破碎带对地下坑道动力响应影响的数值分析

为了研究破碎带的耗能作用及其对坑道结构动力响应的影响,根据某工程实例,建立了地冲击波作用下类岩体中坑道结构响应的计算模型,利用LS-DYNA3D有限元软件,分别计算了无破碎带和存在破碎带情况下坑道结构的动力响应。计算结果的对比分析表明,顶部破碎带使结构的加速度和位移等运动参数有不同程度的降低,但对结构所受到的应力影响不大;与之相反,侧部破碎带的存在使结构的加速度和位移等运动参数明显地增大。与顶部存在破碎带情况相比,侧部存在破碎带情况下坑道结构运动参数的峰值更大,对坑道结构安全更为不利。

Numerical Analysis of the Effect of Fractured Zone on Dynamic Response of Underground Tunnels

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 N 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.