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Ground fissures is a kind of serious geologic hazards in Xi’an, the ground construction, underground pipeline and municipal engineering, etc, were different degree of damage by ground fissures, which makes serious influence on the urban planning and construction of Xi’an, now ground fissures become a major security hidden danger to the construction of subway.Xi’an metro line 2 will be put into operation, metro line 1,3 has commenced construction, line 4 has entered the preparation work, the safety of the metro which goes through fissure has extensive attention by everybody. Due to the subway tunnel across multiple ground fissures, ground fissures to subway tunnel security operations brought serious Hidden trouble. Therefore research the interface mechanics properties of metro tunnel under the ground fissures activities, formulate appropriate of safety monitoring plan, and determine the safety warning tunnel boundary is very necessary.This paper is on the basis of investigation the Xi’an ground fissures space exhibition cloth and activities the characteristic, analyzed the ground fissures activities may cause the subway tunnel deformation and failure mode, and relying on the constructing Xi’an metro line 2, using scale model of 1:20 respectively to simulate the horseshoe expansion tunnel and ground fissures 90°and 60°oblique two cases the cross-section of mechanical properties of metro tunnel, and analyze the test result, it is concluded that the tunnel structure stress characteristics, the deformation modes and the Strata distortion influence on the tunnel bottom gap. Based on the existing subway tunnel safety monitoring technology method, put forward the safety of metro tunnel monitoring programmer which suitable for the subway through the ground fissures. using ground fissure dislocation quantity and tunnel structure stress for observation data, using exponential smoothing, the second moving average, the forecast method of grey relational analysis and regression analysis to forecast, according to the forecast result choose exponential smoothing the prediction model for optimal, and gives the tunnel structure stress warning criterion.
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