The top 5-m of the soil is dry clean sand. According to STP tests on the...

 

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The top 5-m of the soil is dry clean sand. According to STP tests on the site, the N-values are ranging from 5 to 9 with an average of 7. The bottom layer extends to a great depth. According to STP tests on the site, the N-values are ranging from 34 to 46 with an average of 40. The Atterberg limits tests, on bottom layer for particles smaller than 0.425 mm, indicate that the average liquid and plastic limits are 40% and 27%, respectively. The water table is 5 m below the ground level. The following table is prepared based on the particle size distributions of both layers of the soil: % Passing 10% 20% 30% 50% 60% 100% d (mm) 0.12 0.25 0.4 1.2 2 10 Top Layer d (mm) Bottom Layer 0.01 0.03 0.08 0.25 0.5 4 The design specification requires that the whole of top soil layer to be densified to achieve an average SPT value of 40. Plot particle size distribution curve of each soil separately. Use a semi-log graph of % Passing versus Diameter (mm). Classify the soil of each layer, using the symbols the Unified Soil Classification System (USCS). Based on N-values, estimate the initial total unit weight of each layer. Calculate the effective unit weight of bottom layer. If the initial ground level of the site is going to be maintained, determine the minimum amount of backfill, required for this site (i.e. the mass of required dry soil in tonnes). The top 5-m of the soil is dry clean sand. According to STP tests on the site, the N-values are ranging from 5 to 9 with an average of 7. The bottom layer extends to a great depth. According to STP tests on the site, the N-values are ranging from 34 to 46 with an average of 40. The Atterberg limits tests, on bottom layer for particles smaller than 0.425 mm, indicate that the average liquid and plastic limits are 40% and 27%, respectively. The water table is 5 m below the ground level. The following table is prepared based on the particle size distributions of both layers of the soil: % Passing 10% 20% 30% 50% 60% 100% d (mm) 0.12 0.25 0.4 1.2 2 10 Top Layer d (mm) Bottom Layer 0.01 0.03 0.08 0.25 0.5 4 The design specification requires that the whole of top soil layer to be densified to achieve an average SPT value of 40. Plot particle size distribution curve of each soil separately. Use a semi-log graph of % Passing versus Diameter (mm). Classify the soil of each layer, using the symbols the Unified Soil Classification System (USCS). Based on N-values, estimate the initial total unit weight of each layer. Calculate the effective unit weight of bottom layer. If the initial ground level of the site is going to be maintained, determine the minimum amount of backfill, required for this site (i.e. the mass of required dry soil in tonnes).

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Here are the steps to solve this problem 1 Plot the particle size distribution curves for each soil ... View the full answer