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Soil improvement by dynamic consolidation. Short communication
15A
Compressibility, swelling and consolidation See also: 901203, 901271, 901287, 901304, 901305 901111
Secondary compression of the silty clay adjacent to the Swan River Wagner, S; Cray, A Aust Geomech N17, June 1989, P17-19 The Narrows Interchange was constructed on reclaimed land. Surcharging techniques were used to eliminate primary consolidation and some secondary consolidation. Postconstruction settlement was by secondary consolidation. The coefficient of secondary compression measured by laboratory testing soil samples was initially thought to be high, but subsequent back analysis of settlements has indicated the value was realistic. 901112 Strength and volume change behaviour of a sand-bentonite mixture Graham, J; Saadat, F; Gray, M N; Dixon, D A; Zhang, Q Y Can Geotech J V26. N2, May 1989. P292-30S
Triaxial and one dimensional swelling tests were carried out on a compacted sand-bentonite mixture, a potential buffer material for radioactive waste repositories. It expands at low pressure, volume increase being dependent on time and confining pressures up to about 0.aMPa, when swelling becomes inhibited. Strength corresponds to that of the bentonite fraction. The material is dilatant to about 0.8MPa, compressive at higher stress. Effect of stress level on normalized bulk and tangent shear moduli is discussed. A critical state model is suggested for the material. 901113 Compaction due to a cyclic force acting in the inside of a sandy subsoil Sawicki, A; Sliwinski, P Comput Geotech V7. N3, 1989. P223-237
Compaction caused by internal cyclic loading of a sandy subsoil, for instance from reactions to loading imposed by a cyclically stressed anchor or vibroflotation, is analysed. The fundamentals of the compaction theory are presented and the method of analysis illustrated for vertical and horizontal loading. Results of small scale experiments are compared to predictions of the analysis. Practical implications are discussed. 901114 Virtual work derivation of the Biot consolidation finite element formulation Ding, D; Naylor, D J Engng Comput [/6, ?/2, June 1989, P158-162
A derivation for the finite element equations of consolidation by the principle of virtual work and virtual complementary work is presented. This provides a simple alternative to derivation by variational principles or the Laplace transform. The equations are rearranged into a form suitable for time stepping for nonlinear applications. Auth 901115 Soil improvement by dynamic consolidation. Short communication Dayal, U Indian Geotech J VI8, N3, July 1988, P289-297
A case study is presented of the use of dynamic consolidation to reduce liquefaction potential and future surface settlement at a site whose upper 20m consisted of fine sand hydraulic fill,
upper silt, lower silty sand, and lower silt and sand. Change in soil properties was measured by SPT and cone and Menard pressuremeter tests. Relations between applied energy and resulting settlement are illustrated. Improvements in the soil properties of the various layers are described. Settlement and bearing capacity capability before and after compaction are analysed.
901116 One-dimensional Lagrangian consolidation. Technical note McVay, M C; Townsend, F C; Bloomquist, D G J Geoteeli Engng Die ASCE V115, N6, June 1989, P893-898
The general one dimensional large deformation consolidation equation, developed from the theory of mixtures, is modified and presented in a completely Lagrangian form. It is formulated solely in terms of a material reference system, rather than in terms of material and spatial coordinates.
901117 Reservoir aspects of Ekofisk subsidence Sulak, R M; Danielsen, J J Pet Teclmol V41. NT. July 1989, P709-716
Subsidence of the seabed overlying the Ekofisk oil reservoirs is the result of compaction of the porous chalk reservoirs and transmission of this compaction upwards through the overburden to the sea floor. The compaction is the result of pore pressure depletion, largely due to plastic deformation (pore collapse) of the high porosity chalk. Compaction has resulted in pressure maintenance of the reservoirs, with no productivity loss to date.
901118 Rock mechanics of the Ekofisk reservoir in the evaluation of subsidence Johnson, J P; Rhett, D W; Slemers, W T J Pet Teclmol V41. N7, July 1989, P717-722
Ekofisk rocks were subject to uniaxial and hydrostatic compaction tests and creep tests in the laboratory under simulated reservoir conditions. Mineralogy and porosity were examined using SEM and X-ray analyses. Two trend lines of behaviour were found, which related to lower Ekofisk/Tor formation rocks and upper Ekofisk rocks. Pore collapse is the major mechanism of compaction, and magnitude is related to porosity and quartz content. Time dependent behaviour and the effect of waterflooding on rock strength were also examined.
901119 Forecasting of Ekofisk reservoir compaction and subsidence by numerical simulation Boade, R R; Chin, L Y; Slemers, W T J Pet Teclmol V41, N7, July 1989, P723-726
3D finite element analysis using the DYNAFLOW code was used to simulate reservoir compaction and seabed subsidence progress in the Ekofisk field. Laboratory uniaxial, hydrostatic and triaxial data were used in the analysis. Results are presented for selected management options. Good agreement is seen between calculated results and observed subsidence magnitudes, rates, and profiles.
