LAND FRACTURE AND SUBSIDENCE PREVENTION IN XI′AN
西安地裂缝地面沉降与防治对策

Severe land fractures and land subsidence are present due to geo-process and human activities in Xi′an,the largest continental city in northwestern China. Formation and distribution of land fractures have a close relation to the regional tectonics, and the general extension of the land fracture is NE,arranged and paralleted in equal rank,which reflects strong linear distribution regularity and 3-dimension changing characters of vertical displacement.Horizontal spread and horizontal writhe,the regular destruction activities of land fractures restrict the extension of the man-made land fractures,that can only develop in many narrow cut clots,because of the influence of many fractures such as the layer structure,exploring strength,land fractures and land subsidence bring difficulties and economic losses to city planning,study on city geo-hazard mechanism,construction of monitoring system,reinforcement of city program,restriction of human activities, and engineering precaution are effective countermeasures to prevent and alleviate geo-hazard.