What is normal compression line?

If the current state of soil is on the normal compression line it is said to be normally consolidated. If the soil is unloaded it becomes overconsolidated. Soil cannot usually be at a state outside the normal compression line unless it is bonded or structured.

What is compression in soil?

Compression in soils is caused primarily by the rearrangement of soil grains and expulsion of water from the voids accompanied by fracturing of soil grains in coarse-grained soils and compression or swelling of clay particles in fine-grained soils.

What is isotropic compression?

Isotropic compression is a common exercise in soil testing. The modified Cam-Clay model describes the relation between the void ratio and the logarithm of the pressure. In this example, a soil sample is placed inside cylinder 10 cm in diameter and 10 cm in height.

What is Overconsolidated soil?

The soil which had its load removed is considered to be “overconsolidated”. This is the case for soils that have previously had glaciers on them. The highest stress that it has been subjected to is termed the “preconsolidation stress”.

What is a compression index?

Compression index (Cc) is used to predict the compressibility of soil and estimate how much settlement which is occurred due to loads of different engineering structures.

What is compression index in soil mechanics?

Compression index describes variation of void ratio as a function of the change of effective stress plotted in the logarithmic scale. It therefore represents deformative characteristics of overconsolidated soil. Typical range of compression index is 0.1 to 10.

What is pure compression?

If the stress vector itself is opposite to , the material is said to be under normal compression or pure compressive stress along . In a solid, the amount of compression generally depends on the direction. , and the material may be under compression along some directions but under traction along others.

How is the compressibility index calculated?

301 Compressibility Index

1. Compressibility Index = 100(V0 – VF)/V0.
2. V0 is unsettled apparent volume.
3. VF is final tapped volume.

How do you find compression index?

A commonly used measure of the compressibility of lunar soil is the compression index Cc: C c = Δ e Δ log σ v . Here Δ e is the change in void ratio and Δ log σv is the change in the logarithm of applied stress.

What is compression engineering?

In mechanics, compression is the application of balanced inward (“pushing”) forces to different points on a material or structure, that is, forces with no net sum or torque directed so as to reduce its size in one or more directions.

How is compression force measured?

Compression force can be measured by orienting the sample vertically in a test fixture. A compression plate engages the thumb rest and presses down at a controlled rate of speed. The resulting peak force, average force, or force-travel curve is analyzed to ensure that the syringe does not leak and operates as designed.