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The influence of the clay component in loess on collapse of the soil structure
PROPERTIES:DEFORMATION & STRENGTH 964051 Consideration of the possible contributions of m o r p h o u s phases to the sensitivity of glaciomarine clays S. P. Bentley & A. J. Roberts, in: Genesis and properties of
collapsible soils. Proc. workshop, Loughborough, 1994, ed E. Derbyshire & others, (Kluwer; NATO ASI Series C, 468), 1995, pp 225-245. New evidence obtained using state-of-the-art microscopy indicates that amorphous coatings may very well be a real and common phenomenon in many sensitive days. The paper reports these new findings and reviews the existing knowledge base on amorphous phases. A model for sensitivity is developed which unites the possible contributions of amorphous phases with the classical leaching theory of sensitivity. (from Authors) 964052 The influence of the clay component in loess on collapse of the soil structure T. W. Mellors, in: Genesis and properties of collapsible soils. Proc. workshop, Loughborough, 1994, ed E. Derbyshire & others, (Kluwer; NATO ASI Series C, 468), 1995, pp 207216. In tests, air-dry samples were flooded with different fluids whilst under load in order to investigate the influence of the clay fraction within the soils on the collapse process. Not only did the various fluids influence the amount of collapse that occurred on flooding but also the compressibility of the soil structure for subsequent load application post-flooding. The results indicate that the collapse phenomenon occurs through micro-sbearing at the intergranular contacts and is influenced by the clay component in the soils. An explanation of the phenomenon is presented in terms of a modified effective stress equation. (from Author) 964053 The Slovak Carpathians loess sediments, their fabric and properties A. Klukanova & J. Frankovska, in: Genesis and properties of
collapsible soils. Proc. workshop, Loughborough, 1994, ed E. Derbyshire & others, (Kluwer; NATO ASI Series C, 468), 1995, pp 129-147. It appears that the loess mass is composed of various primary rock fragments and minerals, products of their secondary changes and different organic substances. Four basic groups of loess sediments have been characterized. These are: typical loess, sandy loess, clayey loess and loess-like sediments. The results of the laboratory investigations of stress strain behaviour of collapsible loess under two types of triaxial tests are presented and analysed. (from Authors)
Deformation and strength characteristics 964054 An evaluation of the petrophysical and mechanical properflea of reconstruction rocks used in the Sphinx and the arehneologleal sites of the EI-Gemmalia area, Cairo, Egypt H. A. Ibrahim & G. M. E. Kamh, Environmental & Engineering Geoscience, 1(3), 1995, pp 371-375. This article deals with the petrophysical properties (such as effective porosity, bulk density or specific gravity, porosity, water absorption percentage, and rate of water absorption), and the mechanical properties (unconfined compressive strength) of rock samples taken from limestone used for casing the lower parts of the Sphinx, as well as the Islamic archaeological sites at the EI-Gammalia area. This study ahns to evaluate the durability of these limestone rocks, which mainly come from eastern and western limestone plateaux bordering the Nile Valley at Cairo (Tura, Helwan, Pyramid, EI-Matarya, and EI-Marg quarries), used for reconstruction purposes. (Authors)
155A
964O55 New peak sheur strength criteria for animtropic reck joints P. H. S. W. Kulatilake, G. Shou, T. H. Huang & R. M. Morgan, International Journal of Rock Mechanics & Mining Sciences, 32(7), 1995, pp 673-697. In general, roughness profiles of rock joints consist of nonstationary and stationary components. At the simplest level, only one parameter is sufficient to quantify non-stationary joint roughness. The average inclination angle I, along with the direction considered for the joint surface, is suggested to capture the non-stationary roughness. Most of the natural rock joint surface profiles do not belong to the self similar fractal category, but may be modelled by self-aft'me fractals. Using a new term called specific length, it is shown that even though the fraetal dimension D is a useful parameter, it alone is insufficient to quantify the stationary roughness of non-self shnilar profiles. Four new strength criteria are suggested for modelling the ani~otropic peak shear strength of rock joints at low normal effective stress. (from Authors) 964O56 A study of the behaviour of brittle rocks under plane strain and trlaxial loading