The soil extensometer is used for monitoring displacement between two surfaces that may shift with respect to each other. It is widely used for monitoring of soil and rock movement in embankments and dams. The system contains a specially mounted vibrating wire displacement sensor, installed inside the protective tubing, fixed between two anchor beams with connecting rods.
The system contains a specially mounted vibrating wire displacement sensor, installed inside the protective tubing, fixed between two anchor beams with connecting rods. Any change in the relative position between the anchor beams represents deformation taking place and is measured by the displacement transducer.
The extensometer system is supplied with different gauge lengths (gage length is the distance between two anchors).
A number of extensometer units can also be connected in series to measure incremental displacements over large distances. Movement of relative position between two anchor channels at the ends of the soil extensometer is representative of mass movement.
The frequency output can be accurately measured by any vibrating wire readout unit. The data can also be automatically collected at desired frequency, stored and transmitted to remote server by a suitable wireless datalogger. The initial reading of the sensor is taken as the base. Subsequent readings are then compared with the initial reading to determine the magnitude of change in displacement across the opening.
| Sensor Type | Vibrating Wire |
| Range (mm) | 15, 25, 50, 100, specify |
| Accuracy | ± 0.2 % fs normal; ± 0.1 % fs optional |
| Sensitivity | ± 0.02 % fs |
| Non-linearity | ± 0.5 % fs |
| Temperature Limit | – 10°C to 80°C |
| Thermistor | YSI 44005 or equivalent (3 kOhms at 25°C) |
GDS has a variety of instruments for hire, these Instruments, Readouts and Dataloggers are available for product hire on a short-term (fortnightly) or long-term (monthly) basis including, but not limited to, the following:
