What defines the maximum slope for Type B soil?

Type B soil is classified according to the Unified Soil Classification System and the Occupational Safety and Health Administration (OSHA) regulations regarding excavation. The maximum allowable slope for Type B soil is defined to be 45 degrees, which corresponds to a 1:1 ratio (i.e., for every unit of vertical rise, there is a horizontal distance of one unit). This slope is considered stable for Type B soil under typical conditions, meaning it can adequately support weight without yielding or collapsing.

This stability is attributed to the characteristics of Type B soil, which typically consists of cohesive materials such as clay with some granular components, allowing it to retain its structure under normal conditions to a certain angle. In practice, maintaining this slope helps ensure safety during excavation and construction activities, mitigating the risk of soil cave-ins.

The other angles presented in the choices exceed the maximum slope recognized for this type of soil, thus depicting scenarios that could lead to increased risk factors such as landslides or collapses during excavation work.