Study On The Influence Of Soil Plug On Longitudinal Vibration Of Pipe Pile And Test Analysis

Pipe piles are widely used in the areas with poor bearing capacity such as the Yangtze river delta because of its low cost and high bearing capacity.In the process of driving the pipe pile into the foundation,the soil will pour into the pile and form the soil plug.At present,the theory of longitudinal vibration of pipe piles in saturated soils considering soil plugging effect is not comprehensive enough.therefore,based on theoretical analysis.The dynamic response of pipe pile top is discussed in radial and bidirectional heterogeneous soils considering the variation of soil plug parameters.The theoretical solution is verified by numerical simulation and model test.(1)The radial heterogeneity of soil around piles is considered.The bottom bearing of the pile is considered as the dispersion fictitious soil pile model.Based on the complex stiffness transfer model.According to the dynamic equation of saturated soil and the longitudinal vibration theory of pipe pile,the theoretical solution of pipe pile top is deduced.The influence of volume fraction of water,shear wave velocity and height of soil plug on dynamic response of pile tip is analyzed.The results show that the existence of soil plug has a great influence on the dynamic curve of pipe pile tip in radial heterogeneous soil.(2)The bidirectional heterogeneity of soil around piles is considered.The bottom bearing of the pile is considered as the dispersion fictitious soil pile model.Based on the complex stiffness transfer model.According to the dynamic equation of saturated soil and the longitudinal vibration theory of pipe pile,the theoretical solution of pipe pile top is deduced.The influence of volume fraction of water,shear wave velocity and height of soil plug on dynamic response of pile tip is analyzed.The results show that the existence of soil plug has a great influence on the dynamic curve of pipe pile tip in bidirectional heterogeneous soil.(3)The model of soil plug-pipe pile-soil around pile is established by ANSYS.The soil around piles is divided into radial and bidirectional heterogeneity.Pile-soil related parameters are evaluated according to the theory.Compare the velocity time curve with the theoretical diagram.The correctness of the theoretical solution is verified.(4)The influence of soil plug height on dynamic response of pile top is obtained by low strain testing of pipe piles with different soil plug height.The test curve is compared with the theoretical curve to verify the correctness of the theoretical solution.