# 9 Assumption in Terzaghi Theory of Consolidation

## Terzaghi Theory of Consolidation

The theoretical concept of consolidation process was developed by Terzaghi. In order to compute the amount of consolidation( or settlement) after any given time t, Terzaghi derived the following basic equation is a free surface. δu/δt = cv (δu/δz) Where, cv = Coefficient of consolidation.

The above differential equation of consolidation describes the distribution of the hydrostatic excess pressure(u) with time(t) along with depth(z).

### The Assumption in the Terzaghi Theory of Consolidation

In the development of the Terzaghi theory of consolidation, the following 9 assumptions are made:

1. The soil is fully saturated.

2. The soil is homogeneous.

3. The time lag consolidation is entirely due to the low permeability of the soil.

4. Soil particles and water are incompressible.

5. Darcy’s law is strictly valid.

6. Coefficient of permeability is constant during consolidation.

7. The soil is restrained against lateral deformation.

8. Excess pore water drains out only in the vertical direction.

9. The boundary is a free surface.