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Rock mechanics contributions from defense programs
4A
Chemical and physical changes due to water 931022 Groundwater flow in a compressible unconfined aquifer with uniform circular recharge Zlotnik, V; Ledder, G Water Resour Res V28, N6, June 1992, P1619-1630 The distribution of the hydraulic head and its gradient (velocity vector) for transient groundwater flow in an unconfined compressible aquifer under a circular source of recharge have been obtained from the linearised mathematical model by the use of the integral transforms. The result generalises the solution of Dagan (1967) which neglected compressibility. Results indicate that Dagan's formulation is accurate at large times, but gives large relative errors (small absolute errors) at small times. 931023 Finite layer method for groundwater flow models Smith, S S; Allen, M B Water Resour Res II28, N6, June 1992, P1715-1722 The finite layer method is an extension of the finite strip method familiar in structural engineering. Discretization in two dimensions is by truncated Fourier series, variations in the third being approximated by finite elements. The method reduces 3D problems to sets of independent matrix equations, solvable sequentially by PC or concurrently by parallel processor. It is thus suitable for computationally intensive problems such as optimization or the inverse problem. The F L M is demonstrated applied to 4 groundwater flow models: single fully-penetrating well; point source injection; single well in a leaky aquifer; and multiwell field.
Properties of Rocks and Soils 931024 Rock mechanics contributions from defense programs Heuze, F Proc 33rd US Symposium on Rock Mechanics, Santa Fe, 3-5 June 1992 P3-26. Publ Rotterdam." A A Balkema, 1992 Finance from defence programs has played an important role in advancement of rock mechanics over the past 3 decades. Major areas of work are summarised: dynamic instrumentation; measurement of rock properties; physical modelling; development of constitutive relations and numerical models; dynamics of underground explosions and underground structures; cratering explosions; projectile penetration; and underground storage of radioactive waste.
Composition, structure texture and density See a~o: 931222, 931232 931025 Investigation and estimation on discontinuity (including geotomography) Kikuchi, K In: Rock Mechanics in Japan, Volume VI 1'81-84. Publ Tokyo: Japanese Committee for ISRM, 1991 An overview is presented of recent work in Japan on study of the properties, distribution, and influence of discontinuities in rock masses. Laboratory testing of single discontinuities, the use of the crack tensor to represent a system of discontinuities, hydraulic properties of single and multiple discontinuities, and
estimation of their distribution are briefly examined. Applications of this work to discontinuum and continuum modelling of jointed rock masses and seepage flow analysis are outlined. The geotomography technique is described. 931026 Evaluation of the effect of morphological features of flow paths on solute transport by using fractal dimensions of methylene blue staining patterns Hatano, R; Kawamura, N; Ikeda, J; Sakuma, T Geoderma V53, N1/2, May 1992, P31-44 Fractai dimensions were obtained of the methylene blue staining patterns in 5 undisturbed soil columns. These values were examined in relation to Brenner numbers for chloride breakthrough measured under saturated steady state conditions. Values of D of the internal structure of staining patterns decreased with increasing depth, whilst fractal dimensions of the perimeter of stains remained relatively constant. An empirical equation was developed relating Brenner number for chloride breakthrough to depth averages of both fractal dimensions and macroporosity. 931027 Automatic orientation mapping of some types of soil fabric Tovey, N K; Smart, P; Hounslow, M W; Leng, X L Geoderma V53, N3/4, June 1992, P179-200 A method is described which automatically delineates areas of micrographs of soils which have similarly oriented microfabrics. It requires two passes over a digitized image. In the first, an intensity gradient algorithm is used to specify the orientation at each pixel. A second pass then examines the values attributed to each pixel, and if one general orientation is dominant in the neighborhood of one pixel, the central pixel is assigned an appropriate grey scale value. The method has applications to study of fabric development due to mechanical or environmental effects. 931028 Techniques to quantitatively study the microfabric of soils Tovey, N K; Krinsley, D H; Dent, D L; Corbett, W M Geoderma V53, N3/4, June 1992, P217-235 A powerful new technique to examine the mineralogy and microstructure of soils has been developed by combining several existing image processing and analysis methods. It begins with multispectral classification of SEM backscattered electron images and X-ray maps, followed by particle size routines on the segregated mineral grains. These grains are then masked to allow intensity gradient techniques to be used to study orientation patterns within the matrix. Finally, segmentation of the orientation image into similarly aligned domains shows how the orientation of the matrix relates to that of the skeleton mineral grains. The separate techniques may be run automatically in batch mode. 931029 Modifications to a method of rapid assessment of soil macropore structure by image analysis McBratney, A B; Moran, C J; Stewart, J B; Cattle, S R; Koppi, A J Geoderma V53, N3/4, June 1992, P255-274 Pore structure studies based on image analysis are generally time consuming, and three modifications are proposed to the original techniques in order to improve productivity. A technique is described to enable taking of a single monolithic soil sample up to 700ram in length for video digitizing. The use of resins of different colours in the field and laboratory to allow assessment of a larger number of parameters to distinguish
© 1993 Pergamon Press Ltd. Reproduction not permitted
Chemical and physical changes due to water 931022 Groundwater flow in a compressible unconfined aquifer with uniform circular recharge Zlotnik, V; Ledder, G Water Resour Res V28, N6, June 1992, P1619-1630 The distribution of the hydraulic head and its gradient (velocity vector) for transient groundwater flow in an unconfined compressible aquifer under a circular source of recharge have been obtained from the linearised mathematical model by the use of the integral transforms. The result generalises the solution of Dagan (1967) which neglected compressibility. Results indicate that Dagan's formulation is accurate at large times, but gives large relative errors (small absolute errors) at small times. 931023 Finite layer method for groundwater flow models Smith, S S; Allen, M B Water Resour Res II28, N6, June 1992, P1715-1722 The finite layer method is an extension of the finite strip method familiar in structural engineering. Discretization in two dimensions is by truncated Fourier series, variations in the third being approximated by finite elements. The method reduces 3D problems to sets of independent matrix equations, solvable sequentially by PC or concurrently by parallel processor. It is thus suitable for computationally intensive problems such as optimization or the inverse problem. The F L M is demonstrated applied to 4 groundwater flow models: single fully-penetrating well; point source injection; single well in a leaky aquifer; and multiwell field.
