Fibre Optic Rock Bolts for Strain and Shear Monitoring
The Fibre Optic Instrumented Rock Bolt embeds an optical fibre along three machined grooves to monitor the axial and shear strain profile of fully grouted rock bolts. It suits rock mines, storage caverns, and road, rail and coal-mine tunnels, including hazardous and explosive environments.
- Spatial resolution
- 5 cm down to 1 mm
- Accuracy
- better than ±10 microstrain
- Fibre arrangement
- 3 grooves, delta 120°
Overview
In detail
How it works
An optical fibre is embedded along three grooves machined along the length of the rock bolt in a delta 120° arrangement, giving good resolution on both axial strain and shear vector. An optical connector at the end of the bolt is protected by a metal cap during shipping and installation.
Installation
The optical bolt is installed with standard rock-bolt methods. The cap is removed to connect the optical cable running to the optical analyser, then a new cap is fitted to permanently protect the connector and cable where shotcrete is not used. The analyser can be located several hundred metres from the bolts in a safe zone, allowing use in hazardous and explosive environments such as coal mines.
Applications
The system measures a strain profile rather than localised point strains, capturing both shear and axial longitudinal strain. It is suited to rebar, threadbar, NMX, CT, AT and AX grade bolts, and clusters of bolts can be monitored simultaneously.
Reach out and say hi
Specifications
Technical specifications
- Spatial resolution
- 5 cm down to 1 mm
- Accuracy
- better than ±10 microstrain
- Fibre arrangement
- 3 grooves, delta 120°
- Compatible bolt types
- Rebar, threadbar, NMX, CT, AT, AX grade bolts
Downloads
Documentation, openly available
Everything you need to specify, install and integrate the Fibre Optic Rock Bolts for Strain and Shear Monitoring — no login, no paywall.
Related
Often specified alongside
Geosystems
Vibrating Wire Strain Gauge SM-5
- Range
- 3000 µε
- Accuracy
- +/- 0.5% F.S.
- Temp
- −20 to +80°C
- Range
- 200 to 35,000 kPa (standard steps up to 35,000 kPa)
Ready to specify?
Add Fibre Optic Rock Bolts for Strain and Shear Monitoring to your enquiry
Build a list, add your site notes, and an ESS engineer will quote the lot — cables, mounting and calibration included.
