Within an undertaking that embodies true international cooperation, Colas Alterra is currently working in České Budějovice following an order from Colas CZ. The Czech Colas subsidiary requested a quotation in 2019 for the construction of a stormwater drain with microtunnelling technology. Once the offer had been submitted, we clarified the pending technical details at a site visit, and a deal was finally struck for the job, requiring us to start in January 2020.

The complete length of the stormwater drain in question is 778.3 metres, running at depths between 3.5 and 10 metres. The reinforced pipe itself has an internal diameter of 1000 mm, and as an interesting detail, the segments are only 2 metres long opposed to larger pieces generally used in Hungary. Ultimately, the job was split up into nine sections with lengths varying between 60 and 100 metres. For 678.3 metres of pipe jacking works, we have interim deadlines on 31 March, 24 April and 31 July, whereas the deadline for the last 100 metres (which is also the final deadline, of course) are unknown at this point – presumably, this part of the work will only be completed in 2021.

Since we do not have our own cutting head for this diameter, we entered into negotiations with the German manufacturer of pipe jacking equipment, Herrenknecht AG: following the acceptance of our bid, we finalised the machine to be rented and the list of accessories, such as the jacking frame and the slurry line.

Due to a duration of several months and the distance from home, we also had to work out a way to provide human resources. Fortunately, we signed a contract with Polish company AVN Team in 2019, and since then, they have built approximately 700 metres of pipes with microtunnelling methods for us in superb quality. Consequently, they were an obvious choice for this job. In addition, we receive a lot of support from Colas CZ regarding local suppliers, including the arrangement of cranes, the scheduling of pipe section deliveries and the procurement of gas/oxygen.