The Study Of Simulation Of Piles’ Dynamic Test Based On Pile-soil Interaction

Piles foundation take on many significant tasks such as providing bearing capacity,foundation pit support,water stop curtain,foundation treatment,uplift resistance in various projects.Pile foundation is a kind of concealed work.It is difficult to judge whether the quality of piles meets the design requirements of projects,so it is essential to test the quality of piles.Piles’ dynamic test technology is a efficient method to test the integrity and the ultimate bearing capacity of piles which has been widely studied by many scholars.There are plenty of achievements in the research direction of numerical simulation of piles’ dynamic tests so far.However,due to the complexity of pile-soil Interaction and the nonlinearity of soil’s constitutive relationship,the matching degree between numerical simulation and the actual situation is limited.Based on the measured signal of model piles,we get approximate finite element calculation parameters through continuous debugging in this thesis.On this basis,the calculation parameters are used to calculate the simulation of engineering examples.The calculation results indicate that the numerical simulation signals are in good agreement with the signals that measured in engineering projects.First of all,the appropriate calculation method and simulation parameters are determined,and the correctness of the model and the calculation scheme is verified by the contrast experiment between the measured signal of model pile and the simulated signal of ABAQUS.Secondly,the phenomenon is explained that the low strain reflected signals at the bottom of the piles are often not found when the piles are embedded in the rock through the comparative experiments between the numerical simulation and the actual measurement of low strain method.The influence of the sudden change of the soil’s elastic modulus on the low strain reflected signal is discussed by numerical simulation.Then,the signals calculated by numerical simulation and the signals measured by high strain method are compared to verify thecorrectness of the high strain finite element calculation of the friction pile and the end bearing pile.The existing high strain analysis method is verified to be rational by analysing the curves.Finally,the piles’ dynamic test simulation analysis are carried out under the circumstance of different defect degree and different defect position.The relationship function that describe the influence of piles’ defect degree and defect position on the low strain signals’ amplitude ratio is concluded.The influence of piles’ defect degree and defect position on high strain curves is discussed.