Talk:Terzaghi's principle

This articel is wrong. The first part mixes up Terzaghi's Principle of Effective Stress with Terzaghi's Theory of Consolidation. The assumptions are not quite right. The section on Validity is also wrong.

Terzaghi's Principle of Effective Stress states that the stress that is effective in determining teh strength and deformation behaviours of fully saturated soil is obtained by subtracting the pore water pressure from the total stress. The principle has been well validated experimentally and is fundamental to everyday practice in soil mechanics and foundation engineering.

Terzaghi's Theory of Consolidation combined the theory of groundwater flow with the theory of compressibility to produce a description of how water is squeezed out of fully saturated soil, or sucked into it, over a period of time. Such groundwater movements are associated with time-dependent settlements r heave of structures. The modern view is that Terzaghi's tehory describes primary consolidation only. Secondary consolidation, which is significant for some probematic soils and often for silts, appears to involve groundwater flow that is not driven by a hydraulic gradient.

Richard Dean Soil Models Limited

I agree with the previous comment. Much of this article is incorrect.

sigma and sigma dashed need to be switched to give the correct effective stress equation.

Effective stress = total stress - pore water pressure

Richard Engineering Geology and geotechnics - University of Portsmouth —Preceding unsigned comment added by 94.8.90.149 (talk) 12:09, 30 May 2010 (UTC)[reply]

The equation states exactly what you are saying.

(Effective stress = total stress - pore water pressure) is just a rearranged version of (Total stress = Effective stress + pore water pressure) Nwhit (talk) 13:38, :14 March 2012 (UTC)