Geotechnical Evaluation of Fines Content Effect in Gravelly Sand Replacement Soil

Abstract

Abstract The compacted soil replacement procedure has been widely used in Egypt for Overcoming the unfavorable actions of some problematic soils, such as expansive, Collapsing soils and ground fill. Compaction of the replacement soil is necessary for stabilizing it and improving its performance. The supporting capacity of a replacement soil increases with the increase of its dry density. Therefore, the density of the replacement layer is the major factor controlling its behavior under the effect if external stresses. Compacted sand and gravelly sand are preferred materials when used for soil replacement. They tend to have better engineering properties, if they are placed according to the standard specifications. Gravelly-sand soil, which consists of gravel, sand and fines, is widely used as replacement soil in the field. The effect of fines content on possibly achieved density of such soil is experimentally investigated. Another experimental stage of the effect of fines on the bearing capacity of circular footings on gravelly-sand with different percentages of fines was performed. It was found that a fines content of 10 % gives highest dry density, if the soil is compacted according to modified proctor specifications and with the addition of fines, settlement increases and the ultimate bearing carrying capacity decreases.