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# What is coefficient of uniformity of soil?

## What is coefficient of uniformity of soil?

Uniformity Coefficient (Cu) which is a measure of the uniformity of grain size in the soil and is defined as the ratio of the 60% finer size (D60) to D10.

What are D10 D30 & D60?

D60 – 60 % of the soil particles are finer than this size. D30 – 30% of the particles are finer than this size. D10 – 10% of the particles are finer than this size. For example, if you have 100 particles of diameter ranging from 1 mm to 100 mm, D60 is 61 mm (below which 60% of particles are there).

What is uniformity coefficient of sand?

The uniformity coefficient describes how similar in size the sand particles are. The silt content is the percentage of sand with a diameter < 0.1 mm. If the uniformity coefficient is below 1.5, that means that all of the sand particles are very similar in size.

### What is the coefficient of uniformity formula?

Cu= D60/D10 Cu > 6 indicates a densely graded (i.e. well-graded) material with a considerable range of particle size (used for max stability). Cu < 4 indicates a uniformly graded (i.e. open-graded) material having a narrow range of particle size (used for max permeability).

How is the uniformity coefficient of soil calculated?

The size distribution is represented by the Uniformity Coefficient, which enables you to see how well graded your sand sample is. This is done by taking the D60 and dividing by the D10.

Which of the following soil has the uniformity coefficient of more than 10?

Answer: A soil having uniformity coefficient more than 10 is called well graded soil.

#### Why coefficient of uniformity is important?

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 Allen Hazen coefficient?

Explanation: Allen Hazen’s formula is K=CD102, where c is constant, which is taken as approximately equal to 100 when D10 is expressed in cm. Explanation: In 1944, Jacky found out the order of magnitude of k can be obtained from all soils from the formula K= 100Dm2, where Dm denotes grain size.

What is uniformity coefficient used for?

## What is a good uniformity coefficient for soil?

The uniformity coefficient (Cu) is defined as the ratio of D60 to D10. A value of Cu greater than 4 to 6 classifies the soil as well graded. When Cu is less than 4, it is classified as poorly graded or uniformly graded soil.

What is the CU value of the uniformity coefficient?

The uniformity coefficient (Cu) is defined as the ratio of D60 to D10. A value of Cu greater than 4 to 6 classifies the soil as well graded. When Cu is less than 4, it is classified as poorly graded or uniformly graded soil. Uniformly graded soil has identical particles with Cu value approximately equal to 1.

What is the value of coefficient of curvature of soil?

Coefficient of Curvature (Cc) Coefficient of curvature is given by the formula: For the soil to be well graded, the value of Cc must range between 1 and 3. For any single sized soil mass, the value of both Cu and Cc is 1.

### What is the CU value of well graded soil?

A value of Cu greater than 4 to 6 classifies the soil as well graded. When Cu is less than 4, it is classified as poorly graded or uniformly graded soil. Uniformly graded soil has identical particles with Cu value approximately equal to 1. A uniformity coefficient value of 2 or 3 classifies the soil as poorly graded.