嘎隆拉隧道断层区进洞口段轴向地震响应及抗震缝效果研究

Longitudinal Seismic Response and Effect of Aseismatic Joint of Tunnel Entrance in Fault Zone

针对嘎隆拉隧道洞口段,考虑断层影响,对衬砌设置抗震缝和不设置抗震缝2种工况进行模拟计算,对比分析得出:断层对隧道衬砌的影响主要为增加断层处衬砌的剪应力;抗震缝的设置将使隧道衬砌应力从洞口向洞内沿轴向很快趋于稳定,并将降低衬砌30%的峰值主应力;设置抗震缝后将使衬砌节段内的峰值应力均匀分布,且比不设置抗震缝的衬砌应力小,但衬砌的破坏部位将集中在抗震缝处,并有可能导致结构失稳,因此抗震缝的设置间距不宜过短,数量不宜过多。

Considering the effect of fault, two cases which is the lining of Galongla tunnel entrance with aseismatic joint and without aseismatic joint are calculated, the result shows： the fault mainly increases the shear stress of the tunnel lining in fault zones; aseismatic joint will stabilize the longitudinal stress of lining from tunnel entrance quickly, and will decrease the peak response main stress of lining by 30% ; aseismatic joint will average the peak responded stress of inner part of lining between the joint too, and the peak response stress is smaller than which of lining without aseismatic joint, but it will give rise to stress concentrate of lining near the aseismatic joint, which means that aseismatic joint should not be used too frequently and the distance between two aseismatic joint should not be too short.