Question

Consider the following statements:
1. A conspicuous break in the continuity of a grain size distribution curve indicates a mixture of soil from two different layers.
2. A steep grain size distribution curve indicates prevalence of nearly uniform grain size.
3. A flat grain size distribution curve indicates certain range of missing grain sizes.
Which of these statements are correct?

• A. 1, 2 and 3
• B. 2 and 3 only
• C. 1 and 3 only
• D. 1 and 2 only

Answer 1

The correct option is A 1, 2 and 3

Both the position and the shape of the grading curve for a soil can aid in establishing its identity and description. Some typical grading curves are shown.


Curve A - a poorly-graded medium SAND
Curve B - a well-graded GRAVEL-SAND (i.e. having equal amounts of gravel and sand)
Curve C - a gap-graded COBBLES-SAND
Curve D - a sandy SILT
Curve E - a silty CLAY (i.e. having little amount of sand)