Describes the method used to determine the coefficient of permeability of a
soil at the end of a casing. The test consists in injecting water using gravity, into a soil through the
lower opening of a drilling casing. This opening is located below the local
piezometric level. Two test methods are described in the standard: a) the constant head method;
b) the variable falling head method. NOTE - There is a third method in which, after partially emptying the water
from the casing, the time the water takes to go up in the casing is recorded.
This method is not used within the framework of this standard because of the
risk of an uprising of soil during the course of the test.