Question

The following table shows the lab results of a grain size analysis and Atterberg limits for an inorganic soil sample (initial total mass=1029) Assume you measured a liquid limit of 40% and plastic limit of 30% for the sample. Sieve Size/No. Equivalent Sieve Size (mm) Mass Retaining(s) Mass Passing (9) Percent Passing 3" 75 11 50 0 3 19 4.75 20 2 20 15 10 No. 60 5 4 4 4 0.003 2 2 2" 3/4" No. 4 No. 10 No. 20 0.850 No. 40 0.425 0.250 No. 100 0.150 No. 200 0.075 Hydrometer 0.010 Hydrometer Hydrometer 0.001 Classify the sample using the Unified Soil Classification System (USCS): a. Calculate the cumulative percent passing of each sieve sizes to complete the above table Submit all your calculations including formulas in D2L. (3 Marks). b. Calculate the percent of each particles (Gravel, Sand, Silt and Clay) and enter the answers in boxes 1,2,3 and 4 respectively (4 points) c. Plot the respective grain-size distribution curve on a blank grain size chart, label and find D10, D30 and D60 and enter your answers in boxes 5,6 and 7 respectively (4 points for the graph and 3 points for the right answers). d. Plot the Atterberg limit data on the plasticity chart (3 Marks) e. Calculate Coarse fraction, Fine fraction, Cc, Cu and enter your answers in boxes 8,9,10 and 11 respectively (4 points) f. Classify the soil and enter the soil classification designation in box 12_4 points). Note: If a value cannot be calculated, enter N/A for non-available.

Answer 1

a.

Sieve size	Mass retained	Mass passing	Percent passing
75	11	89	89
50	0	89	89
19	3	86	86
4.75	20	66	66
2	20	46	46
0.85	15	31	31
0.425	10	21	21
0.25	5	16	16
0.15	4	12	12
0.075	4	8	8
0.01	4	4	4
0.003	2	2	2
0.001	2	0	0
	100

b. Clay - 2% Silt - 6% Sand - 58% Gravel - 44%

c.

  

PSD CUMULATIVE % FINER 100.00 90.00 80.00 70.00 60.00 50.00 40.00 30.00 20.00 10.00 0.00 0.01 0.010 10 100 D3P D60 PARTICLE SIZE (MM)

D₁₀ =0.12mm  D₃₀ = 0.87mm  D₆₀ = 3.5mm

d. LL = 40% PL = 30% PI = LL - PI = 40 - 30 = 10

60 50 CL CI CH 40 PLASTICITY INDEX (%) 30 20 10 * CL-NL MIRO MH&OH ML & OL 0 10 20 30 70 80 90 100 40 50 600 LIQUID LIMIT (%)