To study the energy dissipation mechanism of fractured zone and its influence on dynamic response of underground tunnels

a calculation model of dynamic response of the tunnels in type Ⅳ rock mass is established under the ground shock.The dynamic response of underground tunnels with and without fractured zones are calculated by the FEM software LS-DYNA. The final results show that the dynamic parameters such as acceleration and displacement are attenuated to some certain extent if fractured zone exsists in the roof

but the peak value of stress of tunnel will be insignificantly affected. On the contrary

the dynamic parameters such as acceleration and displacement increase evidently if fractured zone exists in the lateral side of tunnel.The peak value of stress and dynamic parameters of tunnel with lateral fractured zone are larger than those with overhead fracturer zone.The former is more disadvantageous to the safety of tunnel construction.