Numerical Simulation And Applied Research Foundation Pile Integrity Testing Of Ultrasonic Transmission

Ultrasonic transmission, as a NDT method of structural pile integrity, has been widely applied in the field of Civil Engineering. Compared with such testing methods as ordinary low strain, high strain method and core drilling method, the Ultrasonic transmission’s biggest advantage is the ability to find the structural defects of the foundation pile accurately and intuitively. This method has such merits as it is easy to operate, and has accurate detection.also it is convenient and widely applied. Although the ultrasonic detection technology has outstanding advantages and is widely used in engineering, the numerical simulation and engineering analysis of the experimental test structure pile testing process based on this method still need to be improved.This article takes a cross-sea bridge in Liaoning Province and a testing base of piles in Beijing as background, starts from the basic principle of ultrasonic testing of concrete piles transmission method, uses the finite element software to simulate the whole process of testing defective piles by ultrasonic transmission. Combining with concrete engineering test results, this article analyzes the performance rules of defective piles in ultrasonic transmission test, thus provides the useful methods for the increasing wide range of engineering applications. First of all, the finite original model is established on the pre-processing of finite original software. And the ANSYS/ LS-DYNA acts as the computer power, simulating the common defects appearing in the actual project (holes, broken piles, necking, segregation,trailer coupling laitance, pile bottom sediment) and Ultrasonic testing process simulation is under gone through the concrete’s complete base and defective base. By sorting the velocity and amplitude parameters of LS-PREPOST4.0 post-processing data, the author analyzes waveform numerical results of cross-sectional and longitudinal section of pile multiple structural defecting test. Secondly, making concrete test piles, simulates the defective pile like holes, shrinking, pile bottom sediment.comparing numerical results, summed waveform characteristics of each defect, and provide a further basis of judgment for the abnormal waveform that occurs during measuring concrete piles. Finally, taking a test pile base in Beijing, this paper summarized the pile defects in the testing process of a certain bridge in Liaoning Province based on the basic principle of ultrasonic pile testing. Also according to the numerical simulation of ultrasonic transmission, this paper uses the comprehensive analysis to make a comprehensive consideration of such acoustic parameters as velocity, amplitude, PSD values, etc and also explored a variety of factors related to the internal defects of concrete cross-hole ultrasonic pile testing parameters.