Longitudinal Vibration Of Pipe Pile In Soil With The Considering Of The Construction Effects

In the southeast coastal areas of China,the underground water level is high,soft soil foundations is distributed widely,pipe pile has been widely used in various construction projects with its convenient construction and high bearing capacity.Compared with solid core pile,pipe pile has applicated for a short time as a kind of pile foundation,the relevant theoretical research is still inadequate,especially the study on the properties of pipe pile under dynamic load,is the focus of the research for the pipe pile currently.The former research of the coupling vibration of pile-soil simplified the effect of soil,constructed in the southeast coastal areas,especially in soft soi,on the one hand,the high underground water level is high,on the other hand,the disturbance effect to soil have changed the nature of the original soil,in this case,the pile-soil coupling effect becomes very complex.This article is mainly about theoretical modeling analysis,with the considering of construction effect,established pile-soil coupling vibration model in elemental soil and saturated soil,combined with the pile-soil vibration model test to verify the correctness of the theoretical modeling model.The main content of the paper has the following several aspects:(1)Based on the theory of Novak thin layer method and viscoelastic pile bottom support,set up a pile-soil coupling model with the considering of construction effect in elemental soil.Next the effects of pipe pile length,Pipe pile diameter,wall thickness of pipe pile,compressional wave velocity of pipe pile,shear wave velocity in inner regions are analyzed.(2)Based on saturated porous medium theory,the longitudinal vibration of pipe pile in saturated soil considering of the construction effects was studied.Firstly,a longitudinal coupling vibration model of saturated soil-pile which considered the construction effects was established under vertical dynamic loads.Then,the vibration equation of the frequency domain of saturated soil was obtained by Laplace transform.After applying the boundary conditions and initial conditions to solve the dynamic equation,the analytical solutions in frequency domain were gotten.Next,the semi-analytical solution of the pipe pile and saturated soil in time domain was derived by the inverse Fourier transform.Finally,the influences of compaction,relaxation,and volume ratio of pore water and other major factors which affect the dynamic characteristics of pipe pile were analyzed,to get the reasonable pipe pile vibration theory with the considering of construction effects.(3)The low strain dynamic tests of pile foundation detection of different length to diameter ratio of aluminum and nylon model pile are carried out respectively.Using laboratory test data to test the pipe pile wall thickness,pipe pile material,different pipe pile soil modulus ratio on the curve of the velocity response of pile,then analysis the difference of theoretical results and the experiment results to validate the pipe pile longitudinal vibration theory in the more spheres model in the saturated soil.