Research And Application Of Ultrasonic Transmission Method To The Dynamic Test Of Foundation Pile

Ultrasonic transmission method foundation pile test is a kind of test method that based on the variety of acoustic parameters and waveform during the ultrasonic propagation in concrete to estimate and token the location, range, degree and mechanics character of pile defect. As a spring up foundation non-destructive inspect technology, the ultrasonic transmission method has eminent performance such as high testing veracity, convenient field operation, and not effected by the characteristics of pile length and slenderness ratio. The general dynamic test method like low strain is incapable assimilates to ultrasonic transmission method. In view of the existing problem of estimating foundation pile integrality and defective style by the general test method, the dissertation from the fundamental and method of concrete test by ultrasonic, utilizes the virtue of high frequency test of ultrasonic transmission method, analyzes the dynamics characteristic of ultrasonic transmission record. The dissertation applies the parameter of frequency field and time field, and combine the general test parameter, provides a system thread and test method for reasonable, credibility and concise test of foundation pile. First, the dissertation coordinates and summarizes the ultrasonic transmission test theory and estimate method of pile defect through collecting and reading, then integrates the laboratory ultrasonic testing data, analyzes the infection factors to concrete ultrasonic test result particularly and discusses the control measure to eliminate and reduce testing error. In addition, the dissertation discusses spectrum analysis method to ultrasonic transmission record of pile defect, then uses software and program analysis the ultrasonic transmission record particularly and thoroughly, especially analyzes the infection of the first break time length and concrete defect to ultrasonic spectrum, establishes the relationship between pile integrality and defect style, provides a credibility testing method and theoretical basis. Last, the dissertation uses the method in practice project to estimate pile by PSD, velocity, amplitude and depth curve with spectrum analysis of testing points method, and obtains a successful testing effect. The main innovative idea of this dissertation: Utilizes the virtue of high frequency of ultrasonic transmission method test to analyze the dynamics characteristic of ultrasonic transmission record, applying the frequency field characteristic parameter in foundation pile dynamic testing. Putting forward an integrated estimate method of PSD-velocity-amplitude-spectrum, which provides a basis to estimate the integrality of pile body and character, size and range of pile defect.