Fine-grained (cohesive) soil index properties are:

  • consistency.
  • particle shape and orientation.
  • clay and clay minerals content.
  • water content.

What is CI in soil classification?

CI → Medium plastic inorganic clay. MI → Medium plastic silt. OI → Medium plastic organic clay. (iii) High plastic soils (LL > 50%) CH → High plastic inorganic clay.

What are the consideration in soil classification?

Classification at the Series or higher level is required in order to determine its suitability for aquaculture. Classification systems used for engineering purposes are generally based on particle size characteristics and same other soil physical properties like plasticity.

What are the index properties?

Index properties are the properties of soil that help in identification and classification of soil for general engineering purpose. These properties are generally determined in the laboratory. Disturbed samples or remoulded samples can be used to determine the index property of the soil.

What are the index properties available in soil?

Physical properties of soil which are useful to identify and differentiate soils from one another are known as ‘Index Properties of Soil’. There are mainly 3 types of Index properties of soil and are as follows : Particle size distribution ( coarse grained soil )

What is fine grained soil?

Fine-grained soils have 50% or more material passing the No. 200 sieve. Engineering properties such as strength and compressibility of coarse-grained soil are governed by the grain-size of the particles and their structural arrangement. Fine-grained soil is impermeable due to its small particles size.

Is classification of fine grained soil?

A fine grained soil is classified as clay or silt, depending on the Atterberg limits and not on the percentages. Casagrande (1948) proposed the PI-LL chart shown in Fig. 3.5, where the A- line separates the clays and silts. If the LL and PI values of a fine grained soil plot above the A-line, it is clay.

What is soil index properties?

Index properties are the properties of soil that help in identification and classification of soil for general engineering purpose. The main index properties of coarse grained soils are particle size and relative density where as for fine grained soil the main index properties are consistency and Atterberg’s limit.

What is CU and CC?

The uniformity coefficient (Cu) and the coefficient of gradation (Cc) are the measures of soil gradation. These coefficients help to classify the soil as well graded or poorly graded ones.

What is coarse grained soil?

Coarse-grained soils are defined as those soils whose individual grains are retained on a No. 200 (0.075 mm) sieve. Grains of this size can generally be seen with the naked eye, although a handheld magnifying glass may occasionally be needed to see the smallest of the grains. Gravel and sand are coarse-grained soils.

How is the plasticity index of a soil determined?

The plasticity index is expressed in percent of the dry weight of the soil sample. It shows the size of the range of the moisture contents at which the soil remains plastic. In general, the plasticity index depends only on the amount of clay present.

What are the soil index properties of fine-grained soil?

Fine-grained (cohesive) soil index properties are: consistency. particle shape and orientation. clay and clay minerals content. water content. One of the soil index properties which describe non-cohesive soils is grading otherwise known as particle size distribution. It gives a measure of the sizes and distribution of sizes

What is particle size distribution in soil index?

One of the soil index properties which describe non-cohesive soils is grading otherwise known as particle size distribution. It gives a measure of the sizes and distribution of sizes of the particles that make up a soil and stands out to be the most fundamental of all properties especially in coarse-grained soils with little or no clay particles.

What is the soil index characteristic of clay minerals?

Clay and clay minerals content is important soil index characteristic for both coarse- and fine-grained soils. Clay minerals are fine-sized platy silicates with two basics buildings blocks namely silicate tetrahedron and the aluminium or magnesium octahedron which are highly plastic.

How do you identify coarse grained soil?

When the fine content is in the range of 12-50%, it is a coarse grained soil with substantial fines. The soil is assigned a symbol XY where X is the major coarse grained soil present and the descriptor Y is the symbol of the fines present. A soil in this case can be GM, GC, SM or SC.