What characteristic does not classify soil as Type B?

Soil classification is critical in excavation projects, particularly in understanding the properties and behaviors of different soil types. Type B soils are specifically identified based on certain strength parameters and soil characteristics.

When soil has an unconfined compressive strength above 1.5 tons per square foot (tsf), it is classified as Type A soil rather than Type B. Type A soils are typically strong and stable, often made up of cohesive materials like clay that can bear higher loads without failing. This characteristic directly disqualifies such soil from being classified as Type B.

Type B soils, on the other hand, typically include cohesive soils with a strength between 0.5 tsf and 1.5 tsf, granular cohesionless soils, and even previously disturbed soils. These types have different engineering properties that are important for excavation work. Cohesive soils range in strength up to a limit (1.5 tsf), while granular soils do not exhibit cohesion and have their own stability considerations. Previously disturbed soils often maintain Type B classification due to their variability but generally exhibit characteristics lesser than Type A.

In summary, the characteristic of having an unconfined compressive strength above 1.5 tsf classifies the soil as Type A, which is