Protecting artificially produced cavities in rock involves filling cavities with compressible material and pressing in bores leading to cavities with cement suspension or compressible material

摘要

The method involves breaking out a tunnel profile and temporarily securing it with curved steel sections (11) and/or with sprayed concrete and rock nails. It involves making cavities with the volumes at the outer ends in bores essentially radial to the tunnel axis with a conventional nozzle jet method or eccentric bores, arranging the cavities on a part circle or full circle about the tunnel axis according to the mountain pressure and rock consistency, filling the cavities with compressible material and pressing in the bores (14) leading to the cavities with cement suspension or compressible material.