1.1 This standard ( Part 5 ) lays down methods of test for the determina-tion of the liquid limit and plastic limit of soils. Three methods, namely, mechanical method, one point method and the cone method are given for the determination of liquid limit.
1.1.1 Liquid limits over about 120 percent shall be obtained by the procedure specified in 3 or 4. The one point method shall not be used for highly organic soils ( see Note ).
Note — The one point method may be applicable to the region for which the constants are obtained based upon results of tests on soils from that region. For all national and international reports the results obtained by the method in 3 or 4 may be reported.
1.2 The methods for calculating the following indices which are related to the liquid and plastic limits are also given:
a) Flow index ( see 3.5.2 ),
b) Plasticity index ( see 8 ),
c) Toughness index ( see 9 ),
d) Liquidity index ( or water plasticity ratio ) ( see 10 ), and
e) Consistency index ( see 11 ).
IS 2720 Pt.5-1985 history
1985IS 2720 Pt.5-1985 Soil Test Methods Part 5 Determination of Liquid Limit and Plastic Limit