Article · January 2000 citations 16 reads 1,575 1

Remote Access. Telemetry using a datalogger and a hardwire or cellular telephone can be installed for real-time readings and/or difficult access areas without the need to visit the site. In-place inclinometers are available but, they are expensive and must be considered sacrificial. Another advantage of remote automated systems is that other sensors can be included such as vibrating wire piezometers for water level measurements, potentiometric extensometers for ground surface movement monitoring, and electrolytic bubble extensometers for monitoring tilt. Any of these sensors, including TDR, can be programmed trip an alarm should their output exceed a predetermined threshold. When TDR is installed in highways, traffic control is not necessary. Cables can be run under the pavement and accessed safely from the shoulder.

4. 
   Attachment to Inclinometer Casing. TDR cables can be attached to the outside of conventional inclinometer casing. Although the cable will be affected by the presence of the casing, it usually outlasts the casing and can provide information about movement after the casing has been deformed too much for the probe to pass through.
   

5. 
   Installing in Unusable Inclinometer Casing. If an inclinometer casing is not
   

deformed too much, a TDR cable may be passed through bends to the bottom of the casing. The casing then can then be grouted and the TDR cable read other.

6. 
   Safety. With TDR, data collection can be done from a safe location, even from an office with remote data acquisition equipment. It is not necessary to expose a technician to dangerous traffic, or to landslide and rockfall hazards on moving slopes.
   

7. 
   Data. In most unstable slope situations, the questions that need to be answered are: is it moving?; where is it moving?; and how fast is it moving? TDR provides this information quickly. It is not necessary to download data from a readout box into a computer and then plot the results. The screen on the cable tester shows the cable signature immediately. By comparing cable signatures over time, the location and changes in the rate of movement can be determined. Rates of deformation can be estimated by plotting the magnitude of the spike in the cable with time.
   

Disadvantages
TDRhas some disadvantages when compared with inclinometers. Anyone contemplating using TDR should be aware of these:

1.