Rock Pressuremeter TRI-MOD-S
The TRI-MOD-S rock pressuremeter (flexible dilatometer) measures the in-situ strength and stress-strain properties of very stiff soil and rock in a pre-cored N-size borehole, using a hydraulically inflated probe with six strain gauges to log diametric change under stepped pressure.
- Probe diameter
- 73 mm min., up to 82.0 mm at 10,000 kPa / 76.2 mm at 20,000 kPa
- Working pressure
- 20,000 kPa (3000 psi) max
- Accuracy
- ± 1% FS (pressure gauge)

Overview
In detail
How it works
The probe is a single cylindrical cell, hydraulically inflated, fitted with six strain gauges on cantilevered arms and an inflatable metallic sheath. Stress-control is used to run the test: equal pressure increments are applied and held constant for one minute, with diametric changes logged 30 and 60 seconds after each step. Unload/reload cycles can be performed.
In-situ stress-strain curves are obtained by plotting the changes in each of the three instrumented diameters, or their average, against pressure. The modulus of deformation E used to calculate settlement is E = (1 + n)(ΔP/ΔR)R, where n is Poisson's ratio, ΔP is the corrected pressure increase, and ΔR/R is the relative change of radius.
What's included
The complete kit comprises the probe, a hydraulic manual pump, a pneumatic cylinder for deflating the probe, a datalogger, tubing and electrical cable, and two calibration tubes.
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Specifications
Technical specifications
- Probe diameter
- 73 mm min., up to 82.0 mm at 10,000 kPa / 76.2 mm at 20,000 kPa
- Working pressure
- 20,000 kPa (3000 psi) max
- Accuracy
- ± 1% FS (pressure gauge)
- Diametric resolution
- < 0.01 mm
- Borehole size
- N size (76 mm)
- Strain gauges
- 6 electrical strain followers
- Inflatable sheath length
- 490 mm
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