Hohl-/Badener-/Micafil-/Hermetschloostrasse waste water storage channel

As a result of the Limmattalbahn project, various waste water channels had to be repaired or moved as a precautionary measure. Around 700 metres of new sewerage pipes were installed around Hohlstrasse, Badenerstrasse, Micafilstrasse and Hermetschloostrasse. This also allowed for measures detailed in the General Wastewater Plan (GEP) to be implemented around the prescribed perimeter.

• • The heart of the project is the main storage channel (internal diameter 2.20 m, external diameter 2.70 m), which was drilled in four sections using a micro-tunnelling procedure (full cut with hydroshield, four sections of 300 m, 100 m, 170 m and 90 m in length, two straight sections, two curved sections (radius 250 m), very slight gradient (3.8‰))
• • Stone-tipped propulsion as partial cut in Farbhof area with internal diameter of 1.20 m (Keradrive), approximate length 23 metres
• • Connection of Hohlstrasse to existing waste water channel R 2.50/1.90 m, four shaft sites incl. in-situ concrete channel R 2.20/2.20 m, approximate length 25 metres
• • Crossing of Werdhölzlistrasse under Hohlstrasse (traffic via temporary bridges), three shaft sites incl. in-situ concrete channel R 1.00/2.00 m, approximate length 20 meters
• • Connection of Hermetschloostrasse to existing storage channel ø 2.20 m, two shaft sites incl. in-situ concrete channel R 2.20/2.20 m
• • Various shaft sites with connection to existing channels up to ø 1.20 m incl. drop structure
• • Approximately 25 trenches: One triple starting shaft, one dual starting shaft, one double exit trench, three single exit trenches, various intermediate shafts, replacement measures, GAL starting trenches. The project involved a wide range of techniques: Sheet pile wall, retaining wall, drilled pile wall, mixed-in-place procedure, jetting, injections, shotcrete. Five trenches in contaminated and ground water areas are worthy of special mention as they had to be sealed extremely tightly (risk of transporting contaminated material). Interior construction in new storage channel of around 660 metres in length: Reinforced in-situ concrete bottom d = approx. 20 cm with 10% camber (embankment), Top12 reinforcement including full coating using pipe spreader
• • Interior construction in new in-situ concrete channels including either the method described above or classic dry weather guttering made of bonded stone half shells, embankment reinforced with concrete afterwards
• • Various residential utility connections: Five laid into the propulsion pipe from the outside using propulsion (drill and ram method), including start trenches
• • Bottom installed in existing channel ø 1.25 m with Keraline elements, approximate length 18 metres
• • Road construction: Full renewal of Hermetschloostrasse in the area around the construction site, partial renewal of Micafilstrasse
• • Various ground water replacement measures