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Effectiveness of forced dewatering in soft clay improvement
283A 915141 Deformation analysis of a reclaimed marine foundation subjected to land construction Mimura, M; Shibata, T; Nozu, M; Kitazawa, M S& Found V30. N4. Dee 1990. P119-133 Where large artificial islands are constructed, long term deformation of deep foundation deposits must be taken into account, as well as deformation and stability of near surface layers. Elasto-viscoplastic finite element simulation of coupled stress-flow response of a marine foundation to reclamation is presented. Lateral displacements and settlements are evaluated. A stable process of deformation and stress state is seen during revetment construction and reclamation. Compression of the upper layers is the dominant contributor to settlement. Predictions correspond well to behaviour observed at Koshien Island, Japan.
915142 Field tests of vertical band drains Wei, J; Chua, C H; Chong, M K Proc 2nd International Conference on Foundations and TnnneLv,London, 19-21 Seprember 1989 VI, P383-391. Pub1 Edinburgh: Engineering Technics Press, 1989 Full scale loading tests were carried out on soft clay in 3 pits excavated in the Old Alluvium formation in Singapore. PVC band drains were installed in 2 pits, but using differently shaped mandrels. Field values of coefficient of consolidation are back analysed. Effects on drain efficiency from natural folding during consolidation and lateral deformation due to slip failure are discussed. Effects of installation and well resistance are quantified.
915143 JXBkiency of vertical drainage systems for ground improvement in a very soft clay Almeida, M S S; Lacerda, W A; Ferreira, C S; Terra,BRCSSR Roe 2nd Internarionaf Conference on Foundations and Tunnels, London, 19-21 September 1989 VI. P393-398. Pub1 Edinburgh: Engineering Technics Press, 1989 Performance of various drain types was assessed in an embankment of very soft clays. Five test sections used sand or prefabricated drains, two were undrained. Settlement data were backanalysed to evaluate coefficients of consolidation, which were compared to those from piezocone dissipation tests. Rates of settlement were used to assess drain efficiency.
915144 Efieetiveaea~ of forced dewatering in soft clay improvement Kotera, H; Sakemi, T; Matsui, T Proc 2nd International Conference on FounaWions and Tunnel, London, 19-21 September 1989 VI, P399-406. Pub1 Edinburgh: Engineering Technics Press, 1989 The combined forced dewatering method, using deep wells, vertical drains, and surcharging, was applied to deep, soft alluvial soils in the Tokyo Bay area of Japan. Results demonstrate the efficiency of the treatment in promoting consolidation and strength increase of the soft clay soils. Some parts of the groundwater level lowering can be regarded as the equivalent drainage surcharge. 0
915145 Retaining wall movements due to expansive slag backfill Neely, W J; Weber, H; Jew, C G K Proc 2nd ln~ernationaf Conference on Foundarions and Tunnels, London, 19-21 September 1989 V2, P35-42. PubI Edinburgh: Engineering Technics Press, 1989 A scale pit at a steelworks was constructed in weathered shale using soldier piles and blast furnace slag as backfill. Wall movements over 4 years exceeded 80mm. No correlation was seen with the seasons, and attention was focused on the backfill, which was found to be expansive on hydration. Concrete struts were used for economic, nondisruptive remedial measures. The need to check the backfill closely (chemical analysis and autoclave testing) to ensure inertness before construction is emphasised. 915146 Collapse behaviour of a dry compacted embankment (In French) Delage, P Proc 12th international Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 VI. P587-588. Pub1 Rotterdam: A A Balkema, 1989 Behaviour of a bridge access embankment, constructed using a residual schist with the granulometry of a silty sand, is described. The material was compacted too dry and with insufficient densification. Sudden settlements soon after completion, which led to excessive surface displacements, have been identified as resulting from collapse of the soil following rainfall and rise of water table. 915147 Finite element method approach for collapsing soils Miranda, A N; Van Zyl, D Proc 12th Zn~ernationalConference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 VI, P625-628. Pub1 Rotterdam: A A Balkema. 1989 The constitutive model for unsaturated soils of Fredlund (1979) which includes the effects of the changes in the independent variables described by differences between total stress and pore-air pressure and pore-air pressure and pore-water pressure is introduced. It is incorporated into the finite element code UNSTRUCT (Miranda, 1988) to analyse the behaviour of small earth dams of collapsible soil during their first filling. 915148 Restrained rebound of saturated clay Musso, S Proc 12th In~ernotionuf Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 VI, P629-633. Pub1 Rotterdam: A A Balkema, 1989 Expansive soils in the field are generally restrained from rebounding on wetting. Similar restrictions are found when measuring their swelling pressures in the laboratory. Swell pressure growth under complete inundation is analysed. Different types of restraint imposed by stress measurement devices are considered. A mathematical model is developed, based on Terzaghi’s consolidation theory, which produces an equation for pore pressure which can be solved by the perturbation method. Pore pressure and strain isochrones and the pressure-time function are evaluated for various values of restraint factor, corresponding to geometric and mechanical properties of the specimen and deformability of the measuring device.
