What type of soil is considered the least stable?

Type C soil is considered the least stable among the soil classifications. This classification encompasses soils that tend to have high moisture content, are granular in nature, and have a lower cohesive strength. Such soils are more susceptible to erosion and collapse, especially when disturbed or when subjected to heavy loads.

Examples of Type C soil include loose sands and gravels, which do not retain stability without the support of other materials. In construction and excavation contexts, understanding the stability of soil types is crucial for safety and effective engineering practices. Type C soils are often associated with more stringent safety measures, such as additional shoring or bracing, to prevent potential hazards during construction activities.

In contrast, Type A and Type B soils are recognized for their greater stability and cohesive properties, making them safer for construction without extensive supports when compared to Type C soils.