Stability and movement behavior of soil and rock masses can be determined by the use of borehole extensometers. A typical rod extensometer consists of a reference head, usually installed at the collar of a drill hole, and one or more in-hole anchors, each of which is fixed in place at a known depth in the borehole. As the soil or rock deforms, the distances between adjacent in-hole anchors change, as do the distances between the individual in-hole anchors and the reference head. This allows an accurate determination of distribution, magnitude, rate and acceleration of deformation in the rock or soil mass intersected by the drill hole.
- Monitoring deformation around underground excavations.
- Movement behind the face of excavated slopes.
- Consolidation settlement in soils.
- Bottom heave in open cut excavations.
- Strain in concrete structures.
- Subsidence over mines, tunnels, etc.
- Pile load tests.
- Monitoring of mine pillar deformation.
- Deformation of foundations in and under buildings.
- Roof and wall stability in mines and underground workings.