conditioas M. Yumlu & M. U. Ozbay, International Journal of Rock Mechanics & Mining Sciences, 32(7), 1995, pp 725-733. Identifies the differences in rock behaviour characteristics when tested under plane strain and txiaxial loading conditions. A brief description of the test rig developed for plane strain testing is given. Results from tests on coal, sandstone, norite and quartzite specimens, both under plane strain and triaxial loading conditions are presented. The differences between the results from the plane strain and triaxial tests are interpreted in terms of Vermecr and de Borst strain softening constitutive model as used in the computer program FLAC. (from Authors) 964O57 Physical mechanisms of hard rock fragmentation under mechanical loading: a review L. L. Mishnaevsky Jr, International Journal of Rock Mechanics & Mining Sciences, 32(8), 1995, pp 763-766. The review here seeks to collect the available data in the area of physical mechanisms of rock fragmentation and to determine the problems which are to be solved as well as to establish contradictory results. Investigations published in Russian are also reviewed. (from Author) 964O58 Analysis of Berkovich indentation P.-L. Larsson, A. E. Giannakopoulos, E. Soderlund, D. J. Rowcliffe & R. Vestergaard, International Journal of Solids & Structures, 33(2), 1996, pp 221-248. The Berkovich indentation test is analysed numerically, using the finite element method, and experimentally. The results derived are pertinent to indentation of elastic materials and metals and include universal formulae for the load-indentation depth relation and the hardness, as well as a detailed study of the mechanical fields involved at loading and unloading. Large strain elastic and elastoplastic results are compared with small strain ones and similarities, as well as differences, are discussed in some detail. Special attention is given to a comparison between the characteristics of Berkorich indentation and the Vickers hardness test. (from Authors) 964O59 Laboratory measurements of a complete set of poroelastie modufl for Berea sandstone and Indiana limestone D. J. Hart & H. F. Wang, Journal of Geophysical Research, I00019), 1995, pp 17,741-17,751. Measurements have been completed for poroelastic moduli as a function of confining pressure and pore pressure. For Indiana limestone, best fit values were drained bulk modulus, 21.2 GPa; the undrained bulk modulus, 31.7 GPa; drained Poisson's ratio, 0.26; undrained Poisson's ratio, 0.33; and
collapsible soils. Proc. workshop, Loughborough, 1994, ed E. Derbyshire & others, (Kluwer; NATO ASI Series C, 468), 1995, pp 225-245. New evidence obtained using state-of-the-art microscopy indicates that amorphous coatings may very well be a real and common phenomenon in many sensitive days. The paper reports these new findings and reviews the existing knowledge base on amorphous phases. A model for sensitivity is developed which unites the possible contributions of amorphous phases with the classical leaching theory of sensitivity. (from Authors) 964052 The influence of the clay component in loess on collapse of the soil structure T. W. Mellors, in: Genesis and properties of collapsible soils. Proc. workshop, Loughborough, 1994, ed E. Derbyshire & others, (Kluwer; NATO ASI Series C, 468), 1995, pp 207216. In tests, air-dry samples were flooded with different fluids whilst under load in order to investigate the influence of the clay fraction within the soils on the collapse process. Not only did the various fluids influence the amount of collapse that occurred on flooding but also the compressibility of the soil structure for subsequent load application post-flooding. The results indicate that the collapse phenomenon occurs through micro-sbearing at the intergranular contacts and is influenced by the clay component in the soils. An explanation of the phenomenon is presented in terms of a modified effective stress equation. (from Author) 964053 The Slovak Carpathians loess sediments, their fabric and properties A. Klukanova & J. Frankovska, in: Genesis and properties of
collapsible soils. Proc. workshop, Loughborough, 1994, ed E. Derbyshire & others, (Kluwer; NATO ASI Series C, 468), 1995, pp 129-147. It appears that the loess mass is composed of various primary rock fragments and minerals, products of their secondary changes and different organic substances. Four basic groups of loess sediments have been characterized. These are: typical loess, sandy loess, clayey loess and loess-like sediments. The results of the laboratory investigations of stress strain behaviour of collapsible loess under two types of triaxial tests are presented and analysed. (from Authors)
