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Impact of synthetic leachate on the hydraulic conductivity of a smectitic till underlying a landfill near Saskatoo Saskatcewan
146A
Permeability and capillarity See a~o. 913030. 913314
913134 Contaminant migration through fractured till into an underlying aquifer Rowe, R K; Booker, J R Can Geotech J V27. N4, Aug 1990. P484-495 A simple semi-analytic model to describe contaminant transport through a fractured till layer is presented. It takes into accouni diffusion into the matrix, sorption, radioactive decay, and dilution through groundwater flow. Fracture spacing and aperture, thickness of the fracture zone, diffusion coeffient, dispersivity, matrix porosity, radioactive decay, Darcy velocity, aquifer thickness, distribution coefficient and mass of contaminant can be varied. A limited parametric study is presented and implications of its results are discussed. 913135 Impact of synthetic leachate on the hydraulic conductivity of a smectitie till underlying a landfill near Saskatoon, Saskatchewan Yanful, E K; Haug, M D; Wong, L C Can Geotech J V27. N4. Aug 1990. P507.519 Relatively long terms effects of permeation by a synthetic leachate on a smectitic till used to construct a landfill liner have been studied in the laboratory. Low gradient triaxial permeability tests were carried out for a 7 month period, using six volumes of test leachate. Hydraulic conductivity was about half that of a water permeated sample under the same hydraulic gradient. Clay mineral content was assessed at the end of the test period, and it appeared that the smectite peak was enhanced relative to the illite peak. No detrimental effects on the liner were evident. 913136 Field hydraulic conductivity tests for compacted soil liners Sai, J O; Anderson, J C Geotech Test J VI3. N3. Sept 1990, P215-225 Field methods to measure very low hydraulic conductivities representative of a compacted soil liner are reviewed. Air entry permeameters, borehole methods, porous probes, double ring, box, and single ring infiltrometers, and collection lysimeters arc discussed. The last produces good results but requires very long test times. Sealed double ring infiltrometers are practical to use and have few drawbacks. They should cover at least one REV and several tests should examine spatial variability of conductivity. 913137 Double-porosity modelling of oscillatory gas motion and contaminant transport in a fractured porous medium Nilson. R H: Lie, K H lnt J Num Anal Meth Geomech VI4. N8. Nor 1990. P565585 Variations in gas motion and associated contaminant transport with changes in barometric pressure (atmospheric pumping) in a fractured porous medium are analysed. This has been observed to water table depth in alluvium and fractured volcanic rocks. A double porosity (matrix, fractures) model is used with locally one-dimensional flow in matrix blocks and fractures. Seepage and diffusion between matrix and fractures are included. A fully implicit non-iterative solution scheme is used to solve the difference equations. The model is applied to vertical transport of radioactive gases through the chimney formed by an underground nuclear explosion. ~
913138 Hydraulic diffusivity measurements on laboratory rock samples using an oscillating pore pressure method Kranz, R L; Saltzman, J S: Blacic, J D lnt J Rock ,~lech Min Sci V27. N5, Oct 1990. P345-352 A method in which a pore pressure oscillation is superimposed on the ambient pore pressure at one end of a sample has been developed to measure the hydraulic diffusivity of rocks. Reequilibration between discrete measurements is not necessary, and continuous changes during creep or consolidation can be followed. When both amplitude difference and phase difference between upstream and downstream reservoirs is known, diffusivity and permeability can be calculated at the same time. Optimum frequency of oscillation and ratio of upstream to downstream pore pressure ratios depends on permeability and sample size. For 1 Icm long samples of Berea sandstone, Tennessee sandstone and granite, periods of 1 second, 500-1000 seconds, and over 4000 seconds, respectively, are suitable. 913139 Hydrological properties of Topopah Spring tuff under a thermal gradient - laboratory results Lin, W; Daily, W lnt J Rock Mech Min Sci V27. N5. Oct 1990. P373-385 Hydrological properties of a naturally fractured tuff from the Yucca Mountain site were investigated over a 5 month period under conditions of confining pressure, pore pressure, and temperature simulating near-field conditions expected shortly after placement of a radioactive waste container. Permeability was determined as a function of temperature and time. Electrical resistivity and impedance tomographs were used to study moisture migration. Dissolution and deposition of silica on fracture walls were seen. The rehydration process is not a reversal of dehydration. 913140 Modeling field infiltration into unsaturated clay Thomas, H R; Rees, S W J Geotech Engng Div ASCE VII6, NIO. Oct I990. PI4831501 A numerical solution is obtained to the Richards equation for unsaturated flow. Spatial discretization of the moisture flow domain is achieved using a weighted residual finite elcment approach, and a fully implicit backward difference time-stepping algorithm is used to describe the transient nature of the problem. The numerical procedure, incorporating laboratory and field measured soil and boundary parameters, is used to simulate infiltration into Kimmcridge clay. Good correlation is achieved between numerical predictions and field measurements. 913141 Reliability model for soil liner: postconstruction Bogardi, I; Kelly. W E; Bardossy, A J Geotech Engng Div ASCE v I I r . NIO. Oct 1990. PI5021520 A procedure is presented to estimate postconstruction reliability of liners using data from a test fill. Permeability is considered a spatially correlated, Iognormally distributed random variable. Six systems-reliability measures charaeterise the soil liner represented as a system of blocks and lifts. Test fill data are transferred to full scale permeability/reliability estimates using geostatistical techniques. A relation between number of permeability measurements necessary to monitor construction of a full scale liner, target average permeability, and specified reliability level is developed.
