Abstract：Based on improved Newmark¢s implicit integration method，the earthquake-induced dynamic responses of Galongla Tunnel along Zhamo Highway in Tibet are studied using infinite element dynamic artificial boundary technique；and aseismic mechanism of seismic isolation layer is analysed. Furthermore，the shock absorption effects of two kinds of seismic isolation layers，which are made of rubber and foam concrete respectively，are studied and compared those with numerical method. The results show that better shock absorption effects can be achieved because of the good isolation and cushioning effects of the seismic isolation layer despite that the dynamic response of the tunnel cannot be changed essentially. It also can be seen that there are small differences in shock absorption effects between two kinds of seismic isolation materials；however，foam concrete is recommended because of its durability and economy. Results of this research can provide certain references to stability analysis of underground engineering in highly seismic regions.
