The boundary between the liquid and plastic states;. TABLE 13 Selected results of mechanical soil analyses analyses of disturbed soil samples collected from auger bores 1. For wet soils, it is expressed as both stickiness and plasticity , as defined below. The test is repeated by adding different amount of water with the soil.
As moisture content of a clay-like soil increases, it goes through four distinct states of consistency: These limits as such do not indicate the consistency of undisturbed soil. Thanks, Gus. Theme by MyThemeShop. Increasing the thickness of the water films permits the particles to slide past one another more easily.
The three sections below line A are inorganic silts of varying compressibility, organic silts and organic clays. Transfer this paste to the cup of cone penetrometer apparatus.
Repeat this test by adding different amount of water with the soil. Try to form a thread 3 mm thick and 10 cm long without breaking it;. Both the liquid and plastic limits depend upon the amount and type of clay present in the soil:. It gives us an idea of the shear strength of soil. Soils for engineering use are often classified based on properties relative to foundation support or as they might perform under pavements and in earthworks.
These limits have since been more definitely defined by A. So the amount of water which is responsible for this state of consistency of soil is called liquid limit of soil.
For those nonplastic soil layers where the liquid limit is lower than can be measured less than 15 or is otherwise not determined organic soils , enter a dash. Sand or silt traces of clay little clay.
Sieve Shakers. Two of the Atterberg Limits are of particular interest for aquaculture, the liquid limit and the plastic limit , which are defined from three soil consistencies:. Example of exceptions to the above are:.
Plasticity index in also a measure of cohesiveness with high value of PI indicating high degree of cohesion. Soil Information.
In cases where soils are tested later in the laboratory, adjustments are made to field procedures as needed. Engineering Properties of Silt and Clay. Calculations Preferred calculation is: The percentage moisture content at which a soil changes with decreasing wetness from the liquid to the plastic consistency or with increasing wetness from the plastic to the liquid consistency.
These form the basis of a useful soil classification system see Chapter 11.