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Finite element studies of an embankment on soft ground
248A Virginia. Foundation drains specified in construction drawings could not be located, and drainage system improvements were made to reduce potential uplift pressure. To increase the effective weight of the dam, 75 anchors were installed into the underlying Birmingham shale. Loading tests were over specified periods to evaluate creep behaviour of the shale. A variety of anchor installation methods was used. 914386 Use of geotextiles in the James Bay hydroelectric project Lafleur, J; Pare, J J Geotext Geomem VIO, N1, 1991, P35-52 Geotextiles were used in the project as filters between rockfill shells and morainic impervious cores of temporary cofferdams, and as separators in permanent works to impede penetration of coarse rockfill shell materials dumped directly on finer morainic foundations. They were used in large quantities because of their ease of application and the scarcity of suitable granular materials. It was necessary to specify materials which would not fail by punching by large angular stones. Where better bedding surfaces were available on rolled embankments, lower weight fabrics were used. 914387 A259 Littlehampton bypass embankment construction with vertical drains Anandan, J; Piercy, J Highways Transp 1/38, N2, Feb 1991. PIO-15 The Littlehampton bypass, where it runs alongside the river Arun, will be on extremely soft alluvial clay and silt foundations. To reduce the construction time for the 6m high embankment, enhanced drainage to speed consolidation was chosen. Vertical wick drains in a lm grid pattern, and a lm thick drainage blanket on geotextile at the foundation embankment base interface were used. Staged construction with ground movement monitoring was employed. 914388 Finite element studies of an embankment on soft ground Pickles, A R; Woods, R I Proc 3rd International Syraposium on Numer&al Models in Geomechanics (NUMOG I!1), Niagara Falls, 8-11 May 1989 P628-635. Publ London." Elsevier Applied Science. 1989 A 2km long, 10.3m high embankment was constructed in London Docklands on a general soil profile of 8m of made ground and alluvial silt and peat over London Clay. Piezometers, inclinometers, and extensometers were installed at 3 points to monitor ground movements and pore pressures. Laboratory tests confirmed the suitability of a modified Cam Clay model to describe the alluvium. This was then used in the finite element code CRISP, which implements critical state soil mechanics. Predictions agree well with field measurements.
Hydraulic structures 914389 Cellular sheet-pile floodwall Taylor, R E; Meadows, D F Civ Engng, N Y V61. N1, Jan 1991. P58-60 The Tug Fork River valley in West Virginia and Kentucky has been flooded 37 times this century. About 90% of the valley has slope greater than 12%,over half is steeper than 35%. River banks are unstable and land use intensive. The site has about 20m of alluvium over bedrock. A conventional fiat-base T structure would have required destruction of an unacceptable number of riverfront buildings, and over 20 types of alternative flood control structures were assessed. A circular,
cellular sheet pile wall with drainage was selected. Modification of classical design methods, which assume granular fill, was necessary during construction. 914390 Geotextiles in coastal engineering practice Dembicki, E; Niespodzinska, L Geotext Geomem VIO. N2, 1991. P147-159 Coastal protection structures in Poland use geotextiles both as a filter and as a separator. Flow regime may be unidirectional and steady when used for backfill entrainment behind structures, or variable when used under front line coastal reinforcement. Specification of geotextiles according to the properties of soils met is considered. Laboratory tests to evaluate mechanical and biological resistance of the materials to be used are described.
