In Kyiv, repairs were completed between the metro stations "Demiivska" and "Lybidska". Full traffic of trains on the blue branch will be resumed tomorrow, September 12.
This was reported by the Mayor of Kyiv Vitaliy Klitschko.
The entire complex of works lasted nine months. As the mayor said, during this time they prepared the construction site, laid more than 200 cable networks, developed a pit more than 15 meters deep, dismantled the old part of the tunnel 27 meters long and built a new one.
Also, new tracks were laid there, all engineering networks were restored, safety systems for train traffic were established, and the tunnel frame adjacent to the new section was strengthened on both sides. In addition, the repairmen protected the tunnel between "Demiivska" and "Lybidska" from further penetration of water there and fixed the soil around it.
In total, the renovation cost 383 million hryvnias, which, according to the mayor, is 62 million less than the initial cost.
In parallel with the restoration work, experts conducted research to determine the cause of the depressurization of the tunnel and the flooding of the tracks between the "Demiivska" and "Lybidska" metro stations. In particular, it was confirmed that the cause is errors at the design stage and poor performance of construction and installation work at the construction stage of this section of the tunnel.
Among other things, the tunnel frame according to the project should be operated at a significantly lower level of groundwater, and the tunnel frame was built in poor quality, in violation of the tolerances for the installation of the rings. Also, no compensatory measures were taken to consolidate the soil in order to prevent the negative impact of engineering and geological changes on the tunnel. In addition, the stiffness of the tunnel is less than the design due to the use of wall blocks instead of tray blocks, which led to a decrease in thickness and the absence of ribs.
In addition, laboratory studies confirmed gross violations during construction in the part where there was no chemical fixation of the soil around the tunnel.