Abstract
Rock mass is a medium created through processes that have lasted over four billion years, and its intrinsic feature is the variability of the parameters that describe it. A particularly high variability of mechanical parameters is observed in Carboniferous sedimentary and metamorphic rocks. The mechanical properties, especially the rock mass strength, are essential for the design and maintenance of the stability of excavations conducted in it and for the safe conduct of mining operations. This article presents the test results confirming the random variability of the mechanical parameters of the rock mass. The second part of the article presents the results of numerical simulations mapping the Carboniferous rock mass along with a 1000 m deep tunnel excavation protected by steel arch supports. Numerical simulations were carried out for models with different variability coefficients of strength and deformation parameters, and the obtained results were analyzed in terms of damage zones and rock mass stress state as well as axial forces in the modelled supports. The results of the simulation demonstrate the impact of the variability of rock mass properties on its state in the vicinity of the excavation and, consequently, on the internal forces in the steel supports and their uneven loading along the length of the excavation. This fact should be taken into account in their design.
Highlights
A characteristic feature of rock mass, especially Carboniferous rock mass, is the high variability of both its rock layers and the properties of the rocks that make up the individual layers [1,2,3]
Numerical simulations were carried out for models with different variability coefficients of strength and deformation parameters, and the obtained results were analyzed in terms of damage zones and rock mass stress state as well as axial forces in the modelled supports
The purpose of this article is to determine the impact of the rock mass properties, and in particular, the statistical dispersion of the mechanical parameters that characterize it on the condition of both the rock mass and the supports installed in the mining excavations [23,24]
Summary
A characteristic feature of rock mass, especially Carboniferous rock mass, is the high variability of both its rock layers and the properties of the rocks that make up the individual layers [1,2,3]. The main factor influencing the static load of the supports is the formation of the excavation damage zone [16,17,18,19]. The extent of this zone depends on many factors, the most important of which are the state of stress in the rock mass, rock properties, and the shape and dimensions of the excavation [20,21,22]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