© 1990 Pergamon Press plc. Reproduction not permitted
Compressibility, swelling and consolidation See also: 901203, 901271, 901287, 901304, 901305 901111
Secondary compression of the silty clay adjacent to the Swan River Wagner, S; Cray, A Aust Geomech N17, June 1989, P17-19 The Narrows Interchange was constructed on reclaimed land. Surcharging techniques were used to eliminate primary consolidation and some secondary consolidation. Postconstruction settlement was by secondary consolidation. The coefficient of secondary compression measured by laboratory testing soil samples was initially thought to be high, but subsequent back analysis of settlements has indicated the value was realistic. 901112 Strength and volume change behaviour of a sand-bentonite mixture Graham, J; Saadat, F; Gray, M N; Dixon, D A; Zhang, Q Y Can Geotech J V26. N2, May 1989. P292-30S
Triaxial and one dimensional swelling tests were carried out on a compacted sand-bentonite mixture, a potential buffer material for radioactive waste repositories. It expands at low pressure, volume increase being dependent on time and confining pressures up to about 0.aMPa, when swelling becomes inhibited. Strength corresponds to that of the bentonite fraction. The material is dilatant to about 0.8MPa, compressive at higher stress. Effect of stress level on normalized bulk and tangent shear moduli is discussed. A critical state model is suggested for the material. 901113 Compaction due to a cyclic force acting in the inside of a sandy subsoil Sawicki, A; Sliwinski, P Comput Geotech V7. N3, 1989. P223-237
Compaction caused by internal cyclic loading of a sandy subsoil, for instance from reactions to loading imposed by a cyclically stressed anchor or vibroflotation, is analysed. The fundamentals of the compaction theory are presented and the method of analysis illustrated for vertical and horizontal loading. Results of small scale experiments are compared to predictions of the analysis. Practical implications are discussed. 901114 Virtual work derivation of the Biot consolidation finite element formulation Ding, D; Naylor, D J Engng Comput [/6, ?/2, June 1989, P158-162
A derivation for the finite element equations of consolidation by the principle of virtual work and virtual complementary work is presented. This provides a simple alternative to derivation by variational principles or the Laplace transform. The equations are rearranged into a form suitable for time stepping for nonlinear applications. Auth 901115 Soil improvement by dynamic consolidation. Short communication Dayal, U Indian Geotech J VI8, N3, July 1988, P289-297
A case study is presented of the use of dynamic consolidation to reduce liquefaction potential and future surface settlement at a site whose upper 20m consisted of fine sand hydraulic fill,
upper silt, lower silty sand, and lower silt and sand. Change in soil properties was measured by SPT and cone and Menard pressuremeter tests. Relations between applied energy and resulting settlement are illustrated. Improvements in the soil properties of the various layers are described. Settlement and bearing capacity capability before and after compaction are analysed.
901116 One-dimensional Lagrangian consolidation. Technical note McVay, M C; Townsend, F C; Bloomquist, D G J Geoteeli Engng Die ASCE V115, N6, June 1989, P893-898
The general one dimensional large deformation consolidation equation, developed from the theory of mixtures, is modified and presented in a completely Lagrangian form. It is formulated solely in terms of a material reference system, rather than in terms of material and spatial coordinates.
901117 Reservoir aspects of Ekofisk subsidence Sulak, R M; Danielsen, J J Pet Teclmol V41. NT. July 1989, P709-716
Subsidence of the seabed overlying the Ekofisk oil reservoirs is the result of compaction of the porous chalk reservoirs and transmission of this compaction upwards through the overburden to the sea floor. The compaction is the result of pore pressure depletion, largely due to plastic deformation (pore collapse) of the high porosity chalk. Compaction has resulted in pressure maintenance of the reservoirs, with no productivity loss to date.
901118 Rock mechanics of the Ekofisk reservoir in the evaluation of subsidence Johnson, J P; Rhett, D W; Slemers, W T J Pet Teclmol V41. N7, July 1989, P717-722
Ekofisk rocks were subject to uniaxial and hydrostatic compaction tests and creep tests in the laboratory under simulated reservoir conditions. Mineralogy and porosity were examined using SEM and X-ray analyses. Two trend lines of behaviour were found, which related to lower Ekofisk/Tor formation rocks and upper Ekofisk rocks. Pore collapse is the major mechanism of compaction, and magnitude is related to porosity and quartz content. Time dependent behaviour and the effect of waterflooding on rock strength were also examined.
901119 Forecasting of Ekofisk reservoir compaction and subsidence by numerical simulation Boade, R R; Chin, L Y; Slemers, W T J Pet Teclmol V41, N7, July 1989, P723-726
3D finite element analysis using the DYNAFLOW code was used to simulate reservoir compaction and seabed subsidence progress in the Ekofisk field. Laboratory uniaxial, hydrostatic and triaxial data were used in the analysis. Results are presented for selected management options. Good agreement is seen between calculated results and observed subsidence magnitudes, rates, and profiles.
© 1990 Pergamon Press plc. Reproduction not permitted