the soil prepared to support an asphalt structure or pavement system. It is the foundation for the base and the pavement structure. Subgrade Failure: subgrade failures occur when the prepared soil beneath the asphalt structure can no longer adequately support the weight of the structure or the traffic. Subgrade failures can occur for a number of reasons, including: ground water, excessive load counts (too much weight), and inadequate design. The failure can be corrected by excavating the soft material from the affected area and replacing it with compacted soil or bridging stone material. Subgrade Failure click on image to enlarge
The soil base, which the pavement structure is constructed upon.
The trimmed or prepared portion of the formation on which the pavement is constructed.
The soil upon which the pavement structure and shoulders are constructed.
1. Compacted soil that is ready for a structure or slab. 2. The elevation found at the bottom of a pipe trench. 3. Below grade soil level.
In highway engineering, subgrade is the native material underneath a constructed pavement. It is also called formation level.
