Terrestrial laser scanning in the construction of a numerical model geometry related to underground post-mining facility

Abstract The procedure of building a quasi-3D geometry of a numerical model of an underground post-mining facility is presented in the article. For this purpose, measurements were made, based on the terrestrial laser scanning (TLS) technology, of a fragment of St. John adit, which is part of the underground tourist route “Geopark” St. Johannes Mine in Krobica in Lower Silesia in Poland, in the neighborhood of Krobica, Gierczyn and Przecznica – the places located in the vicinity of the well-known health resort Świeradów Zdrój. TLS, as one of the most advanced mining surveying technologies, enables accurate mapping of even the most complex geometries of underground mining facilities. This opens wide possibilities in the construction of more accurate numerical models of the behavior of the rock mass around such underground objects. As a result, more reliable calculation results are obtained, which are the basis for designing mining support protection, for example, with rock bolting. This translates into an improvement in the safety of underground excavations, in the conditions of exploitation in mining as well as in historical post-mining excavations made available to tourists. In the construction of the geometry of numerical model, software such as Trimble RealWorks was used to orientate individual “point clouds” from measurement stations. CloudCompare software was also used to generate cross sections to the adit axis, and AutoCad software was used for processing and spatial orientation of a selected characteristic cross section. Using the latest version of the FLAC 3D v.9.0 software, the excavation cross-section geometry obtained from measurements was mapped to and discretized (i.e., meshed), giving it a third dimension at the same time.