SUBGRADE IMPROVEMENT USING NO FINES CONCRETE NAILS

J.Ranjitha, M.R.Rajasekhara

Abstract: Black Cotton Soil is very weak in nature and is not preferred as subgrade soil. It has to be stabilized to be used in the the pavement as subgrade material. Many stabilizers and techniques are available in the market as a solution to this problem. The present study, however, is aimed at using alternate and comparatively low cost technique to stabilize the Black Cotton Soil. The soil nailing concept used for reinforcing embankments and is considered and applied accordingly to the subgrade with certain changes in specification. This can enhance the strength of Black Cotton subgrade soil and minimize settlement. The conventional methods of ground improvement technique have proven costlier. In the present study an attempt is made to use the concept of ground improvement technique for stabilizing the black cotton soil Subgrade by driving nails. No fines concrete tapered nails in the form of concrete nails are driven into the subgrade soil at an inclination of 90°. These nails are preferred as they are corrosion resistant in comparison with reinforced steel. The diameter and height is varied to get concrete nails of three different dimensions. California Bearing ratio test value is analyzed. No fines concrete can be effectively used to improve the stability of the weak subgrade than the conventional concrete and is more economical. The method can be adopted effectively for village roads carrying low traffic

Keywords: Weak soil, Subgrade, no fines concrete nail, California bearing ratio(CBR)

DOI: https://doi.org/10.15623/ijret.2018.0702004