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Effects of inter-phase mass transfer in heated clays: a mixture theory
87A 932122 Diffnsional transport of solutes through clay: use of claymodified electrodes Subramanian, P; Fitch, A Environ Sci Teclmol V26, N9, Sept 1992, P1775-1779
alkaline nature of the fly ash, which led to precipitation of heavy metals in the liner, removing them from the effluent. These results suggest compacted fly ash is promising liner material.
Diffusional processes may play an important role in the transport of pollutants across clay liners. The use of clay-modified electrodes (Pt coated with thin clay films) to study diffusion processes is described. The diffusive flux of the solute is monitored by oxidation or reduction at the underlying electrode. Results presented show diffusion of void-filling species is of the same order of magnitude as in aqueous solutions. Diffusion rates of surface-associated species are some six orders of magnitude slower. Solutes with no interaction with the solid surface will thus be expected to be responsible for diffusional breaching of clay liners.
932126 Compositional control of magnetic anisotropy in the Thompson formation, east-central Minnesota Johns, M K; Jackson, M J; Hudleston, P J Tectonophysics V210, N1/2, Aug 1992, P45-58
932123 Theoretical treatment of the effect of microscopic fluid distribution on the dielectric properties of partially saturated rocks Endres, A L; Knight, R Geophys Prospect 1/40, N3, April 1992, P307-324 Laboratory data demonstrate that macroscopic fluid distribution can have significant effect on the dielectric properties of partially saturated rocks. Previously derived models for the dielectric response of a heterogeneous medium are generalised and the case of pore space occupied by multiple fluids is considered. It is shown that pore geometry in which saturation conditions are changing and gas-water geometry within a given pore space have critical influence on dielectric properties. Data from a tight gas sandstone undergoing imbibition/drying are analysed. By approximating previously determined fluid distributions by simple geometric models, experimental data on dielectric response can be simulated. 932124 Effects of inter-phase mass transfer in heated clays: a mixture theory Ma, C; Hueckel, T int J Engng Sci V30, Nll, Nov 1992, P1567-1582
Anisotropies of magnetic low-field susceptibility (AMS) and anhysteretic susceptibility (AAS) have been measured on metagreywackes and slates from the Thompson formation. Comparisons are made between these anisotropies and structural fabric to examine how well the magnetic fabric records the structure in regions of single and superposed deformation. Separation of the magnetic fabric yields information about alignment of individual mineral species not evident from strain studies alone. Compositional dependence of magnetic anisotropy enhances its value in structural studies. 932127 Heat loss calculation in thermal simulation Hansamuit, V; Abou-Kassem, J H; Ali, S M F Trans Porous Media VS, N2, June 1992, P149-166 Four different methods used to estimate the rate of heat loss to the surroundings in thermal oil recovery are compared. They are: analytical solution using a superposition theorem; analytical solution using a numerical approximation to the convolution integral; semi-analytical method; and numerical solution. Computer-compatibility is taken into consideration. The numerical solution is sensitive to grid size in the overburden, the semi-analytical method least difficult to program but also least accurate. The analytical-numerical solution gives the best compromise between accuracy and economics. 932128 Measurement of thermoporoelastic properties of rocks: theory and applications Charlez, P H; Heugas, O Proc I S R M Symposium: Eurock'92, Chester, 14-17 September 1992 P42-46. Publ London: Thomas Telford, 1992
Compacted clay soils are candidate materials for radioactive or hazardous waste barriers. They contain firmly adsorbed water and bulk water, the latter being mobile under sufficient pressure gradient. Elevated temperatures or penetration of chemicals can weaken the adsorption bonds and ultimately lead to degeneration of adsorbed water to bulk water, critically affecting permeability and compressibility of the clay. A mixture theory is used to describe this coupled thermalmechanical-hydraulic behaviour, with focus on mass transfer between absorbed and bulk water. A zone of elevated water pressure forms around a heat source and expands with time. Significant increase in permeability is found within this zone.
Coupling of rock, temperature, and saturating fluid is essential for accurate modelling of deep reservoir rocks. The state laws of thermoporoelasticity are introduced and relations between thermoelastic constants and fluid and matrix properties examined. Experimental procedures to determine poroelastic and thermal expansion coefficients are described. Results are presented for Lavoux and Villeperdue limestones and Vosges sandstone. It is shown that Biot's coefficient calculated using drained and undrained bulk moduli only gives reliable results if the difference between the moduli is sufficiently large.
932125 Interaction of inorganic leachate with compacted pozzolanic fly ash Edil, T B; Sandstrom, L K; Berthouex, P M J Geotech Engng Div ASCE Vl18, N9, Sept 1992, P14101430
932129 Some geotechnical aspects of waste disposal Jessberger, H L Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990, Symposia P131-138. Publ Rotterdam: A A Balkema. 1990
Results of a study on the feasibility of using pozzolanic western coal fly ash, with or without sand, for waste dump liners and covers are presented. Initial permeability requirements can be met. Effects of long-term permeation of inorganic leachate through the liner have been examined. No negative effect on liner permeability was seen, in fact it slightly decreased. The leachate solution pH increased, due to the
Geotechnical design for landfills incorporates safety concepts for the whole system (multibarrier concept) and for the individual components. The following geotechnical aspects of waste management are assessed: site survey; stability testing of the sealing system in the field and laboratory; stability analysis of the waste body; the ability of the clay liner to tolerate deformation; and quality assurance.
