Question

Question 4 In order to determine the in-situ density of the soil at a site, the sand replacement test conducted and the following results were obtained: 2.12 kg 1.85 kg Mass of soil extracted from the hole Mass of soil after oven drying Mass of sand pouring cylinder initially 5.45 kg Mass of sand pouring cylinder finally 3.27 kg Volume of cone in sand pouring cylinder 0.25x103 m3 Density of sand in cylinder 1579 kg/m If the specific gravity of the soil particles is assumed to be 2.65, calculate the bulk density, the dry density, the degree of saturation and air content of the soil. (6 marks) (b) Starting from the basic definitions, show steps to prove the following formula: Gs (1- A) Considering the soil with the same water content in (a), explain, with calculations, whether it is possible to compact the soil to a dry density of 2050 kg/m3. (4 marks) (c) A soil sample was retrieved from an excavation project site, and a constant head permeability test was performed for the soil. The sample length was 70 mm and sample diameter was 75 mm. The total head loss across the sample was 363 mm. The flow rate was measured and it took 203 seconds to fill up a 1-litre beaker. Estimate the coefficient of permeability (k) of the soil based on results of the constant head test. (5 marks)

Answer 1

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