SWCC Machine

The SWCC machine is used for determining the influence of the stress states on the Soil Water Characteristic Curve (SWCC) of a soil sample. This system is developed to perform SWCC test, conforming to ASTM D6836-16. This system allows determination of both wetting and drying SWCC. The suction is generated using a pro pneumatic APC at the top of the sample and a pro hydraulic APC at the base, applying the axis translation technique. Some of the equipment features are as follows

• Air-tight cell fitted with High Air Entry Disc ( 5 bar) for 70 mm diameter and 20 mm height sample.
• Internal submersible load cell.
• On-board data logging with large data storage (up to 14 million records) using SD card (8GB standard).
• High speed sensor conversion (24 bit, up to 4000 samples/sec).
• Frame can also be used with the same cell for constant rate-of-strain (CRS) and Consolidation tests.

Purpose:

• Develop wetting and drying soil water characteristic curves for soils.
• Obtain the unsaturated shear strength parameters.
• Develop stress paths for field applications.
• Establish the relationship between stress state variables and deformation strain state variables for unsaturated soil.
• Determine the fluid flow conditions in unsaturated soils and obtain unsaturated coefficient of permeability.
• Determine the relationship between matric suction pressure and the moisture holding capacity of soils for various confinements.

Ranges:

• Maximum Frame Capacity: 15kN
• Load cell: 25 kN
• Automatic Pressure controller
  • Hydraulic: 1000kPa
  • Pneumatic: 1000kPa
• LSCT Displacement Transducer: 25 mm X 0.001 mm
• Pressure Transducer: 10 Bar
• Maximum Cell Capacity: 2000 kPa

• Characterize matric potential of unsaturated soils with varying moisture contents.
• Unsaturated Hydraulic Conductivity.

• Design parameters for earthen dams, levees, retaining wall
• Modeling water distribution and flow in unsaturated soil.
• Designing foundation on unsaturated soils.

• Puppala, Anand J., Koonnamas Punthutaecha, and Sai K. Vanapalli. “Soil-water characteristic curves of stabilized expansive soils.” Journal of Geotechnical and Geoenvironmental Engineering 132, no. 6 (2006): 736-751.
• Hoyos, L. R., H. R. Thudi, and A. J. Puppala. “Soil-water retention properties of cement treated clay.” In Problematic Soils and Rocks and In Situ Characterization, pp. 1-8. 2007.
• Punthutaecha, K., and A. J. Puppala. “SOIL-WATER CHARACTERISTICS OF FLY ASH STABILIZED SOIL.