Numerical Simulation On Ground Settlement During Shield Tunneling In Water-Rich Sandy Pebble Strata

In recent years, the shield driving method has an important position in urban subway construction with its own characteristic and advantages, like unique intelligent, quickly, safety and so on. At the same time, it produces surface subsidence and disturbance with varying degrees to surrounding soils, which become a very concerned problem in design of shield tunneling construction. Large ground settlement will affect the safety of shield construction and the normal using of surrounding buildings, which causes considerable economic losses. So monitoring and forecast surface subsidence during shield tunneling construction has a very important significance in engineering.In order to study the influence of subway construction on the surface subsidence, in this paper, the surface subsidence rule induced by shield tunneling construction and the corresponding locale monitoring data were analyzed combined with the actual engineering of shield tunneling construction in Shenyang subway of line one, and aiming at characteristics of water-rich sandy pebble strata, as the research object of surface subsidence deformation during shield tunneling construction, according to engineering and field survey data, obtained surface vertical and horizontal displacement change rule during shield tunneling construction, and using ABAQUS a large-scale finite element analysis software, by considering factors of seepage, excavation depth, soil warehouse pressure, soil elastic modulus, liner stiffness and elastic modulus of substitute layer to establish a three-dimensional finite element model with considering various influencing factor more roundly and reasonably, simulating dynamic excavation process of shield tunneling construction, analysis and research the stress field and displacement field of surface deformation, getting the change rule of surface subsidence during shield tunneling construction, and compared with measured data, confirmed the reliability of numerical simulation results. Both monitoring data analysis and finite element model simulation result show that the surface subsidence induced by shield tunneling construction is in the allowable maximum deformation value + 10 mm ~-30 mm range. It provides the favorable theory basis for using shield tunneling construction technology in the applied to Shenyang subway construction.