Numerical analysis of the large-scale water supply network accident consequences on the engineering and geological conditions of a heritage site

Recent accidents in water supply networks have the negative impact on the state of the historical and architectural heritage of the Kyiv-Pechersk Lavra, which has been formed over many centuries and is a UNESCO World Heritage Site. We have analysed the water supply system emergency situation on the territory of the Metropolitan Garden that occurred in October 2022 during the Russian military aggression. It caused surface sinkholes, increased groundwater levels, and significant destruction of a historical underground – the Metropolitan Cellar. The study was carried out using numerical analysis implemented in Plaxis 2D. To resolve the uncertainties of the accident, several options for developing the emergency situation were considered, taking into account the number of probable pipe leakages, their size, etc. Accident parameterization was performed with a leakage volume of 1600.0 m3/day, considering damage to the water supply network in two locations. The volume of the watered soil mass was 7.0-8.5 thousand m3. We evaluated the state of destruction of the southern and southeastern branches of the Metropolitan Cellar. Engineering measures for strengthening the section of the Monastery walls with buttress elements, increasing the width of the foundations by means of additional concrete and piling are studied. The numerical calculations were verified using the results of geophysical surveys. Comparison of analytical calculations, geophysical surveys and field surveys showed that parts of the underground structure were completely destroyed. Their restoration is possible only by modern methods through reconstruction, that will lead to a loss of authenticity, which is unacceptable for historical structures. To take preventive actions for the protection of monuments, it is necessary to conduct continuous monitoring.