Question

A road embankment will be constructed using clayey sand from a local borrow excavation. The embankment has a volume of 100,000 cubic meters. Specifications require the soil to be compacted to at least 95 percent of the maximum dry density obtained in a Standard Proctor test (i.e., relative compaction, RC greater than or = 95%). It is estimated that the as-constructed embankment will be at an average RC of 97% since the contractor must meet or exceed this specification. Standard Proctor tests on this soil produce a maximum dry density of 17.9 kN/m3 at an optimum water content of 16 percent. The soil in its natural condition (prior to excavation) has a water content of 6 percent, degree of saturation of 20 percent,and specific gravity of solids (Gs) of 2.70. Estimate the following:

(a)Volume of soil to be excavated from the borrow area.

(b)Number of truck trips at 25 tonne/load required to move the soil, assuming it remains at its natural water content during transport (1 metric tonne=1000 kg).

(c)Volume of water required to raise the water content of the soil to its optimum value for compaction (neglect the effects of evaporation for this calculation)

Answer 1