Experimental study on the evaluation method of damping effect of linings in tunnel crossing landslides in high-intensity seismic zone
To evaluate the seismic reduction effect of damping structures in landslide tunnels loca-ted in high-intensity seismic areas,a shaking table model test was performed.This test measured the acceleration and dynamic strain of the model under seismic waves of varying intensities.By combining these measurements with the observed macroscopic deformation characteristics,a multi-index evaluation method was used to reveal the regional spatial dynamic response character-istics of the tunnel damping structure.Using the elastoplastic effect,the plastic damping coeffi-cient of the tunnel structure was defined to clarify the damage evolution law.Key results from the study include:(1)Landslide failure exhibits continuous regional damage and failure,with notice-able differences in the sites of tunnel structure damage.(2)There are differences in the number and timing of acceleration,velocity,and displacement peaks at different positions within the tun-nel structure.These local and overall dynamic responses are affected by seismic waves of different frequency bands.(3)The use of sponge rubber material as a damping layer for the tunnel lining shows damping properties but does not change the form of tunnel structural damage or spectral response characteristics.(4)Tunnel structure shows an obvious cumulative effect,which can be divided into three stages:elastic deformation,elastic-plastic deformation,and plastic deforma-tion.Anti-seismic designs for actual tunnel projects should aim to prevent the tunnel structure from prematurely entering the plastic deformation stage.The research results provide a theoreti-cal reference for understanding the deformation mechanisms and developing prevention and con-trol measures for tunnels crossing landslides in high-intensity seismic zones.
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