Key features | Benefits to the user |
Direct control of both Matric Suction and Axial Stress: | It is now generally accepted that unsaturated soil behaviour is governed by two independent stress state variables, i.e. net stress and matric suction (Fredlund and Morgenstern, 1977). |
Axis translation technique: | Matric suction is controlled up to either 500kPa or 1500kPa (depending on the air entry value chosen) by controlling pore air and pore water pressure directly. |
Fully controllable axial load / stress / displacement / strain:
| The Stress Dependant Soil Water Characteristic Curve (SDSWCC) is possible due to the precise control over the axial stress. This poses an advantage over the traditional pressure plate extractor in which no external stress is applied and volume change of the soil specimen is assumed to be zero.
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Fixed ring K0 conditions:
| K0 conditions ensure there is no lateral deformation, therefore sample volume can be calculated directly from the axial deformation recorded.
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Upgrade Options:
| Both the Rowe and Barden and CRS type apparatus, even if first supplied for fully saturated testing only, can be upgraded to an unsaturated version at any time.
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