大荔县地裂缝分布与发育特征研究

Study on Distribution and Development Characteristics of Ground Fissures in Dali County

大荔县位于渭河盆地东北角,所处区域地质环境复杂,断裂构造纵横发育,加之人类活动频繁,给地裂缝的生长和发育提供了良好的地质环境背景。经过详细的野外地质调查和室内资料整理,累计发现地裂缝127条,且发育较为集中。同时,借助钻探、槽探、物探等手段,归纳了大荔县地裂缝的分布与发育特征。研究结果表明:(1)该地区的地裂缝集中分布在断裂带附近的地貌分界处,总体上呈现北多南少,黄土台塬内仅有零星分布;(2)地裂缝在平面形态上主要表现为直线型、折线形和弧线型;(3)在剖面上,构造型地裂缝表现出正断层发育特征,湿陷型地裂缝表现为一条被填充的直线;(4)地裂缝活动与断裂活动具有相关性,并与地面沉降呈现伴生关系。研究可为大荔县地裂缝灾害发育地区的防灾减灾、土地资源合理利用等提供理论依据,具有重要价值。

Dali County is located in the northeast corner of the Weihe Basin,where the regional geological environment is complex,the fault structure is developed vertically and horizontally,and the human activities are frequent,which provides a good geological environment for the growth and development of ground fissures.A total of 127 ground fissures have been found through detailed field geological survey and indoor data collation,and their development is relatively concentrated.At the same time,the distribution and development characteristics of ground fissures in Dali County are summarized by means of drilling,trenching and geophysical exploration.The results show that:(1)The ground fissures in this area are mainly distributed at the geomorphological boundary near the fault zone,generally more in the north and less in the south,and only sporadically distributed in the loess tableland.(2)The ground fissures are mainly linear,polygonal and arc-shaped in plane shape.(3)On the profile,the tectonic ground fissures show the characteristics of normal fault development,and the collapsible ground fissures show a filled straight line.(4)The ground fissure activity is related to the fault activity,and is associated with the land subsidence.The study could provide a theoretical basis for the disaster prevention and mitigation and the rational use of land resources in the area of ground fissures in Dali County,which has important practical value.