The subject of this technical solution are sinkholes in the settlements of Mečenčani and Borojevići, the opening of which was triggered by the earthquake on December 29, 2020. with the epicenter near Petrinja. Not long after the earthquake, surface vents began to appear, mostly in the villages of Mečenčani and Borojevići. After the said earthquake, a total of 139 sinkholes opened.
The works were carried out in 2022 and 2023, starting on October 28, 2022.
The sinkholes were rehabilitated by backfilling using the inverse filter method, and special attention was paid to the fact that the technology of the works does not affect the flow of groundwater and that the materials used for backfilling are inert, that is, they do not pollute the groundwater.
The solution avoided any cement-based injection works in order to prevent pollution of the complex networks of karst underground streams, especially taking into account the proximity of the Pašino Vrelo water pumping station.