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Microwave oven drying for soil moisture content determination
339A 936047 Percolation in layered media - a conductivity approach Hansen, A; Hinrichsen, E L; Stauffer, D Trans Porous Media Vll, NI, April 1993, P45-52 Long square-lattice and cube lattice samples are simulated, consisting of many layers, within each of which the concentration of permeable bonds is constant, whilst each layer has a different concentration, randomly selected from the interval between percolation threshold and unit concentration. The random resistor analogue corresponding to the percolation model is formulated and its conductivity calculated, perpendicular to and parallel to the layers in 2 and 3 dimensions. For layer-parallel conductivity, the effective medium calculation is within 10% of true value. 936048 Self-similar heterogeneity in granular porous media at the representative elementary volume scale Ghilardi, P; Kai, A K; Menduni, G Water Resaur Res V29, N4, April 1993, P1205-1214 Earlier work indicated both pore surface and volume in sandstones are self similar and show the same fractal dimension. Microscale hydraulic conductivity can thus be given as a function of inner and outer cutoffs and fractal dimension, and fractal dimension can be assumed to indicate the processes which shape the structure of the voids. It is shown that the same approach can be extended to other porous materials such as granular aggregates and to describe the soil structure at the REV scale. The particle size distribution from the fractal model of Turcotte (1986) is used. Sedimentation of this mixture is simulated and solid phase and void space geometry of the resulting aggregate analyzed. 936049 Microwave oven drying for soil moisture content determination Nordquist, J E; Edgar, R Proc 28th Symposium on Engineering Geology and Geotechnicai Engineering, Boise, 1-3 April 1992 P419-423. Publ Pocatello: Idaho State University, 1992 Samples of a silty clay, a sandy clay, and a lean clay were oven dried according to ASTM procedures using both microwave and conventional ovens. The microwave treatment consisted of a series of heating, cooling, and weighing sequences until change in sample weight between cycles was less than O. 1% of initial wet mass of the soil. Microwave drying provided rapid and reliable results in a very short time. Field use is possible provided suggested calibration procedures are adhered to. 936050 Determination of clay particle thicknesses and morphology using Scanning Force Microscopy Blum, A E; Eberl, D D Proc 7th International Symposium on Water-Rock Interaction, Park City, 13-18 July 1992 V1, P133-140. Publ Rotterdam: A A Balkema, 1992 Scanning Force Microscopy is described which allows simpler measurement of clay particle thickness than does Transmission Electron Microscopy and also reveals surface morphology in greater detail. S F M has been applied to 5 wellcharacterized clay samples, and particle size distributions are compared to those from other methods. SFM data indicate that there is a strong attractive force between clay particles, which probably accounts for interparticle diffraction seen in XRD, and that clay fundamental particles do not grow by a spiral mechanism on the (001) surface.
Deformation and strength characteristics See also: 936282 936051 Study of permanent deformations of three untreated graded aggregates using cyclic loading tests (In French) Hornych, P; Carte, J F; Paute, J L Bull Liaison Lab Pants Chaussees N184, March-April 1993, P45-55 Cyclic triaxial tests were carried out on 3 untreated aggregates (granite,hard limestone, soft limestone) to examine influences of material type, stresses, and water content on permanent deformations. Residual strains depend primarily on water content and tend to stabilise after several tens of thousands of cycles. Increase in modulus of elasticity with number of cycles was seen. Results are used to develop simple models for permanent deformation for use in pavement design. 936052 New instrument for measuring contact pressure (In French) Dufresne, D; Delyon, F; Levy, Y E Bull Liaison Lab Ponts Chaussees N184, March-April 1983, P87-90 An imprint recorder for measuring interface forces in granular materials is described. It is based on a two component foil, one of which emits dye in quantity proportional to pressure, the other an absorber, which is placed in a section of the specimen. It can be used to measure stresses in loose, cohesionless materials or interface pressures between rigid components. 