大同-西安高铁沿线地裂缝成因分析

摘要

通过地面调查、钻探和地震勘探,在临汾盆地内查明与大同-西安高铁线路相交或隐伏相交的地裂缝(群)共有7条12处,其成因类型有构造型和非构造型两种.构造型地裂缝主要受隐伏断裂控制,非构造型地裂缝主要受古地貌或古地形控制.这些地裂缝形成的本质条件是由断裂或古地貌边界控制的两侧地层差异,该区地下水的开采活动和水位下降是地裂缝超常活动的促发因素,雨水和渠水的入渗和渗漏也可诱发和加剧地裂缝的发生,湿陷性土层的存在使得地裂缝灾害更加突出和明显.通过对地裂缝成因分析,进而为大同-西安高铁沿线采取相应的综合工程防治措施提供依据.%Seven ground fissures and fissure groups were found along Datong-Xi'an high-speed railway line in Linfen basin through field survey, boring and seismic prospecting. There are twelve sites where the railway line crosses the ground fissures and two types of causes for the fissures, namely the tectonic cause and non-tectonic cause. The tectonically-caused lissures are determined by underground faults and the non-tectonic fissures by paleotopographical factors. The essential condition for the ground fissures is soil variation among fault bolts or along the boundaries of paleotopographical layers. The process can be precipitated by overexploitation of underground water causing lowered watertable or rain and ditch water penetration which can both cause and accelerate the formation of ground fissures. Areas with collapsible wet soil usually suffer from amplified ground fissure hazard. Through analyzing the causes for the fissures, the paper expects to provide corresponding preventive and corrustive measures for the comprehensive construction projects around Datong-Xi'an high-speed railway line.