Field Vane Shear Test (VST)
Vane Shear Test (VST) is an in-place shear test in which a rod with thin radial vanes at the end is forced into the soil and the resistance to rotation of the rod is determined. VST addresses testing on land and for testing in drill holes or by self drilling or continuous push methods from the ground surface. VST provides an indication of in-situ undrained shear strength of fine- grained clays and silts or other fine geomaterials such as mine tailings, organic muck, and substances where undrained strength determination is required. Knowledge of the nature of the soil in which each vane test is to be made is necessary for assessment of the applicability and interpretation of the test. The test is not applicable for sandy soils which may allow drainage during the test. The test is routinely performed in conjunction with other field and laboratory tests.
