Civil engineeringLesson 1 of 1 in the course Geotechnical engineering

Soil Consolidation: Stress History, Settlement, and Drainage Rate

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

Save course
Lesson progress
0 / 5

Your progress is kept in this browser only.Sign up to save it

Summary

Soil consolidation explains why saturated soils can continue to settle for months or years after a load is applied. This lesson introduces the soil phases, the role of pore water and effective stress, and the distinction between primary consolidation and secondary compression.

Soil is a three-phase material: solid soil grains form one phase, while the voids contain water, air, or both. In saturated soil, the voids are filled with water. When pressure is applied quickly, water's volumetric stiffness is much greater than that of the soil skeleton. The water initially carries most of the added pressure, creating excess pore water pressure.

All flashcards

Preconsolidation stress
The highest effective stress that a soil has experienced in the past.
Compression index (Cc)
The change in void ratio per tenfold stress increase along the virgin compression curve.
Recompression index (Cr)
A measure of void-ratio change along the recompression part of the stress–void ratio curve.
Coefficient of volume compressibility (mv)
The change in volumetric strain per change in effective stress over a specified interval.
Secondary compression
Time-dependent soil volume change that continues at approximately constant effective stress.

Quiz questions

  1. In an oedometer test, why is lateral deformation of the soil specimen restrained?Answer: To measure vertical compression under one-dimensional conditions.
  2. What defines normally consolidated soil?Answer: Its current effective stress equals its highest past effective stress.
  3. A soil is reloaded but its final stress remains below its preconsolidation stress. Which index describes the settlement path?Answer: The recompression index, Cr.
  4. If the drainage path doubles while Cv and elapsed time stay constant, what happens to the time factor?Answer: It falls to one-quarter of its previous value.
  5. What does the coefficient of consolidation, Cv, represent?Answer: The combined influence of soil compressibility and water-flow behavior on consolidation rate.

Based on the Wikipedia article Soil consolidation, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.

More in Civil engineering

All Civil engineering lessons
Civil engineeringOpen-Channel Flow: Classification, Regimes, and Hydraulic Models5 flashcards · 5 quiz questions · 4 gamesPlay free →Civil engineeringStructural Loads: Categories, Design Factors, and Aircraft Loads5 flashcards · 5 quiz questions · 4 gamesPlay free →