Strukton Afzinktechnieken Mergor has received an honourable mention at the International Tunnelling Awards 2011 in the category Technical Innovation of the Year for the Busan Geoje Fixed Link project. The announcement was made in Hong Kong on 1 December. The winner in this category was the consortium of Arup, REHAU and Züblin.

Immersing the tunnel elements for the Busan Geoje Fixed Link in South Korea was a challenging job under challenging circumstances. Working under extreme and often restrictive conditions yielded a series of important innovations with which Strukton Afzinktechnieken Mergor once again pushed the boundaries of tunnel-immersing technology forward.

The team had to immerse the elements in the open sea, for instance, in a very short timeframe and under extreme conditions.

The depth of the seabed meant that the eighteen tunnel segments, totalling 3.5 kilometres in length, were difficult to connect together underwater. Standard immersing techniques could not be used. The developments that Strukton had to introduce especially for this project included a measuring device for monitoring the correct angles and lengths, so that the position of the tunnel element could be determined to an accuracy of just a few millimetres.

Robot legs were developed that could keep the 48,000-ton elements in place despite the powerful currents.

The depth also meant that the usual techniques such as an access shaft for getting into the tunnel were not feasible. The engineers and divers used a self-propelled diving bell to access the elements.

About the International Tunnelling Awards
The International Tunnelling Awards showcase and reward outstanding projects and achievements in the global tunnelling industry. This year the event is moving to Hong Kong, providing an international platform on which the most innovative and excellent tunnelling feats will be celebrated.