Pregny-Chambésy, Switzerland
| Yard | road tunnel |
|---|---|
| Location | Pregny-Chambésy, Switzerland |
| Subcategory | TUNNEL |
| Application |
The 491m long tunnel project crosses a built-up urban area at a shallow depth with difficult geological and hydrogeological conditions.
During the tunnel excavation work, severe water ingress occurred despite the lowering of the groundwater level. In an initial phase, the tunnel excavation was stabilized with cement using conventional seals. Dynamon SX Injection, an additive for injection suspensions and injection mortar with an integrated pumping aid, and Viscofluid Jet 5000, a biodegradable polymer for increasing the viscosity and stability of cement suspensions, were used. In a second phase, the highly permeable gravel bodies and water-bearing layers with varying groundwater levels were drained from the surface of the tunnel by constructing an injection pile wall. In addition, the sealing in the tunnel had to withstand high water pressure after construction. For this reason, a two-layer vacuum system was installed. |
| Start and finish date | 2017/2023 |
| Application Type | Underground construction |
| Contractor company | ARGE Partner: Marti Construction SA, Meyrin | Marti Tunnel AG, Moosseedorf |
| Installer companies | Renasco AG, Moosseedorf | Renasco Geotechnik, Moosseedorf |
| Specialists involved | Canton of Geneva; DETA / DGGC, Petit-Lancy |
| MAPEI Coordination | Stefan Niederberger |
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