Implications of the principle of effective stress

Abstract

While Terzaghi justified his principle of effective stress for water-saturated soil empirically, it can be derived by means of the neutrality of the mineral with respect to changes of the pore water pressure $$p_w$$ p w . This principle works also with dilating shear bands arising beyond critical points of saturated grain fabrics, and with patterns of shear bands as relics of critical phenomena. The shear strength of over-consolidated clay is explained without effective cohesion, which results also from swelling up to decay, while rapid shearing of water-saturated clay can lead to a cavitation of pore water. The $$p_w$$ p w -neutrality is also confirmed by triaxial tests with sandstone samples, while Biot’s relation with a reduction factor for $$p_w$$ p w is contestable. An effective stress tensor is heuristically legitimate also for soil and rock with relics of critical phenomena, particularly for critical points with a Mohr–Coulomb condition. Therein, the $$p_w$$ p w -neutrality of the solid mineral determines the interaction of solid fabric and pore water, but numerical models are questionable due to fractal features.

Depletion-induced seismicity in NW-Germany: lessons from comprehensive investigations

“…3 [ ĉ0 from about 1 km to 8 km depth skip [12]. The depletion-induced seismicity is bounded, but a technical triggering of natural earthquakes cannot generally be excluded as for our gas fields.…”

“…In a continuum image, the field of the effective stress tensor r 0 ij ðx i Þ is related with p w and the total stress tensor r ij by r 0 ij ¼ r ij À p w d ij (with unit tensor d ij and positive normal components for pressure). This relation was proposed for limit states of water-saturated soil by Terzaghi [30], and can be derived from the neutrality of the solid mineral with regard to changes of p w also for rock [12].…”

“…Biot took the implied volume change of pore water with an arbitrary reference as a state variable. Avoiding this error, Terzaghi's principle of effective stress can be derived from the neutrality of the mineral with regard to changes of p w [12].…”

Analysis on “three-box” model of stress-strain in frozen soil porous media based on representative macroscopic Volume

“…Soil is a complex multiphase porous medium, and its mechanical properties and equilibrium state are the results of the mutual coupling of the phases in the soil and various environmental effects (Ott et al, 2020;Yan et al, 2022;Guo P. et al, 2021). von Terzaghi (1923) proposed the effective stress principle of saturated soils (Gudehus, 2021), which made soil mechanics independent from general mechanics into an independent discipline and prepared for the improvement of present day soil mechanics (Jiang and Huang, 2018). When using the principle of effective stress, the saturated soil can be equated to a single-phase medium so that the soil can be analyzed for deformation and strength using the method of continuous medium mechanics (Liu E. et al, 2018).…”