Silt. Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body. It may also exist as soil deposited at the bottom of a water body.
In North America, a grade-separated junction may be referred to as a grade separation or as an interchange â in contrast with an intersection, at-grade, a diamond crossing or a level crossing, which are not grade-separated. 1 Effects.
In some instances it is not possible, due to safety, spatial constraints or. other conditions, to accommodate all users within an at-grade. intersection. In these cases, constructing an overpass bridge or underpass. structure for the purpose of separating the intersecting facilities should be. studied.