What is the importance of determining the consistency of the soil?
The water holding capacity and the movement of water through the soil for plants is determined by soil consistency. This consistency also determines the relative resistance of the soil to pressure. The soil consistency is usually analyzed at three moisture levels – dry, moist and wet.
What is dry soil consistency?
Soil consistency is the strength with which soil materials are held together or the resistance of soils to deformation and rupture. Soil consistency is measured for wet, moist and dry soil samples. For wet soils, it is expressed as both stickiness and plasticity, as defined below.
What are the two terms used to describe wet soil consistency?
In wet soils the consistency is denoted by terms stickiness and plasticity.
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 are the two factors of permeability?
A number of factors affect the permeability of soils, from particle size, impurities in the water, void ratio, the degree of saturation, and adsorbed water, to entrapped air and organic material.
What are the two expression of soil densities?
Units of density are typically expressed in g cm–3 or Mg m-3. Note that total volume of the soil sample equals the volume of the solids and the volume of the pores. Porosity is usually expressed as a decimal, but it can also be expressed as a percentage by multiplying the decimal form by 100%.
Which soil has highest CEC?
Humus, the end product of decomposed organic matter, has the highest CEC value because organic matter colloids have large quantities of negative charges. Humus has a CEC two to five times greater than montmorillonite clay and up to 30 times greater than kaolinite clay, so is very important in improving soil fertility.
What are the consistency limits of soil?
The three limits are known as the shrinkage limit (WS), plastic limit (WP), and liquid limit (WL) as shown. The values of these limits can be obtained from laboratory tests.
What is another word for moist?
Some common synonyms of moist are damp, dank, humid, and wet. While all these words mean “covered or more or less soaked with liquid,” moist applies to what is slightly damp or not felt as dry.
What is the liquid limit of the 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.
What is a good liquid limit of soil?
9.2. 1 Consistency and Plasticity
| Soil | Liquid limit wL (%) | Plastic limit wp (%) |
|---|---|---|
| Silt, medium plasticity | 35–50 | 22–23 |
| Clay, low plasticity | 25–35 | 15–22 |
| Clay, medium plasticity | 40–50 | 18–25 |
| Clay, high plasticity | 60–85 | 20–35 |
What factors affect permeability?
Factors Affecting Permeability of Soil
- Size of Soil Particle.
- Specific Surface Area of Particles.
- Shape of Soil Particle.
- Void Ratio.
- Soil Structure.
- Degree of Saturation.
- Water Properties.
- Temperature.
What does permeability depend on?
Permeability is largely dependent on the size and shape of the pores in the substance and, in granular materials such as sedimentary rocks, by the size, shape, and packing arrangement of the grains.
What is porosity of soil?
6 Porosity. Soil porosity refers to the fraction of the total soil volume that is taken up by the pore space (Nimmo, 2004). Mainly, pore spaces facilitate the availability and movement of air or water within the soil environment.
What is structure of a soil?
Soil structure is defined by the way individual particles of sand, silt, and clay are assembled. Single particles when assembled appear as larger particles. These are called aggregates . Aggregation of soil particles can occur in different patterns, resulting in different soil structures.
Why is sand low CEC?
These molecules can be nutrients, water, herbicides and other soil amendments. A soil particle’s ability to react with these molecules is called the cation exchange capacity. High sand soils have low CEC values with the number increasing as the soil contains more clay, silt and organic matter.
What two factors are most important for soil having a higher CEC?
Factors influencing the CEC include the soil type, the soil pH and the soil organic matter content. Soils are made up of sand, organic matter, silt and clay particles. Soils with high sand content have low holding capacity for cations compared to clayey and silty soils.
Why do we need Atterberg limits?
In the field, the Atterberg Limits, can be used as a guide indicating how much a soil is likely to settle or consolidate under load. If the field moisture is near the liquid limit, a lot of settlement is likely. The opposite is true if the field moisture is near or below the plastic limit.
What is the liquid limit of soil?
What is the best replacement for moist?
There’s really no replacement. If you look up moist in the dictionary, there are many synonyms: damp, clammy, steamy, humid, dank, sticky, the list goes on.
