Completion of the excavation works of the main tunnel for Mesaimeer Surface and Ground Water Drainage Project

The Public Works Authority ‘Ashghal’ announced that excavation works for the main tunnel of the Mesaimeer Surface and Ground Water Drainage Project were completed at the end of July 2015. The project will discharge the ground water and storm water into the sea thus decreasing the surface water level. This will in turn contribute to the reduction of pumping costs and to the disposal of ground water in construction projects around the country. It will also preserve the foundations of buildings, and reduce land subsidence due to rain.

The excavation works were carried out by “Al Thumama” and “Al Rawada” Tunnel Boring Machines (TBM). Named after the areas they operated in, the two TBMs were specially designed and developed for this project by the German manufacturing company “Herrenknecht AG”, and were used for the first time in Qatar to excavate deep tunnels.

The completion of the main tunnel marks the end of the major works of the Mesaimeer Surface and Ground Water Drainage project. The remaining works include the excavation and construction of sub-tunnels and inspection manholes along the main tunnel. It is worth mentioning that the main tunnel is approximately 10 km long and reaches a depth of approximately 30 m. It extends several kilometers from the shoreline starting from Woqood petrol station roundabout.

The main tunnel is also connected to the existing drainage network in the areas where it will pass, and will hold surface water from the sub-networks that are distributed in different locations covering an area of approximately 170 km². The main tunnel is ultimately linked to a pumping station with a capacity of 19 cubic metres per second, which will discharge the collected storm water from the main tunnel through an offshore outfall several kilometres away from the shoreline to ensure the protection of the shoreline and its surrounding environment.

The Mesaimeer tunnel was excavated using the Earth Pressure Balance (EPB) tunneling technology which is ideal for Doha's cohesive soft ground and rock conditions.All excavation works were carried out at a depth of 30 metres without disrupting the traffic flow or causing any damage to the facilities or buildings surrounding the tunnels. Inspection manholes will be built during the remaining works of the project to ensure proper operations of the tunnel's facilities. The inspection manholes will also enable inspection and periodic maintenance operations within the operations and maintenance plan which will be implemented through the construction of 21 access shafts from the surface to the underground tunnelsat a depth of around 20 to30m.

The Mesaimeer Surface and Ground Water Drainage Project is one of the key projects implemented by Ashghal as part of its plans to upgrade Qatar’s drainage network. The main tunnel runs under the F-Ring Road from the first excavation site in “Al-Thumama” area and will stretch 5.4 km to the west and 4.3 km to the east into the planned pumping station near the new Hamad International Airport. The Mesaimeer Surface and Ground Water Drainage Project is supervised by “CDM Smith”consulting company, and is implemented by “SaliniImpregilo” construction company. The project is expected to be completed in Q1 of 2017.