File Name
Vibrating Wire Inline Extensometer
Resource Type
Brochure| Language | Version | Download |
|---|---|---|
| English | EXB0020G |
|
| Spanish | EXB0031A |
|
Vibrating Wire Inline Extensometer
The Vibrating Wire Inline Extensometer is used to determine the stability and movement behavior of soil, rock, and concrete structures.
Overview
The Vibrating Wire Inline Extensometer is used to determine the stability and movement behavior of soil, rock, and concrete structures. The main advantage of the extensometer is that it has no electrical head protruding out of the borehole, contrary to conventional multi-point borehole extensometers (MPBX). The Inline Extensometer is installed flush with the borehole collar or ground surface and measures movement at different depths in the borehole.
By construction, all displacement transducers are located in the borehole in sealed head/anchor assemblies that are inserted in the borehole and separated by extension sections which can be of variable length depending on the required measurement depths. The extension sections consist of rigid 3/8 inch (9.5 mm) stainless steel rods protected by a 1/2 inch (12.7 mm) SCH40 PVC sheath. The larger diameter of the rigid rod is an additional advantage as compared to the usual 1/4 inch (6.35 mm) of conventional MPBXs, as it provides more accuracy in the measured displacements, both in case of extension and compression movements.
As all displacement transducers are in series in the borehole, the total measurement range of the extensometer is the sum of the individual measurement ranges of each transducers. This allows measurement of considerably larger movements than conventional MPBXs while using lower cost standard range transducers.
VIBRATING WIRE INLINE EXTENSOMETER SPECIFICATIONS
| ITEM | SPECIFICATION |
| Sensor Range | 50, 100, 150, 200 mm Other ranges available on request |
| Accuracy | +/- 0.1 % FS |
| Resolution | 0.025% FS |
| Linearity | <0.5% FS |
| Thermal Zero Shift | <0.05% FSR/°C |
| Operating Temperature | -20°C to 80 °C |
| Min. Borehole Diameter | 75 mm |
| Signal Cable | Two twisted pair cable with polyurethane jacket (one cable per measurement point). |
Vibrating Wire Inline Extensometers are commonly used for:
- Ground movements around tunnels.
- Deformation of concrete piles (tell-tales).
- Deformations of dam abutments and foundations.
- Ground movement behind retaining walls, sheet piling, slurry walls, etc.
- Ground movements in the walls of open-pit mines.
- Fracturing in the roofs and walls of underground caverns.
- Subsidence above tunnels and mine openings.
- Settlement and heave of foundations in soft soil.
View illustrations on how the Vibrating Wire Inline Extensometers are used in underground mines.
Vibrating Wire Inline Extensometer Ordering Info
| EXTENSOMETER HEAD & ANCHOR ASSEMBLY PLEASE SPECIFY ANCHOR TYPE |
PART # | GAUGE LENGTH |
| 50 mm | EXINLINE-1050 | 1 m |
| 100 mm | EXINLINE-1100 | 1 m |
| 150 mm | EXINLINE-1150 | 1.5 m |
| 200 mm | EXINLINE-1200 | 2 m |
Extension Kit Lengths
| ITEM | PART # |
| 0.5 m | EXIL-0500 |
| 1.0 m | EXIL-1000 |
| 1.5 m | EXIL-1500 |
| 2.0 m | EXIL-2000 |
| 3.0 m | EXIL-3000 |
Cable
| ITEM | PART # |
| Signal Cable | EL380004 |
End Anchors
| ITEM | PART # |
| Groutable Anchor | EXIL11000 |
| Groutable Anchor with Spring Legs | EXIL12000 |
| Hydraulic Borros Anchors (Double Acting) | EXIL13500 |
| Hydraulic Bladder Anchor (Please confirm Borehole diameter) |
EXIL14000 |
Top
| ITEM | PART# |
| Anchor kit for mounting top sensor at surface (optional) |
EXA0379 |
Ordering Info Considerations
| Sensor range |
| Extension: compression ratio (10%, 25%, 50%, 75%, 90% – as standard) |
| Number of anchors, type and depths |
| Cable length |
| Accessories & optional equipment |
| Borehole diameter & orientation |
| Environmental considerations |
| Drilling method & soil/rock types |
| Other environmental considerations |
Accessories & Optional Equipment
| ITEM | PART# |
| Grout and/or bleed tubes | Contact RST |
| Vibrating Wire Readout | VW2106 |
| Dataloggers | Contact RST |
| Hydraulic Pump for Borros & Bladder Anchors | EXHYDPUMP |
| 1/8 in. Inflation Line for Hydraulic Bladder Anchors | BP0545 |
| 3/16 in. Inflation Line for Borros Anchors | BP0557 |
| 1/8 in. Tube Union | B-200-6 |
| 1/8 in. Ferrule Set | B-200-SET |
| 3/16 in. Tube Union | B-300-6 |
| 3/16 in. Ferrule Set | B-300-SET |
File Name
Multi-Point Inline Extensometer Installation Manual
Resource Type
Manual| Language | Version | Download |
|---|---|---|
| English | EXM0097I |
|
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