Use the in-place vane shear test to determine the in-place shearing strength of fine-grained soil, which does not lend itself to undisturbed sampling and triaxial testing. Use this test when encountering organic silty clay (muck) or very soft clay. Ensure these materials are free of gravel or large shell particles because pushing the vanes through these obstructions would disturb the sample and probably cause physical damage to the vanes. Use the test with extreme caution in soil that has Standard Penetration Test values harder than 15 blows/12 in. Correct the vane shear results to the soil index properties.