A loose, uncompacted sand fill 6 ft in depth has a relative density of 40%. Laboratory tests indicated that the minimum void ratios of the sand are 0.46 and 0.90, respectively. The specific gravity of solids of the sand is 2.65.
a). What is the dry unit weight of the sand?
b). If the sand is compacted to a relative density of 75%, what is the decrease in thickness of the 6-ft fill?