ISSN:
1432-0495
Keywords:
Key words Fill dike
;
Laminated soft ground
;
Staged construction
;
Monitoring
;
Pore-water pressure
;
Settlement
;
Consolidation rate
;
Stability
;
Undrained and drained analysis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
Notes:
Abstract An instrumented trial-fill dike was constructed on soft, laminated soils of the Lisan Peninsula foreshore of the Dead Sea. The earthwork had base dimensions of 180 m by approximately 70 m wide and was raised in two stages to a maximum height of 12.5 m above original ground level. The geotechnical data of the dike were monitored in order to: assess the short- and long-term strength of the foundation, obtain and analyze the pore-pressure response of the foundation soils for potential use in construction control, obtain data on embankment settlement in order to refine end-of-construction and post-construction settlement assessments, and optimize the height of the dike to be constructed by providing information on the construction sequence for use in calculation of capital costs and alternative layouts and dike heights. The successful completion of the trial dike has demonstrated that steep-side dikes up to 12.5 m high can be constructed rapidly on soft soils. The construction of the trial dike has therefore proved a very substantial benefit to the evaluation of the likely performance of a dike constructed along the Lisan shore. The key factor which made this fast construction possible was the unexpected, very rapid consolidation of the majority of the foundation soil which has been shown to occur. The principal observations from the trial dike were: (1) end of construction settlements may be calculated using drained stiffnesses where E′/su initial has a value of around 65; (2) post-construction settlements can be calculated using a coefficient of secondary compression, Cα equal to 0.015; (3) a rapid increase in undrained shear strength occurred when loading the soil up to a value of su equal to around 30 kPa. The value of su/σv′ was as high as 0.5 at this stage. With further loading the strength increase was more modest and su/σv fell to around 0.25 for a vertical effective stress of 160 kPa; (4) for the undrained stability analyses of the trial dike, the mean vane shear-strength profile provided an appropriate assessment of the short-term factor of safety against failure, 5) For the drained stability analyses of the trial dike, lower bound effective strength parameters for the foundation and embankment fill (c′=0, φ′=30° and c′=2 kN/m2, φ′=33°, respectively), combined with field measurements of end of construction pore water pressures provided an analysis which was broadly compatible with the undrained analysis; and (6) the trial dike has been stable, pre- and post-construction, because of the well drained nature of its foundation which prevented the build up of high pore water pressures and led to rapid consolidation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002540050447
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