Liquid and Plastic Limits as Determined from the Fall Cone and the Casagrande Methods
The shortcomings of the conventional methods of determining the liquid limit using the Casagrande apparatus and the plastic limit by rolling soil balls by hand have led to the investigation of the fall cone (cone penetrometer) as an alternative. The use of the fall cone test to determine the liquid limit has long been adopted by several countries, but the proposal to use this test to determine the plastic limit as well, redefined on the basis of a strength criterion, is rather recent. In this paper the liquid and the plastic limits as determined by these two procedures for a number of natural soils and artificial soil mixtures are presented. A comparative and critical survey of experimental results involving the use of various cones to obtain consistency limits is also included.