Two tunnel boring machines (TBMs) have broken through to a target pit, successfully completing the tunnelling work on section 40 of the Emscher sewer in Germany.
The TBMs were the only machines on the project to use the segmental lining method, which connects pressure resistant segments and seals them into rings that are installed behind the TBM as it moves forward.
The project featured numerous challenges, including a difficult tunnel alignment with several tight curves, a 300 m section of sandy groundwater-bearing subsoil, and limited space to accommodate the three launch shafts.
The inside diameter of the twin tunnels was only 2.6 m, making this one of the smallest diameter tunnels to be lined using this method.
The crew achieved excellent results, with a top performance of up to 177 m per week, and up to 582 m per month.
The Emscher conversion project began in 1992, and has been working with Herrenknecht for almost 25 years, utilising its underground excavation technology for sections 20, 30 and 40.
Over the course of the project, Herrenknecht has supplied TBM technology, AVN machines for pipe jacking and a vertical shaft sinking machine (VSM).
The project is part of an effort to rehabilitate the Rhine River, which has been used as an open channel for sewage, flood and rainwater since industrialisation began in 1850.
The Emscher sewer will separate the sewage and rainwater, and direct it to treatment plants for purification.
Commissioning of the Emscher sewer is anticipated to take place at the end of 2020.
For more information visit the Herrenknecht website.
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