IDRIS – New technology on the Qatar sewage tunnel
TBM and Underground Works Manager - Bouygues Travaux Publics
3.45pm – 4.05pm: Greg Berger and Thibaut Lockhart, Bouygues: Doha’s IDRIS – New technology on the Qatar sewage tunnel
The DSSI-MTS1 project, located in Doha (Qatar), consists of 16.4km of sewer tunnels, 11 shafts, 9 mined galleries and connections between these elements. The tunnels have been excavated by 2 EPBMs, operated jointly by Bouygues Travaux Publics and Bessac, in the specific geological context of the Qatar peninsula, consisting of soft to medium sedimentary rock. Due to durability requirements, a HDPE membrane has been cast on the intrados of the segments, which brings specific constraints to the tunnel construction. Additionally, the alignment of the tunnels is governed by hydraulics, with stringent tolerances.
The shafts have been excavated using a variety of techniques: NATM, D-Walls and the innovative Vertical Shaft Machine; some are crossed by the tunnels, others are offset and linked to the tunnels by a mined gallery, which leads to a variety of different types of junctions, all different and tridimensionally complex.
The purpose of this article is to describe the Design and Construction of this challenging project, and highlight the innovative solutions that have been developed to meet the requirements as efficiently as possible. From early stages of value engineering, through all steps of Design, to the final implementation on site, the major aspects of this comprehensive showcase of underground works will be illustrated.