Evaluation of TDR applications in engineering geological investigations -case study on Darian dam

Due to the expansion and application of technology in soil and rock mechanics, engineering geology and geotechnics, it is possible to use newer, faster and cheaper methods in these fields every day. TDR technology is one of these methods. This technology has been developed by the telecommunication and electricity industry to determine the location of cable faults. The radar is a prime example of the TDR. The basis of this technology is the sending of a short pulse of energy (electromagnetic pulse) that is reflected in the collision with some anomalies. The point location of these anomalies can be determined if the velocity and direction of the pulse can be determined. The electromagnetic pulse reaches the waveguide through the conductor cable and enters the test environment. In this research, this method was used to determine the groundwater level in the Darian dam. The TDR has the ability to detect the air-water interface, and the reported results are consistent with the measured data using traditional methods. Also in one of the situations that are prone to slide, coaxial cable was installed as TDR sensor. The results showed that the TDR recognizes the shearing and stretching zones in the cable as the result of the ground movement successfully. Finally, since manual processing of TDR data was very difficult and requires high accuracy and time, a method for computer processing of this data was provided by the authors.