高地震烈度区岩体地下洞室动力响应分析

 考虑地震荷载特征及地下洞室的特点，利用动力时程分析法，对金沙江两家人水电站地下厂房洞室进行地震动力响应分析。研究自然地震波作用下，有无衬砌工况下的厂房洞室相对位移、点安全系数变化趋势，分析地震波穿越地下洞室时位移变化规律及厂房洞室衬砌抗震效果。结果发现：地震波传播除了受介质、结构面分布的影响外，还受岩体洞室面的影响，洞室自由面附近岩体的振动强度被放大；地下洞室断面质点最大相对位移、点安全系数波动规律与地震波谱相似；地下洞室壁及F4断层未出现较大永久性位移，处于弹性可恢复范围；施加衬砌后洞室的振动强度降低，洞室围岩刚度增大，其所承受的地震荷载亦随之增大，而位移减小，支护后洞室最大相对位移及永久性位移比无支护工况下分别平均下降10.88%和29.20%，洞室衬砌抗震效果良好。研究结果可为类似工程问题提供参考。

DYNAMIC RESPONSE ANALYSIS OF ROCK UNDERGROUND CAVERNS IN HIGHLY SEISMIC REGION

The earthquake is one of main factors resulting in failure of underground caverns. The dynamic response analysis of rock caverns under seismic load is a hot issue during the construction of hydraulic engineering in highly seismic region in West China. The dynamic time-history response analysis method is used to analyze the dynamic stability of Liangjiaren Hydropower Station on the Jinsha River. The trends of relative displacement and point safety factor of underground caverns are studied under the natural seismic wave；and the changing law of displacement when the seismic wave passes through caverns is analyzed；also the aseismic effect of lining is discussed. The results show that seismic wave propagation is affected by medium，structural plane distribution and cavern free surface；the fluctuating laws of the maximum relative displacement and point safety factor are similar with those of seismic spectra and the vibration is enlarged around the rock caverns；also bigger permanent displacement has not been discovered in underground cavern walls and fault F4. After the lining has been applied，the vibration intensity is reduced，the stiffness of the surrounding rock is increased and the surrounding rock bears a larger seismic load，producing a smaller displacement when the lining has bigger rigidity；also the maximum relative displacement and the permanent displacement decrease by 10.88% and 29.20% respectively. The practice shows that the aseismic effect of underground caverns with lining is good. The presented research can provide some references to similar projects.