Research On Nondestructive Testing Methods And Waveform Analysis Of In-service Bridge Pile Foundations Based On ANSYS

As an important branch of traffic engineering,bridge engineering occupies an important position in traffic construction.The bridge pile foundation as a supporting bridge structure is directly related to the stability and safety of the entire bridge.Influenced by factors such as construction level,construction environment and natural disasters,in-service bridge pile foundations often suffer from various defects such as necking,neck widening,fracture,segregation,etc.In order to ensure the normal operation of bridges,the detection of pile foundations in in-service bridges has become a hot spot in pile foundation detection.In this thesis,we studied its application in the detection of in-service bridge pile foundation based on the theory of low-strain reflected wave pile foundation detection method.The ANSYS finite element software was used to establish the in-service bridge pile foundation model,and then we simulated the process of pile foundation detection method of low-strain reflected-wave,the optimal excitation position and detection position were studied.Combined with MATLAB software,an analytical method for inspecting waves of defective pile foundations of existing bridges was proposed,and it provides a theoretical basis for the engineering practice of bridge pile foundation testing in service.The main contents of this paper include the following three aspects:(1)Based on Stress wave theory,the principle and precautions of low-strain reflected-wave pile detection are analyzed.In addition,combining with the different types of waveform curves detected by the actual pile foundation,we studied the determination of the detection waveform of pile foundations with different defects,which laid the foundation for the integrity testing of the in-service bridge pile foundations.(2)We established a complete model of in-service bridges with ANSYS10.0 finite element software,and based on this model,simulated the low-strain detection for high capped pile foundation and low capped pile foundation.The characteristics of the excitation of the top of the pile cap and the excitation of the side of the pier were studied.At the same time,we compared analyzed the X,Y,and Z speed direction curves obtained from different sensor installation positions,determined the best detection excitation position and sensor installation position,and found the best analysis waveform to improve the efficiency and accuracy of pile foundation detection.(3)We simulated the low-strain detection of the in-service bridge’s necking piles,and determined that the detection signal waveform curve was seriously affected by the interference wave.In response to this problem,we proposed a signal separation method to process and analyze the detection curve of the defected piles of the in-service bridges.Combined with the MATLAB software and the previous simulation results,we simulated the signal separation method and confirmed its feasibility in the application of bridge defect detection for the in-service bridge,which provided a certain reference value for the detection and analysis methods of in-service bridge pile foundation.