1991 Pergamon Press pie. Reproduction not permitted
Permeability and capillarity See a~o. 913030. 913314
913134 Contaminant migration through fractured till into an underlying aquifer Rowe, R K; Booker, J R Can Geotech J V27. N4, Aug 1990. P484-495 A simple semi-analytic model to describe contaminant transport through a fractured till layer is presented. It takes into accouni diffusion into the matrix, sorption, radioactive decay, and dilution through groundwater flow. Fracture spacing and aperture, thickness of the fracture zone, diffusion coeffient, dispersivity, matrix porosity, radioactive decay, Darcy velocity, aquifer thickness, distribution coefficient and mass of contaminant can be varied. A limited parametric study is presented and implications of its results are discussed. 913135 Impact of synthetic leachate on the hydraulic conductivity of a smectitie till underlying a landfill near Saskatoon, Saskatchewan Yanful, E K; Haug, M D; Wong, L C Can Geotech J V27. N4. Aug 1990. P507.519 Relatively long terms effects of permeation by a synthetic leachate on a smectitic till used to construct a landfill liner have been studied in the laboratory. Low gradient triaxial permeability tests were carried out for a 7 month period, using six volumes of test leachate. Hydraulic conductivity was about half that of a water permeated sample under the same hydraulic gradient. Clay mineral content was assessed at the end of the test period, and it appeared that the smectite peak was enhanced relative to the illite peak. No detrimental effects on the liner were evident. 913136 Field hydraulic conductivity tests for compacted soil liners Sai, J O; Anderson, J C Geotech Test J VI3. N3. Sept 1990, P215-225 Field methods to measure very low hydraulic conductivities representative of a compacted soil liner are reviewed. Air entry permeameters, borehole methods, porous probes, double ring, box, and single ring infiltrometers, and collection lysimeters arc discussed. The last produces good results but requires very long test times. Sealed double ring infiltrometers are practical to use and have few drawbacks. They should cover at least one REV and several tests should examine spatial variability of conductivity. 913137 Double-porosity modelling of oscillatory gas motion and contaminant transport in a fractured porous medium Nilson. R H: Lie, K H lnt J Num Anal Meth Geomech VI4. N8. Nor 1990. P565585 Variations in gas motion and associated contaminant transport with changes in barometric pressure (atmospheric pumping) in a fractured porous medium are analysed. This has been observed to water table depth in alluvium and fractured volcanic rocks. A double porosity (matrix, fractures) model is used with locally one-dimensional flow in matrix blocks and fractures. Seepage and diffusion between matrix and fractures are included. A fully implicit non-iterative solution scheme is used to solve the difference equations. The model is applied to vertical transport of radioactive gases through the chimney formed by an underground nuclear explosion. ~
913138 Hydraulic diffusivity measurements on laboratory rock samples using an oscillating pore pressure method Kranz, R L; Saltzman, J S: Blacic, J D lnt J Rock ,~lech Min Sci V27. N5, Oct 1990. P345-352 A method in which a pore pressure oscillation is superimposed on the ambient pore pressure at one end of a sample has been developed to measure the hydraulic diffusivity of rocks. Reequilibration between discrete measurements is not necessary, and continuous changes during creep or consolidation can be followed. When both amplitude difference and phase difference between upstream and downstream reservoirs is known, diffusivity and permeability can be calculated at the same time. Optimum frequency of oscillation and ratio of upstream to downstream pore pressure ratios depends on permeability and sample size. For 1 Icm long samples of Berea sandstone, Tennessee sandstone and granite, periods of 1 second, 500-1000 seconds, and over 4000 seconds, respectively, are suitable. 913139 Hydrological properties of Topopah Spring tuff under a thermal gradient - laboratory results Lin, W; Daily, W lnt J Rock Mech Min Sci V27. N5. Oct 1990. P373-385 Hydrological properties of a naturally fractured tuff from the Yucca Mountain site were investigated over a 5 month period under conditions of confining pressure, pore pressure, and temperature simulating near-field conditions expected shortly after placement of a radioactive waste container. Permeability was determined as a function of temperature and time. Electrical resistivity and impedance tomographs were used to study moisture migration. Dissolution and deposition of silica on fracture walls were seen. The rehydration process is not a reversal of dehydration. 913140 Modeling field infiltration into unsaturated clay Thomas, H R; Rees, S W J Geotech Engng Div ASCE VII6, NIO. Oct I990. PI4831501 A numerical solution is obtained to the Richards equation for unsaturated flow. Spatial discretization of the moisture flow domain is achieved using a weighted residual finite elcment approach, and a fully implicit backward difference time-stepping algorithm is used to describe the transient nature of the problem. The numerical procedure, incorporating laboratory and field measured soil and boundary parameters, is used to simulate infiltration into Kimmcridge clay. Good correlation is achieved between numerical predictions and field measurements. 913141 Reliability model for soil liner: postconstruction Bogardi, I; Kelly. W E; Bardossy, A J Geotech Engng Div ASCE v I I r . NIO. Oct 1990. PI5021520 A procedure is presented to estimate postconstruction reliability of liners using data from a test fill. Permeability is considered a spatially correlated, Iognormally distributed random variable. Six systems-reliability measures charaeterise the soil liner represented as a system of blocks and lifts. Test fill data are transferred to full scale permeability/reliability estimates using geostatistical techniques. A relation between number of permeability measurements necessary to monitor construction of a full scale liner, target average permeability, and specified reliability level is developed.
1991 Pergamon Press pie. Reproduction not permitted