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Loess soils: engineering practice in Argentina
149A 903147 New basis for earthwork specification for clay soil Thevanayagam, S; Agrawal, G; AhschaeflL A G
J Geotecb Engng Div ASCE VII5. Nil, Not" 1989, P15991616 Field data were collected from test embankments and ongoing construction. The most important parameter in achieving optimum in-service behaviour was seen to be water content of the lift at time of compaction. Flow charts are presented for the design engineering option, where parameters are known and compaction procedures can be specified, and for the quality assurance option, where parameters of the compacted product are established from inspection testing results. Design charts are presented which relate water content to various field parameters. 903148 Clay waste pond reclamation by sand/clay mix or capping Townsend, F C; McVay, M C; BIoomquist, D G; McClimans, S A
J Geotech Engng Di~ ASCE VII5. Nil, Not" 1989, P16471666 Clay slurries from phosphate benefication require many years of self-weight consolidation before the reclamation stage is reached. Speeding this process by sand/clay (s/c) mixing or capping has been studied using closed form analytical methods and centrifuge model tests. The s/c mix method disposes of sand tailings and increases consolidation rate by increasing density and permeability. Capping applies a greater effective stress than s/c mixing, but cannot be used for very wet slurries. Staged sand capping, s/c mix capping and s/c mixing were, in decreasing order, effective in reducing reclamation time. 903149 Determination of the deformation characteristics of thawing permafrost soils in the construction of the Urengoiskii Gres complex Ponomarev, V D; Maksimenko, E S; Fedoseev, Y G
Soil Mech Found Engng ~ 6 , NI, Jan-Feb 1989. P10-13
903151 Relationship between the fabric characteristics and collapsibility of loess Lei, X Y Proc International Conference on Engineering Problems of Regional Soils, Beifing, 11-15 August 1988 P264-268. Publ Beijing: International Academic Publishers, 1989 Loess samples from many areas of China were examined to determine porosity, pore size distribution, microstructure, and coefficient of collapse. Collapsible soils were characterised by over 40% of total void volume being made up of large and medium pores, throat radius above 0.004mm. Soils with supporting macropore weak-cementation or macropore semicementation type fabrics as dominant structure tended to subside on wetting, with low initial collapse pressures.
903152 Loess soils: engineering practice in Argentina Moll, L L; Roeca, R J; Terzariol, R E Proc International Conference on Engineering Problems of Regional Soils, Beijing, 11-15 August 1988 P283-289. Publ Beijing: International Academic Publishers. 1989 Argentinian loess soils are macroporous formations largely derived from pyroclastic deposits. They may be classified as truly or conditionally collapsible, depending on their collapsibility. They have high erosion potential due to defloccu!ation of their particles. Foundation design measures include deep piles through loess layers, belled piles, and cement-soil piles. Care is taken to prevent possible wetting due to failure of utilities during seismic events. Erosion and piping are minimised by surface drainage. Hydraulic structures have been constructed using heavy tamping or explosive consolidation or soil stabilisation.
903153 Design methods for prediction of loess subsident deformation Mustafayev, A A; Alleva, L A
Proc International Conference on Engineerinh, Problems of Regional Soils, Beijing, !1-15 August 1988 P289-294. Publ Bering: International Academic Publishers. 1989
Effect of thaw on stratified sandy and clay soils was studied. Heaters were installed at 6m spacings and settlement at various depths monitored during thaw. Compression tests were carried out in the laboratory. Results will be used to predict settlement behaviour at the site where significant heat will be generated during construction and operation. Calculated settlements based on laboratory results were larger than those observed. The sandy soils were virtually incompressible with thawing, the clays highly compressible.
Formulae have been developed to predict settlement of loess soils in the natural and foundation loaded states when wetted. Stress state, initial and saturated water contents, permeability. density and depth are all taken into account. Time dependency of subsidence and its final value can be evaluated.
903150 Dredged fill performance: South Biakely Island Poindexter, M E; Walker, J E
903154 Study on pre-consolidation pressure of loess Niu, Z R; Qui, Y H Proc International Conference on Engineering Problems of
Proc Conference on Hydraalic Fill Structures. Fort Collins, 15-18 April 1988 P676-692. Publ New York: ASCE. 1988 (Geoteclmical Special Publication No 21) South Blakely Island is a dyked disposal facility for dredged materials. Progressive trenching has been successfully used to dewater the site. Settlement data are limited, so a predictive program was used. Primary Consolidation and Desiccation of Dredged Fill (PCDDF) uses finite difference analysis to solve the governing equation of finite strain consolidation theory, and includes the capability to consider desiccation of the dredged material surface. P C D D F was also used to evaluate storage capacity and determine remaining disposal life.
Regional Soils, Beijing. 11-15 August 1988 P295-298. Publ Beijing: [mernational Academic Publishers. 1989 The consolidation mechanism of loess soils is different from that of normal soils, as some cementation occurs. The preconsolidation pressure evaluated by the Casagrande OCR criterion will be erroneous. In this case,the Under Density Ratio (UDR) rule of Dcnisov should be applied. The Casagrande method can, however, be applied if completely remoulded loess samples are used, when the solidification effect is destroyed. Water content also affects measured preconsolidation pressure. Evaluation should generally be made at normal site water contents.