Properties of Rocks and Soils 931024 Rock mechanics contributions from defense programs Heuze, F Proc 33rd US Symposium on Rock Mechanics, Santa Fe, 3-5 June 1992 P3-26. Publ Rotterdam." A A Balkema, 1992 Finance from defence programs has played an important role in advancement of rock mechanics over the past 3 decades. Major areas of work are summarised: dynamic instrumentation; measurement of rock properties; physical modelling; development of constitutive relations and numerical models; dynamics of underground explosions and underground structures; cratering explosions; projectile penetration; and underground storage of radioactive waste.
Composition, structure texture and density See a~o: 931222, 931232 931025 Investigation and estimation on discontinuity (including geotomography) Kikuchi, K In: Rock Mechanics in Japan, Volume VI 1'81-84. Publ Tokyo: Japanese Committee for ISRM, 1991 An overview is presented of recent work in Japan on study of the properties, distribution, and influence of discontinuities in rock masses. Laboratory testing of single discontinuities, the use of the crack tensor to represent a system of discontinuities, hydraulic properties of single and multiple discontinuities, and
estimation of their distribution are briefly examined. Applications of this work to discontinuum and continuum modelling of jointed rock masses and seepage flow analysis are outlined. The geotomography technique is described. 931026 Evaluation of the effect of morphological features of flow paths on solute transport by using fractal dimensions of methylene blue staining patterns Hatano, R; Kawamura, N; Ikeda, J; Sakuma, T Geoderma V53, N1/2, May 1992, P31-44 Fractai dimensions were obtained of the methylene blue staining patterns in 5 undisturbed soil columns. These values were examined in relation to Brenner numbers for chloride breakthrough measured under saturated steady state conditions. Values of D of the internal structure of staining patterns decreased with increasing depth, whilst fractal dimensions of the perimeter of stains remained relatively constant. An empirical equation was developed relating Brenner number for chloride breakthrough to depth averages of both fractal dimensions and macroporosity. 931027 Automatic orientation mapping of some types of soil fabric Tovey, N K; Smart, P; Hounslow, M W; Leng, X L Geoderma V53, N3/4, June 1992, P179-200 A method is described which automatically delineates areas of micrographs of soils which have similarly oriented microfabrics. It requires two passes over a digitized image. In the first, an intensity gradient algorithm is used to specify the orientation at each pixel. A second pass then examines the values attributed to each pixel, and if one general orientation is dominant in the neighborhood of one pixel, the central pixel is assigned an appropriate grey scale value. The method has applications to study of fabric development due to mechanical or environmental effects. 931028 Techniques to quantitatively study the microfabric of soils Tovey, N K; Krinsley, D H; Dent, D L; Corbett, W M Geoderma V53, N3/4, June 1992, P217-235 A powerful new technique to examine the mineralogy and microstructure of soils has been developed by combining several existing image processing and analysis methods. It begins with multispectral classification of SEM backscattered electron images and X-ray maps, followed by particle size routines on the segregated mineral grains. These grains are then masked to allow intensity gradient techniques to be used to study orientation patterns within the matrix. Finally, segmentation of the orientation image into similarly aligned domains shows how the orientation of the matrix relates to that of the skeleton mineral grains. The separate techniques may be run automatically in batch mode. 931029 Modifications to a method of rapid assessment of soil macropore structure by image analysis McBratney, A B; Moran, C J; Stewart, J B; Cattle, S R; Koppi, A J Geoderma V53, N3/4, June 1992, P255-274 Pore structure studies based on image analysis are generally time consuming, and three modifications are proposed to the original techniques in order to improve productivity. A technique is described to enable taking of a single monolithic soil sample up to 700ram in length for video digitizing. The use of resins of different colours in the field and laboratory to allow assessment of a larger number of parameters to distinguish
© 1993 Pergamon Press Ltd. Reproduction not permitted