A linear log d – log w model for the determination of consistency limits of soils

Abstract

A linear logarithm–logarithm model for the fall cone penetration depth versus water content relationship (flow curve) has been developed based on the results of an experimental study using the British fall cone apparatus. The fall cone flow curve is expressed by a simple equation with parameters m and c, which represent the slope of the flow curve and the water content at a penetration depth of 1 mm, respectively. For a soil, the flow curve can be determined by applying a linear regression analysis to at least four data points with penetration depths approximately evenly distributed between 25 and 3 mm. It is shown in this paper that both the liquid limit and the plastic limit determined from the linear logarithm–logarithm flow curve are in close agreement with those determined from conventional methods. A one-point method for determination of the liquid limit is developed from the model and is verified by applying statistical analysis to a large volume of experimental data.Key words: fall cone, laboratory tests, consistency limits, clays.