Question

The one dimensional theory of consolidation proposed by Terzaghi derives its name due to fact that

• A. only vertical dimension of the soil sample is used for consolidation test and lateral dimensions are neglected
• B. water in the soil sample in conventional consolidometer escapes in the lateral directions resulting into settlements only in vertical direction
• C. normal stress on the sample is applied in only one (vertical) direction
• D. lateral movements of soil grains are not permitted across any vertical boundary resulting into only vertical settlements to account for the decrease in volume due to escape of water from soil sample

Answer 1

The correct option is D lateral movements of soil grains are not permitted across any vertical boundary resulting into only vertical settlements to account for the decrease in volume due to escape of water from soil sample

Assumptions of Terzaghi's Theory:

1. The soil is homogenous (uniform in composition throughout) and isotropic (show same physical property in each direction).
2. The soil is fully saturated (zero air voids due to water content being so high).
3. The solid particles and water are incompressible.
4. Compression and flow are one-dimensional.
5. Strains in the soil are relatively small.
6. Darcy's Law is valid for all hydraulic gradients.
7. The coefficient of permeability and the coefficient of volume compressibility remain constant throughout the process.
8. There is a unique relationship, independent of time, between the void ratio and effective stress