TGV Atlantic tunnels : Chambron, E World tunnlgV2, N2, April 1989, P92-98

Abstract

This article describes the route selection and tunnelling operations during the construction of the 298.4 km long Atlantic tgv high speed train route between Paris and le mans, together with a branch towards the existing paris-bordeaux railway. Maximum speeds up to 300 kph are planned, reducing to about an hour journey times from Paris to le mans or tours. To minimise the effects of noise and vibration and damage to areas of scenic beauty or special interest, the route was sometimes required to run through open or covered cuttings or over viaducts. Tunnels had to be constructed through 4 areas of high ground: (1) fontenoy-aux-rose (474 m); (2) sceaux (827 M); (3) vernou-vouray (1496 m); (4) villejust (4800 m). The first 3 tunnels were double track, but it was decided that it would be cheaper and faster to build 2 parallel single track tunnels at villejust. These tunnels were constructed by 3 different methods selected primarily to suit the ground conditions; (1) at fontenay and sceaux, a slope was cut for forward support, followed by mechanical excavation; (2) at vernou-vouray, the new Austrian tunnelling method (natm) was used, with excavation by roadheader; (3) the villejust tunnels were bored by 2 bentonite hydroshields, with support by fragmented segmental lining. All these methods achieved their aims successfully.