Reconsidering Secondary Compressibility of Soil

The effects of effective stress and void ratio on the secondary compressibility of the sandy and clayey soils were investigated in this study. the coefficient of secondary compression of ottawa sand in single stage and stepwise loading tests increases with effective vertical stress while that of saturated kaolinite decreases with effective vertical stress. multi-staged loading tests showed that at a given effective stress,the higher the void ratios of the soils,the higher the coefficients of secondary compression of the soils are. it was concluded that the secondary compressibility of a soil depends on not only the effective stress,but also the void ratio of the soil. a general relationship between the coefficient of secondary compression,and effective stress and void ratio was proposed for soil. the discrepancy of the dependency of secondary compressibility on effective stress for different soils was well explained using this relationship,moreover,the quasi-overconsolidated state of clayed soil induced by time effect and the effect of surcharge preloading on the secondary compressibility of soft ground were discussed in light of the general relationship. © 2016,iran university of science and technology.