Prediction of Relative Density of Sand with Particular Reference to Compaction Energy

Abstract

Field compaction of sands usually involves different equipments with the compaction energy varying significantly. The relative density is the better indicator for specifying the compaction of granular soil. If the relative density can be correlated simply by any index property of the granular soil, it can be more useful in the field. The relative density is defined in terms of voids ratio. It is well known that the minimum and maximum voids ratio depend on the mean grain size. However, there is no direct relation available for the voids ratio in terms of grain size. Therefore, in this dissertation, the effect of mean grain size on the relative density of sand has been studied at different compaction energies. In order to arrive at the above, fifty five number of clean sands having D50 ranges from 0.34 to 2.6 mm collected from different river bed of Orissa have been tested in the laboratory. The various index properties like grain specific gravity, grain size distribution of all the samples have been determined. The minimum and maximum voids ratio have been determined. For determining minimum voids ratio; both wet and dry method have been adopted. The voids ratio corresponding to energy level of standard, modified, reduced standard, and reduced modified Proctor tests have been correlated with mean grain size and thus the simple nonlinear empirical relations have been developed. Similarly, the relative densities corresponding to the energy level of above mentioned Proctor tests also have been correlated with mean grain size to arrive at simple empirical equations. The percentage deviation of the relative density estimated by the proposed method is in the range of ± 5 % of the measured value. The above correlations of relative densities will be helpful for the design specifications in the field.