Humboldt H-4212MH — Pocket Shear Vane, Metal - Manual (Page 2)

4) Press the unit into the soil sample until the blades are covered.
5) While maintaining a constant pressure, rotate the outer ring of the
unit. Turn the outer ring until failure occurs. (The speed of rotation
should be a speed that accomplishes failure within 5 to 10 seconds.)
6) Release the outer ring, slowly, once failure has ocurred. The mark on
the outer ring will remain in place indicating the shear value at failure.
7) Multiply readings by 0.2 when using large vane and 2.5 when using
small vane.
Vane Stress Range Usage
Standard 0 to 1 kg/cm 2
Fully saturated cohesive soils
with undrained strength inde-
pendent of normal pressure
Large 0.2 kg/cm 2 Remolded samples
Small 2.5 kg/cm 2 Stiffer clays
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