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In general, the plasticity index depends only on the amount of clay present. It indicates the fineness of the soil and its capacity to change shape without altering its volume. A high PI indicates an excess of clay or colloids in the soil. The greater the PI, the greater the soil compressibility.In general, the
Atterberg limits – Wikipedia
depends only on the amount of clay present. It indicates the fineness of the soil and its capacity to change shape without altering its volume. A high PI indicates an excess of clay or colloids in the soil. The greater the PI, the greater the soil compressibility.
What soil has high plasticity?
Plasticity index Soils with a high PI tend to be clay, those with a lower PI tend to be silt, and those with a PI of 0 (non-plastic) tend to have little or no silt or clay.
What is the meaning of plasticity of soil?
2 Plasticity. Plasticity is the ability of a material to undergo permanent deformation under stress without cracking. Fine-grained soils become plastic as their moisture content is increased, leading to loss in shear strength and stability.
What is the strength of soil?
What gives soil its strength? The mechanical strength of soil is an important concept in considering (and predicting) soil behaviour. We use strength to represent the reaction of a soil to an applied force. High-strength soils resist deformation (compaction especially), break-up (shearing and shattering), and slippage.
What is MDD and OMC?
MDD – Maximum Dry Density. MWD – Maximum Wet Density. OMC – Optimum moisture Content. Zero Air Voids – is the relationship between dry density and corresponding moisture contents, for a specific particle density, assuming that all of the voids are completely filled with water.
What is Atterberg limit of soil?
The Atterberg limits consist of the following key values of moisture content: The Liquid Limit (LL) is the moisture content at which a fine-grained soil no longer flows like a liquid. The Plastic Limit (PL) is the moisture content at which a fine-grained soil can no longer be remolded without cracking.
Can liquid limit be more than 100%?
For Attapulgite, the liquid limit varies from 150 to 250, which are greater than 100 and the shrinkage limit varies from 100 to 125 which are also greater than 100. Therefore, the Atterberg’s limits can be greater than 100.
What is the limit test?
Limit test is defined as quantitative or semi quantitative test designed to identify and control small quantities of impurity which is likely to be present in the substance. Limit test is generally carried out to determine the inorganic impurities present in compound.
What kind of soil is suitable for Atterberg limit test?
Atterberg limits tests establish the moisture contents at which fine-grained clay and silt soils transition between solid, semi-solid, plastic, and liquid states.
What is permeable soil?
The permeability of soil describes how water (or other liquid) and air are able to move through the soil. In the case of rainfall or irrigation, water moves very easily through highly permeable soils and very slowly through soils with low permeability.
How do you test for clay plasticity?
As for other types of materials, a compression test can be used to evaluate the plasticity of clays. The typical test curve gives information about the modulus of elasticity, yield strength, maximum deformation and rupture strength.
What is liquid limit formula?
Use the number of drops along with the water content of the samples to calculate the liquid limit. Subtract the weight of a dry soil sample from the weight of a wet soil sample and multiply by 100. Divide the result by the weight of the wet sample to get the percent water content for that sample.
How do you classify soil?
The United States Department of Agriculture defines twelve major soil texture classifications ( sand, loamy sand, sandy loam, loam, silt loam, silt, sandy clay loam, clay loam, silty clay loam, sandy clay, silty clay, and clay). Soil textures are classified by the fractions of sand, silt, and clay in a soil.
Why do we find the liquid limit of soil?
Value of liquid limit is used to classify fine grained soil. It gives us information regarding the state of consistency of soil on site. Liquid limit of soil can be used to predict the consolidation properties of soil while calculating allowable bearing capacity & settlement of foundation.
What is specific gravity of soil?
Specific Gravity(G) Specific gravity is defined as the ratio of the weight of a given volume of soil solids at a given temperature to the weight of an equal volume of distilled water at that temperature, both weights being taken in air.. The specific gravity of the soil particles lie with in the range of 2.65 to 2.85.
Is high plasticity clay good?
A high PI indicates an excess of clay or colloids in the soil. Its value is zero whenever the PL is greater or equal to the LL. The plasticity index also gives a good indication of compressibility (see Section 10.3). The greater the PI, the greater the soil compressibility.
What causes plasticity of soil?
A plastic soil can be moulded into various shapes when it is wet. Plasticity is an important index property of fine grained soils especially clay. Plasticity is due to presence of clay.
Which kind of soil holds the most water?
The clay soil had the highest water holding capacity and the sand soil had the least; clay>silt>sand. Clay particles are so tiny and have many small pore spaces that make water move slower (the highest water holding capacity). Sandy soils have good drainage but low water and nutrient holding capacities.
Why Does clay have high plasticity?
The cation/anion changes in the clay minerals are different between clay minerals. Therefore, it is expected that the clay that attracts more water molecules to the surface will have more plasticity, more swelling/shrinkage and more volume change, depending on the load on it.
What is plastic limit of soil?
DEFINITION. 2.1 The plastic limit of a soil is the moisture content, expressed as a percentage of the weight of the oven-dry soil, at the boundary between the plastic and semisolid states of consistency. It is the moisture content at which a soil will just begin to crumble when rolled into a thread ⅛ in.
What does a high liquid limit mean?
A high liquid limit normally indicates a high compressibility and a high shrinkage/swelling potential. A high-plasticity index Ip generally results in a low shear strength. A low Ip means that a soil used as foundation will change significantly in consistency even with a small change in water content.
What is the liquid limit of soil?
The liquid limit is the moisture content at which the groove, formed by a standard tool into the sample of soil taken in the standard cup, closes for 10 mm on being given 25 blows in a standard manner. At this limit the soil possess low shear strength.
