EPS颗粒-黄土混合土减震层对黄土地区隧道衬砌结构的减震作用

为了分析聚苯乙烯泡沫塑料（EPS）颗粒-黄土混合土减震层在不同条件下对隧道衬砌结构减震效果的影响，采用通用有限元软件ANSYS建立了在隧道支护体系内设置减震层的数值模型，分析了EPS颗粒掺入比、减震层厚度及地震动强度对隧道衬砌结构动力响应规律的影响。结果表明:设置减震层可以减小传递至隧道衬砌结构的地震能量，从而使得隧道衬砌结构各关键点正应力、剪应力、最大主应力、位移及加速度峰值均有所减小,且一定范围内随着EPS颗粒掺入比的增大，减震效果逐渐明显；减震层的厚度控制在30～50 cm区间内时减震效果最佳；减震层在强震作用下的减震效果更好，该混合土减震层更适合高烈度地震区的抗减震；所得结论可为今后在土体环境尤其是黄土地区开挖的隧道衬砌结构抗减震工程建设提供一定参考。

Damping Effect of Shock Absorption Layer of EPS Bead-loess Mixture to Tunnel Lining Structure in Loess Area

In order to study the damping effects of shock absorption layer of expanded polystyrene sphere （EPS） bead-loess mixture to tunnel lining structure under different conditions, the numerical model of damping layer in the tunnel support system was established using finite element software ANSYS. The influences of mixing ratio of EPS beads, damping layer thickness and seismic intensity on the dynamic responses of tunnel lining structure were analyzed. The results show that the seismic energy transferred to tunnel lining structure can be reduced by setting the damping layer, and the normal stress, shear stress, maximum principal stress, displacement and acceleration peak value of the key points of tunnel lining structure are reduced. The damping effect will be more and more obvious with the increase of the EPS bead content within a certain range. When the thickness of damping layer is controlled in the range of 30 50 cm, the damping effect is the best. The damping effect of damping layer is better under the action of strong earthquake, and the mixed soil damping layer is more suitable for seismic resistance of high intensity seismic zone. The research conclusion can provide reference for the later construction of damping engineering of tunnel lining structure in soil environment, especially in loess area.