Geokon VW Borehole Extensometer

Product Information

Specto Technology is your one source for Borehole Extensometers and borehole logging solutions and are proud to provide you with:

  • Borehole Extensometers from Geokon and Sisgeo
  • Borehole Extensometer sales and support
  • Customized training for you and/or your subcontractors. Click here to view a list of training classes.
  • Best-in-class hosted data solutions to keep your data moving wirelessly from the field to your fingertips
  • Exceptional customer service and support

Borehole extensometers comprise of rods and anchors installed in a borehole to monitor displacements at various depths. A pre-set length of measuring rod is inserted into a nylon tube to avoid soil friction with the rod tip fixed to a groutable steel anchor. Hence, it is also called rod extensometer

Preassembled fibreglass rods are coiled at the factory and shipped ready for installation. The complete assembly is inserted into the borehole and then grouted, fixing the anchors to the rock or soil but allowing free movement of each rod within its sleeve.

Relative movements between the anchors and the reference head may be measured manually with a caliper or automatically using linear transducers that are fixed to the reference head and connected to a datalogger for remote monitoring.

Product Features

  • Automatic or manual reading
  • Multiple or single point rod reference
  • Pre-cut fiberglass rods make installation easy
  • Compatibility with many dataloggers make automation easy
  • Fiberglass is less sensitive to temperature changes than steel rods
  • May be installed at any orientation

Product Benefits

  • No assembly required, compact design with wireless usage
  • Multiple instruments can be installed in the same borehole
  • User specified anchor locations

Typical Applications Include:

  • Monitoring ground settlement/heave from the surface
  • Monitoring ground movement from within an excavation


Flex Rod Borehole Extensometer – Datasheet (Geokon)

User Manual

Borehole Extensometer Manual