Identify the INCORRECT use of particle size distribution curve for soils.

Explanation:

Particle size distribution curve:

• The particle size distribution of soil is presented as a curve on a semilogarithmic plot, the ordinates being the percentage by mass of particles smaller than the size given by the abscissa, used to determine the type of soil (ie gravel, sand, silt or clay)
• The flatter the distribution curve, the larger the range of the particle sizes in the soil.
• The steeper the curve, the smaller the size range.
• A coarse soil is described as well-graded if there is no excess of particles in any size range and if no intermediate sizes are lacking.
• It is useful in soil stabilisation and for the design of pavements.
• In general, well-graded soil is represented by a smooth convace distribution curve. A coarse soil is described as poorly graded

1. If a high proportion of the particle have sizes within narrow limits (a uniform soil)
2. If particles of both large and small sizes are present but with a relatively low proportion of particles of intermediate size (a gap graded or step graded soil or skip graded soil)