The Vane Test or Field Vane Test, FV, is an in situ survey used to determine the undrained shear resistance Su and the sensitivity St of saturated cohesive soils.

The survey consists of pushing into the ground a vane consisting of four steel blades at right angles to each other attached by a coupling to a rod, and then measuring the torque T as the equipment is turned until the ground is broken.

Since the shearing occurs relatively rapidly, the water does not have time to escape; thus, we are dealing with an undrained test (UU).