Literature Review on Effects of Saturation on Soil Subgrade Strength

Abstract: Subgrade is the layer of soil on which the subbase or pavement is constructed, give support to the remaining part of the pavement system. It is critical for highway engineers to begin a subgrade with a California Bearing Ratio (CBR) value of at least 10. Lot of Researches shows that if a subgrade has a CBR value less than 10, the subbase material will divert under traffic loadings in the same way as the subgrade and cause pavement degradation. The subbase, the layer of aggregate material just below the pavement, gives drainage and stability to the pavement. Undrained water in the pavement substantiate layers can freeze and expand, rising internal pressures on the pavement structure. Additionally, flowing water can move soil particles that clog drains and, in fusion with traffic, pump fines from the subbase or subgrade. It is therefore essential that highway engineers develop a strong, permeable subbase with longitudinal subdrains. This paper provides a literature review on effects of saturation on soil subgrade strength.