Geotechnical Flashcards
Discuss the differences between cohesionless and cohesive soils
Cohesionless soils, such as sands and gravels, lack cohesive forces and rely on friction for strength, while cohesive soils, like clays, possess cohesive forces due to clay particles’ cohesive nature, influencing their behavior in terms of shear strength and settlement characteristics.
Explain the concept of effective stress and its role in soil mechanics.
Effective stress in soil mechanics is the intergranular stress carried by the soil skeleton and is crucial as it determines the soil’s strength and deformation characteristics, incorporating the effects of both total stress and pore water pressure.
Discuss the factors affecting soil compaction and their implications for construction projects.
The factors affecting soil compaction, including moisture content, compactive effort, soil type, and initial soil conditions, influence the achieved soil density and, consequently, the strength and settlement behavior of the compacted soil, with implications for the performance of construction projects.
Explain the Proctor compaction test and its significance in soil compaction.
The Proctor compaction test is a laboratory method used to determine the optimal moisture content and maximum dry unit weight of a soil, providing essential information for designing and controlling soil compaction in construction projects.
Discuss the factors influencing the shear strength of soils.
The shear strength of soils is influenced by factors such as soil type, confining pressure, moisture content, and the presence of cohesive forces, collectively determining the soil’s resistance to shear and influencing slope stability and foundation design.
Explain the Mohr-Coulomb failure criterion and its application in determining shear strength.
The Mohr-Coulomb failure criterion is a mathematical model describing the relationship between normal and shear stresses on a failure plane, and its application in geotechnical engineering involves determining the shear strength parameters of cohesion (c) and angle of internal friction (φ) to analyze and design soil structures.
Define the term “consolidation” and explain how it influences settlement in soils.
Consolidation in soil mechanics is the process by which excess pore water pressure dissipates over time due to the compression of soil particles under a load, and it influences settlement by causing the soil to undergo volume reduction as water is expelled, leading to potential long-term settlements.
Area of fill
FInd area of emptied hole x average depth
