Join 60,000+ competitive exam aspirants
or with email
Your Cart
Subtotal₹0
Total₹0
Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
Join 60,000+ competitive exam aspirants
The shape of particle size curve can be represented by
Cu
Cc
Ip
If
Cc
The shape of the particle size distribution curve is defined by the Coefficient of Curvature (Cc). While the Coefficient of Uniformity (Cu) indicates the range of particle sizes present, Cc provides information about the smoothness and shape of the gradation curve.
The shape of the particle size distribution curve is defined by the Coefficient of Curvature (Cc). While the Coefficient of Uniformity (Cu) indicates the range of particle sizes present, Cc provides information about the smoothness and shape of the gradation curve.
Cc=D60×D10(D30)2 — Coefficient of Curvature
Cu=D10D60 — Coefficient of Uniformity
The particle size distribution curve represents the percentage of soil particles passing through various sieve sizes. Cc is defined as the ratio of the square of the diameter at 30% passing to the product of the diameters at 60% and 10% passing. A value of Cc between 1 and 3 for gravelly soils and 1 and 3 for sands generally indicates a well-graded soil, meaning the soil particles are distributed over a wide range of sizes with a smooth, continuous curve.
A well-graded soil must satisfy both the Cu and Cc criteria.
For gravel, a soil is well-graded if Cu>4 and 1≤Cc≤3.
For sand, a soil is well-graded if Cu>6 and 1≤Cc≤3.
Cc is dimensionless.
Helps in identifying gap-graded soils.
Essential parameter for engineering classification of soils.
Does not account for soil plasticity or chemical properties.
Requires full sieve analysis data to calculate.
Filter design in earth dams.
Stability analysis of geotechnical structures.
Classification of soils in the Unified Soil Classification System (USCS).
If Cc falls outside the 1-3 range, the soil is generally considered poorly graded or gap-graded.
Option A (Cu) represents the uniformity of particle sizes (range), not the shape of the curve.
Option C (Ip) is the Plasticity Index, related to soil consistency (Atterberg limits).
B is correct — The Coefficient of Curvature (Cc) represents the shape of the particle size distribution curve.
Remember: Cu measures the spread of sizes (steepness), while Cc measures the curvature (shape).