The route of the pipeline ran beneath a forested area and under three local rivers. Contractor K-Boringen, of Hasselt, Belgium was awarded the work to install the new pipeline, which was part of the Donaudüker Neustadt an der Donau project.
Not only did the installation have to cover the 1,260 m length but it also had, as part of the design route, a vertical curve with a minimum bend radius of 2,000 m. The installation of the pipeline took place between 23 April and 10 August 2018 using the microtunnelling technique. The microtunnelling system used was a Herrenknecht AVN unit.
To ensure the installation precisely followed the planned route the contractor utilised a VMT SLS-Microtunnelling LT guidance system that K-Boringen already owned, K-Boringen having had a long-term working relationship with VMT over many years and many tunnelling operations.
The SLS-Microtunnelling LT guidance system is designed to navigate curved and long distance drives using a motorised total station and laser target unit to determine the horizontal and vertical position, pitch and roll of the TBM/Microtunneller. It operates irrespective of any drift or refraction and requires fewer check measurements than other systems. Additional benefits include automatic measurement of the excavated tunnel, continuous tracking of tunnel movement as well as the option to perform system measurements during the bore advance.
The Neustadt an der Donau bore was completed on time and in budget without the need to utilise any form of gyroscopic measuring assistance.
At a Glance Fact Sheet: