Bidders for the Botlekspoor rail tunnel in Rotterdam have been asked to retender, combining it with a second tunnel, the Sophia. A spokesman for Dutch Railways said that the decision had been taken in the hope that contractors would be able to cut costs by using the same TBMs and the same precasting yards for segments. Contractors have also been asked to increase the i.d. of the Botlekspoor from 7.6m to 8.6m in order to accommodate double stacking containers. The revised design will also be 500m longer because of its deeper bore to accommodate the increased diameter. Ground conditions are known to be poor and settlement restrictions tight.
展开▼
