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Importance and use of SEM for the quality forecast of aggregates for rock-fill dams
161A derived from examination of thin sections. It correlates well with measured drillability and rock strength. It is suggested that the coefficient indicates resistance of the rock microstructure to crack propagation.
884O48 Importance and use of SEM for the quality forecast of aggregates for rock-fill dams Samalikova, M
Proc 5th International Congress International Association of Engineering Geology, Buenos Aires, 20-25 October 1986 V2. P1461-1467. Publ Rotterdam: A A Balkema. 1986 A laboratory program to predict the suitability of crystalline rock aggregates for rock fill is reported, with particular reference to forecasting weathering resistance. Microstructure is determined by scanning electron microscopy, and this, plus results of thermal analysis, thermogravimetric analysis, and Xray diffraction is correlated with mechanical properties. Potentially deleterious minerals are identified. Results for basalts and serpentinites are presented in the form of special tables.
Deformation and strength characteristics See also: 884197. 884335. 884343 884049 Influence of the hydraulic condition on the mechanical behaviour of a sand subject to cyclic Ioadings (In French) Gomcz-Correia, A; Livet, M Bull Liaison Labs Ponts Chaussees NI52. Nor-Dec 1987. PI7-28 Pore pressure in foundation soils affects strength and deformability. Many roads have deteriorated as a result of high foundation pore pressure. Cyclic loading tests simulating traffic loads were carried out on large cylindrical specimens of Fontainebleau sand. The influence of pore pressure, confining pressure and position of the phreatic surface on the development of permanent and reversible strains is investigated and discussed. 884050 Influence of the high porosity of a limestone on the stability of an underground quarry (In French) Denis, A; Durville, J L; Massieu, E; Thorin, R Bull Liaison Labs Ponts Chaussees NI52. Nor, Dec 1987. P69- 74 It was necessary to check the stability of the roof and pillars of the disused quarry before constructing an embankment overhead. The limestone had porosity in the range 28-46% with significant variations over short distances. Mechanical properties were also influenced by water content, and minimum saturated strengths were measured. It was necessary to take many samples and to take rock heterogeneity into account in analysis. The coarse detrital structure of the limestone is the cause of its variability. 884051 Undrained shear strength from piezocone tests Konrad, J M; Law. K T Can Geotech J V24. N3. Aug 1987, P392-405 Existing methods to interpret cone penetrometer tests are reviewed and a new method presented in which undrained shear strength is considered soley related to ultimate cavity expansion pressure, one of the components of tip resistance. The method is tested at 3 sites and gives results consistent with known soil behaviour.
8841)52 Field method for the determination of rock-mass modulus Lo, K Y; Yung. T C B; Lukajic, B Can Geotech J V24. N3. Aug 1987, P406,413 A new method to determine rock modulus is described in which diametric displacement due to in situ stress release is measured and used to calculate the modulus. The method is field tested and supplemented by laboratory tests to examine the effect of anisotropy and specimen size on rock modulus. The method yields a value consistent with previously measured values using extensometers. 884053 Analysis of progressive deformation of the Edmonton Convention Centre excavation Chan, D H; Morgenstern, N R Can Geotech J V24. N3, Aug 1987, P430-440 A strain-softening finite element analysis of deformations during excavation in shale layers with weak bentonite seams is described. Field observations indicate that a progressive failure type of mechanism directly caused by excavation is present, and confirm that the extent of shearing can be calculated by the finite element method. 884054 Use of critical state representations of sand in the method of stress characteristics: Note Jefferies, M G; Been, K Can Geotech J V24. N3, Aug 1987, P441-446 The limitations of critical state representations of sand behaviour are discussed and it is shown that stress dilatancy is an implicit part of a critical state framework. Dilatancy leads to underestimates of bearing capacity factors in the method of characteristics. Kinematic constraints and dilatancy are introduced into a stress characteristics approach while preserving critical state characterization of sand, using the method of associated fields. Auth. 884O55 Residual strength of smectite,-dominated soils from the Kamenose landslide in Japan: Note Gibo, S; Egashira, K; Ohtsubo, M Can Geoteeh J V24. N3. Aug 1987. P456-462 The ring shear test was used to measure residual strength of smectite-dominated soils, and the relation of residual strength to clay fraction content and clay particle orientation investigated. X-ray diffraction was used to determine orientation. Results indicate that orientation of smectite particles on the shear surface affects the residual strength. This is most clearly seen at low effective normal stress. 884O56 Suction-controlled triaxial testing: laboratory procedures in relation to resistance envelope methods. Short communication Anderson, M G; Kemp, M J Earth Surf Process Land VI2, N6. Not-Dec 1987. P649-654 In certain tropical slopes it appears possible that soil suction may play a significant role in maintaining stability. A laboratory suction-controlled triaxial test that can be undertaken to validate the threshold suction predicted by resistance envelope methods is outlined. It is shown that for two sites examined in St Lucia, West Indies, the results from such a test confirm results obtained by use of resistance envelopes. Auth.
