文档介绍：Effective Stress
Introduction
A soil can be visualized as a skeleton of solid particles enclosing continuous voids .which contain water and/or air. For the range of stresses us, rally encountered in practice the individual-solid particles and water can be considered pressible: air, on the other hand, is pressible. The volume of the soil skeleton as a whole can change due to rearrangement of the soil particles into new positions, mainly by rolling and sliding, with a corresponding change in the forces acting between particles. The pressibility of the soil skeleton will depend on the structural arrangement of the solid particles. In a fully saturated sol, since water is considered to be pressible, a reduction in volume is possible only if some of the water can escape from the voids, in a dry or a partially saturated soil a reduction in volume is always possible due pression of the air in the voids, provided there ks scope for particle rearrangement.
Shear stress can be resisted only by the skeleton of solid particles, by means of forces developed at the interparticle contacts. Normal stress may be resisted by the soil skeleton through an increase in the interparticle forces. If the soil is fully saturated, the water filling the voids can also withstand normal stress by an increase in pressure.
The Principle of Effective Stress
The importance of the forces transmitte