Identifying leakage situations using the effect of soil moisture changes on TDR waveforms

Electromagnetic methods in applied geophysics are advancing rapidly. Since the TDR system has grown, its use has led to innovative applications and comparisons with other previous measurement methods. A TDR system consists of a radar (electromagnetic) receiver and generator, a transmission line, and a waveguide. The electromagnetic pulse generated from inside the conductor cable moves towards the waveguide and is tested through the waveguide into the environment under test. In the last few years, the use of the TDR system to identify water leakage situations has been expanding. In this article, by performing tests on two-strand telecommunication cables as TDR sensors, the ability and accuracy of the time domain reflectometry method in detecting leakage situations has been evaluated. In this research, the two-stranded cable was buried under GC gravel clay material, and by increasing the percentage of soil moisture stepwise at two points, the sensitivity of the TDR method to the changes in moisture around the cable was investigated. Based on the TDR waveforms, the points of reflection coefficient changes are located at the distances of 9.5-9 and 4.5 meters, which is completely consistent with the actual distance of the test points. In this research, TDR moisture meter made by soil moisture company model 6050x1 was used. The results of this research show that the TDR method has the ability to be used as a monitoring system to detect leakage in dams, dikes and other geotechnical structures.