隧道横穿高烈度地震区滑坡衬砌减震效果评估方法试验研究

Experimental study on the evaluation method of damping effect of linings in tunnel crossing landslides in high-intensity seismic zone

为评价高烈度地震区滑坡隧道减震结构的减震效果,利用振动台模型试验测试,得到不同强度地震波作用下试验模型的加速度和动应变等数据信息;结合试验模型宏观灾变变形特征,采用多指标评估方法,揭示隧道减震结构区域性空间动力响应特征;基于弹塑性效应定义隧道结构塑性减震系数(PDC),阐明隧道结构的损伤演化规律。研究结果表明:(1)滑坡体破坏表现出区域性损伤破坏的连续性,隧道结构的损伤部位存在区域性差异;(2)隧道结构不同位置的加速度、速度和位移到达峰值的次数和时间存在差异,隧道结构局部及整体的动态响应受不同频段地震波的影响;(3)海绵橡胶材料作为隧道衬砌减震层具有良好的减震效果,但不会改变隧道结构受损变化的形式和频谱响应特性;(4)隧道结构的损伤破坏具有明显的累积效应,整个过程可分为弹性变形阶段、弹塑性变形阶段和塑性变形阶段,实际隧道工程抗减震设计应防止隧道结构过早进入塑性变形阶段。研究成果可为高烈度地震区隧道穿越滑坡区的变形机理及防控措施设计提供一定的理论参考。

To evaluate the seismic reduction effect of damping structures in landslide tunnels located 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 characteristics of the tunnel damping structure.Using the elastoplastic effect,the plastic damping coefficient 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 noticeable 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 tunnel 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 deformation.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 theoretical reference for understanding the deformation mechanisms and developing prevention and control measures for tunnels crossing landslides in high-intensity seismic zones.