Qatar’s Public Works Authority Ashghal has completed the tunnelling works in the Western branch of the main trunk sewer of its Doha South Sewage infrastructure project.
A joint venture between Bouygues Travaux Publics and UCC is the contractor for the project, while CH2M is the project management consultant.
The tunnel boring machine (TBM) broke through into the wall of the tunnel shaft, in the presence of Abdulla Hamad Al Attiyah, Assistant President of Ashghal, and Khalid Saif Al-Khayareen, Drainage Networks Projects Department Manager, along with a number of officials and engineers from the project’s consulting and contracting companies.
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 transfer the sewage flows through pumping stations to the existing Doha South Treatment Works.
Al Attiyah said that the tunnel extends five kilometres underground reaching several areas including Al Sadd, Al Maamoura, and Salwa Road, up to the Doha South Sewage Treatment Works.
He noted that this achievement shows that Ashghal is making progress in all its roads, expressways, and buildings projects, as well as the infrastructure and drainage projects that are being carried out deep underground.
Al Attiyah added that these achievements prove that Qatar is able to move ahead and deliver projects with the required quality and as scheduled.
The Western branch of the Main Trunk Sewer stretches from Al Thumama Area to Salwa Road through Abu Hamour Area, representing about 30% of the total length of the main tunnel.
Al-Khayareen said the Western branch is one of three parts of the main trunk sewer, which will serve the Al Sadd, Al Maamoura, Umm Ghuwailina, and Al Matar areas.
He said the main tunnel will withdraw the drainage water in a smoother way via gravitational factors to get it to the treatment plants, which will help to eliminate around 20 old pumping stations.
The tunnelling works, which started in the beginning of January 2017, took a period of 12 months at an average rate of 13.7m per day.
A TBM named “Al Zubara”, one of the two TBMs used in the project, which were designed specifically for the geological features encountered in Doha, undertook the tunnelling works.
Excavation works were implemented using the Earth Pressure Balance (EPB) tunnelling 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 the Doha South Sewage infrastructure project comprises eastern, western, and northern branches, with a total length of 16km.