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Allott & Lomax, Fairbairn House, , Ashton Lane, Sale, Manchester.
This paper describes the geotechnical aspects of the site investigation and construction of a by-pass to Greenodd Village in the southern part of the Lake District. The proposed route ran along west bank of the River Leven, crossed the main channel of the river and rejoined the existing road south of Greenodd. The investigation revealed that in places deep deposits of soft alluvium existed. Using the field measurements of permeability to determine the rate of consolidation in preference to values measured in the laboratory oedometer tests, it was decided that an embankment could be constructed safely and within a reasonable time. During construction the increase in excess pore pressure was monitored and the rate of filling modified to ensure a minimum factor of safety was achieved.
The project also involved construction of two bridges. From the findings of the site investigation it was decided to adopt pile foundations with the piles being driven steel H piles having an enlarged section set back from the toe. This ensured that the pile reached the required driving set after only a short penetration into the gravel stratum underlying the soft alluvium. Pile tests were carried out on preliminary piles to confirm the adequacy of the design and on works piles to ensure the required load carrying capacity was actually achieved.
