President of the Public Works Authority (Ashghal), HE Engineer Nasser bin Ali Al Mawlawi inaugurated the commencement of excavation works for Mesaimeer Surface and Ground Water Tunnelling – a significant project being undertaken by Ashghal to enhance Qatar’s drainage network.
This inauguration was conducted during a site visit by Ashghal’s President to the work launch site at Al Thummama area. He was accompanied by HE Guido De Sanctis, Italian Ambassador to Qatar, and senior officials from Ashghal including Jalal Yousef Salhi Director of Infrastructure Affairs and Hamad Mohamed Al Tamimi Director of Asset Affairs. Also present at the inauguration were representatives from Ashghal’s roads and drainage Operations and Maintenance department, CDM Smith the project consultant, Salini Impregilo Construction Company the project contractors, and Herrenkenecht, German manufacturing company for the Tunnel Boring Machines (TBM) being used to excavate the tunnels.
The president’s visit marked the commencement of excavation works which are being carried out by “Al Rawda”, one of the two technologically advanced Tunnel Boring Machines (TBM), being used for the first time in Qatar and specially designed and developed for Ashghal’s Mesaimeer drainage project.
The Mesaimeer tunnel for surface and ground water is one of the key drainage projects within Ashghal’s plans for upgrading Qatar’s drainage network. The tunnel will run under the F-Ring Road and extends 9.7 km. It will stretch 5.4 km from Al Thumama to the west and 4.3 km to the east to the planned pumping station near the new Hamad International Airport. Being undertaken by Ashghal to enhance Qatar’s drainage network, the Mesaimeer surface and ground water tunnel will alleviate Doha’s storm water by transporting it from a 170 km² of catchment area, covering southern and western parts of greater Doha. The tunnel will be linked to the existing and planned drainage network in the areas that it will traverse.
To allow access for inspections and regular maintenance of the tunnel, an operations and maintenance plan has been developed to ensure satisfactory operation of all elements. This will be facilitated through 21 access shafts linking ground level to the 20 – 30 m depth of the tunnel.
Named after the areas they will be used to operate in and measuring 4.5 metre in diameter and 121 metre in length (including support equipment), the two TBMs, Al Thumama and Al Rawada, possess a significant capacity to excavate tunnels without causing any adverse effect on surrounding structures and disruption to local traffic. The specially manufactured TBMs operating through pressure balanced excavation technology are ideal for Doha ground conditions at a depth of 30 metres. This technology will facilitate the construction of essential infrastructure tunnelling which is paramount to accomplish a sophisticated tunnel network.
Over the past 16 months, Ashghal has been involved in rigorous planning and preparation process for the tunnelling project. The works included design, fabrication and installation of TBMs, geotechnical investigations and site mobilisation. Excavation works were conducted to prepare the launching tunnel and additional elements to support the TBMs such as portal cranes and other enabling requirements were installed.
The Mesaimeer tunnel project is scheduled to be completed by early 2017. Ashghal also reported that design and tender documents preparation for phase 2 of the project are being finalised. This second phase includes a pumping station with a capacity of 19 cubic metres per second, which will ultimately discharge the collected storm water from the Mesaimeer tunnel through an offshore outfall several kilometres away from the shoreline, thus ensuring protection of the shoreline and surrounding environment.