Question

Discuss the main assumption considered in the derivation of the Terzaghi’s effective stress principle. Do you observe any significant effect of this assumption on the effective stress within the soil mass?

Answer 1

Assumptions in Terzaghi's effective stress principle :

i) The soil must be homogenous or uniform and isotropic

ii) The strain in the soil are relatively small.

iii) volume change and coefficient of volume compressibility must be constant throughout the process.

iv) Soil particles are fully saturated and compressible.

✓ Yes, if the soil is not homogenous and isotropic, the effective stress is different in different in the soil sample and in one side strain may be relatively small, where in another side strain may be relatively high. For that reason, Terzaghi's effective stress principle may not valid.