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Theoretical Soil Mechanics
15 Jan 1943-
About: The article was published on 1943-01-15 and is currently open access. It has received 6612 citations till now. The article focuses on the topics: Soil mechanics & Mathematical model.
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TL;DR: In this article, a comprehensive search of the literature and data sources for hydraulic conductivity and related soil-water data was made in 1978 and data for 1,323 soils with about 5,350 horizons from 32 states were assembled.
Abstract: RELATIONSHIPS of soil water tension and hydraulic conductivity with soil water content are needed to quantify plant available water and to model the move-ment of water and solutes in and through soils. Field and laboratory measurement of these hydraulic soil proper-ties is very difficult, laborous, and costly. To provide the best estimates possible from previous analyses, a com-prehensive search of the literature and data sources for hydraulic conductivity and related soil-water data was made in 1978. From this search, data for 1,323 soils with about 5,350 horizons from 32 states were assembled. From the data, the Brooks and Corey water retention parameters, soil water retention volumes at 0.33 bar and 15 bar, total porosity, and saturated conductivities for the major USDA soil textures classes were developed. Also, relationships for predicting water retention volumes for particular tensions and saturated hydraulic conductivities based on soil properties are presented.
1,598 citations
TL;DR: In this paper, the authors investigated the influence of precipitation and river stage on the sustainable performance of foundations of various urban buildings and infrastructures, as GWL causes changes in the stress state within soil.
Abstract: The sustainable performance of foundations of various urban buildings and infrastructures is strongly affected by groundwater level (GWL), as GWL causes changes in the stress state within soil. In the present study, the components affecting GWL were investigated, focusing on the effects of precipitation and river stage. These components were analyzed using a six-year database established for hydrological and groundwater monitoring data. Five study regions for which daily measured precipitation, river stage, and GWL data were available were compared. Different periods of precipitation, geographical characteristics, and local surface conditions were considered in the analysis. The results indicated that key influence components on GWL are different depending on the hydrological, geological, and geographical characteristics of the target regions. River stage had the strongest influence on GWL in urban areas near large rivers with a high ratio of paved surface. In rural areas, where the paved surface area ratio and soil permeability were low, the moving average showed a closer correlation to GWL than river stage. A moving average-based method to predict GWL variation with time was proposed for regions with a low ratio of paved surface area and low permeability soils.
1,051 citations
TL;DR: The effective elastic moduli of a fluid-saturated solid containing thin cracks depend on the degree of interconnection between the cracks as mentioned in this paper, which can be estimated from the crack geometry or permeability.
Abstract: The effective elastic moduli of a fluid-saturated solid containing thin cracks depend on the degree of interconnection between the cracks. Three separate regimes may be identified: (1) dry (drained), in which fluid in cracks can flow out of bulk regions of compression, (2) saturated isobaric, in which fluid may flow from one crack to another but no bulk flow takes place, and (3) saturated isolated, in which there is no communication of fluid between cracks. Transitions between these cases involve fluid flow, resulting in dissipation of energy. Relaxation of shear stresses in viscous fluid inclusions also results in dissipation. Viscoelastic moduli are derived, by using a self-consistent approximation, that describe the complete range of behavior. There are two characteristic frequencies near which dissipation is largest and the moduli change rapidly with frequency. The first corresponds to fluid flow between cracks, and its value can be estimated from the crack geometry or permeability. The second corresponds to the relaxation of shear stress in an isolated viscous fluid inclusion; its value may also be estimated. Variations of crack geometry result in a distribution of characteristic frequencies and cause Q to be relatively constant over many decades of frequency. Fluid flow between cracks accounts for attenuation of seismic waves in water-saturated rocks and attenuation observed in laboratory measurements on water-saturated rocks and partially molten aggregates. Attenuation in a partially molten upper mantle is probably due to fluid flow between cracks, although grain boundary relaxation in an unmelted upper mantle could also account for the seismic low-velocity zone. Grain boundary relaxation in the mantle may cause the long-term shear modulus to be around 20% less than that measured from seismic observations.
835 citations
TL;DR: In this paper, the suction stress characteristic curve (SSCC) for unsaturated soil is presented, and the experimental evidence shows that both Mohr-Coulomb failure and critical state failure can be well represented by the SSCC concept.
Abstract: The concept of the suction stress characteristic curve (SSCC) for unsaturated soil is presented. Particle-scale equilibrium analyses are employed to distinguish three types of interparticle forces: (1) active forces transmitted through the soil grains; (2) active forces at or near interparticle contacts; and (3) passive, or counterbalancing, forces at or near interparticle contacts. It is proposed that the second type of force, which includes physicochemical forces, cementation forces, surface tension forces, and the force arising from negative pore-water pressure, may be conceptually combined into a macroscopic stress called suction stress. Suction stress characteristically depends on degree of saturation, water content, or matric suction through the SSCC, thus paralleling well-established concepts of the soil–water characteristic curve and hydraulic conductivity function for unsaturated soils. The existence and behavior of the SSCC are experimentally validated by considering unsaturated shear strength data for a variety of soil types in the literature. Its characteristic nature and a methodology for its determination are demonstrated. The experimental evidence shows that both Mohr–Coulomb failure and critical state failure can be well represented by the SSCC concept. The SSCC provides a potentially simple and practical way to describe the state of stress in unsaturated soil.
715 citations
Additional excerpts
...In 1943, Karl Terzaghi defined effective stress as stress representing “that part of the total stress which produces measurable effects such as compaction or an increase of the shearing resistance” Terzaghi 1943 ....
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...…stress calculated following the SSCC concept respects the classical effective stress definition in saturated soil mechanics, i.e., the effective stress is “that part of the total stress which produces measurable effects such as compaction or an increase of the shearing resistance” Terzaghi 1943 ....
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TL;DR: In this paper, the authors discuss the migration of petroleum from its formation in a source rock to its subsequent possible entrapment in a reservoir and discuss the chemical and physical properties of petroleum gases and liquids, particularly their phase behaviour under subsurface conditions.
Abstract: This paper discusses the migration of petroleum from its formation in a source rock to its subsequent possible entrapment in a reservoir. The chemical and physical properties of petroleum gases and liquids are stressed, particularly their phase behaviour under subsurface conditions which is shown to be a very important factor in determining migration behaviour. Engineering correlations are presented for estimating the properties of petroleum fluids under geologically realistic conditions. The directions and magnitudes of the forces acting on migrating petroleum are deduced from the combined effects of buoyancy and water flow in compacting sediments. These forces are combined, using a fluid potential description. This procedure allows the direction of migration to be denned. The rate of migration is then estimated from the properties of the sediments involved, allowing a distinction to be made between ‘lateral’ and ‘vertical’ carrier beds. This simplified approach is suitable for rapid predictive calculations in petroleum exploration. It is compared with the more complex 3-D computer modelling approaches which are currently becoming available. Migration losses are related to the cumulative pore volume employed by the petroleum in establishing a migration pathway. The petroleum migration mechanism is shown to be predominantly by bulk flow, with a small diffusive contribution for light hydrocarbons over distances less than c. 100 m. The loss factors involved in secondary migration are estimated from field evidence. The mechanism of reservoir filling is presented as a logical extension to those described for migration. This, together with the inefficiency of in-reservoir mixing by diffusion or convection, is shown to tend to cause significant lateral compostional gradients in reservoirs over and above the gravitationally induced vertical gradients described by other workers.
686 citations