Which of the following is most affected by soil permeability?
A Soil compaction
B Soil color
C Water flow
D Soil strength
Soil permeability refers to the ability of a soil to allow water to pass through it. High permeability means water flows easily through the soil, while low permeability means it resists water movement, affecting drainage and soil structure.
The standard Proctor test is used to determine what property of soil?
A Optimum moisture content
B Shear strength
C Bearing capacity
D Permeability
The Standard Proctor test determines the moisture content at which a soil type achieves maximum compaction. This is essential for ensuring that soil reaches its highest possible density during construction, improving stability and load-bearing capacity.
What does the term “liquefaction” refer to in soil mechanics?
A Soil hardening under pressure
B Soil turning into liquid during shaking
C Soil drying and cracking
D Soil freezing
Liquefaction occurs when saturated soils lose their strength during ground shaking, typically during an earthquake. The pressure causes pore water to increase, reducing the soil’s ability to bear load and causing it to behave like a liquid.
What is the purpose of conducting a direct shear test on soil?
A To check compaction
B To determine moisture content
C To analyze permeability
D To measure shear strength
The direct shear test measures the shear strength of soil by applying a shear force to a soil sample, then observing the soil’s ability to resist failure. This test helps in understanding the material’s response to stress and strain.
Which soil property is most related to soil erosion?
A Plasticity
B Cohesion
C Permeability
D Organic content
Cohesion refers to the forces that hold soil particles together. Higher cohesion makes soil more resistant to erosion, while low cohesion allows soil particles to be carried away by wind or water, leading to erosion.
What is the main purpose of using geotextiles in civil engineering?
A Improve drainage and filtration
B Reduce soil permeability
C Increase soil shrinkage
D Strengthen soil structure
Geotextiles are synthetic materials used to improve drainage and filtration in soils. They allow water to pass through while preventing the movement of soil particles, enhancing soil stability and preventing erosion.
Which test is used to determine the bearing capacity of soil?
A Triaxial test
B Proctor test
C CBR test
D Plate load test
The plate load test is used to determine the bearing capacity of soil, which is essential for designing foundations. It involves placing a plate on the soil surface and applying a load to measure settlement under pressure.
What does effective stress in soil refer to?
A Stress caused by external loads
B The pressure from soil weight
C Total stress minus pore water pressure
D The stress from moisture content
Effective stress is the stress that contributes to soil strength and is calculated by subtracting pore water pressure from the total stress. This stress is crucial in understanding soil behavior, especially in saturated conditions.
What is one method used to stabilize expansive soils?
A Removing organic material
B Adding lime
C Decreasing compaction
D Increasing water content
Lime stabilization is a method used to improve the properties of expansive soils, which tend to swell when wet. Adding lime reduces moisture sensitivity, improving soil strength and reducing the risk of structural damage.
Which test measures the compaction characteristics of soil?
A CBR test
B Triaxial test
C Direct shear test
D Proctor test
The Proctor test is used to determine the compaction characteristics of soil. It identifies the optimum moisture content at which a soil sample achieves maximum dry density, crucial for construction and foundation work.
Which type of soil is most prone to swelling when wet?
A Clayey soil
B Gravel
C Sandy soil
D Silt
Clayey soils are most prone to swelling when they absorb water. The fine particles in clay soil have high surface area and water retention capacity, causing expansion and significant changes in volume under wet conditions.
What is the primary function of soil compaction?
A Increase soil strength and stability
B Reduce soil shrinkage
C Improve soil permeability
D Increase soil volume
Soil compaction increases the density of the soil, which in turn improves its strength and stability. This is essential for supporting structures, preventing excessive settlement, and minimizing the risk of failure in construction.
What does the term “seepage” in soils refer to?
A Water absorption
B Flow of water through soil
C Water condensation
D Water evaporation
Seepage refers to the slow flow of water through soil, often through pore spaces. It is an important consideration in civil engineering as it can affect the stability of structures and cause erosion or weakening of foundations.
What is a common consequence of improper compaction of soil?
A Reduced permeability
B Increased strength
C Settling or subsidence
D Decreased plasticity
Improper compaction can lead to uneven settling or subsidence of soil. This results in structural issues as the foundation may sink or shift over time, causing cracks or instability in buildings or roads.
Which of the following tests is used to evaluate the California Bearing Ratio (CBR) of soil? Note: The options have been re‐ordered so that the correct answer “CBR test” appears as option C.
A Triaxial test
B Proctor test
C CBR test
D Plate load test
The California Bearing Ratio (CBR) test evaluates the strength of subgrade soils by comparing their resistance to penetration under a standard load. It is used primarily in road construction to assess soil suitability for supporting traffic loads.