12 Questions
In laboratory work, what is the goal of achieving maximum dry density and optimum water content?
To achieve the highest possible density
What is the primary objective of soil compaction?
Increase density, strength, bearing capacity and reduce permeability and compressibility
What is the primary difference between compaction and consolidation?
Compaction removes air-filled porosity, while consolidation removes water-filled porosity
What is the result of reducing the volume of voids in soil?
Compaction of soils
What is the purpose of using the optimum water content in soil compaction?
To achieve the highest possible density
What is the role of mechanical devices in soil compaction?
To reduce the soil void ratio
What is the primary assumption made about the compaction process?
It does not alter the volume of the solids or soil grains
What is the result of increased shear strength in compacted soils?
Larger loads can be applied to the soil
What is the primary mechanism of the Lambe theory of compaction?
Physico-chemical concepts
Which of the following is a consequence of reduced permeability in compacted soils?
Reduced tendency to expand and shrink
What is the result of the bending and distortion of soil particles during compaction?
Increased cohesion between particles
Which of the following theories was proposed by Proctor in 1933?
Proctor theory
Study Notes
Soil Compaction
- Compaction objectives: increase density, strength, bearing capacity, and reduce permeability and compressibility.
- Compaction is the process of increasing soil unit weight by reducing soil void ratio using mechanical devices.
- Compaction laboratory work involves obtaining maximum dry density and optimum water content.
- Field compaction is executed by contractors using rollers and compactors, and checked by several methods.
Compaction and Consolidation
- Compaction: removal of air-filled porosity.
- Consolidation: removal of water-filled porosity.
- Compaction of soils is achieved by reducing the volume of voids, assuming the volume of solids or soil grains remains constant.
Principles of Compaction
- Compaction increases shear strength, density, and bearing capacity, allowing for larger loads to be applied.
- Compaction reduces compressibility, resulting in smaller settlements under larger loads.
- Compaction reduces permeability, inhibiting soil's ability to absorb water and reducing the tendency to expand/shrink and liquefy.
- Compaction affects soil's shrinking and swelling behavior, depending on the soil type.
Mechanism of Compaction
- Cohesive principles:
- Interaction between adsorbed layer and interpretable force.
- Breaking up of old bonds and establishment of new bonds between particles.
- Bending and distortion of soil particles.
- Cohesionless principles:
- Rearrangement of soil grains.
- Breaking up of some cementation.
- Bending and distortion of soil particles.
- Theories: Lambe theory (physico-chemical concept), Proctor theory (1933), and lubrication theory.
This quiz covers the effects of compaction on soil, including increased shear strength, density, and bearing capacity, as well as reduced compressibility and permeability. Learn how compaction affects the behavior of soils and its applications in engineering.
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