Qatar's Public Works Authority (Ashghal) said it has fully completed the tunneling works in the Western branch of the Main Trunk Sewer of the Doha South Sewage infrastructure project.

A joint venture between Bouygues Travaux Publics and UCC is the contractor for the project, while 'CH2M' has been roped in as the project management consultant.

The project site witnessed the breakthrough of the Tunnel Boring Machine into the wall of the tunnel shaft, in the presence of Abdulla Hamad Al Attiyah, the assistant president at Ashghal and Khalid Saif Al Khayareen, the manager of Drainage Networks Projects Department Manager, along with a number of officials and engineers from the project’s consulting and contracting companies.

Ashghal said this major milestone represents the completion of one of the three main branches forming the Main Trunk Sewer of Doha South Sewage infrastructure project, which will convey the sewage flows through pumping stations to the existing Doha South Treatment Works.

The 5-km-long tunnel covers several key areas including Al Sadd, Al Maamoura, and Salwa Road, up to the Doha South Sewage Treatment Works.

On this occasion, Al Attiyah said today’s achievement shows that Ashghal was still making progress in all its roads, expressways, buildings projects as well as the infrastructure and drainage projects that are being carried out deep underground.

The Western branch of the Main Trunk Sewer, completed today (January 7), stretches from Al Thumama Area to Salwa Road through Abu Hamour Area, representing about 30 per cent of the total length of the main tunnel.

The tunneling works, which began in January last year, have been completed within a year clocking an average rate of 13.7 m per day.

Tunneling works were implemented using a TBM named “Al Zubara”, and it’s one of the project’s two TBMs which were designed specifically for the geological features encountered in Doha.

Excavation works were implemented using the Earth Pressure Balance (EPB) tunneling technique, which is ideal for Doha's soft ground and rock conditions, at a depth ranging between 30 and 40m, without impacting the traffic flow or the buildings surrounding the tunnel.

The Main Trunk Sewer of Doha South Sewage infrastructure project comprises three branches; Eastern, Western, and Northern with a total length of 16 kilometres, said the statement from Ashghal.

The Main Trunk Sewer is being constructed using pre-cast segments, where it takes six segments to build one concrete ring of the tunnel, which includes 13,537 concrete rings with an internal diameter of three metres.

The project also includes the construction of seven lateral interceptor sewers with a total length of about 24 km which will convey flows from areas in the centre of Doha to the main tunnel.

This is in addition to the construction of 11 shafts at a depth ranging from 20 to 40 metres, which will be used to excavate the main tunnel, said the statement.

The Doha South Sewage Infrastructure Project is designed to serve areas in the south of Doha and the expected population growth,, it stated.

The project can be linked to future infrastructure projects, and when completed, it will enable the decommissioning of more than twenty old pumping stations currently located in the residential and commercial areas in the south of Doha, it added.

Ashghal started implementing the Doha South Sewage Infrastructure Project in August 2015, and 70 per cent of the works are completed so far. The project is set for completion in the first quarter of 2019.-TradeArabia News Service