Civil engineer guide to fighting positions, shelters, obstacles

AFH 10-222 Volume 14 1 August 2008 154
A3.3.10. Wet Shaking Test. The wet shaking test is performed only on the
material passing the No. 40 sieve (see Figure A3.5 for illustrations). A representative
portion of the sample (enough material to form a ball of material
about 3/4-inch in diameter) is mixed with water until it can be molded or
shaped without sticking to the fingers. The sample (soil pat) is then spread
across the palm of the hand with the blade of a knife or small spatula. Shake
the hand with the soil pat horizontally and strike that hand vigorously with
the other hand. Check the soil for a reaction where water comes to the surface,
producing a smooth, shiny appearance. This appearance is described as
livery. Squeeze the sample between the thumb and forefinger using the other
hand. Check to see if the surface water quickly disappears, the surface becomes
dull, and the material becomes firm, resisting deformation. Continue to
apply pressure and check to see if cracks occur and the sample crumbles like
a brittle material. Very fine sands and silts can be readily identified with the
wet shaking test. However, it is rare to find fine sands and silts without some
amount of clay, which causes varying reactions to the wet shaking test. Even
a small amount of clay will tend to greatly retard this reaction when the water
comes to the surface. Table A3.8 can be used to draw conclusions using the
wet shaking test.
Figure A3.5. Illustration of Wet Shaking Test.