The magnet extensometer is a system, based on British Building Research techniques, for measuring either settlement or heave at various depths in soil, embankments, earthfill dams and dikes. The system consists of an access tube with external corrugate pipe, magnet rings, as well as a telescopic bottom section with datum ring and suspension head. Magnet rings (targets) are positioned externally to the access tube, and then placed in the ground where movements may occur. Magnet rings move together with the surrounding soil along the axis of the access tube. Readings are obtained with a portable unit linked to the reed switch probe that is lowered down the access tube. Comparison of data taken, over time provides profiles of ground settlement or heave.

Technical specifications

SYSTEM COMPONENTS
0D111P30000    3M section access tube
0D111P15000    1.5 m section access tube
0D111PV5500    Corrugated pipe, OD 55mm
0D111TF6000    Telescopic end and datum
0D111TS1000    Suspension head
0D111AF6000    Spring magnet ring ID 60mm, max span 300mm
0D111AR6000    Magnet settlement plate iD60mm, plate 300 mm

C121 PORTABLE READOUT (MAGNET DETECTOR PROBE UNIT)
0C121005000    Readout, 50m flat cable
0C121010000    Readout, 100m flat cable
0C121015000    Readout, 150m flat cable
0C121KITR00    Dipping probe spare kit
Probe dimensions    0D 16mm, length 250mm
Cable division    Milimetre, class II ECC
Cable sheath    nylon
System accuracy    ±1mm
Temp. operating range    -40C +80C.