Soil is composed of solid particles with different sizes and shapes that form a skeleton and the voids are filled with water and air. The soil is saturated if all the voids are filled with water. Otherwise, the soil is partially saturated. If all the voids are filled with air, the soil is said to be dry. It is a common practice in soil mechanics to assume that the solid particles do not deform and the water phase is incompressible. Hence, external loading is supported by the skeleton and the water. The “effective stress” is the average stress on a plane through the soil mass, rather than the contact stress between the solid particles. The stress on the water and the air is called “pore pressure".
Different characteristics of soil behavior are:
- Shear strength and deformation characteristics:
The energy applied to a soil
through external loads may both overcome the frictional resistance between the
soil particles and also to expand the soil against the confining pressure. The soil
grains are highly irregular in shape and have to be lifted over one another for
sliding to occur.
2. Plasticity
An increase in applied stress usually brings about some irrecoverable deformation, without any signs of cracking or disruption. Most soils only have a very small elastic region and show plasticity from the onset of loading.
3. Strain-hardening/softening
After an initial extension, the soil behaves as if it had acquired better elastic properties and a higher elastic limit, while at the same time it had lost a great part of the plastic strain After an initial extension, the soil behaves as if it had acquired better elastic properties and a higher elastic limit, while at the same time it had lost a great part of the plastic strain.
Tidak ada komentar:
Posting Komentar