Underground Construction - Hydrogeology: Objectives, Methods, Applications - page 271

Table 22 Discharge collected by underground constructions.

Old railway tunnels Discharge in m 3 ·s -1

Simplon (Swiss-Italian Alps) 1.2

Col de Tende (French-Italian Alps) 1.1

Mont d'Or (Jura) 3.0 to 10.0

Hydroelectric tunnels (Savoy)
Ponturin 1.8

Versoyen 6.0

La Coche 2.0

Highway tunnels
Gran Sasso (Italy)

up to 20.0

• the Lötschberg railway tunnel (Bernese Alps, Switzerland), projected
to run 14.6 km, cut across, on July 24th, 1908, an ancient sub-glacial
channel fi lled with highly aquiferous alluvium (Figure 130). This
opening provoked the intrusion into the gallery of 80,000 m 3 of material,
taking over, in only 15 minutes, 1,800 m of the site and burying 24
workers. The collapse had repercussions all the way to the surface, 180
m above, creating a funnel 80 m across and 5 m deep in the Gasteren
plain. The partially completed gallery was abandoned and walled
off, and the tunnel was completed on March 31st, 1911, following a
different underground path (Gignoux & Barbier, 1955);

Figure 130 Lötschberg tunnel (Switzerland). Geologic profi le of the abandoned path (from
Gignoux & Barbier, 1955).
1-Granite. 2-Jurassic limestone. 3-Alluvial fi ll.

• the Boubard railway tunnel (Vierzon to Saincaize line), 590 m long
under a cover no thicker than 26 m, went into service in 1849. The
excavation of the tunnel, confronted with sizeable infl uxes of water
through a complex folded structure associating water-bearing
limestone and clay with poor mechanical qualities, was marked by
multiple material and human accidents. After it was commissioned,