Experimental Research On Pile Diameter Detection And Defect Inversion Of Pile

Pile Testing is of great importance to engineering quality inspection and there are tons of methods to do it,such as Low-strain Testing,High-strain Testing,Cross-hole Sonic Logging,etc.In recent years,Cross-hole Sonic Logging,which is mainly focused on in-time signal and complemented by in-frequency signal,can produce an outcome supported by large amounts of data,So far,some scientists have used numeric simulation to find Characteristic Frequency that represent the size the cross section to test the pile foundation according to the properties of Stress Wave Propagation in solid materials.In this article,I will do some relative experiments based on those theories and modify some methods in testing,since the experimental data are provided for the internal defect inversion of the pile and the preliminary inversion is carried out by extracting finite groups of data and using MATLAB.The first part of experiment is to design and create test pile.Due to the needs of experiments,I use two Hand Dug Piles and design it by adding Step-wise Variable Cross-Section and Abrupt Variable Cross-Section and setting a lot of defects with different size and categories.Within the 28 days before piles are formed,I collect tons of data to calibrate the altitude of defects and the state of compression,which lays a good foundation for the success of following experiments.In the test of pile radius,I apply titling test to test the normal parts,defects and the parts with extended radius and then import data into MATLAB to get the corresponding frequency spectrum,afterwards,I find the characteristic frequency that represents the pile radius and compare it with the real data to get the relative conclusion.And based on the tilting test,I use some software to get the pile speed chart by dividing the regional grid in pile,adding test points bilaterally and thus make there is at least one transmit and receive ray passing by and then extracting data.At last but not least,I use those charts to analyze defects and give some relevant suggestions.In this paper,I use a great mass of experimental data,processing software and inversion procedures and do a great number of researches in the pile diameter and internal defect information to get the wave velocity time effect.And by means of the improvement of pile diameter detection methods and through the assistance of using wave speed to test defects,I expect we can use those methods in daily engineering practice.