汶川地震中隧道结构的震害分析

摘要

汶川地震中,地下结构特别是隧道这一长线型结构震害严重.参照汶川地震中两条严重受损隧道的地形地貌、地质构造、围岩特征、断面及支护参数等相关资料,利用隧道结构的地震破坏机理,对其破坏形态进行理论分析,研究破坏产生的原因.研究发现除了震中距、地震波入射方向、隧道结构形式、基岩交界面、施工情况等因素外,特殊地段没有采取特殊的支护或加固措施,是造成隧道破坏的关键,尤其是当隧道遇到断层破碎带、不稳定边坡、高地应力区等不良地质环境时,地震对隧道的惯性力破坏及地基失效破坏作用巨大.因此,进行抗震设计时应采取具有针对性的支护设计方案,防止由于局部破坏,影响整条隧道的正常使用.%Underground structure, especially the long linear tunnel, was severely damaged in Wenchuan earthquake. Based on the general failure mechanism of underground structure, the failure patterns and the damage causes of two severely damaged tunnels in Wenchuan earthquake were analyzed according to topographic features, geological structure, characteristics of surrounding rocks, sections and support parameters and so on relative references. The research indicates that the key factors of tunnel seismic damage are not taking special support or reinforcement measures in special district besides epicentral distance, incident angle of seismic wave, structural form of tunnel, interface of structure and rocks, construction etc. Earthquake will play great role in inertial force damage and foundation failure of tunnel, especially when tunnel subjects to fault fracture zone, unstable slope of tunnel portal, high ground stress and so on adverse geological environment. So, the targeted supporting design should be taken to prevent local failure in special district from affecting the normal use of the whole tunnel when anti-seismic design is conducted.