What is defined as a layer of material that has a compacted thickness of not more than 6 inches?

A layer of material that has a compacted thickness of not more than 6 inches is referred to as a lift. In earthwork and construction practices, the term lift is used to describe each layer of material that is placed and compacted during the construction process. The purpose of creating lifts is to ensure proper compaction and stability of the materials used, which is essential for the integrity of the structure being built.

In contrast, the other terms have distinct meanings in construction and earthwork. A sample typically refers to a portion taken to represent a larger group or quantity for testing purposes. A lot usually signifies a collection of items or material that is considered as a whole for quality control evaluations. A batch often describes a specific quantity of material produced during a single run of a process, such as concrete mixing. Therefore, in the context of layers of compacted material, the term lift is the appropriate and correct choice.