February 21st, 2022
Soletanche Polska is executing 3 strategic rail works in Łódź for the construction of Cross – City Tunnel
Construction of a cross-city tunnel will create a connection between the two stations: Łódź Kaliska and Łódź Fabryczna. Thanks to this investment, Łódź Fabryczna station will become a through station (now, it’s a terminal station for regional connections). This will enable shortening the transit of domestic, national, and international connections through Łódź. As a result, Łódź will become one of the most important transport junction in Poland.
Soletanche Polska is executing 3 objects of this investment: two entry chambers for tunnel boring machines and a train stop in the historical central part of the city.
The construction of Odolanowska starting chamber
The project consists of two shafts made in the technology of diaphragm walls connected with each other by a connector with barrettes anchoring the foundation slab. The starter shafts are circular in shape. The walls of the starting shafts are 80 cm thick and 35 m deep. All the diaphragm walls represent 21,000 m³ of concrete.
The construction of Długosza starting chamber
This is the smaller chamber from which the TBM Faustyna which his shield is a diameter of 8.7 m. The starting chamber is in a form of a circle with an internal diameter of 24 m. It has been realised in the technology of diaphragm walls with bars anchoring the foundation slab. The wall thickness is 80 cm, the excavation depth is around 22 m. The surface of the chamber walls reaches 1500m².
The construction of Łódź Śródmieście station
The foundations will be made of diaphragm walls, the deepest parts of which will reach 40 m. The perimeter of the slurry walls will be 16,265 m². The depth of the excavation will reach 25 m below the street. The stop will have three levels. On level -1 there will be service and commercial points, while level -2 will be occupied by platforms. This is the most difficult geotechnical task, as the walls of the facility are in a tight urban area, right between historic buildings. The work will be carried out in stages to minimise the impact on traffic.
A design variant that has won the customer’s support
An increasingly important issue for investors when analysing construction proposals is not only the price associated with using a given geotechnical solution, but also the time that it can save at a subsequent stage in the construction work. One of these solutions involves avoiding the need to extend the underground structure, by using the diaphragm wall process to construct a circular shaft:
- This circular diaphragm wall structure provides very secure support for deep trenches
- It works very well, even in difficult soil conditions, with high levels of groundwater. (The structure is made watertight using the Soletanche Bachy group’s patented solution – the CWS® (continuous water stop) watertight seal system.)
Thanks to the geotechnical expertise and knowledge of special foundations of our Polish subsidiary, this variant then imposed itself as the basic solution in the rest of the project.
