The Relationship between the Land Subsidence and the Ground Fissure in Xi' an
Wu Zaibao Miu Xiangsheng Yang Guqiang (Xi'an College of Geology)
The land subsidence and the ground fissure are one of the serious problems of environmental engineering geology in Xi'an. On the basis of a great many practical data, the writer analyses the basic geological environment in Xian, determines the difference of geological structures on different geomor- phic units, and delimits the engineering geological layers in this paper. In the case of over extracting the underground water, the characteristics of all changes, such as the underground water level, the subsidence and the ground fissures in space, time and movemental way,show that the over-extraction of the underground water is the main cause of Xi'an subsidence, that geologic tectonism is the basis of the ground fissures, and that the soil deformation caused by pumping the underground water aggravates the development of the ground fissures.