File Name
Metallic Time Domain Reflectometry
Resource Type
Brochure| Language | Version | Download |
|---|---|---|
| English | MIB0010H |
|
| Portuguese | MIB0088A |
|
| Spanish | MIB0604A |
|
Metallic Time Domain Reflectometry
Metallic Time Domain Reflectometry (TDR) is a simple and economical way of detecting and interpreting rock and soil mass response to underground and surface mining using coaxial cables grouted in boreholes.
Overview
Metallic Time Domain Reflectometry (TDR) is a simple and economical way of detecting and interpreting rock and soil mass response to underground and surface mining using coaxial cables grouted in boreholes. TDR
can be used effectively to locate rock and soil mass movements.
TDR involves the installation of a coaxial cable in a borehole filled with grout that matches existing soil or rock conditions. A TDR unit is employed to generate a voltage pulse along the cable and receive reflections. Reflections are generated by cable deformations, abrasions and severing. Crimps at known locations along the cable are used to provide depth datum.
As movement occurs, the reflections along the cable change as the cable deforms. By connecting the TDR200 to a PC through Type A Micro B USB cable, TDR reflections can be interpreted by software, thereby inferring location, type and rate of earth movement. TDR systems can be combined with data loggers and multiplexers to allow remote readings of multiple cables.
| Specifications | |
| Item | Specification |
| Tensile Strength | 113 kg |
| Maximum Tensile Force | 1100 N (247 lb) |
| Maximum (Recommended) Clamp Spacing | 0.6 / 1 m (2 / 3.25 ft) |
| Minimum Bending Radius, Single Bending | 70 mm (3 in.) |
| Minimum Bending Radius, Repeated Bending | 125 mm (5 in.) |
| Bending Moment | 6.5 Nm (4.79 lb-ft) |
| Installation Temperature | – 40 to +60 °C (-40 to 140 °F) |
| Operation Temperature | – 50 to +85 °C (-58 to 185 °F) |
| Storage Temperature | – 70 to +85 °C (-94 to 185 °F) |
| Inner Conductor | Copper-Clad Aluminium Wire, 4.8 mm (0.19 in.) |
| Dielectric | Foam Polyethylene, 11.9 mm (0.47 in.) |
| Outer Conductor | Corrugated Copper, 13.8 mm (0.54 in.) |
| Jacket Material | Polyethylene, PE 15.8 mm (0.62 mm) |
| Weight | 0.2 kg/m (0.14 lb/ft) |
| Characteristic Impedance | 50 ± 1 Ω |
| Relative Propagation Velocity | 88% |
| Capacitance | 76 pF/m (23.2 pF/ft) |
| Inductance | 0.19 μH/m (0.058 μH/ft) |
| Maximum Operating Frequency | 8.8 GHz |
| Jacket Spark Test RMS | 8000 V |
| Peak Power Rating | 38 kQ |
| RF Peak Voltage Rating | 1950 V |
| DC Resistance, Inner Conductor | 1.57 Ω/km (0.45 Ω/1000ft) |
| DC Resistance, Outer Conductor | 2.7 Ω/km (0.82 Ω/1000ft) |
Time Domain Reflectometry is commonly used for:
- Monitoring rock and soil movement.
- Monitoring subsidence above abandoned underground mines.
- High wall slope monitoring in open-pit mines.
View illustrations on how Time Domain Reflectometry is used for:
Metallic Time Domain Reflectometry Ordering Info
| ITEM | PART # |
| TDR Coaxial Cable with Connector Kit | EL810918 |
| FLEXDAQ Data Logger (with TDR200) | Contact RST for details |
| Portable Time Domain Reflectometer | ELGL3000 |
File Name
Metallic Time Domain Reflectometry (MTDR) System Installation and User Manual
Resource Type
Manual| Language | Version | Download |
|---|---|---|
| English | ICM0104A |
|
Speak with an Expert
I’m very happy with the quality of the instrumentation and technical support from RST, as always. They worked with us from the initial stages of the project to ensure that we were fully prepared and equipped to use the RSTAR network for the first time. They delivered everything within the tight project time frame to ensure that there were no delays on site, and the submersible tilt meters looked like new even after over twelve months of being submerged in Thames water!
-Richard Lipscombe, BEng (Hons), Director & Principle Consultant - RL Geotechnical Ltd