4.13 An undisturbed cylindrical soil sample is 60 mm in diameter and 152 mm long. It has a mass of 816 g. After finding the mass of the entire sample, a small portion was removed and a moisture content test was performed on it. The results of this test on the subsample were: Mass of can = 22.01 g Mass of can + moist soil = 124.97 g Mass of can + dry soil = 112.72 g Using G = 2.70, compute w, y, ya, e, and S.

4.8 A sample of soil was compacted into a 1/30 ft³ laboratory mold. The weight of the compacted soil was 4.1 lb and its moisture content 13.1%. Using a specific gravity of solids of 2.70, compute the unit weight, dry unit weight and degree of saturation of this compacted soil. This compacted soil sample was then submerged in water. After 2 weeks, it was found that the sample had swelled and that its total volume had increased by 5%. Compute the new unit weight and moisture content of the soil sample after 2 weeks of submersion in water.

1.) Classify the soil behavior types (SBT) for the entire depth log using the Cone Penetration Test (CPT) data. Turn in a depth log of your profile with each SBT type clearly delineated.

4.15 A strata of clean, light-colored quartz sand located below the groundwater table has a moisture content of 25.6%. The minimum and maximum void ratios of this soil are 0.380 and 1.109, respectively. Select an appropriate value of G, for this soil, compute its relative density, and determine its consistency using Table 4.4.

Questions: 1. The coefficient of uniformity Cu of a soil is 10 and its coefficient of curvature Cc is 0.90. You would classify the soil as: a. Even-graded b. Medium-graded c. Gap-graded 6. An oedometer sample had a final water content of 12.5 % and a specific gravity of 2.7. What was its final voids ratio? a. 0.338 b. 0.238 C. 1.338 100 9. In a falling head permeameter test the length of the sample is 120mm and its area is 4417.86 mm². The area of the standpipe is 132.73 mm². At the start of a test the water level in the standpipe was 410mm and fell to 185mm after 490s have elapsed. What is the permeability of the soil? a. 6.16*10-3 m/s b. 1.25*10-3 mm/s c. 5.85*10-3 mm/s ooo 16m 11. An embankment is to be constructed over a 2m thick sand layer, underlain by a 16m thick saturated soft clay layer, which is underlain by a sand layer. The embankment will trigger consolidation of the clay layer. For the clay cv-3.1 m²/year. How long will it take for 90% of the consolidation process to be completed? 0.848 d²=st== a. 19.8 years b. 70 years c. 17.5 years 3.1m 8 m 12.A uniformly distributed Toad of 100 kN/m² is applied on a clay layer. After one ū ₁s=100& year the average excess pore pressure is 40 kN/m². The average degree of consolidation of the clay at this time is: 22 a. 40% b. 60 % c. It cannot be determined based on the information given ū=, oni₂ BEng Civil Engineering -Soi Mechanics -May 2022 1:1. U= U = Uei- let. 100- /c 2 7. An oedometer sample had the following voids ratios: e=0.364 under an effective stress of 0 kPa, e=0.351 under an effective stress of 100 kPa and e=0.338 under an effective stress of 200 kPa. What is the coefficient of volume compressibility my of the soil in the range 100 - 200 kPa? a. 1.9 x 10-4 m²/kN b. 9.53 x 10-5 m²/kN c. 9.62 x 10-5 m²/kN 00

2. (5 pts) As part of a quality control program, the field inspection engineer conducted a sand cone test to determine the field density. The following data were recorded using the sand cone method. • Total weight of moist soil removed from the Hole: • Weight of sand cone apparatus before filling Hole: • Weight of sand cone apparatus after filling Hole: • Weight of sand to fill Cone: • Unit weight of Ottawa Sand: 7.94 Ib 14.42 lb 4.19 lb 3.43 lb 98.0 lb/ft³ Also, the water content was obtained from an oven dry method with the following data (Disregard the tin cup weight) • Weight of soil in a tin cup before drying: • Weight of soil in a tin cup after drying: 1.35 lb 1.20 lb With the dataset shown above, determine the dry unit weight of the field-compacted soil (show all your work).

CENG 3232 Soil Mechanics Assignment # 3 Show all your calculations to receive the full credit. 1. (5 pts) Classify the following soils by the AASHTO classification system. No need to calculate the group index. Pick one of the soils and briefly explain how you arrive at your final answer. Soil A B с D E Inorganic Soil A B с D Sieve Analysis (% Passing) No. 40 80 92 88 55 75 E No. 10 98 100 100 85 92 No. 200 50 80 25 34 62 Liquid Limit Sieve Analysis (% Passing) No. 4 No. 200 92 48 60 40 99 76 90 60 80 35 38 56 37 28 43 2. (5 pts) Classify the following soils by the USCS. Pick one of the soils and briefly explain how you arrive at your final answer. Liquid Limit Plasticity Index 30 26 60 41 24 29 23 22 20 28 Plasticity Index Soil Type Designation 8 4 32 12 2 Group Symbol

1. (10 pts) The results of a standard Proctor test are given in the following table. a. Complete the table, assuming Gs = 2.6. Show one sample calculation on how you obtain the three unit weights (Y. Ya, and yz). Note that the standard mold volume is 1/30 ft³. Compaction Trial No. 1 2 3 4 5 6 Weight of moist soil in the mold (lb) 3.65 4.12 4.48 4.38 3.91 3.63 Water Content (%) 7.2 9.5 12.5 14.9 17.1 18.1 (Moist) Unit Weight (lb/ft³) Dry Unit Weight (lb/ft³) Dry Unit Weight w/ Zero Air Void (lb/ft³) b. Plot the dry unit weight data vs. water content and determine the maximum dry unit weight and optimum water content. Also, add the Zero Air Void curve in the plot. When plotting, use an MS Excel chart option (Scatter with Smooth Lines and Markers). Attach your plot (an MS Excel file) indicating the OMC and max dry unit weight. c. Determine the degree of saturation at OMC you determined (i.e., the water content and dry unit weight are known) Hint: Recall Se=wGs and ya=Gryw/(1+e) d. If the dry unit weight you achieved in the field is 105 lb/ft³, what is the relative compaction (%) of the compacted soil?/nCENG 3232 Soil Mechanics Compaction e. If the construction specification requires the field compaction to be 95% of the maximum dry unit weight, what is the range of water content that can be referenced in the field? f. As a field civil engineer, what would you do to increase the degree of compaction?

4.36 A sand with G₁ = 2.66 and e=0.60 is completely dry. It then becomes wetted by a ris- ing groundwater table. Compute the unit weight (lb/ft3 or kN/m³) under the following conditions: (a) When the sand is completely dry. (b) When the sand is 40% saturated (S = 40%). (c) When the sand is completely saturated.

Step1. Pick a 500 foot by 500 foot section on the TAMUK campus to select an area of interest and print a soil map. Obtain necessary soil data to complete this exercise. The soil survey can be located at the website: https://websoilsurvey.nrcs.usda.gov/app/ Step2. Review the following data to be used in this exercise. Compaction curve for data given in Example 3.2 Dry density Pr (glom) 1.85 1.80 1.75 21.70 165- 160 1.55 1.50 10 12 16 Water content (%) 14 Figure 3.9 Step3. Review the attached specification (The spec. has been uploaded in blackboard) Problem Statement: With the lab results given in Step 2, does the soil in your area of interest meet the attached specifications if the nuclear density gauge reading showed a dry density value of 1.7542 g/cm³? Explain your conclusions.