936053 Interpretation of reservoir rock mechanical properties by direct methods. A study on two oil-bearing limestone units Fattohi, Z R; Al-kayat, B Environ Geoi V21, N1/2. April 1993, P37-41 Laboratory core-measured values of bulk density, porosity, resistivity, transit time, and strength have been correlated with wireline well log data for two limestone reservoir units. Interpretations are made in terms of index values between measured and inferred data. An engineering classification scheme was suggested. Acoustic wave velocity and dynamic modulus were also calculated and an attempt made to predict fracture pressure gradient for the formation. The potential for using directly measured data to evaluate in situ rock behaviour is demonstrated. 936054 Effect of frictional fill thickness on the shear strength of rock Papaliangas, T; Hencher, S R; Lumsden, A C; Manolopoulos, S lnt J Rock Meeh Min Sei V30, N2, April 1993, P81-91 Direct shear tests have been carried out on models of a sandstone joint with mean roughness amplitude 7mm and containing various thicknesses of pulverised fuel ash. Peak shear strength decreases as fill thickness increases. A minimum is approached when ratio of fill thickness to mean roughness amplitude if/a) is 1.25-1.50, depending on normal stress. Residual strength decreases less markedly with increasing f/a and tends to a constant value for f/a °1.0. When f~a, the failure plane may occur partly through fill and partly along the rock interface. When f/a °0.8, peak strength is between that of the fill and the rock-fill interface. Equations for peak and residual friction coefficients are given.
© 1993 Pergamon Press Ltd. Reproduction not permitted
Deformation and strength characteristics See also: 936282 936051 Study of permanent deformations of three untreated graded aggregates using cyclic loading tests (In French) Hornych, P; Carte, J F; Paute, J L Bull Liaison Lab Pants Chaussees N184, March-April 1993, P45-55 Cyclic triaxial tests were carried out on 3 untreated aggregates (granite,hard limestone, soft limestone) to examine influences of material type, stresses, and water content on permanent deformations. Residual strains depend primarily on water content and tend to stabilise after several tens of thousands of cycles. Increase in modulus of elasticity with number of cycles was seen. Results are used to develop simple models for permanent deformation for use in pavement design. 936052 New instrument for measuring contact pressure (In French) Dufresne, D; Delyon, F; Levy, Y E Bull Liaison Lab Ponts Chaussees N184, March-April 1983, P87-90 An imprint recorder for measuring interface forces in granular materials is described. It is based on a two component foil, one of which emits dye in quantity proportional to pressure, the other an absorber, which is placed in a section of the specimen. It can be used to measure stresses in loose, cohesionless materials or interface pressures between rigid components. 936053 Interpretation of reservoir rock mechanical properties by direct methods. A study on two oil-bearing limestone units Fattohi, Z R; Al-kayat, B Environ Geoi V21, N1/2. April 1993, P37-41 Laboratory core-measured values of bulk density, porosity, resistivity, transit time, and strength have been correlated with wireline well log data for two limestone reservoir units. Interpretations are made in terms of index values between measured and inferred data. An engineering classification scheme was suggested. Acoustic wave velocity and dynamic modulus were also calculated and an attempt made to predict fracture pressure gradient for the formation. The potential for using directly measured data to evaluate in situ rock behaviour is demonstrated. 936054 Effect of frictional fill thickness on the shear strength of rock Papaliangas, T; Hencher, S R; Lumsden, A C; Manolopoulos, S lnt J Rock Meeh Min Sei V30, N2, April 1993, P81-91 Direct shear tests have been carried out on models of a sandstone joint with mean roughness amplitude 7mm and containing various thicknesses of pulverised fuel ash. Peak shear strength decreases as fill thickness increases. A minimum is approached when ratio of fill thickness to mean roughness amplitude if/a) is 1.25-1.50, depending on normal stress. Residual strength decreases less markedly with increasing f/a and tends to a constant value for f/a °1.0. When f~a, the failure plane may occur partly through fill and partly along the rock interface. When f/a °0.8, peak strength is between that of the fill and the rock-fill interface. Equations for peak and residual friction coefficients are given.
© 1993 Pergamon Press Ltd. Reproduction not permitted