What does the term “settlement” in soil mechanics refer to?
A Soil shrinkage
B Decrease in soil volume
C Movement of soil due to external load
D Increase in soil volume
Settlement refers to the downward movement of the ground surface due to the compression of soil layers under an applied load. It is important for evaluating the performance of foundations and avoiding structural damage over time.
What is the main function of a plate load test?
A Measure soil compaction
B Assess bearing capacity of soil
C Determine shear strength
D Measure permeability
The plate load test is primarily used to assess the bearing capacity of the soil at a specific depth. This test applies a load to a plate placed on the ground and measures the settlement, helping determine the soil’s load-bearing ability.
Which of the following tests directly measures the shear strength of soil?
A Triaxial test
B CBR test
C Proctor test
D Plate load test
The triaxial test is used to directly measure the shear strength of soil by applying stress in all directions and recording the point at which the soil fails. This is important for understanding how soil behaves under various loading conditions.
What does the Standard Proctor test determine?
A Liquid limit
B Soil permeability
C Shear strength of soil
D Optimum moisture content for compaction
The Standard Proctor test is used to find the optimum moisture content at which a soil sample can achieve maximum compaction. This is essential for ensuring stable and strong foundations and compacted embankments.
What is the purpose of the California Bearing Ratio (CBR) test?
A To determine moisture content
B To assess soil strength for road design
C To measure soil compaction
D To determine shear strength
The CBR test measures the strength of subgrade soils, particularly for road construction. It evaluates the soil’s resistance to penetration under a standard load, helping engineers design pavements and roads with appropriate thickness and stability.
Which type of soil typically requires the use of geotextiles?
A Clay
B Sand
C Gravel
D Silt
Geotextiles are most commonly used in clayey soils to improve drainage, filtration, and separation. They prevent soil erosion and improve stability by controlling water flow and providing reinforcement, especially in areas with poor drainage or expansive soils.
What does the stress-strain curve of soil represent?
A Soil’s behavior under applied stress
B Relationship between shear strength and compaction
C Soil’s permeability with increasing load
D Relationship between soil depth and moisture content
The stress-strain curve represents how a soil deforms under increasing stress. The curve helps in understanding the soil’s elastic and plastic behavior, its ultimate strength, and how it will perform under load during construction projects.
What is the main cause of soil erosion?
A Soil freezing
B Water and wind action
C High compaction
D Low moisture content
Water and wind are the primary forces responsible for soil erosion. Water can carry away loose soil particles, while wind can pick up and transport soil from exposed surfaces. Both lead to loss of fertile soil and degrade land quality.
What type of soil is most commonly associated with high plasticity?
A Clay
B Sandy soil
C Gravel
D Silt
Clay has high plasticity, which means it can be easily molded and retains its shape when subjected to stress. This property is critical for understanding the soil’s behavior in construction, as high plasticity can influence stability and compaction efforts.
What is the primary use of soil stabilization in civil engineering?
A To increase soil plasticity
B To reduce soil permeability
C To improve soil’s strength and durability
D To increase moisture content
Soil stabilization improves the physical properties of soil, especially its strength and durability. This is done by mixing soil with stabilizers such as lime, cement, or other chemicals to make it more resistant to erosion and better suited for foundation work.
What is the relationship between soil permeability and particle size?
A Depends on soil depth
B Directly proportional
C Inversely proportional
D No relation
Soil permeability is directly proportional to particle size. Larger particles, like sand, have larger pores that allow water to pass through more easily, while smaller particles like clay have finer pores that restrict water flow.
What is the primary factor that affects soil consolidation?
A Soil texture
B Soil depth
C Soil color
D Applied load and permeability
Soil consolidation is affected by applied load and permeability. When a load is applied to saturated soil, the water in the pores is expelled over time, causing the soil to compress. The rate of consolidation depends on the permeability of the soil.
What does a direct shear test measure?
A Soil’s shear strength
B Soil’s compressibility
C Soil’s permeability
D Soil’s liquid limit
The direct shear test measures the shear strength of soil by applying a horizontal force to a soil sample until it fails. This test helps engineers understand how soil will perform under stress and is vital for foundation and slope stability design.
What is the primary reason for conducting a triaxial test on soil?
A To analyze soil plasticity
B To assess soil permeability
C To determine shear strength
D To determine moisture content
The triaxial test is used to determine the shear strength of soils by applying stress in all directions. It simulates real-world loading conditions and helps engineers evaluate how soil will behave under different stress conditions during construction.
How does soil compaction affect its shear strength?
A No effect on shear strength
B Increases permeability
C Reduces shear strength
D Increases shear strength
Compaction increases soil density by reducing voids, leading to higher shear strength. Compacted soil is more resistant to deformation under load and is less likely to fail, making it essential for supporting structures like buildings and roads.