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Critical reappraisal of colloidal activity of clays
218A Physico-chemical properties
Davidson, and power law functions, the first providing the best fit. The samples were primarily oilfield cores, although some quarried rock was used.
See also: 915020
915104
915100 Influence of polysnccharides on kaolinite structure and properties in a kaolinite-water system
Critical reappraisal of colloidal activity of clays
Pandian, N S; Nagaraj, T S J Geotech Engng Div ASCE V117, N2, Feb 1991, P285-296
Yong, R N; Mourato, D Can Geotech J V27, N6. Dee 1990, P774-788 The influence of two soil organics (xanthan and dextran polysaccharides) on development of structure and resultant physicochemical properties of soil-polysaccharide systems was investigated in the laboratory. The systems were formed in suspensions under conditions simulating those in subsurface soils. Rheology, zeta potential, aggregate size, settling properties, and specific surface area were studied. Both polysaccharides were shown to develop floes, which can affect permeability and transport properties of the soil. Models of the interaction of the polysaccharides and kaolinite are proposed. 915101 Cation trausport and retardation processes in view of toxic waste deposition problem in clay rocks and clay liner encapsulation
Czurda, K A; Wagner, J F Engng Geol V30, Nl, March 1991, P103-113 (paper to Applied Sciences for Low-level Radioactive and Chemical Wastes, Proc 28th International Geological Congress, Symposium El2)
The sorption capacity of clay rocks for a variety of metals was examined in batch and column experiments. The migration of chloride solutions through undisturbed samples of Tertiary and Quaternary clays, silts, and marls was studied using diffusion tests at different concentration gradients and percolation tests at different hydraulic gradients. Solution parameters and rock parameters (mineralogy, grain size, CEC, structure, specific surface, pore water chemistry) affect transport. Batch tests produced markedly higher retardation factors than column tests. 915102 New sorbing grouts for radioactive and toxic heavy metals
Amould, M; Clement, C; Gouvenot, D; Struillou, R Engng Geol V30, NI, March 1991, P127-139 (paper to Applied Sciences for Low-level Radioactive and Chemical Wastes, Proc 28th International Geological Congress, Symposium El 2)
The ability of two injectable grouts, consisting of the standard cement plus bentonite together with siliceous materials, special clays or zeolites, and chemical additives, to retard transport of radioactive and toxic heavy metal cations has been examined. Absorption on to suspensions of crushed grout and high hydraulic gradient percolation of concentrated solutions were studied. Extrapolation of results to concentrations likely at waste repositories shows the special grouts perform more satisfactorily than normal grout materials. 915103 Measurement of dielectric response of water+aturated
rocks
Taherian, M R; Kenyon, W E; Safinya, K A Geophysics V55, NI2. Dee 1990. P1530-1541 Complex permittivity (dielectric constant and conductivity) measurements were made on brine-saturated rocks in the frequency range IO-1300 MHz. Data sets across the frequency range from 271 samples were fitted using Cole-Cole, Cole0
Many properties of soils are influenced by physicochemical characteristics of their constituents. Atterberg limits and Skempton’s colloidal activity (ACT), the ratio of plasticity index to clay fraction, are quantitative parameters representing the composite effects of soil constituents and their interaction with pore water. A micromechanical interpretation of these parameters and their interrelations is presented. Liquid limit is seen to be a reflection of the surface activity of a soil. It should be possible to predict engineering properties of a soil primarily in terms of liquid limit, based on the correlations which have been developed. 915105 Diffusion in saturated soil. I: background
Shackelford, C D; Daniel, D E J Geotech Engng Div ASCE VI 17, N3, March 1991, P467484
Diffusion is a dominant transport mode for contaminants in soils. Steady state diffusive transport through soil is first examined and influence of tortuosity, reduction of cross-sectional area, and surface concentration effects on the basic diffusion equation assessed. An effective diffusion coefficient is defined. Transient diffusion of both nonreactive and reactive solutes and their apparent diffusion coefficients are then analysed. Effects of coupled flow processes, with solute transport from causes in addition to diffusion, and measurement of the diffusion coefficient are discussed. 915106 Diffusion in saturated soil. II: results for compacted clay
Shackelford, C D; Daniel, D E J Geotech Engng Div AXE V117. N3, March 1991. P485506
Laboratory tests investigated the diffusion of cations (Cd, Zn, K) and anions (Br, Cl, I) from a simulated leachate into kaolinite and Lufkin clays. A closed form solution and a semianalytical solution (POLLUTE) were used to compute values of effective diffusion coefficient, which for the case studied of chloride/kaohnite were relatively insensitive to effects of moulding water content or method of compaction. Measured diffusion coefficients of Cl and Br ions were in good agreement with reported values, but those for the heavy metal species were surprisingly high. Reasons for this is discussed. 915107 Correlatfon of strain with anisotropy of magnetic susceptibflity CAMS)
Borradaile, G J Pure Appl Geophys V135. NI. 1991. P15-29 Existing correlations between strain and anisotropy of lowfield magnetic susceptibility have been re-examined using the parameter of Hrouda (1982) to express both anisotropies. Good correlations between strain and susceptibility are seen between a lower limit of strain (excluding the incomplete imprint of predeformation anisotropy) and an upper limit (excluding the effects of saturation anisotropy). For comlations to hold, the influence of stress-controlled recrystallisation should be minimal and mineralogical sources of susceptibility must predate deformation.
