To improve the living conditions of the people of Casablanca and promote urban and demographic development, the largest city in Morocco is to be better protected from flooding by the Bouskoura river. To this end a sewage project has been realized that diverts water from the river directly into the Atlantic when the water level is too high.
The first phase of the project consists of a 3 kilometer long open channel running along the river bed. From the end of this channel, an approximately 5.2 km long tunnel with a capacity of 140m³/s carries the water toward the ocean.
The tunnel section was excavated by a Herrenknecht Multi-mode TBM. This special type of machine is highly adaptable to changing ground conditions such as those found in Casablanca and can be converted from one tunnelling mode to another inside the tunnel. The TBM was supported by additional equipment from Herrenknecht subsidiary Techni-Métal Systèmes (TMS). TMS supplied 3 multi-service vehicles (MSV) for the smooth and efficient supply of the tunnel jobsite with concrete lining segments. Another MSV was equipped with a crane and other items for maintenance purposes and could also be used to transport personnel.
The multi-mode machine excavated the first, 1.6 km long section of the Casablanca Sewer in closed EPB mode with screw conveyor muck removal, the remaining distance of about 3.6 km in open mode with belt conveyor discharge. The approach paid off: the final breakthrough took place in early February 2017 already and not, as originally planned, in March.