Subgrade Reaction Modulus(Ks) of Clayey Soils Based on Field Tests

One of the most important engineering challenges in the design of structure that are in contact with soils is the reaction of soil in contact with structure. In the engineering works، for design of the structure، instead of modeling the subsoil in all its complexity، it can be replaced by a much simpler system called subgrade reaction model. In this paper in order to evaluate the in situ modulus of the clayey deposits of the Qazvin alluvium، the results of a large number of in situ tests that carried out by the researchers have been analyzed. Vertical plate load tests، standard penetration tests and test pit exploration are conducted on over 170 different locations. The results of the plate load and standard penetration tests are analyzed and discussed. The correlation between subgrade reaction modulus (Ks)، modulus of elasticity (Es) and corrected standard penetration test blow counts (N) are presented for clayey deposits of the Qazvin alluvium. Results show that there is a good correlation between subgrade reaction modulus (Ks) and SPT blow counts.