Soil Strainmeter

Soil Strainmeter

Applications

Typical applications of the Durham Geo Soil Strainmeter include:

  • Monitoring horizontal strain in embankment dams.
  • Monitoring tension cracks in earth structures.
  • Stainless model for monitoring strain in rockfill dams.

Operation

The soil strainmeter employs a potentiometer and a rod mounted between two anchors to monitor horizontal movements of the surrounding soil. These components are linked together so that movement of one anchor relative to the other causes a change in the output of the potentiometer. The initial reading of the strainmeter is used as a datum. Subsequent readings are compared to the datum to calculate the magnitude, rate, and acceleration of movement.

Strainmeters are usually installed in series along the axis of anticipated deformation. Strainmeters may also be arranged in arrays or in groups with different alignments. A gauge length of 3 to 6 meters is typical, but will vary according to the expected magnitude of movement and the type of structure being monitored.

There are two models of the strainmeter available: the standard strainmeter for soils and the stainless-steel strainmeter for rockfill dams.

Advantages

Easy Installation: The strainmeter is designed for easy assembly, easy extension of gauge lengths, and easy adjustment.

Reduced Cable Costs: The double-sensor version provides cable economies since a single length of cable can serve two sensors and two gauge lengths.

Manual or Automatic Readout: Strainmeters can be read manually with a portable indicator or can be connected to a data logger for unattended readings.

Standard or Stainless: The standard model is designed for use in soil embankments, and the stainless model is designed for use in rockfill dams.

For more information

Please download the data sheet for the Soil Strainmeter. The data sheet can be viewed and printed with Adobe Acrobat Reader.

Soil Strainmeter Specifications

STANDARD SOIL STRAINMETER
Single-Sensor Strainmeter 51705600 Single-Sensor components include one sensor housing with with one potentiometer, one stainless steel all-thread rod, telescoping PVC pipe, and two anchors. Signal cable is ordered separately
Double-Sensor Strainmeter 51705620 Double-Sensor components include one sensor housing with two potentiometers mounted back to back, two stainless steel all-thread rods, telescoping PVC pipe, and three anchors. Signal cable is ordered separately
Gauge Length Gauge length for each sensor is adjustable between 480 to 1525 mm (19 to 60"). Longer gauge lengths are made by adding one or more gauge extension kits
Sensor Type Linear potentiometer
Sensor Range 150 mm (6")
Sensor Linearity ±0.3% FS
Resolution 0.01% FS with extensometer indicato
Materials PVC Plastic and Stainless Steel
GAUGE LENGTH EXTENSION KITS
Standard 1.5m Extension Kit 51705650 Adds 1.5-meter (5') extension to gauge length of strainmeter. One or more kits can be added to the strainmeter. However, it is recommended that the total distance between anchors does not exceed 6 meters. Assembly requires PVC-ABS cement
Standard 3m Extension Kit 51705660 Adds 3-meter (10') extension to gauge length of strainmeter. One or more kits can be added to the strainmeter. However, it is recommended that the total distance between anchors does not exceed 6 meters. Assembly requires PVC-ABS cement
STAINLESS STRAINMETER
Single-Sensor Strainmeter 91707610 Single-Sensor components include stainless steel housing with one potentiometer, one stainless steel all-thread rod, telescoping stainless steel pipe, and two steel anchors. Signal cable is ordered separately
Double-Sensor Strainmeter 91707620 Double-Sensor components include stainless steel housing with two potentiometers mounted back to back, two stainless steel all-thread rods, telescoping stainless steel pipe, and three steel anchors
Gauge Length Gauge length is adjustable between 480 to 1525 mm (19 to 60"). Longer gauge lengths are made by adding one or more gauge extension kits
Sensor Type Linear potentiometer
Sensor Range 150 mm (6")
Sensor Linearity ±0.3% FS
Resolution 0.01% FS with extensometer indicator
Materials Stainless Steel
STAINLESS EXTENSION KITS
Stainless 1.5m Extension Kit 91707630 Adds 1.5-meter (5') extension to gauge length of strainmeter. One or more kits can be added to the strainmeter. However, it is recommended that the total distance between anchors does not exceed 6 meters
Stainless 3m Extension Kit 91707640 Adds 3-meter (10') extension to gauge length of strainmeter. One or more kits can be added to the strainmeter. However, it is recommended that the total distance between anchors does not exceed 6 meters
SIGNAL CABLE
Signal Cable 50613824 Shielded cable with four 22-gauge, tinned copper conductor with polyvinyl chloride (PVC) jacket
Double-Sensor Signal Cable 50613527 Shielded cable with seven 22-gauge tinned-copper conductors with polyurethane jacket
Universal Terminal Box 57711600 Provides connections for 12 sensors and an indicator. Sensors selected by rotary switch. Weatherproof fiberglass box measures 290 mm wide x 345 mm high x 135 mm deep
DATA LOGGERS
Compatible data loggers include the Campbell Scientific CR1800, CR1000 and CR6. Eight double-sensor strainmeters or sixteen single-sensor strainmeters can be connected to each AM16/32 multiplexer. See separate data sheet for details