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.
| 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 |
Vibrating wire inline extensometers are commonly used for:
- Earth movements around tunnels.
- Deformation of concrete piles (cores).
- Deformation of abutments and dam foundations.
- Earth movement behind retaining walls, sheet piles, mud walls, etc.
- Earth movement in the walls of open pit mines.
- Fractures in the roofs and walls of underground caverns.
- Subsidence above tunnels and mine openings.
- Settlement and uplift of foundations in soft soil.
Vibrating Wire Inline Extensometer Ordering Info
| EXTENSOMETER HEAD & ANCHOR ASSEMBLY |
PART # |
GAUGE LENGTH |
| PLEASE SPECIFY ANCHOR TYPE |
| 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 confirmBorehole 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 |
