In: Civil Engineering
Mr. and Mrs. Dursley of number four, Privet Drive, were proud to say that they were perfectly normal, thank you very much. Unfortunately, someone, or something, had left 13very large, very deep, boot-shaped depressions in their front yard. Each depression has a volume of 1 ft3(for a total volume to be filled with 13ft3). The Dursleys plan to angrily purchase 22 kg (total weight) bags of topsoil from a local store to fill the holes. Each bag of topsoil has a water content of 10%, a total unit weight of 80 pcf, a specific gravity of 2.35 (the soil contains organic matter which has lower specific gravity than mineral soil solids). During transport, you should assume the bags will spill in the back of the Dursley’s Vauxhall Vectra hatchback, therefore the soil will have a looser total unit weigh of 70 pcf with the same 10% water content during transport. Vauxhall Vectra has 16.9 ft3of trunk space. During compaction, the soil is wetted to a 20% gravimetric water content and compacted toa total unit weight of 120pcf (the Dursleys are furious about these holes and take out the anger on compacting soil). The work will be conducted on a Thursday. How many bags of topsoil will be needed to fill these holes?
solution is attached in the image posted below.
hope it helps you.
for solving you should know the weight of solid in soil remains constant in bags as well as compacted soil.
first calculate total volume of soil require to fill in the holes. then weight of solid in the found volume.
now take 1ft3 of bag of soil and find the weight of solid in it. then compute total bags required to equal the weight of solid in both case . then compute volume of 22kg of bag of soil then compute number of bags.