The Study On Bearing Behavior Of High-profile Ladder-type Variable Cross-section Ferrule Combined Pile

In this paper,based on the summary of the research results of high-pressure plug-in composite pile,a new technique of high-spray ladder-type variable cross-section ferrule combined pile and composite foundation is put forward.Through the large proportion of indoor model test and numerical simulation analysis and other means,the bearing behavior of equal section pile,step type variable cross section pile and high spray ladder type variable cross section ferrule under vertical load is compared.The main research contents are:1.A large-scale model test of high-spray ladder-type variable cross-section ferrule combined pile under vertical load is carried out.The distribution law of load-settlement and pile-side friction of composite piles under the action of vertical load under the action of vertical load is studied.The results show that the load-carrying capacity of high-spray ladder-type variable cross-section ferrule composite piles> stepped variable cross-section piles> equal-section piles.2.Through3 DFLAC,A numerical model of stepped type variable cross-section pile and high-spray ladder-type variable cross-section ferrule combined pile and equal-section pile is established.The working behavior of equal section piles,ladder-type variable cross-section piles and high-spray ladder-type variable cross-section ferrule combined pile under vertical load is compared.The influence of the variable position,the thickness of cement concrete,the strength of cement soil,the cohesion of soil and the friction angle of soil on the bearing capacity of high-spray ladder-type variable cross-section ferrule are discussed.The numerical simulation results show that the loading capacity of the composite piles with high spray ladder type variable cross-section is> the variable cross-section pile> the cross-section pile;the variable diameter,the cement soil thickness,the cement soil strength,the soil cohesion,Which can improve the bearing capacity of single pile and reduce the settlement of pile.