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Elevated permeabilities caused by termites (In French)
348A 916136 Method for estimating effective porosity and ground-water velocity Hall, S H; Luttrell, S P; Cronin, W E Ground Water V29, N2, March-April 1991, P171-174
Use of Darcy's law or single well drift and pumpback tracer analysis to estimate groundwater velocity requires prior knowledge of effective porosity. If local hydraulic gradient is known and results are available from a drift and pumpback test at a well where hydraulic conductivity is known, two independent relations between velocity and porosity are available. By treating these as nonlinear simultaneous equations, local velocity and porosity can be evaluated.
916137 Literature review and model (COMET) for colloid/metals transport in porous media Mills, W B; Liu, S; Fong, F K Ground Water V29, N2, March-April 1991, P199-208
Recent evidence suggests colloidal particles can move through the subsurface, providing a mobile solid phase for contaminant migration. Field and laboratory studies on this phenomenon have been reviewed, the level of understanding of the controlling mechanisms examined, and literature concerning colloid transport mechanisms studied. A colloid-metal transport model (COMET) has been developed and incorporated into the EPA CML model simulating solute migration away from a landfill. Effects on transport of including colloid migration are discussed.
916138 Numerical assessment of a landfill compliance limit Hensel, B R; Keefer, D A; Griffin, R A; Berg, R C Ground Water II29, N2, March-April 1991, P218-224
The PLASM and random walk groundwater flow and contaminant migration models have been used to assess contaminant transport for 16 generalised geological sequences representative of hydrogeological conditions over 90-95% of Illinois. Results are used to assess the potential impact of proposed regulatory compliance distances for landfill siting. For nonhazardous wastes and compliance distances of 30m and 150m, about 50% and 55%, respectively, of the state would appear hydrogeologicalty stljtable.
916139 Douglas-Jones predictor-conreOar program for simulating onedimensional unsaturated flow in soil. Computer note Babajimopoulos, C Ground Water V29, N2, March-April 1991, P267-270
A solution to the one dimensional unsaturated flow equation for soils is presented, based on a Douglas-Jones finite difference implicit method for solution of the Richards equation. Hydraulic conductivity and specific moisture capacity functions are estimated using an implicit iinearization scheme. Predictions of moisture content are compared to those of two Galerkin finite element solutions and with field data. A fully documented listing of the F O R T R A N computer program is available.
916140 Decrease of the permeability as a function of depth in crystalline rocks. Data from Eiassona area (Greece) (In French) Soulios, G; Christaras, B; Kilias, A; Athanasias, S; Christou, O; Kontzoglou, J lnt Assoc Engng Geol Bull N42, Oct 1990, P95-99
31 exploration drillings were carried out around Elassona in carbonate, ultrabasic, schist, and crystalline rocks. Water injection tests were used to determine the permeability (K) for every 3m of depth. Regression analysis showed strong correlation between decrease in K and increase in depth. The standard deviation of K at a constant depth was large, and coefficient of variation was independent of depth. 916141 Elevated permeabilities caused by termites (In French) Wiesner, E lnt Assoc Engng Geol Bull N42, Oct 1990, Pl17-121
Laboratory and field measurements of permeability often differ. An extreme case is reported from the Selingue dam site on the alluvial plane of the Sankarani river in Mali. Lateritic weathering has left a ferralitic plinthic soil. A 5-20cm thick layer of holes was found just above the water table, across most of the valley. This is attributed to termite action over centuries. Only the lateritic concretions remain and site permeabilities are extremely high. 916142 Perturbed earth processes due to a thermally induced deformation in a discontinuous granite mass Awadalla, A M Int J g i n Geoi Engng II8, N4, Dec 1990, P319-331
Factors affecting the hydraulic properties of a fractured rock mass are first outlined: friction and roughness of the fracture surface, tortuosity, discontinuity spacing, and confining pressure. The effects of thermally induced stress on the discontinuous mass are then superimposed to give a flow-stresstemperature relation. Predictions from this model are compared to field data from the Stripa mine, Sweden. 916143 Measurement of parameters impacting methane recovery from coal seams Harpalani, S; Schraufnagel, A Int J Min Geol gngng V8, N4, Dec 1990, P369-384
The behaviour of coalbed gas reservoirs has been examined. Microscopy showed blocks of matrix and pores separated by microfractures, validating the use of a dual porosity model in simulation. Adsorption/desorption isotherms suggest a major part of the gas is released only after pressure falls below about 4MPa, primarily due to desorbing gas. Volumetric strain experiments show an increase in matrix volume with increasing gas pressure. When these results were input into a coalbed reservoir simulator, output over 5 years was 50% greater than that when matrix shrinkage is not included. 916144 Solution of steady unconfined seepage towards semi-infinite slopes Muleshkov, A; Banerjee, S Int J Num Anal Meth Geomech 1/15, N4, April 1991, P271288
An analysis of the 2D problem of unconfined seepage towards a semi-infinite slope is presented, based on complex variables techniques. Conformal mappings have been used to reduce the problem to solving an ordinary differential equation. The
© 1991 Pergamon Press pie. Reproduction not permitted
Use of Darcy's law or single well drift and pumpback tracer analysis to estimate groundwater velocity requires prior knowledge of effective porosity. If local hydraulic gradient is known and results are available from a drift and pumpback test at a well where hydraulic conductivity is known, two independent relations between velocity and porosity are available. By treating these as nonlinear simultaneous equations, local velocity and porosity can be evaluated.
