Reference no: EM132624848

CET 4130 Soil Mechanics - Metropolitan State University of Denver

Problem 1. A sand sample has a total unit weight of 18.75 kN/m3 and a water content of 5.7%. The minimum and maximum void ratios are 0.38 and 0.92, respectively. Determine the relative density of this sand sample.

Problem 2. A nuclear power plant is be constructed at a site. The site soil must be assessed to determine if it satisfies the requirements proposed by the Nuclear Regulatory Commission for a compacted backfill. The regulation mandates that a sand or silty sand must be used that meets the following grain size gradation:

Sieve No.	Percent Finer by Mass [%]
	Minimum	Maximum
4	85	100
10	70	100
20	40	98
40	20	95
60	10	80
100	6	50
140	4	28
200	3	25

To meet the seismic regulations, a grain size analysis was conducted for a soil sample.

Sieve No.	Percent Finer by Mass [%]
4	100
10	98.1
20	76.6
40	32.6
60	14.8
100	10.3
140	9.0
200	8.3

Based on the information provided, answer the following questions:

1. Plot the grain size distribution curve for the site soil.
2. Determine the percentage by mass of gravel, sand, and fine-grained materials.
3. Determine d10 and the median grain size, d50.
4. Determine the coefficient of uniformity, Cu, and the coefficient of curvature, Cc.
5. Plot the grain size distribution curve for the analyzed soil as well as for the minimum and maximum grain size requirements of the NRC. Does the site soil meet the grain size requirements of the NRC or will another soil need to be transported the site?

Sieve Analysis

	Mass Retained [g]
Sieve No.	Soil A	Soil B	Soil C
4	0	0	0
10	20.2	48.2	15
20	25.7	19.6	98
40	40.4	60.3	90
100	18.1	37.2	182
200	27.2	22.1	109
Pan	68.2	0	6

Atterberg Limits

	A	B	C
Liquid Limit, LL	23	Non-plastic	Non-plastic
Plastic Limit, PL	8

Problem 4. For the 14 given soils, classify the soils according to USCS. Make a new table with soil sample number in the left column and the USCS group symbol(s) in the right column. Assume no organics are present.

No.	Gravel [%]	Sand [%]	Silt and Clay [%]	Liquid Limit [%]	Plasticity Index [%]	Cu	Cc
1	30	40	30	33	12	-	-
2	52	28	20	41	19	-	-
3	0	18	82	30	11	-	-
4	0	26	74	35	14	-	-
5	12	62	26	38	20	-	-
6	9	50	41	42	21	-	-
7	29	67	4	-	-	3.4	2.6
8	4	44	52	29	11	-	-
9	12	40	48	32	13	-	-
10	28	38	34	29	14	-	-
11	0	98	2	-	-	7.2	2.2
12	31	65	4	-	-	5.4	3.6
13	10	82	8	39	8	3.9	2.1
14	0	24	76	55	26	-	-

Problem 5. A soil sample from a borrow pit was obtained. A sieve analysis, Casagrande Cup test, and a thread rolling test were all conducted. The results are as follows:

Sieve Analysis:

Sieve No.	Percent Finer [%]
20	100
40	99.8
60	98.1
80	87.4
100	78.3
200	56.0

Casagrande Cup

Test No.	Mass (Soil+Water) [g]	Mass Soil [g]	Number of Blows, N
1	75.61	40.02	31
2	77.21	40.66	30
3	75.34	38.67	26
4	74.15	37.15	22
5	73.66	35.78	18

Thread Roll Test

Test No.	Mass (Soil+Water) [g]	Mass Soil [g]
1	50.21	37.65
2	50.55	37.89
3	49.88	37.51
4	49.74	37.33
5	50.01	37.74

Determine the LL, PL, PI, LI, and Activity. Make a Plasticity Chart, showing the A-line, U-line, and plot the soil sample on your Plasticity Chart.