Character Analysis Under Load Of SMW Method Pipe Jacking Well

As a non-excavation construction technology,pipe jacking method has unparalleled advantages in the laying of pipelines and has been more and more widely used.The working well is an important part in pipe jacking engineering,and is the only procedure that needs excavation ground.The construction cost of the work well accounted for more than half of the total cost of the project.In working well production,the common construction methods are caisson method,continuous wall method and Soil Mixing Wall method.The SMW method has good economic benefit and social benefit,therefore,the SMW method working well is of great significance to study.In this paper,combined with the previous research of pipe jacking well and SMW pile,research the stress and deformation of the working well,using finite element software ABAQUS to establish the three-dimensional numerical model of SMW method working well.The main work and research results are as follows:(1)This paper concludes and summarizes the main design theory of retaining wall by SMW method,and the construction method of SMW construction work well.Through some assumptions and simplifications,establishes a 3D numerical model of SMW method work well,then analyses the stress and deformation of the structure,which includes top beam,bottom plate,H-beam and cement-soil wall.(2)In the process of jacking construction,the top beam and the bottom plate mainly do the overall move,local deformation is small.It is usually considered that the top beam and the bottom plate are used for connecting the H-beam of spaced distribution,which makes them becoming a force whole.(3)The deformation of the cement-soil wall and the H-beam is consistent,the jacking force mainly bear by H-beam.When bearing the jacking force,the cement-soil wall and the H-beam occur the larger deformation in the compression area,but the deformation of other parts is mainly the overall movement.(4)Through the analysis of stress distribution on the back soil under different jacking force,determine the ultimate stress state of the back soil,and put back the simplified stress distribution mode of the back soil under the ultimate stress state.(5)According to the orthogonal test of four factors and three levels,it is concluded that the optimal design combination of retaining structure is that the thickness of the top beam is 0.8m,the thickness of the bottom plate is 0.45 m,the elastic modulus of the cement-soil wall is 500 MPa,and the elastic modulus of the soil under the bottom plate is unchanged.