The process of shotcreting (rock bolt support) consists of the following stages preparation of underground working space surface, installation and assembling of support elements (anchors, arches, expanded lath), cover lamination, cover protection, quality management. The acceptable distance between heading and shotcreting lining is defined in project according to particular engineering and geological conditions.
Immediate shotcreting after heading allows achieving the best results. In weatherproof ground with above-average competence the distance between heading and shotcreting is allowed to be 50 m. In bad-weather ground with above-average competence shotcreting must be done immediately. When tunnel construction is performed by means of drill-and-blast method the shotcreting is done after face cleaning.
The distance between heading and shotcreting is forbidden in strong-weather ground, where local falls, intensive decompaction and fracturing can take place. When the heading is performed by means of drill-and-blast method the first shotcrete layer is sprayed on the crown and available part of walls immediately after blasting, ventilation and wall trimming. The last layers are sprayed after ground cleaning.