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Laboratory investigation of earth walls simultaneously reinforced by strips and random reinforcement
142A 893286 Appraisal of the test grouting data for the Tehri dam, India Shome, S K; Kumar. V; Gupta. U P int Assoe Engng Geol Bull N38, Oct 1988, P127-132 Test grouting was undertaken in the 3 rock units (grade I, II and III phyllites) of the project area through inclined boreholes at various depths to determine groutability of the rock and optimum spacing of the grout holes. As water loss in boreholes was found to be due mainly to fracture permeability, the discontinuity pattern was analysed in detail to determine optimum orientation of the grout holes. When permeability values of 1 lugeon were obtained after grouting, optimum grouting efficiency had been achieved. Effective grout travel distance was 0.75m.
893290 Laboratory investigation of earth walls simultaneously reinforced by strips and random reinforcement Arenicz. R M: Chowdhury, R N Geotech Test J VI1, N4, Dec 1988, P241-247 Shear strength of a backfill material influences performance of reinforced earth structures and may be enhanced by random reinforcement. Laboratory tests on model walls were used to analyse the effect of several types of random reinforcement on strength of a beach sand. 5 types of reinforcement were tested, and a sixth test undertaken with no reinforcement. Random reinforcement increased the soil strength by up to 13% by enhancing the effective friction angle under conditions of bond failure.
893287 Polymer silicate grouts for stabilizing deformed foundations and soils Sokolovich, V E; Zhilkina, T A Soil Mech Found Engng V25. NI, Jan-Feb 1988, PI-4
893291 Geotextiles in India Mandal, J N Geotext Geomem V6, N4. 1987, P253-274
For remedial stabilisation, cement grouts may be used only if cracks are large, epoxy grouts require predried concrete and high injection pressure,while carbamide resins are adversely affected by calcium carbonate in the concrete. New grouts based on silicates with isocyanate hardeners have been developed to overcome these problems. Their chemistry is described, and strength properties and hardening characteristics illustrated and compared to other grouts. Some examples of use of silicate grouts in alkaline ground are described.
Geotextiles are widely used to improve ground bearing capacity, for erosion control, filter protection, drainage, and soil reinforcement. Manufacture, development of applications, and available types of geotextiles are examined. Their performance for reinforcement and filtration is discussed, and economic comparison is made between geotextiles and other more conventional, cheaper reinforcing elements. Their applications in India are described. The potential for wider use of natural geotextiles, which are considerably cheaper than synthetics, is assessed.
893288 RF grout system for improving sandy soils Shah, D L; Shroff, A V Proc Eighth Asian Regional Conference on Soil Mechanics and Foundation Engineering, Kyoto, 20-24 July 1987 VI, P205-208. Publ Japan." Japanese Society for Soil Mechanics and Foundation Enghwering, 1987 Recorsinal-Formaldehyde resin grouts produce irreversible and insoluble gels and have controlled gel times. A program to develop an optimum grout mix for injection into fine sandy soils is described. Shear rate-shear strength-time and viscositytime relations were determined for a variety of resin mixtures with both acid and basic catalysts. Stress strain relations of grouted soils were also determined. The interaction and bonding between the gel and soil were studied using IR spectroscopy and scanning electron microscopy.
Reinforced earth
893292 Laboratory determination of clay-geotextile interaction Fourie, A B; Fabian, K J Geotext Geomem V6, N4, 1987, P275-294 Current specifications preclude the use of cohesive fill with metallic or geotextile reinforcement because of volume change potential and inherent low strength of cohesive soils. Undrained and drained shear box and pullout tests on a silty clay were used to estimate potential of woven and nonwoven geotextile reinforced cohesive fill for use when granular fill is not available. Results show shear strength of clay can be improved in both drained and undrained loading. Pullout resistance is proportional to normal stress for high transmissivity textiles and dependent on tensile properties of the textile. Low transmissivity fabrics do not develop high pullout resistance under undrained testing.
893289 Erosion control with geotextiles Civ Engng, London Oct 1988, P34-36
893293 Influence of soil reinforcement on the behaviour of a strip footing Elamin, A M; Cousens, T W; Mackey, R D Proc lnt Conference on Foundations and Tunnels, London, 2426 March 1987 V2, P61-67. Publ Edinburgh: Engineering Technics Press, 1987
Recent publications by CIRIA and PIANC are briefly summarised. Geotextile reinforcement and geotextile filters for revetments are discussed. The geotextile characteristics must be chosen to match the soil, and it must interact with the soil by friction and interpenetration and conform to local soil profiles. For fine sands and silts which are prone to particle motion below the geotextile, multilayer textiles with a lower zone of coarse fibres which interact with the surface of the soil to produce a high friction coefficient are suggested.
