Grouting and lining methods proposed for url tunnels and shafts at the Yeniseyskiy site (Krasnoyarsk region, Russia)

The designs of the underground research laboratory (URL) at the Yeniseyskiy site provide for two vertical shafts and a complex involving a few horizontal access and research tunnels to be excavated as phase one of the project. The URL tunnels will be excavated at a depth of 525 m below the daylight surface (or —70 m below the Baltic Sea level). Rock sections with different strength levels will be penetrated by excavations, which has been confirmed by geological exploration. Taking into account the purpose of the tunnels and shafts, a differentiated approach to the selection of mining support structures is required during their construction, in particular, providing for some strengthening methods to be applied in most challenging areas of the rock mass. Therefore, at the URL construction stage, grouting and lining methods should be refined and tested in the border zone of the excavations.