Cross-Hole Sonic Logging
”Cross-Hole Analyzer, for reliable cross-hole sonic logging and improved quality assurance of concrete foundation”
Cross-Hole Analyzer (CHA) is a non-destructive test and is used to determine the quality and consistency of cast in place pile. Selected bored pile is pre-installed with 50mm diameter mild steel tubes (number of tubes depends on pile size, ranging from 2 to 6 tubes or more) secured to the steel cage that span the whole axial length and cast together in concrete.
During testing, the tubes will need to be filled with clean water. A transmitter will be lowered down into one tube to send a high frequency signal that travel through the concrete and detected by a receiver in another tube. As these sensors are raised and/or lowered along the length of the pile, the CHA will record, at regular depth intervals, the time that the signal takes to travel from the transmitter to the receiver (first arrival time), as well as the signal energy. These two parameters will indicate the concrete quality between the pair of tubes at particular depth for any soil inclusion in the pile. The entire shaft length is logged and the test is then repeated for each pair of tubes, allowing for a full and thorough investigation of defects both along the length and by its quadrant.
Shaft cross section with four tubes,
six path are tested
Schematic diagram for Cross-Hole