Wave-induced pore pressures and effective stresses in a porous bed
TL;DR: In this article, a general theory for the pore pressures and effective stresses induced in a porous bed by ocean waves is developed, where pore fluid as well as the soil skeleton are considered compressible.
Abstract: A general theory for the pore pressures and effective stresses induced in a porous bed by ocean waves is developed. The pore fluid as well as the soil skeleton are considered compressible and the f...
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01 Jan 1993
TL;DR: In this paper, the authors focus on the fundamentals of poroelasticity, and discuss the formulation and analysis of coupled deformation-diffusion processes, within the framework of the Biot theory of pore elasticity.
Abstract: Publisher Summary
This chapter focuses on fundamentals of poroelasticity. The presence of a freely moving fluid in a porous rock modifies its mechanical response. Two mechanisms play a key role in the interaction between the interstitial fluid and the porous rock: (i) an increase of pore pressure induces a dilation of the rock; and (ii) compression of the rock causes a rise of pore pressure, if the fluid is prevented from escaping the pore network. These coupled mechanisms bestow an apparent time-dependent character to the mechanical properties of the rock. If excess pore pressure, induced by compression of the rock, is allowed to dissipate through diffusive fluid mass transport, further deformation of the rock progressively takes place. The rock is more compliant under drained conditions than undrained ones. The chapter discusses the formulation and analysis of coupled deformation–diffusion processes, within the framework of the Biot theory of poroelasticity. The Biot model of a fluid-filled porous material is constructed on the conceptual model of a coherent solid skeleton and a freely moving pore fluid.
1,056 citations
TL;DR: In this article, an analytical study of a soil layer subject to a periodic surface force is presented, and the results of the analysis are given in a non-dimensional, generally valid, form and should find practical application in assessing the type of approximation that is applicable in new problems.
Abstract: The behaviour of saturated, porous media under dynamic or quasi-static loads was first formulated by Biot (1941, 1960). For dynamic problems a simplification was recently proposed by one of the Authors. As the two formulations must coincide over a range of problems and as for slow transients both must be adequately represented by pure consolidation theory, this Paper examines the respective ranges of validity by an analytical study of a soil layer subject to a periodic surface force. The analysis also indicates under what conditions such extremes as undrained or quasi-static assumptions can be safely used. Results of the analysis are given in a non-dimensional, generally valid, form and should find practical application in assessing the the type of approximation that is applicable in new problems. Le comportement des milieux poreux satures soumis a des charges dynamiques ou quasi statiques a ete analyse pour la premiere fois par Boit (1941, 1960). Pour les problemes dynamiques, une simplification a ete re...
549 citations
TL;DR: In this article, the wave-induced stress in a porous elastic medium is studied on the basis of Biot's linearized theory which is a special case of the mixture theory, and several examples of potential interest to geophysics and foundation mechanics are treated analytically.
Abstract: Summary. Wave-induced stress in a porous elastic medium is studied on the basis of Biot's linearized theory which is a special case of the mixture theory. For sufficiently high frequencies which are pertinent to ocean waves and seismic waves, a boundary layer of Stokes' type is shown to exist near the free surface of the solid. Outside the boundary layer, fluid and the solid skeleton move together according to the laws of classical elasticity for a single phase. This division simplifies the analysis of the equations governing the two phases; and several examples of potential interest to geophysics and foundation mechanics are treated analytically.
291 citations
TL;DR: In this paper, a methodology is proposed for analysing soft-sediment deformation structures within their overall sedimentological and palaeoenvironmental context in order to refine and improve criteria for distinguishing the action of ‘external’ (allogenic) triggers, including earthquakes, from ‘internal” (autogenic) trigger.
290 citations
Cites background from "Wave-induced pore pressures and eff..."
...– pressure fluctuations associated with water waves, especially storm waves (Bjerrum, 1973; Henkel, 1970; Madsen, 1978; Nataraja and Gill, 1983; Okusa, 1985); – impact of breaking water waves (Dalrymple, 1979, 1980); – pressure fluctuations related to differential turbulence in water flows (Dzulynski and Smith, 1963; Kuenen, 1953); – tsunamis (Benson et al....
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TL;DR: In this article, an analytical solution for the wave-induced soil response is developed for a seabed of finite thickness subject to a three-dimensional (3D) wave system produced by two intersecting waves of equal properties.
Abstract: An analytical solution for the wave-induced soil response is developed for a seabed of finite thickness subject to a three-dimensional (3-D) wave system produced by two intersecting waves of equal properties. These 3-D exact solutions for the pore pressure and effective stresses, proposed for a non-cohesive soil matrix of finite depth in a homogeneously unsaturated and anisotropic condition, are readily reducible to the limiting two-dimensional cases of progressive and standing waves, for which no explicit solutions are available for finite thickness. The effects of soil isotropy, degree of saturation, seabed thickness and grain size on the wave-induced pore pressure are discussed in detail. The explicit solutions presented in this study for the wave-induced pore pressure and effective stresses should benefit the laboratory experiments and field monitoring programs carried out in soil of finite depth.
276 citations