The Quality Analysis Of Integrity Of Foundation Pile Based On Dynamic Test

With vigorous development of civiling engineering in our country, pile foundation has becoming one of the most important foundation forms, which is extensively used in high-rise buildings, railways, bridges, nuclear power stations, marine platform, coast dock and large dynamical machine foundation, and so on. But some kinds of defects such as gapping, break, separation are usually found in bored case-in-place piles, which maybe reduces bearing value of pile and does harm to the superstructure, furthermore, make pile lose carrying capacity. So, in order to ensure good quality of piles, it has become more important to carry out quality testing for piles as many as possible by using a simple and fast pile dynamic testing method.Defective piles are established model of the vibration frequency response and speed of response model, and damping analysis of pile, pile length, pile soil stiffness coefficient, elastic wave velocity and other parameters of pile on the frequency response curves and different soil, different defects nature, different pile when the pile diameter changes damping level of the relationship between the relative volatility. Wuhan-Guangzhou passenger line to the black section of the Chiang family units spend the pile bridge engineering background, combined with relevant regulations, the use of fuzzy comprehensive method was evaluated. Mainly by the following results:(1) With the increase of damping force of pile, to reduce second-order frequency range increases, but the frequency is not the general trend has nothing to do with the length of the pile; when the pile soil stiffness increases, the frequency value is essentially unchanged ; with the pile length increases, the frequency values showed a decreasing trend of the last tends to a straight line.(2) No matter what the soil, soil with a side of the damping coefficient, the defect when the defect level of a certain location the greater the amplitude ratio is smaller; with a side of the soil damping, the defect level of a certain position when the deeper the defect the greater the amplitude ratio.(3) The use of fuzzy comprehensive evaluation method to practical engineering pile collected acoustic parameters (velocity, amplitude and frequency) for a comprehensive assessment, that a comprehensive evaluation of fuzzy mathematics method for pile foundation inspection is feasible. And acoustic parameters of the pile of concrete with varying degrees of sensitivity to the defect, the defect amplitude and frequency are more sensitive to amplitude and frequency can increase the weight fuzzy vector, and thus the quality of concrete piles to make more stringent judgment.