THE USE OF TIME DOMAIN REFLECTOMETRY (TDR) TO MONITOR AN ACTIVE LANDSLIDE

摘要

The northernmost 1/2 mile of the 1999 realignment of SR 87 (approx. MP 224) has experienced slope and retaining wall failures that were initiated during the 2004/2005 winter storms. Subsequently, on March 21, 2008, a landslide closed SR 87. Arizona Department of Transportation (ADOT) addressed the 2008 landslide with an emergency remediation project, and is now evaluating the potential impacts of the recent and ancient landslide complex with an extensive investigation and monitoring program. The monitoring program consists of multiple Inclinometers, TDR cables and VWP. The TDR cables have been monitored with automatic data acquisition and data transfer. The monitoring system was also set up to alert multiple personnel once threshold values had been exceeded. Measurement of displacement using the TDR could be obtained for approximately 4 to 8 times greater displacements than were measured by the inclinometers. Results suggest the TDR can be used to determine rate of ground movement provided calibration curves are obtained for each location. The cost of the TDR system was very inexpensive when added to the inclinometer installation. Some of our lessons learned will be enumerated.