A Study Of Surface Subsidence Law Of Large Span Box Culvert Under The Existing Railway Line

With the continuous development of the national economy, the rapid development of urbanization in China, the number of urban population is also growing rapidly. The rapid growth of population brings the continuous development of urban road construction, the railway and highway intersection is inevitable and obviously increased. Box culvert is an important method to solve the problem of new and existing road intersection, and its application is more common. This paper is based on the wear Shanghai Kunming railway frame bridge engineering in Fengcheng City Wuhua Road, the jacking construction of ground subsidence monitoring, and study the law of its development. This paper mainly focuses on the following aspects: 1. in the process of box culvert jacking, the mechanism of surface subsidence is discussed and studied. The effects of formation damage, pore water, pipe roof and grouting on the surface subsidence are discussed; 2. using the finite element theory, the process of box culvert jacking is studied. The basic principles of finite element and Midas GTS/NX in wearing the theories and methods of typical engineering application is introduced; by using the finite element software Midas GTS/NX numerical simulation model is built, the simulation box culvert jacking process. Analysis in the construction process of surface settlement; 3. through the construction site measured data, analysis of box culvert jacking construction process of the law of surface subsidence,And the numerical simulation results are compared and analyzed. Through the above analysis, the following main conclusions are drawn: 1. Box culvert jacking process caused by a wide range of pavement settlement, its sphere of influence, mainly in the distance of box culvert within 22.5m on the two sides of the axis; 2. With box culvert jacking, closer to the axis of the region, and the settlement rate of horizontal displacement increased faster; 3. The relationship between the measurement point and the pavement of box culvert jacking distance, can be roughly divided into micro settlement stage, increasing settlement stage, slow subsidence stage and later stage of settlement; 4. The surface subsidence is simulated and analyzed, and the results were compared with field test, found that the two rules are similar, the pavement of the largest settlement area in the culvert axis at the same size.