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Project
Package 3 of the East Coast Expressway Phase II is 13km long and it runs from Cheneh Interchange to Kijal Interchange. Ground treatment was instituted where the highway passes through areas of swampy ground and soft alluvial deposits. The objectives are to ensure embankment stability and to restrict settlements within acceptable limits. The project is expected to be completed by 2010
Soil Condition
Typically soft ground comprises silty clay (cu = 10 to 15 kPa) ranging from 4 to 7m depth. In general, water content is 50 – 60% and plasticity index 20 – 30%.
Solution
Dynamic Replacement was specified in areas where soft soil thickness is less than 5m. The tamping weights of between 10 and 15 tonnes, were dropped free fall from heights of up to 15m. The sand columns were installed down to a maximum depth of 5m. Below that, soil properties remain essentially unchanged.
Construction
At the peak of construction, total of 3 DR rigs were mobilized to site. The state-of-art Keller DR crane is capable of lifting a 30 tonnes tamper and drop free fall from heights of up to 30m. Pre-programmed computer sequencing allowed consistent repeated drops without reliance on the operator’s reflexes. This enhanced not only the quality of the finished product but safety on site
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