Geology Expert On Stability Of Slopes Part 1

Types Of Slopes

Slopes vary in shape (mainly steepness), origin of the underlying soil (fill, cut, natural), and type of geology or soil (clay, sand, bedrock). As a general statement, the steeper and higher the slope and the weaker the soil or bedrock, the more prone the slope is to failure.

Slope Gradient

Slopes vary in their steepness. Most current fill and cut slopes (manufactured slopes) are graded to have a 2:1 (horizontal to vertical) gradient; that means for every one foot up, the slope extends 2 feet out. Steeper slopes were either constructed before about 1985 or are natural slopes that have not been graded. A natural slope can be near vertical. Many older graded slopes were built to a gradient of 1.5:1.