Final answer:
Soil classified as GM under the USCS is a silty gravel that is categorized based on its composition and particle size. It is important in engineering for understanding the soil's properties related to construction.
Step-by-step explanation:
Soil classified as GM under the USCS (Unified Soil Classification System) refers to a silty gravel with more fines and is unconsolidated. This classification is part of a system used by engineers to categorize various soil types based on their grain size distribution and composition. In this classification, 'G' stands for gravel, while 'M' indicates that the soil has significant amounts of silt. It is important to understand the distinct characteristics of a GM soil when it comes to engineering and construction, as its bearing capacity, drainage, and stability are impacted by the amount of silty content.