1991 Pergamon Press plc. Reproduction
not permitted
Davidson, and power law functions, the first providing the best fit. The samples were primarily oilfield cores, although some quarried rock was used.
See also: 915020
915104
915100 Influence of polysnccharides on kaolinite structure and properties in a kaolinite-water system
Critical reappraisal of colloidal activity of clays
Pandian, N S; Nagaraj, T S J Geotech Engng Div ASCE V117, N2, Feb 1991, P285-296
Yong, R N; Mourato, D Can Geotech J V27, N6. Dee 1990, P774-788 The influence of two soil organics (xanthan and dextran polysaccharides) on development of structure and resultant physicochemical properties of soil-polysaccharide systems was investigated in the laboratory. The systems were formed in suspensions under conditions simulating those in subsurface soils. Rheology, zeta potential, aggregate size, settling properties, and specific surface area were studied. Both polysaccharides were shown to develop floes, which can affect permeability and transport properties of the soil. Models of the interaction of the polysaccharides and kaolinite are proposed. 915101 Cation trausport and retardation processes in view of toxic waste deposition problem in clay rocks and clay liner encapsulation
Czurda, K A; Wagner, J F Engng Geol V30, Nl, March 1991, P103-113 (paper to Applied Sciences for Low-level Radioactive and Chemical Wastes, Proc 28th International Geological Congress, Symposium El2)
The sorption capacity of clay rocks for a variety of metals was examined in batch and column experiments. The migration of chloride solutions through undisturbed samples of Tertiary and Quaternary clays, silts, and marls was studied using diffusion tests at different concentration gradients and percolation tests at different hydraulic gradients. Solution parameters and rock parameters (mineralogy, grain size, CEC, structure, specific surface, pore water chemistry) affect transport. Batch tests produced markedly higher retardation factors than column tests. 915102 New sorbing grouts for radioactive and toxic heavy metals
Amould, M; Clement, C; Gouvenot, D; Struillou, R Engng Geol V30, NI, March 1991, P127-139 (paper to Applied Sciences for Low-level Radioactive and Chemical Wastes, Proc 28th International Geological Congress, Symposium El 2)
The ability of two injectable grouts, consisting of the standard cement plus bentonite together with siliceous materials, special clays or zeolites, and chemical additives, to retard transport of radioactive and toxic heavy metal cations has been examined. Absorption on to suspensions of crushed grout and high hydraulic gradient percolation of concentrated solutions were studied. Extrapolation of results to concentrations likely at waste repositories shows the special grouts perform more satisfactorily than normal grout materials. 915103 Measurement of dielectric response of water+aturated
rocks
Taherian, M R; Kenyon, W E; Safinya, K A Geophysics V55, NI2. Dee 1990. P1530-1541 Complex permittivity (dielectric constant and conductivity) measurements were made on brine-saturated rocks in the frequency range IO-1300 MHz. Data sets across the frequency range from 271 samples were fitted using Cole-Cole, Cole0
Many properties of soils are influenced by physicochemical characteristics of their constituents. Atterberg limits and Skempton’s colloidal activity (ACT), the ratio of plasticity index to clay fraction, are quantitative parameters representing the composite effects of soil constituents and their interaction with pore water. A micromechanical interpretation of these parameters and their interrelations is presented. Liquid limit is seen to be a reflection of the surface activity of a soil. It should be possible to predict engineering properties of a soil primarily in terms of liquid limit, based on the correlations which have been developed. 915105 Diffusion in saturated soil. I: background
Shackelford, C D; Daniel, D E J Geotech Engng Div ASCE VI 17, N3, March 1991, P467484
Diffusion is a dominant transport mode for contaminants in soils. Steady state diffusive transport through soil is first examined and influence of tortuosity, reduction of cross-sectional area, and surface concentration effects on the basic diffusion equation assessed. An effective diffusion coefficient is defined. Transient diffusion of both nonreactive and reactive solutes and their apparent diffusion coefficients are then analysed. Effects of coupled flow processes, with solute transport from causes in addition to diffusion, and measurement of the diffusion coefficient are discussed. 915106 Diffusion in saturated soil. II: results for compacted clay
Shackelford, C D; Daniel, D E J Geotech Engng Div AXE V117. N3, March 1991. P485506
Laboratory tests investigated the diffusion of cations (Cd, Zn, K) and anions (Br, Cl, I) from a simulated leachate into kaolinite and Lufkin clays. A closed form solution and a semianalytical solution (POLLUTE) were used to compute values of effective diffusion coefficient, which for the case studied of chloride/kaohnite were relatively insensitive to effects of moulding water content or method of compaction. Measured diffusion coefficients of Cl and Br ions were in good agreement with reported values, but those for the heavy metal species were surprisingly high. Reasons for this is discussed. 915107 Correlatfon of strain with anisotropy of magnetic susceptibflity CAMS)
Borradaile, G J Pure Appl Geophys V135. NI. 1991. P15-29 Existing correlations between strain and anisotropy of lowfield magnetic susceptibility have been re-examined using the parameter of Hrouda (1982) to express both anisotropies. Good correlations between strain and susceptibility are seen between a lower limit of strain (excluding the incomplete imprint of predeformation anisotropy) and an upper limit (excluding the effects of saturation anisotropy). For comlations to hold, the influence of stress-controlled recrystallisation should be minimal and mineralogical sources of susceptibility must predate deformation.
1991 Pergamon Press plc. Reproduction
not permitted