Tuesday, 7 August 2018

Mechanical Analogy on The Principle of Consolidation/Spring Analogical Model

Mechanical Analogy on The Principle of Consolidation

The principal of consolidation can be explained with the help of mechanical model as described by Terzaghi. This model is also known as Spring analogical model the model.

The model consists of a cylinder with a friction-less piston as shown in the figure.
Spring Analogical Model
The piston is supported on one or more helical metallic spring. There are some adjustable holes in the piston.If the cylinder is completely filled up with water up to the bottom of the Piston, the spring will be represented as the soil mass and the water will be represented as the pore water in the soil mass.

By closing the Piston holes, if some pressure(p) is applied through the Piston, the whole pressure will be transferred to the water and upward pressure(u) will be increased and become equal to( p)such a condition represents a highly impermeable clay-water system.

If the hole in the Piston are opened, the water will immediately escape through the holes and a part of load carried by the water is transferred to the springs.This process of transfer of load from water to spring goes on till the flow stops and the entire load is carried by the springs.

When the spring water system attains equilibrium condition under the imposed load, the settlement of the piston is analogous to the compression of clay-water system under external pressure.