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Origin and properties of glacial till and diamictons
146A 855063 Weak shocks and steady waves in a nonlinear elastic rod or granular material Wright, T W Int J Solids Struct V20, N9/10, 1984, P911-919
Theories for a nonlinear elastic rod and a granular material are shown to be identical. Both cases admit shocks of two different types. Both also support steady waves, which may be either periodic or solitary waves. Auth. 855064 New method for evaluating liquefaction potential Arulmoli, K; Arulanandan, K; Seed, H B J Geotech Engng Div ASCE VIII, N1, Jan 1985, P95-114
A probe for in situ indexing of grain and aggregate properties of sand, using electrical parameters, is described. The parameters are correlated with parameters defining liquefaction potential. Relative density and cyclic stress ratios evaluated using the probe were in reasonable agreement with conventional laboratory measurements. The potential applicability of the probe was demonstrated by correctly estimating liquefaction and non-liquefaction areas at major earthquake sites.
Classification and identification 855O65 Characterization and interpretation of rock mass joint patterns La Pointe, P R; Hudson, J A Geoi Soc Am Special Paper N199, 1985, 37P
The geometry of joint patterns has been analysed and quantified by the use of conventional statistics, geostatistics and printed circuit board analogs. Biases in joint pattern studies are examined and probability theory and scanline techniques are used to minimise them. A means of estimating RQD from spacings histograms and formulae for estimating areal and volumetric joint densities from scanlines or borehole measurements are proposed. Spatial variability of joints is assessed geostatistically. A geostatistical theory for the analysis of joint patterns is developed and techniques for creating synthetic joint patterns, based on the characterisation methods, presented. Printed circuit board replicas of joint patterns are used to demonstrate how the interaction of joint patterns governs mass flow systems for rocks. These techniques are applied to an area of Niagara dolomite at Lannon, Wisconsin, USA.
Geology Tectonic processes See also." 855042 855066 Relaxation of the earth after a dip slip earthquake: dependence on rheology and geometry Lang, G; Vilotte, J P; Neugebauer, H J Phys Earth Planet Inter I:36, N3/4, Dec 1984, P260-275
Displacements of lithospheric plates after large dip slip earthquakes correspond to a purely elastic earth, whilst relaxation of deviatoric stress is by viscous processes. Surface deformation on stress relaxation can be measured. The effects of different geometries and rheologicai properties on surface deformation are modelled using the finite element method.
855067 Model of the lithosphece with a creep threshold stress Peters, R G Tectonophysics V l l l, N1/ 2, Jan 1985, P3-23
Gravity and bathymetry observations at the Emperor Seamounts are explained by introducing a model for creep of the lithosphere which includes a threshold stress, below which there is no deformation. Such a deformation mechanism has been demonstrated for metals and ceramics, although not for silicate ceramics at suitably low stress.
Environmental effects, weathering and soil forma, tion See also. 855010, 855043 855068 Field rainfall simulator studies on two clay soils of the Darling Downs, Queensland. IlL An evaluation of current methods for deriving soil erodibilities (K factors) Loch, R J Aust J Soil Res V22, N4, 1984, P40)-412
Soil erodibility factors for the Universal Soil Loss Equation (USLE) are often derived using simulated rainfall. The effects of plot size and erosion processes on K values measured in this way are considered and problems in calculation of K from rainfall simulator data, using the USLE, are highlighted. The procedures presently used do not account for erosion process/runoff rate interactions. It is concluded that single-event soil loss models may provide a means for producing better estimates of annual average soil losses, suitable for the calculation of K. 855O69 Scanning electron microscope study of bedrock microfractures
in granites underhigh arctic conditions Watts, S H Earth Surf Land Process VIO, N2, March-April 1985, P161172 Heavily weathered surface specimens of granite from Arctic Canada have been examined by scanning electron microscopy. Both salts and organic materials, which could enhance microfracturing, were seen in surface cracks. The importance of lithological parameters, environmental factors and organic activity on weathering are examined and it is concluded that it is unlikely that any one mechanism in isolation is the cause of bedrock breakdown. 855070 Origin and properties of glacial lill and diamictons Lutenegger, A J; Kemmis, T J; Hailberg, G R In: GeologieM Eneironment and Soil Properties (paper prepared in conjunction with the ASCE Geoteclmical Engineering Division and the ASCE Convention, Houston, Texas, 17-21 Oct 1983) P310-331. Publ New York." ASCE, 1983
Deposition by land based glaciers may be subglaciat, beneath the ice mass, or supraglacial, on or adjacent to the glacial ice. The deposits from the two processes differ significantly in texture, density and structure. Subglacial deposits are more uniform in texture and have a narrower range of matrix texture and composition than supraglacial till These primary qualities control important geotechnical properties. Differentiation of glacial deposits in this manner can be useful in site investigation and in evaluating material properties for design.
