Textural Classification - Free MCQ Practice Test with solutions, GATE Civil

Soil classification of composite soils exclusively based on the particle size distribution is known as textural classification.

Triangular classification of U.S. public road administration is a commonly used system for textural classification.

Since the textural classification is based on the percentages of sand, silt, and clay size making up the soil .such a classification is more suitable for describing coarse-grained soil.

to use the textural classification chart, for a given percentages of three constituents forming a soil, lines are drawn parallel to three sides of the equilateral triangle.

A triangle, having equal length of sides (i.e. Equilateral triangle) is used in textural classification chart.

HRB classification system, also known as public road administration (PRA) is based on both the particle-size composition and plasticity characteristics.

Highway research board classification system is also known as public road administration (PRA) system.

Based on HRB system, the soil is divided into 7 primary groups, designated as A-1, A-2…A-7.

As group index is a mean of rating the value of a soil as a sub-grade material
It can be used for finding the performance and quality of the soil.

Group index of a soil usually varies by
1. Liquid limit
2. Plastic limit
3. Amount of material passing through the 75-micron IS sieve.