Geotechnical Engineering — Quiz 2

Questions in this quiz (10)

1. In a specific gravity test using a pycnometer, the mass of oven-dried soil is $$150\ \mathrm{g}$$, the mass of the pycnometer filled with water is $$650\ \mathrm{g}$$, and the mass of the pycnometer with soil and water is $$745\ \mathrm{g}$$. Determine the specific gravity of the soil solids.

   • 2.73
   • 2.65
   • 2.45
   • 2.58

2. A soil sample is taken from the field for water content determination. The mass of the wet soil sample is $$185.4\ \mathrm{g}$$ and the mass after oven-drying is $$156.2\ \mathrm{g}$$. Determine the water content of the soil.

   • 15.7%
   • 20.6%
   • 84.3%
   • 18.7%

3. A sand deposit has a maximum void ratio of $$0.92$$ and a minimum void ratio of $$0.48$$. The in-situ void ratio is $$0.65$$. Calculate the relative density of the sand.

   • 38.6%
   • 70.7%
   • 61.4%
   • 29.3%

4. A clay soil has a natural water content of $$32\%$$, liquid limit $$45\%$$, and plastic limit $$22\%$$. Calculate the liquidity index.

   • 0.57
   • 0.43
   • 0.71
   • -0.57

5. A soil sample has $$35\%$$ passing No.200 sieve, $$85\%$$ passing No.4 sieve, liquid limit $$42\%$$, plastic limit $$25\%$$. Classify using USCS.

   • SM
   • CL
   • SW-SC
   • SC

6. A non-cohesive sand with $$8\%$$ fines, $$C_u=8$$ and $$C_c=2.5$$. Classify using USCS.

   • SW
   • SP
   • SM
   • SW-SM

7. 34% of soil sample passes through No.200 sieve. The soil liquid limit is $$39$$ and plastic limit is $$29$$. What is the AASHTO classification for this soil?

   • A-2-4
   • A-2-5
   • A-5
   • A-6

8. For the soil layers below, determine the vertical effective stress at point A.

   • 800 psf
   • 1100 psf
   • 1400 psf
   • 1700 psf

9. A retaining wall is 12 ft high. Backfill density is $$120\ pcf$$. Saturated below 5 ft. Friction angle $$30^\circ$$. Determine resultant active force.

   • 2880 lbs
   • 3880 lbs
   • 4880 lbs
   • 8880 lbs

10. A retaining wall 12 ft high with saturated soil below 5 ft. Determine overturning moment.

    • 5000 lb.ft
    • 8000 lb.ft
    • 11000 lb.ft
    • 15520 lb.ft