Coefficient of subgrade reaction for footings on cohesionless soils

Abstract

Eighty-three standard plate load tests were carried out on dry, poorly-graded, medium to fine sand at Brownville, Nebraska, U.S.A. The values of the coefficient of subgrade reaction, k, for these tests are correlated with the corresponding values of the relative density, dr, determined for the sand at both sides of the plate. The results show that k is exponentially dependent on dr. Sixty plate load tests were carried out at different sites in the U.S.A., England, Australia, Czechoslovakia, Jamaica and Hong Kong. The soils at these sites are different (clayey silty sand, fine to coarse sand, sandy gravel, gravel and decomposed granite). The values of the coefficient of subgrade reaction, k, for these tests are correlated with the corresponding values of the standard penetration n value for each deposit. A probabilistic distribution of the ratio K : n is given. From a comprehensive study of the results of the available plate load tests (143) together with corresponding values of relative density and standard penetration values, ranges are suggested for k corresponding to various degrees of packing of the cohesionless soils. (A) /TRRL/