Research On Fast And Non-destructive Methods Of Pile Integrity Of Inservice High-piled Beam-slab Wharf

As one of the most important structure form, beam-slab high-piled wharfs are widely applied in Chinese coastal ports. A great quantity of piles are damaged every year because of some natural causes and human factors, including seawater erosion、typhoon、overload of transportation and collision of ships.The upper structures (beam, panel, etc) above the pile cap makes it difficult to test the integrity of piles, where the conventional methods are not available, so it’s still a engineering problem urgently to be solved to find fast and non-destructive methods which deal with the existence of mass of long piles underwater and upper structures.Based on the research achievements at home and abroad, feasibilities of every method being applyed on the high-piled wharf are analyzed. Two- velocity method is proved to be effective by data processing after numerical simulation and in-site test. The application of "correlation function" method is initially discussed. The main contents and conclusions are as follows:(1) Make sense of the development history of dynamic testing on the basis of collecting the existing means. Summarize the methods according to the dynamic responses of structure and introduce the new modified technologies according to the low-strain reflected wave method, like Two-Velocity,Bend-Wave,Ultraseismic-Wave , Impedance-Log, etc. The advantage and feasibility of every technology applied to the pile integrity detection are discussed, which form a relatively comprehensive view of current research status.(2) Two-velocity method is effective to reduce the disturbance resulted from the upper structure by separating the stress wave and has good prospects. Setting up the numerical model of wharf considering the soil and upper structures by means of ANSYS-DYNA. Defects of different forms are arranged on diverse depth of piles and then testing the feasibility of this method.(3) Carry out the field test on a typical high-piled wharf segment of Tianjin Port with the help of professional testing institution. Using the worldwide most advanced PIT(Pile Integrity Test) two channel device, results of Two-Velocity test are acquired, which correspond with the curves got from the previously numerical simulation. It proved that Two-Velocity method is available for detecting the integrity of piles of high-piled wharf.(4) Based on the principle that existing injuries could change the dynamic characters of structures ,Correlation Function Method can be applied to detect several piles at the same time by calculating the correlation function between sensors put on different parts. Build the practical wharf numerical model including batter piles on multi layer of soils considering the contact of pile and soil and then calculate the multi natural frequencies and modes of vibration that reveals the advantage of correlation function as the indicator of PIT. Damages set in diverse depths are clearly displayed after testing on the numerical bents model, which demonstrates the availability of correlation function method...