Slopes See also." 914123, 914282, 914295 914391 Factors controlling debris avalanche initiation Buchanan, P; Savigny, K W Can Geotech J ti27, N5, Oct 1990, P659-675 Debris torrents occurring during a 1983 storm in the Smith Creek basin, Washington, have been studied. Four classes of avalanche are recognised: wedges, discontinuity surfaces, logging roads, and drainage channels. Geometry, soil conditions, and modelled water tables were used in limit equilibrium stability analysis to back calculate root cohesion at failure. Four groups of root cohesion are proposed and correlated with vegetation type. Most likely failure surfaces were calculated and compared to those seen. Effects of soil matrix suction and root cohesion on soil shear strength are discussed. The information gained is applied to a prior event. Direct field modelling and measurement is required for confirmation of this work. 914392 Application of distinct element analysis to three simple block models aimed at practical application to toppling failure of fissured rock slopes. Technical note lshida, T Comput Geoteeh V9, N4, 1990, P341-353 A series of tests was carried out to examine the accuracy and characteristics of the District Element Method, which uses nondeformable elements. Results of DEM simulation and physical model tests are compared for failure of simple block models of 10 blocks in a pillar, 4 blocks in a mass, and toppling of blocks on a stepped base. The DEM is indicated to be a good numerical method for application to toppling failure of fissured rock slopes. 914393 Stability of fabric reinforced cohesive soil slopes Sawicki, A; Lesniewska, D Geotext Geomem VIO. N2, 1991, P125-146 An analysis of reinforced cohesive soil slopes is presented within the framework of the rigid-plastic thffbry of reinforced earth. The basic equations of the theory are solved using the method of characteristics. Bearing capacity of the slope and location and shape of the failure surface are evaluated. Various sets of initial conditions are applied in order to study the influence of particular parameters on overall stability. The approach is rigorous from the viewpoint of limit plasticity and provides a framework within which discussion of other methods is possible.
1991 Pergamon Press plc. Reproduction not permitted
Hydraulic structures 914389 Cellular sheet-pile floodwall Taylor, R E; Meadows, D F Civ Engng, N Y V61. N1, Jan 1991. P58-60 The Tug Fork River valley in West Virginia and Kentucky has been flooded 37 times this century. About 90% of the valley has slope greater than 12%,over half is steeper than 35%. River banks are unstable and land use intensive. The site has about 20m of alluvium over bedrock. A conventional fiat-base T structure would have required destruction of an unacceptable number of riverfront buildings, and over 20 types of alternative flood control structures were assessed. A circular,
cellular sheet pile wall with drainage was selected. Modification of classical design methods, which assume granular fill, was necessary during construction. 914390 Geotextiles in coastal engineering practice Dembicki, E; Niespodzinska, L Geotext Geomem VIO. N2, 1991. P147-159 Coastal protection structures in Poland use geotextiles both as a filter and as a separator. Flow regime may be unidirectional and steady when used for backfill entrainment behind structures, or variable when used under front line coastal reinforcement. Specification of geotextiles according to the properties of soils met is considered. Laboratory tests to evaluate mechanical and biological resistance of the materials to be used are described.
Slopes See also." 914123, 914282, 914295 914391 Factors controlling debris avalanche initiation Buchanan, P; Savigny, K W Can Geotech J ti27, N5, Oct 1990, P659-675 Debris torrents occurring during a 1983 storm in the Smith Creek basin, Washington, have been studied. Four classes of avalanche are recognised: wedges, discontinuity surfaces, logging roads, and drainage channels. Geometry, soil conditions, and modelled water tables were used in limit equilibrium stability analysis to back calculate root cohesion at failure. Four groups of root cohesion are proposed and correlated with vegetation type. Most likely failure surfaces were calculated and compared to those seen. Effects of soil matrix suction and root cohesion on soil shear strength are discussed. The information gained is applied to a prior event. Direct field modelling and measurement is required for confirmation of this work. 914392 Application of distinct element analysis to three simple block models aimed at practical application to toppling failure of fissured rock slopes. Technical note lshida, T Comput Geoteeh V9, N4, 1990, P341-353 A series of tests was carried out to examine the accuracy and characteristics of the District Element Method, which uses nondeformable elements. Results of DEM simulation and physical model tests are compared for failure of simple block models of 10 blocks in a pillar, 4 blocks in a mass, and toppling of blocks on a stepped base. The DEM is indicated to be a good numerical method for application to toppling failure of fissured rock slopes. 914393 Stability of fabric reinforced cohesive soil slopes Sawicki, A; Lesniewska, D Geotext Geomem VIO. N2, 1991, P125-146 An analysis of reinforced cohesive soil slopes is presented within the framework of the rigid-plastic thffbry of reinforced earth. The basic equations of the theory are solved using the method of characteristics. Bearing capacity of the slope and location and shape of the failure surface are evaluated. Various sets of initial conditions are applied in order to study the influence of particular parameters on overall stability. The approach is rigorous from the viewpoint of limit plasticity and provides a framework within which discussion of other methods is possible.
1991 Pergamon Press plc. Reproduction not permitted