Model tests were conducted to investigate the major factors thought to affect the behaviour of reinforced foundations. The plane strain model used was a sand foundation reinforced with atuminium foil and loaded by means of a strip footing. Initial fill density was varied. The tests show that improvements due to reinforcement are a function of reinforcement length, depth to the uppermost layer of reinforcement, the number of layers and the spacing between the layers, and are dependent on stress levels.
See also: 893227, 893336
1989 Pergamon Press plc. Reproduction not permitted
893290 Laboratory investigation of earth walls simultaneously reinforced by strips and random reinforcement Arenicz. R M: Chowdhury, R N Geotech Test J VI1, N4, Dec 1988, P241-247 Shear strength of a backfill material influences performance of reinforced earth structures and may be enhanced by random reinforcement. Laboratory tests on model walls were used to analyse the effect of several types of random reinforcement on strength of a beach sand. 5 types of reinforcement were tested, and a sixth test undertaken with no reinforcement. Random reinforcement increased the soil strength by up to 13% by enhancing the effective friction angle under conditions of bond failure.
893287 Polymer silicate grouts for stabilizing deformed foundations and soils Sokolovich, V E; Zhilkina, T A Soil Mech Found Engng V25. NI, Jan-Feb 1988, PI-4
893291 Geotextiles in India Mandal, J N Geotext Geomem V6, N4. 1987, P253-274
For remedial stabilisation, cement grouts may be used only if cracks are large, epoxy grouts require predried concrete and high injection pressure,while carbamide resins are adversely affected by calcium carbonate in the concrete. New grouts based on silicates with isocyanate hardeners have been developed to overcome these problems. Their chemistry is described, and strength properties and hardening characteristics illustrated and compared to other grouts. Some examples of use of silicate grouts in alkaline ground are described.
Geotextiles are widely used to improve ground bearing capacity, for erosion control, filter protection, drainage, and soil reinforcement. Manufacture, development of applications, and available types of geotextiles are examined. Their performance for reinforcement and filtration is discussed, and economic comparison is made between geotextiles and other more conventional, cheaper reinforcing elements. Their applications in India are described. The potential for wider use of natural geotextiles, which are considerably cheaper than synthetics, is assessed.
893288 RF grout system for improving sandy soils Shah, D L; Shroff, A V Proc Eighth Asian Regional Conference on Soil Mechanics and Foundation Engineering, Kyoto, 20-24 July 1987 VI, P205-208. Publ Japan." Japanese Society for Soil Mechanics and Foundation Enghwering, 1987 Recorsinal-Formaldehyde resin grouts produce irreversible and insoluble gels and have controlled gel times. A program to develop an optimum grout mix for injection into fine sandy soils is described. Shear rate-shear strength-time and viscositytime relations were determined for a variety of resin mixtures with both acid and basic catalysts. Stress strain relations of grouted soils were also determined. The interaction and bonding between the gel and soil were studied using IR spectroscopy and scanning electron microscopy.
Reinforced earth
893292 Laboratory determination of clay-geotextile interaction Fourie, A B; Fabian, K J Geotext Geomem V6, N4, 1987, P275-294 Current specifications preclude the use of cohesive fill with metallic or geotextile reinforcement because of volume change potential and inherent low strength of cohesive soils. Undrained and drained shear box and pullout tests on a silty clay were used to estimate potential of woven and nonwoven geotextile reinforced cohesive fill for use when granular fill is not available. Results show shear strength of clay can be improved in both drained and undrained loading. Pullout resistance is proportional to normal stress for high transmissivity textiles and dependent on tensile properties of the textile. Low transmissivity fabrics do not develop high pullout resistance under undrained testing.
893289 Erosion control with geotextiles Civ Engng, London Oct 1988, P34-36
893293 Influence of soil reinforcement on the behaviour of a strip footing Elamin, A M; Cousens, T W; Mackey, R D Proc lnt Conference on Foundations and Tunnels, London, 2426 March 1987 V2, P61-67. Publ Edinburgh: Engineering Technics Press, 1987
Recent publications by CIRIA and PIANC are briefly summarised. Geotextile reinforcement and geotextile filters for revetments are discussed. The geotextile characteristics must be chosen to match the soil, and it must interact with the soil by friction and interpenetration and conform to local soil profiles. For fine sands and silts which are prone to particle motion below the geotextile, multilayer textiles with a lower zone of coarse fibres which interact with the surface of the soil to produce a high friction coefficient are suggested.
Model tests were conducted to investigate the major factors thought to affect the behaviour of reinforced foundations. The plane strain model used was a sand foundation reinforced with atuminium foil and loaded by means of a strip footing. Initial fill density was varied. The tests show that improvements due to reinforcement are a function of reinforcement length, depth to the uppermost layer of reinforcement, the number of layers and the spacing between the layers, and are dependent on stress levels.
See also: 893227, 893336
1989 Pergamon Press plc. Reproduction not permitted