The Load-Carrying Behavior Of Vortex Squeeze Pile

Squeezed pile is a new type of foundation structure with high efficiency.The expanding section increases the contact area between the expanding pile and the foundation soil,which can give full play to the interaction between the pile and the soil,and the stability of the pile body and the foundation soil is greatly increased.The research purpose of this paper is to evaluate the load-Carrying capacity of the squeezed pile,study on the mechanism of vortex squeeze expanding pile soil-pile process.Through indoor experiment and numerical simulation,obtain the vortex squeezed pile compressive strength of 12 kinds of pile bearing capacity and uplift bearing characteristics,based on the calculation method of bearing capacity of the vortex squeezed pile.The main research work of this paper is as follows:(1)It put forward vortex squeeze expanding pile forming technical method for the first time.The coupling mechanism of fluid concrete and soil in the process of squeezing and expanding is studied.It derived from the cavity into the concrete mechanical conditions of soil.It is established the extrusion expansion model and equations of generalized vortex form based on the hole expansion theory and Vesic theory.(2)It applied Mohr-Coulomb criterion and the modified Cambridge model,deduces the squeezed elastic zone / plastic zone stress solution,solution of displacement and limit expansion pressure,provides a theoretical basis for the bearing capacity of vortex squeeze expanding pile calculation,settlement calculation and load transfer mechanism.(3)It study on vortex squeeze expanding pile compressive and uplift bearing characteristics under different number,diameter and spacing of expanding section by experiment.According to the test data of mechanical properties of 12 different shapes and sizes of the tension / compression load model pile,including the Q-S curve,the axial force distribution of the pile,the vertical bearing capacity and settlement deformation of the single pile are summarized.Further study of the sand medium expanding pile tensile and compressive deformation characteristics,the uniform pile and single pile and double expansion part expanding parts of pile and expanding of pile bearing characteristics.(4)ABAQUS numerical analysis model is established based on the test data of the physical model of pile squeezing expansion,the quantitative analysis of the vortex squeezed expanding pile compressive / uplift bearing characteristics,including expanding compression pile / pile foundation soil by the failure pattern,load settlement relationship and load transfer law,comparative analysis and the indoor test results are in good agreement with that of expanding pile bearing capacity than the traditional uniform pile has obvious advantages.(5)According to the results of laboratory tests and numerical simulation,by modifying the traditional pile with expanded diameter formula,vortex pressure expanding pile compressive / uplift calculation method and formula of bearing capacity is put forward,more accord with the actual conditions,provide theoretical and data support for the engineering application of vortex squeezed pile next.