This set of Geotechnical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Frost Action”.
1. Frost heave is defined as ___________
a) Rise of ground water surface
b) Freezing of water in soil
c) Increase in volume due to freezing
d) None of the mentioned
View Answer
Explanation: Rise of ground water surface in a soil mass due to frost action is termed as frost heave.
2. If the void ratio is 40% in saturated soil, then the expansion of the soil will be __________
a) 5 %
b) 2.3 %
c) 3.6 %
d) 4 %
View Answer
Explanation: There is an increase of about 9% in the volume, when water is converted in to ice. Therefore
Expansion of the soil = 0.009×40
=3.6 %.
3. What are the types of soils, that are prone to frost action?
a) Sand and Silt
b) Clay
c) None of the mentioned
d) All of the mentioned
View Answer
Explanation: Only silts and fine sands are prone to frost action because these soils have large capillary rise due to relatively fine particles.
4. What is the maximum capillary tension for a tube of 0.05 mm diameter at 4°c?
a) 6.05 KN/m3
b) 0.617 KN/m3
c) 5.45 KN/m3
d) 3.00 KN/m3
View Answer
Explanation: Maximum capillary height at 4°c is
(hC) max = 0.3084/d =0.617 m
Capillary tension = (hc) max × γmax
=6.05 KN/m3.
5. A well graded soil is said to be frost susceptible if more than _________
a) 10 % particle are smaller than 0.002 mm
b) 3 % particle are smaller than 0.002 mm
c) 3 % particle are smaller than 0.005 mm
d) 10 % particle are smaller than 0.005 mm
View Answer
Explanation: A well graded soil is reckoned to be frost susceptible if 3 % particle are smaller than 0.002 mm and for poor graded soil 10 % particle are smaller than 0.002 mm.
6. The ground surface up to which water freeze is called ___________
a) Frost heave
b) Frost boil
c) Frost line
d) Ice lenses
View Answer
Explanation: Frost line is the depth or boundary below the ground surface up to which water may freeze.
7. The temperature at which the soil freezes in the pores of the soil depend on __________
a) Pore size
b) Frost action
c) Saturation
d) Capillary tension
View Answer
Explanation: As the water freezes in larger pores, and remain unfrozen in the smaller pore the temperature falls downs.
8. Silt soils are more susceptible to frost action than __________
a) Sand soil and Clayey soil
b) Gravel soil
c) None of the mentioned
d) All of the mentioned
View Answer
Explanation: Silt soils have more plasticity index than sand and clays and hence the softening effect due to excess water will be more severe in silts.
9. Soil should possess___________for the formation of ice lens.
a) Low moisture content
b) High porosity
c) High capillarity
d) All of the mentioned
View Answer
Explanation: For the formation of ice lens and frost heave, soil should possess high capillarity so that the soil possesses a high capacity to pull water.
10. Which of the following is an effect of frost boils?
a) Formation of pot holes
b) Increased frost depth
c) Formation of capillary saturation
d) All of the mentioned
View Answer
Explanation: Due to frost boils, there is a formation of pot holes by extrusion of soft soil and water under the dynamic action of wheel loads.
11. Which of the following action can be used to prevent deep frost penetration in the ground surface in building?
a) Removing the frost susceptible soil
b) Placing insulating blankets of sand and gravel
c) Providing proper drainage
d) Interposing a pervious gravel blanket
View Answer
Explanation: Placing insulating blankets of 15 to 30 cm thick layer of sand and gravel on the ground surface above the frost susceptible to prevent deep penetration method.
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