916137 Literature review and model (COMET) for colloid/metals transport in porous media Mills, W B; Liu, S; Fong, F K Ground Water V29, N2, March-April 1991, P199-208
Recent evidence suggests colloidal particles can move through the subsurface, providing a mobile solid phase for contaminant migration. Field and laboratory studies on this phenomenon have been reviewed, the level of understanding of the controlling mechanisms examined, and literature concerning colloid transport mechanisms studied. A colloid-metal transport model (COMET) has been developed and incorporated into the EPA CML model simulating solute migration away from a landfill. Effects on transport of including colloid migration are discussed.
916138 Numerical assessment of a landfill compliance limit Hensel, B R; Keefer, D A; Griffin, R A; Berg, R C Ground Water II29, N2, March-April 1991, P218-224
The PLASM and random walk groundwater flow and contaminant migration models have been used to assess contaminant transport for 16 generalised geological sequences representative of hydrogeological conditions over 90-95% of Illinois. Results are used to assess the potential impact of proposed regulatory compliance distances for landfill siting. For nonhazardous wastes and compliance distances of 30m and 150m, about 50% and 55%, respectively, of the state would appear hydrogeologicalty stljtable.
916139 Douglas-Jones predictor-conreOar program for simulating onedimensional unsaturated flow in soil. Computer note Babajimopoulos, C Ground Water V29, N2, March-April 1991, P267-270
A solution to the one dimensional unsaturated flow equation for soils is presented, based on a Douglas-Jones finite difference implicit method for solution of the Richards equation. Hydraulic conductivity and specific moisture capacity functions are estimated using an implicit iinearization scheme. Predictions of moisture content are compared to those of two Galerkin finite element solutions and with field data. A fully documented listing of the F O R T R A N computer program is available.
916140 Decrease of the permeability as a function of depth in crystalline rocks. Data from Eiassona area (Greece) (In French) Soulios, G; Christaras, B; Kilias, A; Athanasias, S; Christou, O; Kontzoglou, J lnt Assoc Engng Geol Bull N42, Oct 1990, P95-99
31 exploration drillings were carried out around Elassona in carbonate, ultrabasic, schist, and crystalline rocks. Water injection tests were used to determine the permeability (K) for every 3m of depth. Regression analysis showed strong correlation between decrease in K and increase in depth. The standard deviation of K at a constant depth was large, and coefficient of variation was independent of depth. 916141 Elevated permeabilities caused by termites (In French) Wiesner, E lnt Assoc Engng Geol Bull N42, Oct 1990, Pl17-121
Laboratory and field measurements of permeability often differ. An extreme case is reported from the Selingue dam site on the alluvial plane of the Sankarani river in Mali. Lateritic weathering has left a ferralitic plinthic soil. A 5-20cm thick layer of holes was found just above the water table, across most of the valley. This is attributed to termite action over centuries. Only the lateritic concretions remain and site permeabilities are extremely high. 916142 Perturbed earth processes due to a thermally induced deformation in a discontinuous granite mass Awadalla, A M Int J g i n Geoi Engng II8, N4, Dec 1990, P319-331
Factors affecting the hydraulic properties of a fractured rock mass are first outlined: friction and roughness of the fracture surface, tortuosity, discontinuity spacing, and confining pressure. The effects of thermally induced stress on the discontinuous mass are then superimposed to give a flow-stresstemperature relation. Predictions from this model are compared to field data from the Stripa mine, Sweden. 916143 Measurement of parameters impacting methane recovery from coal seams Harpalani, S; Schraufnagel, A Int J Min Geol gngng V8, N4, Dec 1990, P369-384
The behaviour of coalbed gas reservoirs has been examined. Microscopy showed blocks of matrix and pores separated by microfractures, validating the use of a dual porosity model in simulation. Adsorption/desorption isotherms suggest a major part of the gas is released only after pressure falls below about 4MPa, primarily due to desorbing gas. Volumetric strain experiments show an increase in matrix volume with increasing gas pressure. When these results were input into a coalbed reservoir simulator, output over 5 years was 50% greater than that when matrix shrinkage is not included. 916144 Solution of steady unconfined seepage towards semi-infinite slopes Muleshkov, A; Banerjee, S Int J Num Anal Meth Geomech 1/15, N4, April 1991, P271288
An analysis of the 2D problem of unconfined seepage towards a semi-infinite slope is presented, based on complex variables techniques. Conformal mappings have been used to reduce the problem to solving an ordinary differential equation. The
© 1991 Pergamon Press pie. Reproduction not permitted