1991 Pergamon Press plc. Reproduction
not permitted
915142 Field tests of vertical band drains Wei, J; Chua, C H; Chong, M K Proc 2nd International Conference on Foundations and TnnneLv,London, 19-21 Seprember 1989 VI, P383-391. Pub1 Edinburgh: Engineering Technics Press, 1989 Full scale loading tests were carried out on soft clay in 3 pits excavated in the Old Alluvium formation in Singapore. PVC band drains were installed in 2 pits, but using differently shaped mandrels. Field values of coefficient of consolidation are back analysed. Effects on drain efficiency from natural folding during consolidation and lateral deformation due to slip failure are discussed. Effects of installation and well resistance are quantified.
915143 JXBkiency of vertical drainage systems for ground improvement in a very soft clay Almeida, M S S; Lacerda, W A; Ferreira, C S; Terra,BRCSSR Roe 2nd Internarionaf Conference on Foundations and Tunnels, London, 19-21 September 1989 VI. P393-398. Pub1 Edinburgh: Engineering Technics Press, 1989 Performance of various drain types was assessed in an embankment of very soft clays. Five test sections used sand or prefabricated drains, two were undrained. Settlement data were backanalysed to evaluate coefficients of consolidation, which were compared to those from piezocone dissipation tests. Rates of settlement were used to assess drain efficiency.
915144 Efieetiveaea~ of forced dewatering in soft clay improvement Kotera, H; Sakemi, T; Matsui, T Proc 2nd International Conference on FounaWions and Tunnel, London, 19-21 September 1989 VI, P399-406. Pub1 Edinburgh: Engineering Technics Press, 1989 The combined forced dewatering method, using deep wells, vertical drains, and surcharging, was applied to deep, soft alluvial soils in the Tokyo Bay area of Japan. Results demonstrate the efficiency of the treatment in promoting consolidation and strength increase of the soft clay soils. Some parts of the groundwater level lowering can be regarded as the equivalent drainage surcharge. 0
915145 Retaining wall movements due to expansive slag backfill Neely, W J; Weber, H; Jew, C G K Proc 2nd ln~ernationaf Conference on Foundarions and Tunnels, London, 19-21 September 1989 V2, P35-42. PubI Edinburgh: Engineering Technics Press, 1989 A scale pit at a steelworks was constructed in weathered shale using soldier piles and blast furnace slag as backfill. Wall movements over 4 years exceeded 80mm. No correlation was seen with the seasons, and attention was focused on the backfill, which was found to be expansive on hydration. Concrete struts were used for economic, nondisruptive remedial measures. The need to check the backfill closely (chemical analysis and autoclave testing) to ensure inertness before construction is emphasised. 915146 Collapse behaviour of a dry compacted embankment (In French) Delage, P Proc 12th international Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 VI. P587-588. Pub1 Rotterdam: A A Balkema, 1989 Behaviour of a bridge access embankment, constructed using a residual schist with the granulometry of a silty sand, is described. The material was compacted too dry and with insufficient densification. Sudden settlements soon after completion, which led to excessive surface displacements, have been identified as resulting from collapse of the soil following rainfall and rise of water table. 915147 Finite element method approach for collapsing soils Miranda, A N; Van Zyl, D Proc 12th Zn~ernationalConference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 VI, P625-628. Pub1 Rotterdam: A A Balkema. 1989 The constitutive model for unsaturated soils of Fredlund (1979) which includes the effects of the changes in the independent variables described by differences between total stress and pore-air pressure and pore-air pressure and pore-water pressure is introduced. It is incorporated into the finite element code UNSTRUCT (Miranda, 1988) to analyse the behaviour of small earth dams of collapsible soil during their first filling. 915148 Restrained rebound of saturated clay Musso, S Proc 12th In~ernotionuf Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13-18 August 1989 VI, P629-633. Pub1 Rotterdam: A A Balkema, 1989 Expansive soils in the field are generally restrained from rebounding on wetting. Similar restrictions are found when measuring their swelling pressures in the laboratory. Swell pressure growth under complete inundation is analysed. Different types of restraint imposed by stress measurement devices are considered. A mathematical model is developed, based on Terzaghi’s consolidation theory, which produces an equation for pore pressure which can be solved by the perturbation method. Pore pressure and strain isochrones and the pressure-time function are evaluated for various values of restraint factor, corresponding to geometric and mechanical properties of the specimen and deformability of the measuring device.
1991 Pergamon Press plc. Reproduction
not permitted