Following are the results of a field unit weight determinati

Following are the results of a field unit weight determination test on a soil with the sand cone method: Calibrated dry density of Ottawa sand 1667 kg/m3 Calibrated mass of Ottawa sand to fill the cone 0.117 kg Mass of jar +cone + Ottawa sand (before use) 5.99 kg Mass of jar +cone +Ottawa sand (after use) 2.81 kg Mass of moist soil from hole 3.331 kg Moisture content of moist soil 1 1.6% Determine Mass of Ottawa sand to fill the hole in the field in kg. . Volume of hole in the field in m ·Moist unit weight of compacted soil in the field (kg/m) Dry unit weight of compacted soil in the field (kg/m)?

Solution

According to given data,

Mass of ottawa sand used= Mass of jar + cone + ottawa sand(before use)- Mass of jar+cone+ottawa sand(after use)

=5.99-2.81 =3.18 kg

Mass of ottawa sand in test hole= Mass of sand used - Mass of sand to fill the cone

=3.18 - 0.117 =3.063 kg

Volume of test hole =Mass of ottawa sand in hole / Density of ottawa sand used

=3.063/1667 =0.001837m³

Moist unit weight of compacted soil = Mass of wet moist soil / Volume of hole

=3.331 / 0.001837=1813.28 kg/m³

Dry unit weight of compacted soil = (Moist unit weight ) / ( 1+ ( moisture content / 100))

=1813.28/1.116 = 1624.8 kg/m³