# Effective Stress

Effective Stress

Effective Stress is a force that keeps a collection of particles rigid. Usually this applies to sand, soil or gravel.

If you pinch a stack of coins between your fingers, the stack stays together. If you then loosen the pressure between your fingers, the coin stack falls apart. Similarly, a pile of sand keeps from spreading out like a liquid because the weight of the sand keeps the grains stuck together in their current arrangement, mostly out of static friction. This weight and pressure is the effective stress.

Effective stress is easy to disrupt by the application of additional forces; every footstep on a sand pile demonstrates this. It is an important factor in the study of slope stability and soil liquefaction, especially from earthquakes.

### Other articles related to "effective stress, effective, stress":

Effective Stress - Technical Discussion
... Karl von Terzaghi first proposed the relationship for effective stress in 1936 ... For him, the term ‘effective’ meant the calculated stress that was effective in moving soil, or causing displacements ... It represents the average stress carried by the soil skeleton ...
Critical State Soil Mechanics - Formulation
... distortions occur without any further changes in mean effective stress, deviatoric stress (or yield stress, in uniaxial tension according to the von Mises ... The first equation determines the magnitude of the deviatoric stress needed to keep the soil flowing continuously as the product of a frictional constant (capital ) and the mean ... particles will decrease as the logarithm of the mean effective stress increases ...
Terzaghi's Principle
... states that when a rock is subjected to a stress, it is opposed by the fluid pressure of pores in the rock ... consolidation, states that all quantifiable changes in stress to a soil are a direct result of a change in effective stress ... The effective stress is related to total stress and the pore pressure by the relationship reading that total stress is equal to the sum of effective stress and pore water ...
Soil Mechanics - Effective Stress and Capillarity: Hydrostatic Conditions
... Although the pore air is relatively compressible, and hence takes little normal stress in most geotechnical problems, liquid water is relatively incompressible and if the voids are ... The principle of effective stress, introduced by Karl Terzaghi, states that the effective stress σ' (i.e ... the average intergranular stress between solid particles) may be calculated by a simple subtraction of the pore pressure from the total stress where σ is the total stress and u is ...
Shear Strength (soil) - Drained Shear Strength
... (Terzaghi 1942) combined it with the principle of effective stress ... In terms of effective stresses, the shear strength is often approximated by Where σ' =(σ - u), is defined as the effective stress ... σ is the total stress applied normal to the shear plane, and u is the pore water pressure acting on the same plane ...

### Famous quotes containing the words stress and/or effective:

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