Theories for a nonlinear elastic rod and a granular material are shown to be identical. Both cases admit shocks of two different types. Both also support steady waves, which may be either periodic or solitary waves. Auth. 855064 New method for evaluating liquefaction potential Arulmoli, K; Arulanandan, K; Seed, H B J Geotech Engng Div ASCE VIII, N1, Jan 1985, P95-114
A probe for in situ indexing of grain and aggregate properties of sand, using electrical parameters, is described. The parameters are correlated with parameters defining liquefaction potential. Relative density and cyclic stress ratios evaluated using the probe were in reasonable agreement with conventional laboratory measurements. The potential applicability of the probe was demonstrated by correctly estimating liquefaction and non-liquefaction areas at major earthquake sites.
Classification and identification 855O65 Characterization and interpretation of rock mass joint patterns La Pointe, P R; Hudson, J A Geoi Soc Am Special Paper N199, 1985, 37P
The geometry of joint patterns has been analysed and quantified by the use of conventional statistics, geostatistics and printed circuit board analogs. Biases in joint pattern studies are examined and probability theory and scanline techniques are used to minimise them. A means of estimating RQD from spacings histograms and formulae for estimating areal and volumetric joint densities from scanlines or borehole measurements are proposed. Spatial variability of joints is assessed geostatistically. A geostatistical theory for the analysis of joint patterns is developed and techniques for creating synthetic joint patterns, based on the characterisation methods, presented. Printed circuit board replicas of joint patterns are used to demonstrate how the interaction of joint patterns governs mass flow systems for rocks. These techniques are applied to an area of Niagara dolomite at Lannon, Wisconsin, USA.
Geology Tectonic processes See also." 855042 855066 Relaxation of the earth after a dip slip earthquake: dependence on rheology and geometry Lang, G; Vilotte, J P; Neugebauer, H J Phys Earth Planet Inter I:36, N3/4, Dec 1984, P260-275
Displacements of lithospheric plates after large dip slip earthquakes correspond to a purely elastic earth, whilst relaxation of deviatoric stress is by viscous processes. Surface deformation on stress relaxation can be measured. The effects of different geometries and rheologicai properties on surface deformation are modelled using the finite element method.
855067 Model of the lithosphece with a creep threshold stress Peters, R G Tectonophysics V l l l, N1/ 2, Jan 1985, P3-23
Gravity and bathymetry observations at the Emperor Seamounts are explained by introducing a model for creep of the lithosphere which includes a threshold stress, below which there is no deformation. Such a deformation mechanism has been demonstrated for metals and ceramics, although not for silicate ceramics at suitably low stress.
Environmental effects, weathering and soil forma, tion See also. 855010, 855043 855068 Field rainfall simulator studies on two clay soils of the Darling Downs, Queensland. IlL An evaluation of current methods for deriving soil erodibilities (K factors) Loch, R J Aust J Soil Res V22, N4, 1984, P40)-412
Soil erodibility factors for the Universal Soil Loss Equation (USLE) are often derived using simulated rainfall. The effects of plot size and erosion processes on K values measured in this way are considered and problems in calculation of K from rainfall simulator data, using the USLE, are highlighted. The procedures presently used do not account for erosion process/runoff rate interactions. It is concluded that single-event soil loss models may provide a means for producing better estimates of annual average soil losses, suitable for the calculation of K. 855O69 Scanning electron microscope study of bedrock microfractures
in granites underhigh arctic conditions Watts, S H Earth Surf Land Process VIO, N2, March-April 1985, P161172 Heavily weathered surface specimens of granite from Arctic Canada have been examined by scanning electron microscopy. Both salts and organic materials, which could enhance microfracturing, were seen in surface cracks. The importance of lithological parameters, environmental factors and organic activity on weathering are examined and it is concluded that it is unlikely that any one mechanism in isolation is the cause of bedrock breakdown. 855070 Origin and properties of glacial lill and diamictons Lutenegger, A J; Kemmis, T J; Hailberg, G R In: GeologieM Eneironment and Soil Properties (paper prepared in conjunction with the ASCE Geoteclmical Engineering Division and the ASCE Convention, Houston, Texas, 17-21 Oct 1983) P310-331. Publ New York." ASCE, 1983
Deposition by land based glaciers may be subglaciat, beneath the ice mass, or supraglacial, on or adjacent to the glacial ice. The deposits from the two processes differ significantly in texture, density and structure. Subglacial deposits are more uniform in texture and have a narrower range of matrix texture and composition than supraglacial till These primary qualities control important geotechnical properties. Differentiation of glacial deposits in this manner can be useful in site investigation and in evaluating material properties for design.