High resolution time domain reflectometry and coaxial cable for soil nail monitoring

Abstract Soil nailing is a popular application in soil slope stabilization. Failure of soil nailing could be mainly due to the issue of installation such as inaccuracy of actual length of the soil nail and integrity of cement grout annulus during grouting. This study focuses on using non-destructive technique of time domain reflectrometry (TDR) to monitor the quality of soil nail. TDR is originally used to detect changes in geometry and electromagnetic properties (dielectric or magnetic) happening along its transmission cable and detect the damage or leakage from the cable. The objective of this study is to use high resolution TDR and coaxial cable to detect changes of grout condition in soil nail. Results confirm the suitability of high resolution TDR and coaxial cable to detect void length which relates to grout condition in soil nail. The findings conclude that high resolution TDR model T631 and coaxial cable type RG-6 are capable to detect even small size void and is suitable to be applied for soil nail monitoring.