution model for the deformation indices,the impact of isolation layers on the probabili-ty density evolution process of the tunnel inclination angle was evaluated under various conditions.Structural inclination angle limits were selected as evaluation criteria,and cumulative distribution function curves were employed to assess the influence of different seismic isolation layers on the seismic reliability of the tunnel.The findings indicate that seismic isolation layers do not alter the overall trend of the deformation indices under random ground motion,while they significantly reduce the overall mean values.For a given thickness of the isolation layers,the reduction in the inclination angle becomes more pronounced as the elastic modulus increa-ses,achieving a maximum reduction of 7.393％.Furthermore,seismic isolation layers make the deformation response of tunnels more stable and concentrated under random seismic conditions.With a constant thickness of the isolation layers,the effect becomes more pronounced as the elastic modulus increases.Additionally,the presence of isolation layers improves the structural reliability of tunnels subjected to random seismic motion.When the thickness of the isolation layers keeps constant,the improvement in reliability increases with the in-crease of elastic modulus values,reaching up to 6.236％.
stochastic ground motionseismic isolation layerprobability density evolutiondeformation indexseismic reliability
万方数据
维普
