In an excavation with layered soil where type B overlays type C, what is the correct sloping profile?

In excavation safety, the sloping profile is critical for maintaining stability and reducing the risk of cave-ins. Layered soils have different characteristics, and in this case, type B soil, which has some cohesion and is generally more stable than type C soil, is placed over type C soil, which is more prone to collapse.

For type B soil, the acceptable sloping ratio for excavations is often considered to be 1 1/2 horizontal to 1 vertical (1.5:1). This means for every 1.5 units of horizontal displacement, there should be 1 unit of vertical depth. This slope is designed to handle the cohesive properties of type B soil and provides a more stable excavation than a steeper slope would offer.

In this layered scenario, adhering to the 1 1/2h:1V slope is essential to ensure safety from potential cave-ins, especially considering that type C soil below could create additional risks if not properly managed. Other slopes, such as 2:1 or 3:1, would typically apply to different soil conditions or higher stability soils, thus offering less optimal safety measures for the specific characteristics of this excavation situation.