Abstract: To investigate the rockfall impact resistance characteristics of shed tunnels with rubber particle cushions, similar model tests of shed tunnels with sand cushion and rubber particle cushion, as well as SPH-FEM coupled numerical simulation work, were carried out respectively. The mechanical response characteristics of shed roof and column structures under rockfall impact were explored. The research results demonstrate that the rubber particle cushion exhibits superior performance in inhibiting stress propagation. Compared to sand cushion, the peak strain values at the longitudinal N1 and transverse M1 positions of the shed roof with rubber particle cushion decreases by 28.54% and 30.02% respectively, while the peak compressive strain of the columns decreases by 65.47%. The numerical calculation results of the shed tunnel with actual on-site dimensions indicate that the reduction range of the peak stress is between 32.62% and 42.47% at the longitudinal N1~N4 positions and between 9.04% and 56.82% at the transverse M1~M6 positions of the shed roof with rubber particle cushion. The peak displacement reduction of the top plate web is 6.20%, the compressive stress reduction of the column is 36.61%, and the rockfall impact acceleration reduction can reach 34.91%. The rubber particle buffer cushion layer has obvious energy dissipation and shock absorption effects.

Key words: tunnel engineering; rockfall impact; rubber particles; buffer cushion layer; indoor experiment; SPH-FEM simulation

摘要： 为研究橡胶颗粒垫层棚洞防落石冲击特性，分别开展了砂土垫层、橡胶颗粒垫层棚洞相似模型试验及SPH-FEM耦合数值仿真工作，探究了落石冲击作用下棚洞顶板及立柱结构的力学响应特性。研究结果表明：橡胶颗粒垫层具有阻止应力传播的优越特性。相较于砂土垫层，橡胶颗粒垫层棚洞顶板纵向N1、横向M1位置应变峰值降幅分别达28.54%、30.02%，立柱压应变峰值降幅为65.47%。现场实际尺寸棚洞数值计算结果表明：橡胶颗粒垫层棚洞顶板的纵向N1~N4位置应力峰值降幅范围在32.62% ~ 42.47%，横向M1 ~ M6位置应力峰值降幅范围在19.04%~56.82%；顶板腹部位移峰值降幅为6.20%，立柱压应力降幅达36.61%，落石冲击加速度移降幅可达34.91%，橡胶颗粒缓冲垫层耗能减震效果明显。

关键词: 隧道工程；落石冲击；橡胶颗粒；缓冲垫层；室内试验；SPH-FEM仿真