Dynamic Response Analysis Of Surrounding Rock In The Condition Of Subway Tunnel Oblique Crossing With Ground Fissures Under Vibration Loads Of Train

At present, we have found more than 14 ground fissures Since middle of last century for the first time that we found the ground fissure in Xi’an. At present stage key construction projects take active measures to avoid the ground fissures under normal circumstances, which causes land waste in Xi’an. But we cann’t avoid the ground fissures in engineering construction for the linear engineering which crosses larger area. In recent years, due to the increasing traffic pressure, metro, as a kind of efficient, safe and economic, environmental and comfortable way of public transportation, can effectively alleviate traffic pressure on the ground. The pace of Xi’an subway construction has been also quicken intensively. Metro line 2 has been opened in 2011. Metro line 1 has been opened in 2013. Metro line 3 will also be opened in 2015. But due to the existence of the ground fissures, engineering treatment technology of metro projects in the region of the ground fissures and the subway operation safety monitoring of the process has become the focus of academic and engineering.This paper takes Xi’an metro line 1 and line 2 as engineering background, and this paper researched ground fissures under the condition of 30° oblique horseshoe tunnel ? assise ? ground fissure problem of dynamic response. We made a self ? built test model box according to the theory of similarity with the help of geological disasters in large-scale physical model test center at Chang’an University. according to the physical model test with proportion of 1:20, we can monitor acceleration, soil stress, relative displacements in the subway tunnel surrounding soil under dynamic load with different working conditions, explore the rule of tunnel-assise-ground fissure problem of dynamic response and the influence of the ground fissure to propagation of vibration wave. We can obtain the following results through physical model test:(1) We can obtain the acceleration rules of horizontal direction, vertical direction and under different frequencies with the simulated dynamic load on the subway;(2) We can obtain the soil stress rules in the subway tunnel surrounding soil with the simulated dynamic load on the subway;(3) We can obtain the vertical relative displacements rules between tunnel and surrounding soil with the simulated dynamic load on the subway;This paper researched ground fissures further under the condition of 30° oblique with horseshoe tunnel, which was based on the existing study of ground fissures under the condition of 90° and 60°oblique with horseshoe tunnel. The research idea and method of this paper has extensive application value. The paper is supported by the National Natural Science Fundation(No.41172257).