The Research And Application Of Gravity Cement-Soil Retaining Wall With Embedded Steel Pipes In Soft Soil Foundation Pit

As a composite cement-soil retaining wall,the gravity cement-soil retaining wall with embedded steel pipes is often used in soft soil foundation pit with excavation depth of 4 ~ 7m.At present,the study about composite cement-soil wall is more concentrated in compound pile wall of steel and cement,while the embedded steel pipe retaining wall lack adequate research.To solve the above problems,this paper has done the following work:(1)This paper use ABAQUS to establish the plane strain model of cement-soil retaining wall,and research on the influence of some factors including wall width,wall elastic modulus,foundation pit depth and pit top overload on the stress distribution,exploring the material failure mode of cement-soil retaining wall.The results show that when the width of the cement-soil wall is small,the wall has a tension zone with a shape of the "minor arch",which is mainly distributed near the outer edge of the wall.And the range of the tension zone is closely related to the width of the wall,the depth of the pit,the pit top overload etc.When the cement-soil wall width is large enough,there is no tension zone in the wall.(2)Based on the above-mentioned plane strain model,a complete three-dimensional model of gravity-type cement-soil wall is established,which used to study the effect of steel pipe on horizontal displacement,bottom heave and wall stress distribution and analyze some factors that affect the effect of steel pipe,as well as the effect of width of the wall and pipe spacing on steel pipe.It is found that the steel pipe can effectively decrease the tension area of the wall and reduce the maximum tensile stress value of the wall.However,the effect of the steel pipe on the horizontal displacement of the wall is not obvious.(3)With analyzing the stress of the steel pipe,it is found that the stress of the embedded steel pipe is low compared with its strength and the strength reserve of the embedded steel pipe is sufficient.