2 EPB Shields from Herrenknecht have provided first-class work during tunnel excavation of the large scale >>Abu Hamour Southern Outfall Project<<. After just about 5 kilometers of tunnelling each, both high-tech machines broke through the target shaft precisely to the millimeter in quick succession of each other. The segmental lining method has proven successful in the smaller diameter range for the first time in Qatar. The newly created sewage tunnels are important to better protect the city and the inhabitants of Doha from floods after heavy rainfalls.

Doha/Schwanau, September 23, 2015. Both Herrenknecht TBMs each with a diameter of 4.47 meters only required 12 and 14 months respectively for their tunnel sections. Under the professional guidance of the responsible construction company Salini-Impregilo they achieved remarkable top performances of up to 165 meters per week. At a depth of around 30 meters, the EPB method proved to be the optimum choice to master the cohesive soil with its high proportion of rock in Doha. Herrenknecht designed a special cutting wheel with a large opening ratio for the customer - resulting in correspondingly efficient material excavation. High maximum push forces ensured top advance rates for both machines. The final breakthrough on 29th of July marked the conclusion of Phase 1 of the tunnelling work on the >>Abu Hamour Southern Outfall Project<<.

"Both EPB Shields with segmental lining were perfectly suited for the project requirements in Doha", said Simone Centis, project manager at Salini-Impregilo, during the breakthrough celebration. "The great partnership with Herrenknecht helped us to find the best technical answers for the often heterogeneous soil. This allowed for highest possible efficiency during tunnelling and project progress".

Qatar is one of the driest places on Earth. When it rains heavily in Doha, this can result in dangerous flooding because the metropolis is only a few meters above water level, and therefore above the groundwater level. The >>Abu Hamour Southern Outfall Project<< should help to reduce this danger in the future. A tunnel system will drain-off superfluous water and relieve the existing pumps, which lower the high water level. This will save considerable energy and costs for the public. Further projects to improve the drainage situation in Doha and its surroundings are planned or already being constructed, i.e. the Inner Doha Re-sewerage Implementation Strategy (IDRIS) Project.

Herrenknecht technology is also working underground to improve the traffic situation in Qatar's metropolis. With over 50 tunnel kilometers already completed for the Doha Metro, 21 EPB Shields from Herrenknecht with a diameter of around 7 meters have already accomplished facts.