What does a low coefficient of uniformity mean?

What does a low coefficient of uniformity mean?

It is the parameter estimated using the gradation curve as obtained through the sieve analysis. The smaller coefficient of uniformity value means that the sample gradation is uniform. The value of C u equal to 1 means that the soil consists of only one grain size.

What does the coefficient of uniformity tell you?

uniformity coefficient (u-ni-form’-i-ty). A numerical expression of the variety in particle sizes in mixed natural soils, defined as the ratio of the sieve size through which 60% (by weight) of the material passes to the sieve size that allows 10% of the material to pass.

What is the uniformity coefficient of well graded soil?

A well graded soil will have a uniformity coefficient greater than about 4 for gravels and 6 for sands, and a coefficient of gradation between 1 and 3 (for gravels and sands). A soil might have a combination of two or more uniformly graded fractions.

What is a good coefficient of uniformity?

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 CC and CU?

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. Coefficient of Cuvature (Cc) is a value that can be used to identify a poorly graded soil.

What is the coefficient of curvature?

Curvature coefficient, Cu > 5 indicates a well-graded soil, i.e. a soil which has a distribution of particles over a wide size range. Cc between 1 and 3 also indicates a well-graded soil. Cu < 3 indicates a uniform soil, i.e. a soil which has a very narrow particle size range.

How do you calculate CC and CU?

To find Cu and Cc. Cu – Uniformity coefficient. Cu = D60/D10. Cc – Coefficient of curvature.

What is formula of coefficient of curvature?

The coefficient of curvature is a measure of gradation of particles and given by the following expression: Cc = (D30)2/D60.D10. Where, D60 = Size of the particle corresponding to 60% finer.

What is coefficient of curvature CC?

What is CU and CC in soil?

What is the coefficient of permeability?

Definitions. The coefficient of permeability of a soil describes how easily a liquid will move through a soil. It is also commonly referred to as the hydraulic conductivity of a soil. This factor can be affected by the viscosity, or thickness(fluidity) of a liquid and its density.

Which soil has the greatest permeability?

Gravel
Clay is the most porous sediment but is the least permeable. Clay usually acts as an aquitard, impeding the flow of water. Gravel and sand are both porous and permeable, making them good aquifer materials. Gravel has the highest permeability.

What do you need to know about the uniformity coefficient?

These coefficients help to classify the soil as well graded or poorly graded ones. 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 does the coefficient of uniformity of granular soil mean?

The granular soil having the value less than 6 for uniformity coefficient is said to be poorly graded or uniformly graded soil. The smaller coefficient of uniformity value means that the sample gradation is uniform. The value of C u equal to 1 means that the soil consists of only one grain size.

What is the coefficient of uniformity of sand?

Poorly graded soil like beach sand has the uniformity coefficient value about 2 or 3. Good well graded soil may have the value of C u about 15 or greater. When coefficient of uniformity value is very higher, it means that the largest grain size present in soil sample is very large compared to the lowest size grain.

Which is higher the coefficient of curvature or the cu?

A higher value of Cu indicates that the soil mass consists of soil particles with different size ranges. 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.