Study And Application Of Signal Matching Method For High Strain Dynamic Testing Of Pile

High strain dynamic testing method has been widely applied, along withhigh-speed development of pile foundation engineering.The traveling wave theory and the theoretical knowledge of high straindynamic testing are described in this paper. The dynamic model of pile-soil systemis established on the basis of high strain CAPWAP C matching procedure, and acorresponding MATLAB matching calculation is compiled.Multiple high strain test data, which are collected from different types andsizes of piles in engineering field, are imported in the MATLAB calculationprogram. The ultimate bearing capacity of pile is quantitative evaluated by thecalculation results.Static load test is also did on these piles at the same time. The dynamic modelof pile-soil system and MATLAB matching calculation are proved to be correct andreasonable by comparing with the static load test data.Several high strain curves from different piles are calculated by the calculationprocedure, it shows that the deviations of the calculation are not identical ondifferent types and sizes of piles by contrast analysis. The precision problem ofbearing capacity calculating by the matching calculation in this paper is discussed.The bearing capacity of the piles in engineering field is calculated by using highstrain Case pile bearing capacity formula, and the results have been compared withthe data of signal matching program and static load test. The influence of Casedamping coefficient value on the pile bearing capacity result is analyzed.The distribution graph of the soil resistance around pile is drawn, and thedistribution law and the pile bearing capacity influence character of the soilresistance around the pile are comprehended intuitively; the graph of theupward traveling wave and the downward traveling wave across the pile sectionreveals the propagation law of stress wave in the pile. The movement path anddeformation character of the soil around the pile could be obtained from the spacemesh of the pile particle displacement. The influence elements which breed error to the matching results are analyzed,and the influence character of the matching parameter’s adjustment on the matchingresults is also present intuitively.