山岭隧道衬砌-减震层体系动力响应研究

Research on Dynamic Response of Lining-Damping Layer System in Mountain Tunnel

为了探寻隧道设置减震层时影响减震层减震性能的关键因素,建立了设置减震层的隧道有限元数值模型,将数值模型与振动台试验进行对比,验证了数值模型的可靠性。改变减震层设计参数和围岩条件,通过对隧道结构的主应变、相对变形率以及围岩的塑性区进行分析,研究不同参数条件下减震层的减震效果。结果表明:设置减震层后隧道加速度响应的传递函数在15~30 Hz频段范围内减小,说明减震层通过吸收地震波中的高频成分,减小地震波能量向隧道的传递,进而减小隧道的地震响应。参数分析结果表明:减震层弹性模量越小厚度越大,减震层的减震效果越加明显,但隧道结构的相对变形率也随之上升。相比于增加减震层厚度,降低减震层弹性模量对减震效果的提升更为显著。在坚硬围岩中的设置减震层相比于软弱围岩减震效果更显著。

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.