A 22 kilometre embankment section of the Betuweroute freight railway line has been designed and constructed by an alliance of ProRail (Dutch railway infra manager) and HBSC (a combination of 4 large Dutch and Belgium contractors) in an area of highly compressible soils. The contractual form of an alliance was chosen to maximise synergy between the various contractual parties. The objective of the alliance was to build the embankment for the lowest possible costs within the contractual time frame, guaranteeing the quality of the final product. One of the main risks of the alliance was the uncertainty whether the post-construction settlement specifications could be met using a traditional sand fill with wick drains to accelerate settlements. Settlement predictions with various theoretical models showed an unacceptably large variation in results. Field measurements with settlement beacons also showed large variations. The combined use of an isotache settlement model and a Monte Carlo simulation has resulted in a much more reliable method for the prediction of postconstruction settlements. In November 2003, four years after the start of the alliance, the project will be completed within the contractual time frame and ample within the original project budget. Knowledge and experience on settlement predictions, gained in the Sliedrecht-Gorinchem contract of Betuweroute has already been adopted in several other projects. For the covering abstract see ITRD E135448.
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