Research on Dynamic Response of Lining-Damping Layer System in Mountain Tunnel
In order to explore the key factors that affect the damping performance of tunnels with damp-ing layers,a finite element numerical model for such tunnels was established.The model's reliability was verified by comparing with results from shaking table tests.By changing the design parameters of the damping layer and surrounding rock conditions,and analyzing the principal strain,relative defor-mation rate,and plastic zone of the tunnel structure,the layer's damping effects under different param-eters were studied.The results showed that the transfer function of the tunnel acceleration response de-creased within the frequency range of 15~30 Hz after the installation of the damping layer.It indicated that the damping layer reduced the transmission of seismic wave energy to the tunnel by absorbing the high-frequency components of the seismic waves,thereby reducing the tunnel's seismic response.Pa-rameter analysis indicated that a damping layer with a lower elastic modulus and greater thickness had a more pronounced damping effect.However,this also led to an increase in the relative deformation rate of the tunnel structure.Compared with increasing the thickness of the damping layer,reducing its elastic modulus could improve its damping effect more significantly.The damping layer was more ef-fective in hard surrounding rock than in soft surrounding rock.