© 1993 Pergamon Press Ltd. Reproduction not permitted
alkaline nature of the fly ash, which led to precipitation of heavy metals in the liner, removing them from the effluent. These results suggest compacted fly ash is promising liner material.
Diffusional processes may play an important role in the transport of pollutants across clay liners. The use of clay-modified electrodes (Pt coated with thin clay films) to study diffusion processes is described. The diffusive flux of the solute is monitored by oxidation or reduction at the underlying electrode. Results presented show diffusion of void-filling species is of the same order of magnitude as in aqueous solutions. Diffusion rates of surface-associated species are some six orders of magnitude slower. Solutes with no interaction with the solid surface will thus be expected to be responsible for diffusional breaching of clay liners.
932126 Compositional control of magnetic anisotropy in the Thompson formation, east-central Minnesota Johns, M K; Jackson, M J; Hudleston, P J Tectonophysics V210, N1/2, Aug 1992, P45-58
932123 Theoretical treatment of the effect of microscopic fluid distribution on the dielectric properties of partially saturated rocks Endres, A L; Knight, R Geophys Prospect 1/40, N3, April 1992, P307-324 Laboratory data demonstrate that macroscopic fluid distribution can have significant effect on the dielectric properties of partially saturated rocks. Previously derived models for the dielectric response of a heterogeneous medium are generalised and the case of pore space occupied by multiple fluids is considered. It is shown that pore geometry in which saturation conditions are changing and gas-water geometry within a given pore space have critical influence on dielectric properties. Data from a tight gas sandstone undergoing imbibition/drying are analysed. By approximating previously determined fluid distributions by simple geometric models, experimental data on dielectric response can be simulated. 932124 Effects of inter-phase mass transfer in heated clays: a mixture theory Ma, C; Hueckel, T int J Engng Sci V30, Nll, Nov 1992, P1567-1582
Anisotropies of magnetic low-field susceptibility (AMS) and anhysteretic susceptibility (AAS) have been measured on metagreywackes and slates from the Thompson formation. Comparisons are made between these anisotropies and structural fabric to examine how well the magnetic fabric records the structure in regions of single and superposed deformation. Separation of the magnetic fabric yields information about alignment of individual mineral species not evident from strain studies alone. Compositional dependence of magnetic anisotropy enhances its value in structural studies. 932127 Heat loss calculation in thermal simulation Hansamuit, V; Abou-Kassem, J H; Ali, S M F Trans Porous Media VS, N2, June 1992, P149-166 Four different methods used to estimate the rate of heat loss to the surroundings in thermal oil recovery are compared. They are: analytical solution using a superposition theorem; analytical solution using a numerical approximation to the convolution integral; semi-analytical method; and numerical solution. Computer-compatibility is taken into consideration. The numerical solution is sensitive to grid size in the overburden, the semi-analytical method least difficult to program but also least accurate. The analytical-numerical solution gives the best compromise between accuracy and economics. 932128 Measurement of thermoporoelastic properties of rocks: theory and applications Charlez, P H; Heugas, O Proc I S R M Symposium: Eurock'92, Chester, 14-17 September 1992 P42-46. Publ London: Thomas Telford, 1992
Compacted clay soils are candidate materials for radioactive or hazardous waste barriers. They contain firmly adsorbed water and bulk water, the latter being mobile under sufficient pressure gradient. Elevated temperatures or penetration of chemicals can weaken the adsorption bonds and ultimately lead to degeneration of adsorbed water to bulk water, critically affecting permeability and compressibility of the clay. A mixture theory is used to describe this coupled thermalmechanical-hydraulic behaviour, with focus on mass transfer between absorbed and bulk water. A zone of elevated water pressure forms around a heat source and expands with time. Significant increase in permeability is found within this zone.
Coupling of rock, temperature, and saturating fluid is essential for accurate modelling of deep reservoir rocks. The state laws of thermoporoelasticity are introduced and relations between thermoelastic constants and fluid and matrix properties examined. Experimental procedures to determine poroelastic and thermal expansion coefficients are described. Results are presented for Lavoux and Villeperdue limestones and Vosges sandstone. It is shown that Biot's coefficient calculated using drained and undrained bulk moduli only gives reliable results if the difference between the moduli is sufficiently large.
932125 Interaction of inorganic leachate with compacted pozzolanic fly ash Edil, T B; Sandstrom, L K; Berthouex, P M J Geotech Engng Div ASCE Vl18, N9, Sept 1992, P14101430
932129 Some geotechnical aspects of waste disposal Jessberger, H L Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990, Symposia P131-138. Publ Rotterdam: A A Balkema. 1990
Results of a study on the feasibility of using pozzolanic western coal fly ash, with or without sand, for waste dump liners and covers are presented. Initial permeability requirements can be met. Effects of long-term permeation of inorganic leachate through the liner have been examined. No negative effect on liner permeability was seen, in fact it slightly decreased. The leachate solution pH increased, due to the
Geotechnical design for landfills incorporates safety concepts for the whole system (multibarrier concept) and for the individual components. The following geotechnical aspects of waste management are assessed: site survey; stability testing of the sealing system in the field and laboratory; stability analysis of the waste body; the ability of the clay liner to tolerate deformation; and quality assurance.
© 1993 Pergamon Press Ltd. Reproduction not permitted