Cone Penetrometer
Encyclopedia
The Fall cone test apparatus is an alternative method to the Casagrande Device in measuring the Liquid Limit of a soil sample (See:Atterberg Limits
). It is usually considered to be a more scientific approach because it is based less upon human judgment. In this method, a sample is placed in a 55 mm diameter, 40 mm deep metal cup. A stainless steel cone weighing 80 g (including the shaft) and having a 30° angle is positioned so that its tip just touches the sample. The cone is released for 5 seconds so that it may penetrate the soil. The liquid limit is defined as the water content
of the soil which allows the cone to penetrate exactly 20 mm during that period of time. Because it is difficult to obtain a test with exactly 20 mm penetration, the procedure is performed multiple times with a range of water contents and the results are interpolated.
Atterberg Limits
The Atterberg limits are a basic measure of the nature of a fine-grained soil. Depending on the water content of the soil, it may appear in four states: solid, semi-solid, plastic and liquid. In each state the consistency and behavior of a soil is different and thus so are its engineering properties...
). It is usually considered to be a more scientific approach because it is based less upon human judgment. In this method, a sample is placed in a 55 mm diameter, 40 mm deep metal cup. A stainless steel cone weighing 80 g (including the shaft) and having a 30° angle is positioned so that its tip just touches the sample. The cone is released for 5 seconds so that it may penetrate the soil. The liquid limit is defined as the water content
Water content
Water content or moisture content is the quantity of water contained in a material, such as soil , rock, ceramics, fruit, or wood. Water content is used in a wide range of scientific and technical areas, and is expressed as a ratio, which can range from 0 to the value of the materials' porosity at...
of the soil which allows the cone to penetrate exactly 20 mm during that period of time. Because it is difficult to obtain a test with exactly 20 mm penetration, the procedure is performed multiple times with a range of water contents and the results are interpolated.