Literature Review on Effects of Saturation on Soil Subgrade Strength

Abstract

The remainder of the pavement system is  supported by the subgrade, the soil layer on top of which  the subbase or pavement is constructed. The California  Bearing Ratio (CBR) value of a subgrade must be at least  10. This is essential for highway engineers. Numerous  studies demonstrate that if a subgrade has If the subbase  material has a CBR value < 10, it will deflect under traffic  loads in a similar way to the subgrade and harm the  pavement. Pavement drainage and stability are provided by  the subbase, a layer of aggregate material immediately  beneath the pavement. The inferior, that Undrained water  can freeze and expand in the layers supporting the  pavement, placing intense internal strain on the pavement  structure. Additionally, running water can transport debris  from the subbase or subgrade and, in conjunction with  traffic, pump it out of the drains. Highway engineers must  consequently provide a solid, permeable subbase with  longitudinal sub-drains. The effects of saturation on the  stability of the soil subgrade are reviewed in this essay.