Director of the National Scientific Center "Bokarius Institute of Forensic Expertise" , an institution that is conducting an examination of the destruction of the Kyiv subway tunnel between Lybidska and Demiivska stations, Serhiy Tyulenev, in a comment to UNN, said that the results of the research should be expected in two to three weeks. He also told what the experts saw during the inspection of the tunnel.
"On December 12 of this year, experts from the Construction and Technical Research Laboratory of the Bokarius Institute of Forensic Expertise conducted an inspection of the tunnel run and during this inspection it was found that work is currently underway to fix the screws by injecting polymer solutions behind the reinforced concrete frame. At the time of the inspection of the precast concrete frames, many cracks were found, some of them through, through which water and rock enter the tunnel. Some of the cracks have beacons without a date of installation, and some of them are damaged. Some prefabricated elements of the lining have detached the protective layer, exposing the working reinforcement, which in turn is affected by corrosion. Corrosion damage is also observed on the bolts of the prefabricated elements, and some upper and side elements of the vault have shifted relative to each other. The leaching of cement binder on the surfaces of the tubes in the form of efflorescence, sagging and stalactite formation was also detected. There are also leaks at the joints between precast elements. There are diagonal cracks with spalling in the monolithic pavement concrete. The pavement concrete contains rock residues, such as dusty sand, which was washed through the through cracks. There are openings in the tubing (tunnel frame) that are not closed for injecting mortar behind the tunnel lining. And during the inspection of the facility, which took place on December 19, it was found that temporary unloading structures were installed in the destroyed areas, the technical condition of the tubes deteriorated, new cracks appeared, the width of the old cracks is constantly increasing, and some tubes are destroyed with the elements of the tube itself falling out. Water enters the tunnel through cracks in the structures. For a complete study, we also examined the hydraulic structure, namely the open channel through which the Lybid River flows. Above the surface of the tunnel, there are dips in the ground, asphalt paths, the asphalt itself, and the kiosks have significant deformations," Tyulenev said in a comment to UNN.
Details
According to him, it is currently planned to conduct a commission construction and technical expertise. The examination requires the involvement of relevant specialists to clarify the issues of proper compliance with the norms, rules of construction and operation of the subway.
"The object of the study will be to determine the compliance or non-compliance of the waterproofing work performed, the design documentation for the construction of the structure between Dymiivska and Lybidska metro stations, the technical condition of the tunnel structure between the metro stations, the causes of damage and destruction of the tunnel structure between these stations. The commission's construction and technical expertise will be completed in about two to three weeks, depending on the documents provided. We will already have an expert opinion," said Tyulenev.
At present, the causes of the subway tunnel's destruction are being established, namely, whether these are violations in the design or construction, or during operation, or external factors (this is construction near the subway tunnel). For this purpose, the subway tunnel was inspected, all the necessary documentation is being studied, and the reasons will be found out by experts and the conclusion will contain expert opinions. He noted that the experts are not ready to give preliminary conclusions on whether the destruction was sudden or could have been foreseen.
Recall.
On December 8, new cracks appeared in the subway tunnel between Demiivska and Lybidska stations, allowing water to seep in, posing a real threat to the safety of passengers. As a result, 6 stations of the Blue Line were closed for at least 6 months. Subsequently, a shuttle train service was launched between Teremky and Demiivska stations in Kyiv.