Model Test On The Interaction Between Metro Tunnel And Ground Fissure Under The Condition Of Tunnel Crossing With Small Angle And Paralleling With Short Distance To Ground Fissure

Up to now, there have already been14ground fissures in urban area of Xi’ansuccessively, due to coupling of endogenic and exogenic forces, etc., leaving a major securityhidden danger for urban construction. With Xi’an Metro Line2bringing into service, theconstruction of rail transit of Xi’an begin to speed up, but a series of new problems followed.Line3is the third commenced-line of Xi’an Metro after Line1and Line2. Line2and Line1crossing ground fissure with90°and large angle respectively, different from those precedents,Line3crossing ground fissure with small angle or paralleling to ground fissure with shortdistance in certain regions. And the construction of Xi’an Metro after the Line3may meet thesame problem, too. For this reason, it is particularly necessary to make sure how the groundfissures affect the tunnel structure under the condition mentioned above, and to solve theproblem.Using large-scale (1:5) model test about the ground fissure and Horseshoe-ShapedTunnel structure as the main method, do research on the characteristic of ground fissuresassociated with Xi’an Metro Line3and possible hazard and risk of the metro project, thispaper reveals the deformation mechanisms, failure characteristic pattern and range ofinfluence of metro tunnel under the condition mentioned above.Establishing numerical analysis mode with MIDAS/GTS3D finite element program,focus on the model about tunnel structure crossing ground fissure with small angle andparallel to the ground fissure with different distance, analyze the mode in displacement,internal force, deformation and other aspects. Then, use the Calculation to compare with theresults of model test as optimizing and supplement.At last, this paper presents the conclusion about the structure deformation range of metrotunnel crossing ground fissure with small angle and recommendations about the safe distanceof metro tunnel parallel to ground fissure. To provide the scientific theoretical guidance fordesign, construction and security operations of Xi’an metro, and to enrich the researchachievement about the influence on underground structure from ground fissure.