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Influence of sand drain length on consolidation of clay layer
353A 916177 Secondary compression of sabkha 'saline' soils Dhowian, A W
Engng Geol V30, N2, April 1991, P155-169 Sabkha soils are arid climate deposits of mainly loosely cemented sandy silt to silty clay particles. They contain appreciable organic content and are highly compressible. Secondary compression contributes significantly to settlement. Settlements predicted using conventional consolidation theory and the rheological model of Lo (1961) were compared to those measured on a sabkha deposit loaded by an instrumented test embankment. The Lo model provided a better estimate of rate of settlement than Terzaghi theory, and gave good prediction of magnitude of primary and secondary consolidation settlements.
916178 Analytical study of the cone penetration test in clay Teh, C I; Houlsby, G T
Geoteclmique V41, N1, March 1991, P17-34 An analysis is presented of quasi-static penetration of a cone penetrometer into clay, idealised as a homogeneous, elasticperfectly plastic (Von Mises) material. Soil displacement and stress changes around the cone are evaluated by the strain path method, with equilibrium corrections via large strain finite element analysis. Values of the cone factor are derived, and a parametric study of factors which influence it carried out. Consolidation around the cone is analysed using uncoupled Terzaghi-Rendulic theory and a finite difference scheme. A new interpretation method for piezocone consolidation data is suggested.
916179 Influence of the density of finite element networks on consolidation analysis. Technical note Suklje, L; Majes, B
Geoteclmique V41, N1, March 1991, P139-142 Re-examination of an earlier publication on consolidation of a layered soil deposit (Suklje and Majes, 1989) indicates that if too coarse a mesh is used in the finite element analysis, uncertainty results in the settlement-time curve in its lower part. It is suggested that each layer be discretized by a sufficiently dense network of finite elements to obtain reliable results. If such a requirement exceeds available computing power, the numerical analysis must be simplified according to the nature of the problem.
916180 Stress ratio effects on collapse of compacted clayey sand Lawton, E C; Fragaszy, R J; Hardcastle, J H
J Geotech Engng Div ASCE 11117, N5, May 1991, P714-730 A double-triaxiai test procedure has been developed to investigate weathering induced collapse potential of soils subjected to anisotropic stress states. Results from a slightly expansive clayey sand suggest volume strain resulting from a change in stress state or wetting is independent of principal total stress ratio but dependent on mean normal total stress. Individual components of axial and radial strain, however, are strongly influenced by stress ratio. For a given mean normal total stress, axial collapse increases and radial collapse decreases with increasing stress ratio.
916181 Compaction behavior of North Sea chalk in contact with seawater Rhett, D W Rock Mechanics Contributions and Cludlenges: Proc 31st US
Symposium, Golden, 18-20 June 1990 P695.702. Publ Rotterdam: A A Balkema, 1990 Uniaxial strain compression tests were carried out on Ekofisk field chalk to evaluate effects of seawater flooding on the compaction behaviour. Reservoir experience was simulated by maintaining axial ram pressure and decreasing pore pressure in stages, with equilibrating periods in between. Waterfloods were simulated by flowing heated artificial seawater or Tot Formation water. Control samples (formation brine/oil saturated) were first tested, then seawater flooding, then seawater/formation brine flooding. Influence of pore fluid chemistry on compaction is discussed. 916182 Collapse potential of compacted soil Huang, D; Nelson, J D; Sharma, S
Proc 1990 Annual Symposium on Geology and Geotechnical Engineering, Instrumentation and Computer Applications, Pocatello, 4-6 April 1990 P14.1-14.14. Publ Pocatello: Idaho State University, 1990 Oedometer tests were used to study the collapse potential of a compacted silty clay. Effects of moisture content, dry density, applied stress, and loading procedures were investigated. Collapse strain is proportional to log of applied stress. Total strain from consolidation and collapse is independent of consequences of loading or wetting or stress path, provided final stress condition is the same. Collapse strain decreased with increasing dry density and pre-wetting water content, but was effectively independent of loading procedure. Collapse strain can be minimised if remoulding is at slightly over optimum water content and compacted dry density at maximum. 916183 Influence of sand drain length on consolidation of clay layer Rao, N V R L N; Reddy, M G Proe Indian Geoteclmical Conference, 1989, Geotechniques of Problematic Soils and Rocks, Visakhapatnam, 14-16
December 1989 V1, P225-229. Publ New Delhi." Sarita Prakashan, 1989 The effect of sand drain length on consolidation of a clay layer is examined using a finite difference numerical approach. Penetration of 50, 70, and 100% into the clay layer and spacings of 0.4, 0.6, 0.8, and 1.0 layer thicknesses are considered for both single and double drainage conditions. Design charts and a worked example are presented. Partially penetrating drains are economically attractive. 916184 Coefficient of pressure at rest in Subapenninc blue clays in Matera (Southern Italy) Cherubini, C; Giasi, C I; Guadagno, F M
Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 I/2, P1163-1169. Publ Rotterdam: A A Balkema, 1990 The various expressions commonly used to calculate the coefficient of earth pressure at rest (Ko) are outlined. Laboratory tests were carried out on undisturbed samples of Subapennine blue clay. Values of Ko were measured in oedometer tests during loading and, where possible, unloading. The most widely used expressions for Ko are seen to be able to provide sufficiently accurate descriptions of change in pressure as a function of stress level.
