Direct Shear
An in-house direct shear apparatus is available, originally designed by Teysseire (2005) to reproduce large in-situ shear tests under unsaturated conditions. The device is 250 x 250 mm in plan and 110 mm height. A maximum shearing displacement of 20 mm can be applied to the specimen, by movement of the lower part of the box while the upper part is kept stationary. The upper plate of the box is covered by a 5 mm thick porous stone, imposing a normal stress of 1.4 kPa. The apparatus is equipped with a horizontal LVDT (to measure the shear displacement), 3 vertical LVDTs (to measure dilation or contraction), 2 horizontal load cells (to measure the shear load), 1 vertical load cell (to measure the vertical stress), and 6 tensiometers (to measure suction).
The technical specifications of the direct shear test apparatus are summarized as follows:
- Dimensions: 250 mm x 250 mm x 110 mm
- Maximum horizontal displacement: 20 mm
- Maximum shear stress: 320 kPa
- Maximum vertical stress: 160 kPa
- Suction measurement with tensiometers
