Detection of Buried Pipes in a Model Sand Bath Using Impulsive Sound Waves

摘要

A method of detecting pipes buried underground has been developed by placing a transmitter on the ground surface, by using a pulse echo method, carrying out special signal processing of the received signals and constructing an underground cross-sectional display. Tests for detecting buried pipes were carried out in two sand baths. The results of these tests confirm that the method is extremely effective, since it was possible to detect 80mm PVC pipes and carbon steel pipes used for plumbing, which were buried within 1.3m of the ground surface, since it was possible to detect 150mm pipes buried at depths of 1.2m irrespective of the pipe material, i.e., carbon steel pipes used for plumbing, asbestos pipes, clay (pottery) pipes and PVC pipes, and since the present equipment was sufficiently sensitive to detect two 75mm PVC pipes buried at different depths directly beneath each other and obliquely to each other. The advantages of the equipment for the detection of buried objects and the signal processing method are that it is easy to operate and it is possible to confirm the presence of buried pipes from a series of output waveforms by varying the delay times even when measurements have been made in only one position. Finally, the authors would like to thank the staff of the CEL of Ibaraki ECR part of Nippon Telegraph and Telephone Public Corporation who cooperated in the measurements. (ERA citation 07:051398)