By Ashley Karen
Soletanche Polska has carried out its first compensation grouting project on the new Łódź underground railway construction.
As tunnels in Poland usually pass under roads rather than buildings, compensation grouting is not a commonly used technology in this country. However, the technique was employed on the new Lódz line to guarantee the tunnel boring machine’s safe passage beneath historic residential areas.
The new underground railway network construction, which will link the two stations, Lódz Kaliska and Lódz Fabryczna, is notably complicated as the alignment travels across the city, like under residential areas.
Soletanche Polska had to stabilize the ground and decrease the settlement of houses directly above the tunnel under construction, so the company used compensation grouting for the first time.
After preparation, comprising drilling boreholes, injection rods’ installation, and testing pre-injection phase, the Soletanche Polska team proceeded with the final step of active grouting, undertaken while the tunnel boring machine was performing. However, if subsidence happened, grout was injected to stabilize the soil.
Computerized control enabled real-time observation of parameters, pressure checks, and preparation of daily reports.
