Atterberglimieten

Atterberglimiten, commonly referred to as the Atterberg limits, are a set of moisture-content thresholds used in soil mechanics to describe the consistency and behavior of fine-grained soils. Named after the Swedish soil scientist Albert Atterberg, the limits help engineers assess how a soil will respond to changes in moisture, load, and drainage. The three principal limits are the liquid limit (LL), the plastic limit (PL), and the shrinkage limit (SL). The plasticity index (PI) is defined as PI = LL − PL and serves as a measure of the soil’s plastic behavior.

The liquid limit is the water content at which soil changes from a plastic to a liquid state, typically determined with the Casagrande method. The plastic limit is the water content at which soil transitions from plastic to a semi-solid state, usually found by rolling a soil thread to a specified diameter until it crumbles. The shrinkage limit is the moisture content below which further drying does not result in a decrease in soil volume.

These limits are used to classify fine-grained soils, particularly clays and silts, within soil classification systems such as the USCS. They provide guidance for predicting workability, compaction, strength, and settlement behavior of soils subjected to moisture changes. Higher LL and PI values generally indicate more plastic and potentially more compressible soils.

Limitations include dependence on testing methods, sample preparation, and soil composition. The Atterberg limits are most meaningful for cohesive soils and may be less informative for coarse-grained soils or soils with significant organic content.