| About 13 ground fissures trending in an east-northeasterly direction have been found in downtown and suburban area of Xian, which cause great danger to municipal construction and industrial fabrication. Currently ground fissures have endangered hundreds of buildings and have become a main geological hazard in Xian. In Xian subway construction project, the subway tunnel will come across several ground fissures due to the continuity of subway tunnel. Therefore prediction to the differential settlement of Xian ground fissures in order to analyze its influence to subway tunnel and provide technical support for subway tunnel has become an urgent problem for Xian subway construction.According to the current prediction theory for differential settlement of Xian ground fissures, movement discipline is studies and prediction theories on differential settlement such as Verhulst model and numerical analysis are compared. In regard to the 11 ground fissures across subway line 2, the design value for differential settlement is supposed and design guide for subway tunnel is advised.For further study on the influence of ground fissures to land subsidence under the excavation of subway tunnel and to the stress and strain in tunnel lining, ADINA, a nonlinear FEM program, is adopted in this thesis. Considering the effect of FSI (fluid-structure-interaction), fluid-mechanical -settlement models of subway tunnel constructed in area containing ground fissures and under ground water are established, utilizing the strong power of FSI module in ADINA. The progress of seepage, deformation and settlement is also simulated numerically. Nonlinear FEM models for steel reinforced concrete lining and wall rock are supposed. Stress field and strain field in lining structure and wall rock is analyzed and the stress sheet, the strain sheet and deformation sheet for the whole structure is supposed. Through the analysis of diagrams, some advice is proposed for the design of steel reinforced concrete lining.
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