Monitoring critical geotechnical parameters in the Göta valley

Published 2010-05-24 00:00:00 | Updated 2010-06-16 20:59:55

When the Swedish Road Administration and the Swedish Railroad Administration needed a system for monitoring critical geotechnical parameters along one the biggest infrastructure projects in Sweden, the “BanaVäg i Väst” project, they turned to Bergsäker.

The “BanaVäg i Väst” project is a joint project where both the European highway E45 and the railroad track, running next to each other, will be upgraded with more lanes and a double track. Both the E45 and the railroad are important routes, central to freight and passenger traffic in the western part of Sweden.

The geotechnical situation along large parts of this route is very complicated. The problem is not primarily the risk of landslide. The challenge instead lies in building in such a way as to avoid future subsidence problems. The road and the railway rest on clay, between 30 and 100 metres deep. The clay contains water, which is pressed out when the pressure from above increases. The present road, which was expanded in the 1960s, has dropped between half a metre and one metre, which means that the road level is now clearly within the flood risk zone of the River Göta.

Due to the very poor geotechnical conditions in many places along the distance, slope stability (with in-place inclinometers) and pore water pressure are monitored with continuous recording measuring instruments. Permissible threshold levels were initially identified for each parameter and location where after alarm levels were set in the system at each measuring point.

The readings are automatically transferred via GPRS to a central database every hour. All involved personnel have immediate access to the measurement data via Internet and can study and analyze it. This enables using an active design approach and can at the same time be used for safety purposes.

Expansion of the road and the railway were already included in the regular road plan and will now be realized as part of the so-called Trollhättan Package. The first work started in 2004, and the entire route from Göteborg to Trollhättan will be completed by 2012.

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