Atterberghatárértékek

Atterberghatárértékek, often translated as Atterberg limits, are a fundamental concept in soil mechanics used to characterize the fine-grained soil behavior. These limits describe the moisture content at which a soil transitions from one state to another. There are three primary Atterberg limits: the liquid limit, the plastic limit, and the shrinkage limit.

The liquid limit (LL) is the moisture content at which the soil behaves as a liquid. At this point, the soil will flow under a very small shear stress. It is typically determined using the Casagrande apparatus, where a standardized sample of soil is subjected to repeated blows of a small hammer until it flows a specific distance.

The plastic limit (PL) is the moisture content at which the soil begins to exhibit plastic properties. Below this limit, the soil crumbles when rolled into thin threads. It is determined by rolling a small mass of soil on a flat surface until it reaches a diameter of 3 mm and then observing its behavior.

The plasticity index (PI) is the difference between the liquid limit and the plastic limit (PI = LL - PL). This index indicates the range of moisture content over which the soil is plastic. Soils with a higher plasticity index are considered more plastic.

The shrinkage limit (SL) is the moisture content at which further reduction in moisture content does not cause a decrease in the volume of the soil sample. Below the shrinkage limit, the soil is in a solid state.

These Atterberg limits are crucial for classifying soils, predicting their engineering properties such as compressibility and shear strength, and determining their suitability for various construction purposes. They are widely used in geotechnical engineering and soil science.