Assessing the Suitability of Various Materials for Improving Subsurface Drainage

Indian Road Network has a major problem of drainage. Permeability is the main property for proper drainage. Most of the roads in India deteriorated due to improper drainage. Thus, the present study has been conducted to investigate the variation of permeability (k) with porosity (n) at different depths of various materials used in construction of road. The soil in the study segment stretch has been excavated and replaced with three new layers of materials consisting of sand, gravel sub-base (G.S.B) and wet mix to increase permeability.For the purpose of analysis eleven numbers of samples were collected. Sieve analysis of two excavated soil samples was carried out to give us an idea about the type and gradation of soil. For the rest of the remaining nine samples hydraulic tests was carried out in a permeameter to determine the values of permeability (k) and porosity at different depths of various material used in construction of roads. Specific gravity for different materials was also computed. Numbers of equations were developed to find relationship between permeability (k) and porosity (n). The equations developed can be used to estimate permeability and porosity at different depth. The results from the study indicate high correlation between permeability and porosity.