Analysis Of The Genetic Mechanism Of Ground Fractures Along Xi'an Subway Line 2

Ground fracture is a typical regional geo-hazard, which bring damage to various types of buildings, transportation facilities, city lifeline projects and the land resources.The hazard has brought enormous economic loss to the construction of Xi'an for several years, and brought inconvenience to lives of the people. Now, Xi'an Subway is under construction. A number of ground fractures are crossed by the subway, which will bring adverse effect to the subway construction and operation. Therefore, it is of great significance to research on the distribution, activity regularity and genetic mechanism of ground fractures.Based on the results of the investigation of ground fractures along Xi'an Subway Line 2 and past information, the distribution and moving laws of ground fractures along subway are introduced firstly. Ground fractures along the subway include Xi'an ground fractures, ground fractures in Chang'an District of Xi'an, and geotectonic ground fracture NO.f0. There are 11 main fractures and 2 secondary fractures of Xi'an ground fractures and 3 Chang'an ground fractures crossed by Xi'an Subway Line 2.Secondly, genetic mechanism of ground fractures along the subway is analysed, and Xi'an ground fracture is mainly analysed. A large number of data about exploration, groundwater and surface subsidence is analysed, it shows that Xi'an ground fracture is on the base of tectonic activity , and the extraordinary movement of it is mainly caused by pumping deep-seated confined water; others fractures along the subway were caused by different stratum structure near the geomorphic boundary, different physical and mechanical properties of ground in the same strata, or tectonic effects.At the same time, the unequal settlement of both sides of the fractures belt caused by pumping groundwater is simulated by using 2-D finite element software in this paper, and the results show that pumping groundwater accelerates the movement of ground fracture based on regmatic stratum structure.Finally, the prevention and countermeasures of the ground subsidence have been put forward by analyzing influencing factors and the disaster-causing mechanism of the ground fracture.