1988 Pergamon Press plc. Reproduction not permitted
884O48 Importance and use of SEM for the quality forecast of aggregates for rock-fill dams Samalikova, M
Proc 5th International Congress International Association of Engineering Geology, Buenos Aires, 20-25 October 1986 V2. P1461-1467. Publ Rotterdam: A A Balkema. 1986 A laboratory program to predict the suitability of crystalline rock aggregates for rock fill is reported, with particular reference to forecasting weathering resistance. Microstructure is determined by scanning electron microscopy, and this, plus results of thermal analysis, thermogravimetric analysis, and Xray diffraction is correlated with mechanical properties. Potentially deleterious minerals are identified. Results for basalts and serpentinites are presented in the form of special tables.
Deformation and strength characteristics See also: 884197. 884335. 884343 884049 Influence of the hydraulic condition on the mechanical behaviour of a sand subject to cyclic Ioadings (In French) Gomcz-Correia, A; Livet, M Bull Liaison Labs Ponts Chaussees NI52. Nor-Dec 1987. PI7-28 Pore pressure in foundation soils affects strength and deformability. Many roads have deteriorated as a result of high foundation pore pressure. Cyclic loading tests simulating traffic loads were carried out on large cylindrical specimens of Fontainebleau sand. The influence of pore pressure, confining pressure and position of the phreatic surface on the development of permanent and reversible strains is investigated and discussed. 884050 Influence of the high porosity of a limestone on the stability of an underground quarry (In French) Denis, A; Durville, J L; Massieu, E; Thorin, R Bull Liaison Labs Ponts Chaussees NI52. Nor, Dec 1987. P69- 74 It was necessary to check the stability of the roof and pillars of the disused quarry before constructing an embankment overhead. The limestone had porosity in the range 28-46% with significant variations over short distances. Mechanical properties were also influenced by water content, and minimum saturated strengths were measured. It was necessary to take many samples and to take rock heterogeneity into account in analysis. The coarse detrital structure of the limestone is the cause of its variability. 884051 Undrained shear strength from piezocone tests Konrad, J M; Law. K T Can Geotech J V24. N3. Aug 1987, P392-405 Existing methods to interpret cone penetrometer tests are reviewed and a new method presented in which undrained shear strength is considered soley related to ultimate cavity expansion pressure, one of the components of tip resistance. The method is tested at 3 sites and gives results consistent with known soil behaviour.
8841)52 Field method for the determination of rock-mass modulus Lo, K Y; Yung. T C B; Lukajic, B Can Geotech J V24. N3. Aug 1987, P406,413 A new method to determine rock modulus is described in which diametric displacement due to in situ stress release is measured and used to calculate the modulus. The method is field tested and supplemented by laboratory tests to examine the effect of anisotropy and specimen size on rock modulus. The method yields a value consistent with previously measured values using extensometers. 884053 Analysis of progressive deformation of the Edmonton Convention Centre excavation Chan, D H; Morgenstern, N R Can Geotech J V24. N3, Aug 1987, P430-440 A strain-softening finite element analysis of deformations during excavation in shale layers with weak bentonite seams is described. Field observations indicate that a progressive failure type of mechanism directly caused by excavation is present, and confirm that the extent of shearing can be calculated by the finite element method. 884054 Use of critical state representations of sand in the method of stress characteristics: Note Jefferies, M G; Been, K Can Geotech J V24. N3, Aug 1987, P441-446 The limitations of critical state representations of sand behaviour are discussed and it is shown that stress dilatancy is an implicit part of a critical state framework. Dilatancy leads to underestimates of bearing capacity factors in the method of characteristics. Kinematic constraints and dilatancy are introduced into a stress characteristics approach while preserving critical state characterization of sand, using the method of associated fields. Auth. 884O55 Residual strength of smectite,-dominated soils from the Kamenose landslide in Japan: Note Gibo, S; Egashira, K; Ohtsubo, M Can Geoteeh J V24. N3. Aug 1987. P456-462 The ring shear test was used to measure residual strength of smectite-dominated soils, and the relation of residual strength to clay fraction content and clay particle orientation investigated. X-ray diffraction was used to determine orientation. Results indicate that orientation of smectite particles on the shear surface affects the residual strength. This is most clearly seen at low effective normal stress. 884O56 Suction-controlled triaxial testing: laboratory procedures in relation to resistance envelope methods. Short communication Anderson, M G; Kemp, M J Earth Surf Process Land VI2, N6. Not-Dec 1987. P649-654 In certain tropical slopes it appears possible that soil suction may play a significant role in maintaining stability. A laboratory suction-controlled triaxial test that can be undertaken to validate the threshold suction predicted by resistance envelope methods is outlined. It is shown that for two sites examined in St Lucia, West Indies, the results from such a test confirm results obtained by use of resistance envelopes. Auth.
1988 Pergamon Press plc. Reproduction not permitted