青藏铁路沿线断裂活动的灾害效应

青藏铁路沿线发育大量不同方向、不同性质、不同类型和不同规模的活动断裂。这些活动断裂对地震分布具有显著的控制作用,形成了12条区域性地震构造带。一些重要的活动断裂的平均运动速度达4～15mm/a,能够孕育6～7级以上的强烈地震,导致严重的地震灾害。在青藏高原北部常年冻土区,断裂活动不仅导致路基变形、路面破裂和工程破坏,还诱发不均匀冻胀、构造裂缝和移动冰丘等地质灾害,对青藏铁路、青藏公路和输油管道等线路的工程安全产生不良影响。断裂蠕滑运动与地下水活动、不均匀冻胀的耦合效应使青藏公路安多段路基松动和路面强烈变形,对青藏铁路的工程安全造成潜在威胁。

HAZARD EFFECTS OF ACTIVE FAULTING ALONG THE GOLMUD-LHASA RAILWAY ACROSS THE TIBETAN PLATEAU

Many active faults with different trending, different features,different types and different scales distribute along the Golmud Lhasa railway across the Tibetan Plateau. These active faults control the epicenters of earthquakes and form 12 regional seismic tectonic zones. Some active faults have strike slip rate of 4-15 mm per year and are possible to produce strong earthquakes of Ms≥6-7. Active faulting of the permanent freezing areas of northern Tibetan Plateau can not only induce deformation of highway and railway, but also form hazard effects, eg. heterogeneous freezing, surface fracturing, underground ice doming and moveable ice doming, which endanger the safety and lifetime of the Golmud Lhasa railway, highway and pipeline across the Tibetan Plateau. The coupling of active faulting, underground water activity and heterogeneous freezing has caused the strong deformation of the highway in the south of Ando and has the possibility to destruct the Golmud Lhasa railway.