Borehole extensometers are used to monitor displacement at different depth in the same borehole.
The Rigid rod is fixed at a groutable steel anchor.
Among the application there are: heave monitoring in excavations, settlement monitoring, deformation and subsidence measures in foundations, tunnels, mines, excavation and rocks movements.
Rods movements can be measured manually with a caliper or with a displacement transducer and a data logger.
Borehole extensometer (or rod extensometer) can monitor more than one points in the same borehole.