A SIMPLE, EFFECTIVE METHOD FOR DETERMINING THE BULK-DENSITY OF STONY SOILS

A new technique of determining bulk density based upon the excavation method is especially useful in stony soils and surface mine spoils. The technique involves determining the volume of an excavated hole using an expanding urethane foam which solidifies to form a perfect cast of the hole. Volume of the cast is determined by water displacement. Comparison of this method with the sand method of volume determination in a surface mine spoil showed no difference in calculated values of bulk density. However, bulk densities determined by driving a steel core of known volume into the stony surface mine spoil were consistently 12-17% lower than those determined by excavation. The new technique may be applied to sloping soil surfaces and may be used for bulk density determinations at depth in the exposed vertical face of a soil pit.