The 'primary consolidation' of a clay layer settles because:
Choose the correct answer
Immediate elastic compression of soil grains
Dissipation of excess pore water pressure → effective stress increase → void ratio decrease (water squeezed out)
Erosion of clay particles
Swelling of clay minerals on wetting
Correct Answer
B. Dissipation of excess pore water pressure → effective stress increase → void ratio decrease (water squeezed out)
Why is this the answer?
Primary consolidation: excess pore water pressure (generated by load application) dissipates through drainage → effective stress increases → volume decreases. Time rate: cv×t/H²_dr (Tv = dimensionless time factor). Final settlement: Δe/(1+e0)×H from oedometer Cc and pressure increment. Complete primary consolidation: u_excess → 0, effective stress = final applied stress. Secondary: continued creep after u=0.
Related Soil Mechanics MCQs
More solved Soil Mechanics questions for AE/JE Civil Engineering exams.
- The 'Hvorslev parameters' c_e and φ_e in soil mechanics refer to:
- The 'International Building Code' (IBC) and IS codes classify building sites for...
- 'Vibro-flotation' (vibro-compaction) is used to densify:
- The 'shear strength' of soil measured in an 'undrained triaxial test' (UU test) is:
- The 'IS 2911' code series covers:
- The 'Swedish slip circle method' (Fellenius method) for slope stability is conservative...
Practice more Civil Engineering questions
This MCQ belongs to JE Level Premium Test Series. Full tests include timed attempts, rank comparison and subject-wise analysis.