Geotechnical Engineering — Quiz 5

Questions in this quiz (10)

1. An excavated slope in uniform soil is shown. The soil has a cohesion of $$19.2\ \mathrm{kPa}$$ and an internal friction angle of $$15^\circ$$. The weight of the soil above the trial failure plane is $$3036\ \mathrm{kN/m}$$. The trial failure plane makes an angle of $$20^\circ$$ with the horizontal, and the vertical height is $$15\ \mathrm{m}$$. What is most nearly the factor of safety against sliding?

   • $$1.6$$
   • $$2.3$$
   • $$2.9$$
   • $$3.4$$

2. Which of the following soils has the cohesive property?

   • Silt
   • Clay
   • Sand
   • Gravel

3. The saturated unit weight of a soil is $$20\ \mathrm{kN/m}^3$$. The submerged effective unit weight of the soil is most nearly:

   • $$9.81\ \mathrm{kN/m}^3$$
   • $$19.21\ \mathrm{kN/m}^3$$
   • $$20.0\ \mathrm{kN/m}^3$$
   • $$10.2\ \mathrm{kN/m}^3$$

4. A chunk of moist soil weighs $$49\ \mathrm{lb}$$ with a volume of $$0.46\ \mathrm{ft}^3$$. After oven drying, the weight decreases to $$38\ \mathrm{lb}$$. The specific gravity and void ratio of the soil are $$2.64$$ and $$1.1$$, respectively. The degree of saturation of the soil is most nearly:

   • $$39\%$$
   • $$49\%$$
   • $$59\%$$
   • $$69\%$$

5. More than $$50\%$$ of a soil is retained on a $$\#200$$ sieve. The soil is most nearly:

   • Sand-Silt
   • Gravel-Clay
   • Sand-Gravel
   • Fine Soil

6. In a clay soil, the liquid limit is $$30$$. The soil is most nearly:

   • High-liquid limit
   • High plastic
   • Low plastic
   • None of the above

7. For the flow net shown below, what is the total rate of seepage per unit width of sheet pile through the permeable stratum? The coefficient of permeability of the soil is $$2\times10^{-3}\ \mathrm{ft/s}$$.

   • $$1.11\times10^{-2}\ \mathrm{ft}^3/\mathrm{s}$$
   • $$1.33\times10^{-2}\ \mathrm{ft}^3/\mathrm{s}$$
   • $$13.3\times10^{-2}\ \mathrm{ft}^3/\mathrm{s}$$
   • None of the above

8. A $$10\ \mathrm{ft}$$ clay layer has a void ratio of $$1.1$$. Upon increase in vertical stress by a building, the void ratio decreases by $$0.02$$. The settlement of the clay layer is most nearly:

   • $$0.84\ \mathrm{in}$$
   • $$0.94\ \mathrm{in}$$
   • $$1.04\ \mathrm{in}$$
   • $$1.14\ \mathrm{in}$$

9. Normal consolidation means what?

   • Soil is too much compacted by roller
   • Soil has past pressure equal to the current pressure
   • Soil can withstand greater pressure compared to current overburden pressure
   • Too much compaction may destroy the soil

10. Consolidation settlement is a function of what?

    • Plastic limit
    • Plasticity Index
    • Shrinkage index
    • Liquid limit