Borehole Rod Extensometer
The Borehole Rod Extensometer measures settlement, displacement and deformation in soil and rock using a reference head connected to one or more in-hole anchors by rigid or flexible rods. It is commonly installed in natural or cut slopes to monitor slope stability.
- Measurement
- Magnitude, distribution, rate and acceleration of deformation, measured at the reference head
- Configuration
- Reference head with one or more in-hole anchors on rigid or flexible rods inside a flexible sleeve
- Readings
- Mechanical or electrical, transmitted to a collar reference plate

Overview
In detail
How it works
The extensometer consists of a reference head and one or more in-hole anchors, each placed at a known depth and connected to the reference head by a rigid or flexible rod running inside a flexible sleeve that keeps the rod de-bonded from the grout. As the soil or rock deforms, the distances between the in-hole anchors and the reference head change, and the magnitude, distribution, rate and acceleration of deformation can be measured at the reference head.
Deployment
The instrument is commonly installed in natural or cut slopes to monitor slope stability, transmitting anchor displacements from failure planes in rock or zones of movement in soil masses to a collar reference plate via mechanical or electrical readings. It can also detect settlement when installed appropriately.
Configuration
The extensometer range is available in a wide variety of reference heads, anchors, rods and measuring sensors to suit different applications.
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Specifications
Technical specifications
- Measurement
- Magnitude, distribution, rate and acceleration of deformation, measured at the reference head
- Configuration
- Reference head with one or more in-hole anchors on rigid or flexible rods inside a flexible sleeve
- Readings
- Mechanical or electrical, transmitted to a collar reference plate
- Options
- Wide variety of reference heads, anchors, rods and measuring sensors
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