The validity of the cubic law for laminar flow of fluids through open fractures consisting of parallel planar plates has been established by others over a wide range of conditions with apertures ranging down to a minimum of 0.2 µm. The law may be given in simplified form by Q/Δh = C(2b)3, where Q is the flow rate, Δh is the difference in hydraulic head, C is a constant that depends on the flow geometry and fluid properties, and 2b is the fracture aperture. The validity of this law for flow in a closed fracture where the surfaces are in contact and the aperture is being decreased under stress has been investigated at room temperature by using homogeneous samples of granite, basalt, and marble. Tension fractures were artificially induced, and the laboratory setup used radial as well as straight flow geometries. Apertures ranged from 250 down to 4µm, which was the minimum size that could be attained under a normal stress of 20 MPa. The cubic law was found to be valid whether the fracture surfaces were held open or were being closed under stress, and the results are not dependent on rock type. Permeability was uniquely defined by fracture aperture and was independent of the stress history used in these investigations. The effects of deviations from the ideal parallel plate concept only cause an apparent reduction in flow and may be incorporated into the cubic law by replacing C by C/ƒ. The factor ƒ varied from 1.04 to 1.65 in these investigations. The model of a fracture that is being closed under normal stress is visualized as being controlled by the strength of the asperities that are in contact. These contact areas are able to withstand significant stresses while maintaining space for fluids to continue to flow as the fracture aperture decreases. The controlling factor is the magnitude of the aperture, and since flow depends on (2b)3, a slight change in aperture evidently can easily dominate any other change in the geometry of the flow field. Thus one does not see any noticeable shift in the correlations of our experimental results in passing from a condition where the fracture surfaces were held open to one where the surfaces were being closed under stress.

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VALIDITY OF CUBIC LAW FOR FLUID FLOW IN A DEFORMABLE ROCK FRACTURE - eScholarship

Selective cesium removal from radioactive liquid waste by crown ether immobilized new class conjugate adsorbent.

Molecular dynamics simulation is used to study the mechanisms involved in the adsorption of various ions to the basal surfaces of kaolinite. Analysis of simulation data indicates that cations and anions adsorb preferably on the siloxane and gibbsite surfaces of kaolinite, respectively. Strong inner-sphere adsorption of chlorine at aluminum vacancies on the gibbsite surface and the occurrence of chlorine-driven inner-sphere adsorption of cesium and sodium on the gibbsite surface for high ionic strengths are observed. Cesium ions form strong inner-sphere complexes at ditrigonal cavities on the siloxane surface. Outer-sphere cesium is highly mobile and only weak adsorption may occur. A small amount of sodium adsorbs on the siloxane surface as inner-sphere complexes at less clearly defined sites. Like cesium, sodium only forms very weak outer-sphere complexes on this surface. Inner-sphere complexes of cadmium and lead do not occur on either surface. Relatively strong outer-sphere cadmium and lead complexes are present on the siloxane surface at ditrigonal cavities.

Molecular Dynamics Modeling of Ion Adsorption to the Basal Surfaces of Kaolinite

An EXAFS study on the effects of natural organic matter and the expandability of clay minerals on cesium adsorption and mobility

Caesium incorporation and retention in illite interlayers

Origin and Function of Soils Introduction Soil Origin and Formation Soil Classification Basic Soil Functions Concluding Remarks References Nature of Soils Introduction Clay Minerals Nonclay Minerals Soil Organic Matter Soil Particles Soil Structure Interparticle Bonds Microorganisms in Soils Laboratory Determinations Concluding Remarks References Soil-Water Systems Introduction Water Retention Clay-Water Interactions Soil-Water Energy Characteristics Water Uptake and Transfer Chemical Reactions in Porewater Physical Reactions and Hydration Concluding Remarks References Swelling Clays Introduction Swelling Phenomena Water Uptake and Swelling Water Movement Concluding Remarks References Stressors, Impacts, and Soil Functionality Introduction Stressor Sources and Stressors Stressor Impacts Soil Functionality Index (SFI) Time-Related Change of Functionality Concluding Remarks References Mechanical Properties Introduction Mechanical Attributes Concept of Effective Stress Shear Strength of Soils Mechanisms in Granular Soil Strength Cohesive Soil Strength Porewater Pressure Shear Resistance Mechanisms Compressibility and Consolidation Creep Behaviour Concluding Remarks References Thermal and Hydraulic Properties Introduction Thermal Properties Water Movement under Thermal Gradient Hydraulic Properties Swelling Clay Hydraulic Conductivity Vapour and Gas Conductivities Concluding Remarks References Sorption Properties and Mechanisms Introduction Solutes, Contaminants, and Pollutants Contaminant Interactions with Soil Particles Contaminant Sorption Mechanisms Laboratory Determination of Partitioning Partitioning and Soil Composition Concluding Remarks References Mobility and Attenuation of Contaminants Introduction Interactions and Mobility Mobility and Attenuation Microstructure and Diffusive Transport Attenuation of Organic Chemicals Concluding Remarks References Environmental Soil Behaviour Introduction Soil Evolution and Ageing Processes Time-Related Changes and Soil Evolution Biodegradation and Biotransformation of Contaminants Freeze-Thaw Seasonal Impact Concluding Remarks References

Environmental Soil Properties and Behaviour

Local structural information of Cs in smectite hydrates by means of an EXAFS study and molecular dynamics simulations

Introduction Radioactive and Hazardous Solid Waste Isolation Nature of Clays Clay-water Reactions and Partly-saturated Water Transport Contaminant-clay Interactions and Impacts Thermal, Hydraulic, Mechanical, Chemical and Biological Processes Clay Evolution and Long Term Buffer/Barrier Performance Field and Mockup Experiments Modelling for Prediction and Performance Assessment Safety Assessment and Performance Determination

Masashi Nakano

Papers

Environmental Soil Properties and Behaviour

Local structural information of Cs in smectite hydrates by means of an EXAFS study and molecular dynamics simulations

Containment of High-Level Radioactive and Hazardous Solid Wastes with Clay Barriers

Overview of rehabilitation schemes for farmlands contaminated with radioactive cesium released from Fukushima power plant

Stiffening of smectite buffer clay by hydrothermal effects