Deformation and strength characteristics 964054 An evaluation of the petrophysical and mechanical properflea of reconstruction rocks used in the Sphinx and the arehneologleal sites of the EI-Gemmalia area, Cairo, Egypt H. A. Ibrahim & G. M. E. Kamh, Environmental & Engineering Geoscience, 1(3), 1995, pp 371-375. This article deals with the petrophysical properties (such as effective porosity, bulk density or specific gravity, porosity, water absorption percentage, and rate of water absorption), and the mechanical properties (unconfined compressive strength) of rock samples taken from limestone used for casing the lower parts of the Sphinx, as well as the Islamic archaeological sites at the EI-Gammalia area. This study ahns to evaluate the durability of these limestone rocks, which mainly come from eastern and western limestone plateaux bordering the Nile Valley at Cairo (Tura, Helwan, Pyramid, EI-Matarya, and EI-Marg quarries), used for reconstruction purposes. (Authors)
155A
964O55 New peak sheur strength criteria for animtropic reck joints P. H. S. W. Kulatilake, G. Shou, T. H. Huang & R. M. Morgan, International Journal of Rock Mechanics & Mining Sciences, 32(7), 1995, pp 673-697. In general, roughness profiles of rock joints consist of nonstationary and stationary components. At the simplest level, only one parameter is sufficient to quantify non-stationary joint roughness. The average inclination angle I, along with the direction considered for the joint surface, is suggested to capture the non-stationary roughness. Most of the natural rock joint surface profiles do not belong to the self similar fractal category, but may be modelled by self-aft'me fractals. Using a new term called specific length, it is shown that even though the fraetal dimension D is a useful parameter, it alone is insufficient to quantify the stationary roughness of non-self shnilar profiles. Four new strength criteria are suggested for modelling the ani~otropic peak shear strength of rock joints at low normal effective stress. (from Authors) 964O56 A study of the behaviour of brittle rocks under plane strain and trlaxial loading conditioas M. Yumlu & M. U. Ozbay, International Journal of Rock Mechanics & Mining Sciences, 32(7), 1995, pp 725-733. Identifies the differences in rock behaviour characteristics when tested under plane strain and txiaxial loading conditions. A brief description of the test rig developed for plane strain testing is given. Results from tests on coal, sandstone, norite and quartzite specimens, both under plane strain and triaxial loading conditions are presented. The differences between the results from the plane strain and triaxial tests are interpreted in terms of Vermecr and de Borst strain softening constitutive model as used in the computer program FLAC. (from Authors) 964O57 Physical mechanisms of hard rock fragmentation under mechanical loading: a review L. L. Mishnaevsky Jr, International Journal of Rock Mechanics & Mining Sciences, 32(8), 1995, pp 763-766. The review here seeks to collect the available data in the area of physical mechanisms of rock fragmentation and to determine the problems which are to be solved as well as to establish contradictory results. Investigations published in Russian are also reviewed. (from Author) 964O58 Analysis of Berkovich indentation P.-L. Larsson, A. E. Giannakopoulos, E. Soderlund, D. J. Rowcliffe & R. Vestergaard, International Journal of Solids & Structures, 33(2), 1996, pp 221-248. The Berkovich indentation test is analysed numerically, using the finite element method, and experimentally. The results derived are pertinent to indentation of elastic materials and metals and include universal formulae for the load-indentation depth relation and the hardness, as well as a detailed study of the mechanical fields involved at loading and unloading. Large strain elastic and elastoplastic results are compared with small strain ones and similarities, as well as differences, are discussed in some detail. Special attention is given to a comparison between the characteristics of Berkorich indentation and the Vickers hardness test. (from Authors) 964O59 Laboratory measurements of a complete set of poroelastie modufl for Berea sandstone and Indiana limestone D. J. Hart & H. F. Wang, Journal of Geophysical Research, I00019), 1995, pp 17,741-17,751. Measurements have been completed for poroelastic moduli as a function of confining pressure and pore pressure. For Indiana limestone, best fit values were drained bulk modulus, 21.2 GPa; the undrained bulk modulus, 31.7 GPa; drained Poisson's ratio, 0.26; undrained Poisson's ratio, 0.33; and