Slopes of Formation
The side slopes of both the embankment and the cutting depend upon the shearing strength of the soil and its angle of repose. The stability of the slope is generally determined by the slip circle method. In actual practice, average soil such as sand or clay may require a slope of 2:1 (horizontal:vertical) for an embankment and 1:1 or 0.5:1 or even steeper particularly when rock is available for cutting.
To prevent erosion of the side slopes due to rain water, etc., the side slopes are turfed. A thin layer of cohesive soil is used for this purpose. Alternatively, the slopes are turfed with a suitable type of grass. Sometimes the bank also gets eroded due to standing water in the adjoining land. A toe and pitching are provided such cases.