The 2.966 m, twin-tube Grouft Road Tunnel is the longest structure on the Route du Nord, which links the northern economic regions of the Grand Duchy of Luxemburg with the capital. The “Route d’Echternach-Contournement Mersch” section is 14.7 km long, with 7.5 km of the road underground through 3 tunnels, and a further 1.4 km over bridges. The tunnel sections include the 2.695 m long Gousselerbierg tunnel, the Grouft tunnel and the 1.850 m long Stafelter tunnel.
The waterproofing concept has to accommodate water under hydrostatic pressure including a base invert profile and seepage water handling through a permanent drainage system. Longer tunnels structures can pass through substantially “dry” as well as “wet” water-bearing zones. The change-over between the areas under hydrostatic pressure and those with drainage water, always have to be detailed and executed very carefully to avoid any future problems.
The Material Characteristics
Soft PVC with a total thickness of >= 2 mm acc. DIN 1849-2 including signal layer
Tensile strength at break:
>= 12N/mm2 machine & cross direction acc. EN ISO 527
Elongation at break:
>= 250% machine & cross direction acc. EN ISO 527
Module of elasticity E1-2:
<= 20 N/mm2 machine & cross direction acc. EN ISO 527
Impact resistance (500 g):
Dynamic perforation test: no leakage at 750 mm acc. EN 12691
acc. EN 1296 (70d/70ºC), change of tensile strength and elongation
<= 20%, no cracks at -20°C
Behaviour after storage in aqueous solutions:
(28d/23°C; H2SO3(5%); Ca(OH)2(sat.); NaCl(10%) acc. EN 1847: change of tensile strength and elongation <= 20%, No Cracks at -20°C.
Fire resistance with low smoke behaviour:
class V.2 acc. SIA V 280
No toxic substances and no heavy metals, free of halogenated flame retardants like bromide compounds, without DOP plasticizer, environmentally friendly.
The technical proposal for Tunnel Grouft provides for this section a special solution including a two-component flexible waterproofing tape, suitable for gluing with epoxy adhesive and for welding with the PVC-P waterproofing membrane.
Owner: Grand Duché de Luxembourg, Ministüre des Travaux Publics
Client: Administration des Ponts et Chaussées (Luxembourg)
Design: Lombardi Engineering, Luxconsult, TR.Engineering
AMGR: Félix Giorgetti, Galère S.A., Max Bögl, Tralux, Wyss & Freytag Ingenieurbau AG
Membrane Applicator: IRACO (Luxembourg) & Renesco
Construction supervision: GEOS, TR-Engineering