The Analysis Of Integrity Of Foundation Pile Based On Dynamic Test

With vigorous development of construction industry in our country, pile foundation has becoming a kind of important foundation forms. But some kinds of defects such as contraction,separation,break are usually found in bored cast-in-place piles, which maybe reduce bearing value of pile and do harm to the superstructure, furthermore, make pile lose carrying capacity. So measurement can be taken to strengthen defective piles after accurately judging the defective type, location and degree. Otherwise, it must threaten the safety of building and the people's life. Therefore, the test of pile's integrity is a problem, which engineers pay much close attention to. Now, the confirmation of defective position has already come to the high level, but the quantitative analysis of defective degree is the most urgent problem, which has not realized completely. The paper has studied how to use frequency determine the defective degree.First, response model in time domain of pile under the transient state of stimulated vibration is reduced according to damping wave equation, initial condition and boundary condition. Then, vibrant response characters in frequency domain are also reduced. These provide basis on analyzing response curve in frequency domain.Second, response model of defective pile is established. By analyzing frequency equation under different bottom condition, response model that measures pile's defect is established, then frequency equation of defective pile is reduced and Matlab calculation program is works out from it. Based on the program we have acquired large data. Relation formula between defective frequency and defective degree is got according to these data.Last, the accuracy and appliance of quantitative analysis theory is proved by apply it to the defective piles in engineer practice on this region.