© 1991 Pergamon Press plc. Reproduction not permitted
Engng Geol V30, N2, April 1991, P155-169 Sabkha soils are arid climate deposits of mainly loosely cemented sandy silt to silty clay particles. They contain appreciable organic content and are highly compressible. Secondary compression contributes significantly to settlement. Settlements predicted using conventional consolidation theory and the rheological model of Lo (1961) were compared to those measured on a sabkha deposit loaded by an instrumented test embankment. The Lo model provided a better estimate of rate of settlement than Terzaghi theory, and gave good prediction of magnitude of primary and secondary consolidation settlements.
916178 Analytical study of the cone penetration test in clay Teh, C I; Houlsby, G T
Geoteclmique V41, N1, March 1991, P17-34 An analysis is presented of quasi-static penetration of a cone penetrometer into clay, idealised as a homogeneous, elasticperfectly plastic (Von Mises) material. Soil displacement and stress changes around the cone are evaluated by the strain path method, with equilibrium corrections via large strain finite element analysis. Values of the cone factor are derived, and a parametric study of factors which influence it carried out. Consolidation around the cone is analysed using uncoupled Terzaghi-Rendulic theory and a finite difference scheme. A new interpretation method for piezocone consolidation data is suggested.
916179 Influence of the density of finite element networks on consolidation analysis. Technical note Suklje, L; Majes, B
Geoteclmique V41, N1, March 1991, P139-142 Re-examination of an earlier publication on consolidation of a layered soil deposit (Suklje and Majes, 1989) indicates that if too coarse a mesh is used in the finite element analysis, uncertainty results in the settlement-time curve in its lower part. It is suggested that each layer be discretized by a sufficiently dense network of finite elements to obtain reliable results. If such a requirement exceeds available computing power, the numerical analysis must be simplified according to the nature of the problem.
916180 Stress ratio effects on collapse of compacted clayey sand Lawton, E C; Fragaszy, R J; Hardcastle, J H
J Geotech Engng Div ASCE 11117, N5, May 1991, P714-730 A double-triaxiai test procedure has been developed to investigate weathering induced collapse potential of soils subjected to anisotropic stress states. Results from a slightly expansive clayey sand suggest volume strain resulting from a change in stress state or wetting is independent of principal total stress ratio but dependent on mean normal total stress. Individual components of axial and radial strain, however, are strongly influenced by stress ratio. For a given mean normal total stress, axial collapse increases and radial collapse decreases with increasing stress ratio.
916181 Compaction behavior of North Sea chalk in contact with seawater Rhett, D W Rock Mechanics Contributions and Cludlenges: Proc 31st US
Symposium, Golden, 18-20 June 1990 P695.702. Publ Rotterdam: A A Balkema, 1990 Uniaxial strain compression tests were carried out on Ekofisk field chalk to evaluate effects of seawater flooding on the compaction behaviour. Reservoir experience was simulated by maintaining axial ram pressure and decreasing pore pressure in stages, with equilibrating periods in between. Waterfloods were simulated by flowing heated artificial seawater or Tot Formation water. Control samples (formation brine/oil saturated) were first tested, then seawater flooding, then seawater/formation brine flooding. Influence of pore fluid chemistry on compaction is discussed. 916182 Collapse potential of compacted soil Huang, D; Nelson, J D; Sharma, S
Proc 1990 Annual Symposium on Geology and Geotechnical Engineering, Instrumentation and Computer Applications, Pocatello, 4-6 April 1990 P14.1-14.14. Publ Pocatello: Idaho State University, 1990 Oedometer tests were used to study the collapse potential of a compacted silty clay. Effects of moisture content, dry density, applied stress, and loading procedures were investigated. Collapse strain is proportional to log of applied stress. Total strain from consolidation and collapse is independent of consequences of loading or wetting or stress path, provided final stress condition is the same. Collapse strain decreased with increasing dry density and pre-wetting water content, but was effectively independent of loading procedure. Collapse strain can be minimised if remoulding is at slightly over optimum water content and compacted dry density at maximum. 916183 Influence of sand drain length on consolidation of clay layer Rao, N V R L N; Reddy, M G Proe Indian Geoteclmical Conference, 1989, Geotechniques of Problematic Soils and Rocks, Visakhapatnam, 14-16
December 1989 V1, P225-229. Publ New Delhi." Sarita Prakashan, 1989 The effect of sand drain length on consolidation of a clay layer is examined using a finite difference numerical approach. Penetration of 50, 70, and 100% into the clay layer and spacings of 0.4, 0.6, 0.8, and 1.0 layer thicknesses are considered for both single and double drainage conditions. Design charts and a worked example are presented. Partially penetrating drains are economically attractive. 916184 Coefficient of pressure at rest in Subapenninc blue clays in Matera (Southern Italy) Cherubini, C; Giasi, C I; Guadagno, F M
Proc 6th International Congress International Association of Engineering Geology, Amsterdam, 6-10 August 1990 I/2, P1163-1169. Publ Rotterdam: A A Balkema, 1990 The various expressions commonly used to calculate the coefficient of earth pressure at rest (Ko) are outlined. Laboratory tests were carried out on undisturbed samples of Subapennine blue clay. Values of Ko were measured in oedometer tests during loading and, where possible, unloading. The most widely used expressions for Ko are seen to be able to provide sufficiently accurate descriptions of change in pressure as a function of stress level.
© 1991 Pergamon Press plc. Reproduction not permitted