Ten years of bored tunnels in The Netherlands: Part II structural issues

摘要

In 1997 for the first time construction of bored tunnels in the Netherlands soft soil was undertaken.Before that date essentially only immersed tunnels and cut-and-cover tunnels were constructed in theNetherlands. The first two bored tunnels were Pilot Projects, the 2nd Heinenoord tunnel and the Botlek Railtunnel. Since then a series of other bored tunnels has been constructed and some are still under constructiontoday. At the beginning of this period, amongst others Bakker (1997), gave an overview of the risks related tobored tunnels in soft ground and explained about a plan for research related to the Pilot projects. Ten years havepassed, a lot of monitoring and research has been done. In this paper that is split in two parts a summary isgiven of some of the most characteristic observations of these past 10 years of underground construction in theNetherlands. In this second part, the emphasis will be on structural related issues discussed whereas in part one,frontal stability, grouting and soil deformations are discussed.