1990 Pergamon Press plc. Reproduction not permitted
J Geotecb Engng Div ASCE VII5. Nil, Not" 1989, P15991616 Field data were collected from test embankments and ongoing construction. The most important parameter in achieving optimum in-service behaviour was seen to be water content of the lift at time of compaction. Flow charts are presented for the design engineering option, where parameters are known and compaction procedures can be specified, and for the quality assurance option, where parameters of the compacted product are established from inspection testing results. Design charts are presented which relate water content to various field parameters. 903148 Clay waste pond reclamation by sand/clay mix or capping Townsend, F C; McVay, M C; BIoomquist, D G; McClimans, S A
J Geotech Engng Di~ ASCE VII5. Nil, Not" 1989, P16471666 Clay slurries from phosphate benefication require many years of self-weight consolidation before the reclamation stage is reached. Speeding this process by sand/clay (s/c) mixing or capping has been studied using closed form analytical methods and centrifuge model tests. The s/c mix method disposes of sand tailings and increases consolidation rate by increasing density and permeability. Capping applies a greater effective stress than s/c mixing, but cannot be used for very wet slurries. Staged sand capping, s/c mix capping and s/c mixing were, in decreasing order, effective in reducing reclamation time. 903149 Determination of the deformation characteristics of thawing permafrost soils in the construction of the Urengoiskii Gres complex Ponomarev, V D; Maksimenko, E S; Fedoseev, Y G
Soil Mech Found Engng ~ 6 , NI, Jan-Feb 1989. P10-13
903151 Relationship between the fabric characteristics and collapsibility of loess Lei, X Y Proc International Conference on Engineering Problems of Regional Soils, Beifing, 11-15 August 1988 P264-268. Publ Beijing: International Academic Publishers, 1989 Loess samples from many areas of China were examined to determine porosity, pore size distribution, microstructure, and coefficient of collapse. Collapsible soils were characterised by over 40% of total void volume being made up of large and medium pores, throat radius above 0.004mm. Soils with supporting macropore weak-cementation or macropore semicementation type fabrics as dominant structure tended to subside on wetting, with low initial collapse pressures.
903152 Loess soils: engineering practice in Argentina Moll, L L; Roeca, R J; Terzariol, R E Proc International Conference on Engineering Problems of Regional Soils, Beijing, 11-15 August 1988 P283-289. Publ Beijing: International Academic Publishers. 1989 Argentinian loess soils are macroporous formations largely derived from pyroclastic deposits. They may be classified as truly or conditionally collapsible, depending on their collapsibility. They have high erosion potential due to defloccu!ation of their particles. Foundation design measures include deep piles through loess layers, belled piles, and cement-soil piles. Care is taken to prevent possible wetting due to failure of utilities during seismic events. Erosion and piping are minimised by surface drainage. Hydraulic structures have been constructed using heavy tamping or explosive consolidation or soil stabilisation.
903153 Design methods for prediction of loess subsident deformation Mustafayev, A A; Alleva, L A
Proc International Conference on Engineerinh, Problems of Regional Soils, Beijing, !1-15 August 1988 P289-294. Publ Bering: International Academic Publishers. 1989
Effect of thaw on stratified sandy and clay soils was studied. Heaters were installed at 6m spacings and settlement at various depths monitored during thaw. Compression tests were carried out in the laboratory. Results will be used to predict settlement behaviour at the site where significant heat will be generated during construction and operation. Calculated settlements based on laboratory results were larger than those observed. The sandy soils were virtually incompressible with thawing, the clays highly compressible.
Formulae have been developed to predict settlement of loess soils in the natural and foundation loaded states when wetted. Stress state, initial and saturated water contents, permeability. density and depth are all taken into account. Time dependency of subsidence and its final value can be evaluated.
903150 Dredged fill performance: South Biakely Island Poindexter, M E; Walker, J E
903154 Study on pre-consolidation pressure of loess Niu, Z R; Qui, Y H Proc International Conference on Engineering Problems of
Proc Conference on Hydraalic Fill Structures. Fort Collins, 15-18 April 1988 P676-692. Publ New York: ASCE. 1988 (Geoteclmical Special Publication No 21) South Blakely Island is a dyked disposal facility for dredged materials. Progressive trenching has been successfully used to dewater the site. Settlement data are limited, so a predictive program was used. Primary Consolidation and Desiccation of Dredged Fill (PCDDF) uses finite difference analysis to solve the governing equation of finite strain consolidation theory, and includes the capability to consider desiccation of the dredged material surface. P C D D F was also used to evaluate storage capacity and determine remaining disposal life.
Regional Soils, Beijing. 11-15 August 1988 P295-298. Publ Beijing: [mernational Academic Publishers. 1989 The consolidation mechanism of loess soils is different from that of normal soils, as some cementation occurs. The preconsolidation pressure evaluated by the Casagrande OCR criterion will be erroneous. In this case,the Under Density Ratio (UDR) rule of Dcnisov should be applied. The Casagrande method can, however, be applied if completely remoulded loess samples are used, when the solidification effect is destroyed. Water content also affects measured preconsolidation pressure. Evaluation should generally be made at normal site water contents.
1990 Pergamon Press plc. Reproduction not permitted