高速铁路经活动断裂带地质选线研究

Study on Geological Route Selection of Active Fault Zone Passed by High-speed Railway

活动断裂易诱发地震,一般强烈地震多发生在活动性较强的大断裂带的拐弯、分叉和几个断裂的交汇处。沿活动断裂带地震动峰值加速度明显增高,地面变形量大,可导致高速铁路严重受损。中卫至兰州铁路客运专线位于六盘山-祁连山地震带和龙门山地震带内,地震地质条件极为复杂,香山-天景山、海原活动断裂带是制约线路方案选择的关键地质因素。通过分析断裂带在航片、卫片上所显示的线形特征,在野外地质调绘、物探、钻探、槽探的基础上,采用光释光测龄法进一步确定活动断层最新活动年代,评价区内断裂带活动特性、活动年代及平均走滑速率,总结活动断裂带地质选线原则。为了从源头上减少或避免地震及次生地质灾害对高速铁路的破坏,提出了高速铁路通过活动断裂带的最佳方式、位置、工程设置类型及所采取的防护措施,为今后高速铁路穿越活动断裂带提供借鉴。

Active faults induce earthquakes easily,and generally violent earthquakes occur at the intersection of the strong active faults,the bifurcation and the intersection of several faults. The peak acceleration of ground motion along the active fault zone increases obviously,and the ground deformation is severe,which could cause serious damage to the high-speed railway project.Zhongwei-Lanzhou Railway Passenger Dedicated Line is located at Liupan-Qilian Mountains seismic belt and Longmen Mountains seismic zone,the seismic geological condition is very complicated,Xiangshan-Tianjingshan Mountain and Haiyuan active fault zone are the key geological factors for route selection. By analyzing the fault zone linear characteristics displayed in aerial and satellite on chip,based on the field geological mapping,geophysical prospecting,drilling,trenching,the method of optical stimulated luminescence dating is used to further determine the latest activities age of the active faults,evaluate the activity characteristics,activity age and average slip rate of the fault zone,and summarize the geological route selection principles of active fault zone. In order to reduce or avoid the destruction of the earthquake and secondary geological disasters on the high-speed railway from the source,this paper puts forward the best way,location,project setting type of high-speed railway crossing active fault zone and the protective measures,which could provide a reference for future high-speed railway crossing active faults.