The instrumentation, construction, and field performance of a full-scale geotextile reinforced test embankment constructed on a soft compressible soil is presented. A relatively high-strength polyester woven geotextile was used as reinforcement. The construction sequence, the observed pore pressure response, and the vertical and horizontal displacements are reported. The development and propagation of cracks in relation to the construction sequence and the manner in which the embankment failed are described. The field data suggest that the shear strength of the foundation soil was mobilized at a fill thickness between 5 and 5.7 m. However, due to the stabilizing effect of the geotextile reinforcement, the embankment did not fail until the geotextile reached its ultimate tensile strength and tore when the fill thickness reached 8.2 m. The failure of the embankment was of a viscoplastic nature and although additional fill could be placed after failure of the geotextile and embankment at 8.2 m, no additional gain in the net height (i.e., relative to the surrounding area) could be maintained above the maximum of 6.6 m recorded when the fill thickness reached 8.2 m. Key words : embankment, geotextile reinforcement, field behaviour, stability, deformations, pore pressures.

No abstract

The ultimate lateral resistance and the lateral deflection at working loads of rigid vertical walls and piles with a free head subjected to horizontal load and embedded in two-layered soils of sand and clay have been investigated. Part 1 deals with the behaviour of rigid walls, and the analyses are compared with the results of model wall tests in layered soils. Part 2 treats the behaviour of rigid piles, and the analyses are compared with the results of model tests on piles and pile groups in layered soils and some field case records.

Arching theory predicts a significant reduction in earth pressures behind retaining walls of narrow backfill width. An extensive series of centrifuge tests has been performed to evaluate the use of flexible subminiature pressure cells in the centrifuge environment and their subsequent use to measure lateral earth pressures behind retaining walls of narrow backfill width. Although the flexible earth pressure cells exhibit hysteresis and nonlinear calibration behaviour, the extensive calibration studies indicate that stiff diaphragm type earth pressure cells may be used with replicate models to measure earth pressures. Measurements of lateral pressures acting on the unyielding model retaining walls show good agreement with Janssen's arching theory. Tests on backfills bounded by vertical planes of dissimilar frictional characteristics indicate arching theory with an average interface friction angle provides a reasonable estimate of lateral earth pressures.Key words: fascia retaining walls, silos, earth pressures, pressure cells, centrifuge modelling.

No abstract