Analysis of geotextile reinforced embankments over soft clays

Analysis of geotextile reinforced embankments over soft clays

201A Dams and embankments See also: 865083 865245 Elastoplastic study of the behaviour of a railway bed and its foundation by finite element analysi...

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201A

Dams and embankments See also: 865083

865245 Elastoplastic study of the behaviour of a railway bed and its foundation by finite element analysis (In French) Profillidis, V A; Humbert, P Bull Liaison Lab Ponts Chaussees NI41, Jan-Feb 1986, P1319 A three dimensional finite element model has been made of a railway embankment, which takes into account the elastoplastic behaviour of the base, subbase and subgrade (ballast, gravel and sand). Influences of base and subbase thickness and the mechanical characteristics of the subgrade have been studied. Calculated settlements have been compared with those from a full scale embankment, and the model duly adjusted.

865246 Great Yarmouth bridge abutment uses polystyrene as lightweight fill Ground Engng VI9, NI, Jan 1986. P20-23 The first use of polystyrene as a fill in a road construction project in Britain is at a bridge site in Great Yarmouth. Site investigation and the bypass embankment design are noted. The combination of restricted contact period and other constraints prevented sufficient preloading of the site of the north abutment of this railway bridge. The ground had not been loaded by the Former railway, and without preloading the vertical scttlemcnt and associated lateral loads imposed by conventional backfill materials would have proved unacceptable. The most practical solution was to employ lightweight fill materials for forming the 7m high embankment, principally extruded polystyrene. Styrofoam, a rigid foam board with a closed cell structure was used.

865247 Plastic foam in road embankments Aaboe, R Ground Engng vIg, NI, Jan 1986, P30-31 The use of expanded polystyrene in the form of blocks For road fills is briefly reviewed. It is of most use under extremely difficult subsoil conditions where other lightweight materials, which are relatively much heavier, would not provide sufficient stability. Case histories, material properties and the cost of this fill material are examined.

865248 Analysis of geotextile reinforced embankments over soft clays Ingold, T S Highways Transp V33. N3, March 1986, P3-8 It is now possible to construct embankments on soft foundation soils without having to use flat sided slopes or staged construction, if a basal layer of geotextile is used to enhance short term stability and maintain embankment integrity until the foundation soil consolidates sufficiently to support the embankment. A parametric study of embankments over soft ground is made and design methods and philosophy illustrated. An analytical method is introduced where the time dependent gain in Foundation soil strength is offset against the time dependent loss in geotextile tensile strength and stiffness.

865249 Environmental approach to coal refuse disposal Sciulli, A G; Ballock, G P; Wu, K K Min Engng V38, N3, March 1986, P181-186 Common environmental problems associated with coal refuse disposal are discussed. Design concepts to minimize potential hazards are suggested. Discussion focuses on site selection, embankment design and construction, site preparation, facility operation, abandonment and reclamation. Measures that should be adopted in the design phases and during construction of the facility are noted. Recommendations concerning special problems, including seepage, water contamination and mine sealing are made.

865250 Centrifuge modelling of embankments on clay foundations Davies, M C R; Parry, R H G Soils Found V25, 84, Dee 1985, P19-36 The performance of low embankments on soft clay foundations, during and after construction, was studied using centrifuge models. Sand embankments on a foundation of normally consolidated clay overlain by overconsolidated soil were used. in one test the embankment collapsed soon after construction. It was possible to study the progressive failure and to record pore pressures, strains and the development of the slip surface in the instrumented embankment. Total and effective stress analyses of the stability were assessed. Greater embankment heights were achieved on the same foundation using staged construction. Pore pressures were seen to rise following the end of construction, largely due to pore pressure spreading. During consolidation maximum horizontal displacements at the toe were proportional to ccntrelinc settlements.

865251 Shallow slips in highway embankments constructed of overconsolidated clay Greenwood, J R: Holt, D A; Hcrrick, G W Proc Symposium on Failures in Earthworks, London, 6-7 March 1985 P79-92. Publ London: Thomas Tel~brd, 1985 Highway embankments in overconsolidated clay are liable to shallow slope failure some years after construction. The extent of the problem is examined, and probable failure mechanisms and the effects of various soil,slope design and drainage parameters are discussed. Field trials of different repair methods on a failed embankment in Gault clay are described. The use of geogrids is seen as an economical alternative to the conventional excavation and granular replacement method. Comments are made on future design of embankments in overconsolidated clay.

865252 Performance of embankments and cuttings in Gault Clay in Kent Garrett, C; Wale, J H Proc Symposium on Failures in Earthworks, London, 6-7 March 1985 P93-111. Publ London: Thomas Telford, 1985 Parts of the M20, M25 and M26 motorways in Kent, UK, run along an outcrop of Gault clay, notorious for its swelling/shrinkage behaviour. Near-surface layers have, additionally, been deleteriously affected by periglacial action. Past practice with this material was studied, and investigations into its properties and behaviour were carried out. By using appropriate full scale trials and methods of analysis, technically and economically sound earthworks designs were developed, which have been validated in construction and in service.

:~ 1986 Pergamon Journals Ltd. Reproduction not permitted