What term describes the relative consistency of a cohesive soil in its natural state?

The term that refers to the relative consistency of cohesive soil in its natural state is known as the liquidity index. This index is a crucial parameter in geotechnical engineering as it helps classify the behavior of fine-grained soils based on their water content.

The liquidity index quantifies how close the soil is to the liquid limit, which is a point at which the soil begins to behave like a liquid rather than a solid. A liquidity index of 0 indicates that the soil has a water content equal to its plastic limit, while a value of 1 indicates that it is at its liquid limit. Thus, the liquidity index provides insight into the soil’s consistency and plasticity, allowing engineers to understand how it will perform under various conditions, such as during construction or when subjected to loading.

In this context, while other terms mentioned relate to various properties of soils—like the plasticity index, which measures the range of moisture content over which the soil remains plastic, or the flow index, which relates to the soil's flowability—the liquidity index is specifically tailored to describe how cohesive soils behave in their natural state based on moisture content.