Tunnelling in the Desert, Wakrah and Wukair Tunnel, Doha, Qatar

• Published in: Expanding Underground - Knowledge and Passion to Make a Positive Impact on the World pp. 985 - 993
• Main Authors: Stypulkowski, J.B., Najder Olliver, A.M., Al-Khayareen, Khalid Saif F S
• Format: Book Chapter
• Language: English
• Published: United Kingdom CRC Press 2023; Taylor & Francis Group
• Edition: 1
• Subjects: Calcareous Siltstone; TBM Tunnelling; Horizontal Curves; Hoek Brown Failure Criterion; Sewer Tunnel; Geological Strength Index; Mixed Face Conditions; Overburden; PHM; Shallow Marine Limestone; Rock Mass; PWA; Overhead High Voltage Transmission Lines; TBM; Above Ground; Tunnel Alignment; Deep Geological Formations; Sequential Excavation Method; BIM; Alignment Range; BIM Model; Logistics Tunnels; Ground Investigation; SEM; SCL
• DOI: 10.1201/9781003348030-118

The Public Works Authority (PWA) of the State of Qatar, or ASHGHAL, has launched the Wakrah and Wukair Drainage Tunnel, which is a 13km-long and 4.5m-ID sewer tunnel serving Doha's growing population in the years to come. The depths range from 50 to 60m, which will make the tunnel entirely in the Rus Calcareous (RUS) and Rus Gypsum (RUSGYP) formations, thus this will be the deepest and most challenging TBM tunnelling project in Qatar to date. Little was known about the ground conditions and the specifics of the deep geological formations along the planned alignment at project inception. Therefore, an extensive ground investigation campaign was launched in several phases to confirm the feasibility of the project, as the key to every successful tunnel project is to properly identify and mitigate the risks. The authors will present the findings of the investigations along with the design considerations for weak/soft rock masses commonly found in Doha, Qatar. The authors will also provide an introduction to the specifics of the PWA's latest project and tunnelling aspects of it.