Study On Numerical Simulation Of The Progress Of Pipe Jacking And Field Test Of Steel Tube Slab

STS is introduced from South Korea which is a new construction method of undercutting with shallow overburden,and it is mainly used in crossing under the existing highway,bridge and tunnel construction.Pipe roof structure of STS has good stability and less soil disturbance,so STS will have a wide application and development space.Combining the improved South Korean STS structure and cavern-pile method,STS is being used in subway station construction of China.However,there are many potential problems and exists a lot of uncertainty in the engineering construction,such as geological conditions of applicability,accuracy control and jacking force estimation etc,and few domestic scholars had carried out an in-depth discussion and research,so it is necessary to analyze the theory and application of STS.Based on jacking field test of Olympic Center Station,this paper studies by the method of theoretical derivation,numerical simulation and field monitoring.First through theoretical derivation,based on tunnel face support pressure protection theory and wedge calculation model,this paper acquires core soil soil length in the process of jacking and the considering with the flange of the jacking force calculation formula,and estimates jacking force of field test of pipe jacking;secondly,the paper uses FLAC3D numerical simulation software to simulate the order of pipe jacking and soil length under different conditions;finally,according to the Olympic Sports Center station field test,this paper analyzes surface subsidence,deformation of the steel tube,jacking force,steel pipe offset,corrective measures.Theoretical calculation and numerical simulation study show that it is need to set aside a certain length of core soil to offset tube in front of the earth pressure and reduce ground deformation.;the different order has different order in disturbance of the soil,and the order which is from the middle to both sides of the top of the construction method has more applicability.Without considering grouting,the pipe jacking force is about 2300 kN,otherwise is 700kN.Field data shows that the law of surface shows uplift after the settlement deformation,jacking force varies almost linearly and grouting and jacking method of jacking force has a great influence.