Abstract
Red shale is widely distributed among the deep mine areas of Kaiyang Phosphate Mine, which is the biggest underground phosphate mine of China. Because of the effect of various factors, such as high stress, ground water and so on, trackless transport roadways in deep mine areas were difficult to effectively support for a long time by using traditional supporting design methods. To deal with this problem, some innovative works were carried out in this paper. First, mineral composition and microstructure, anisotropic, hydraulic mechanical properties and other mechanical parameters of red shale were tested in a laboratory to reveal its deformation and failure characteristics from the aspect of lithology. Then, some numerical simulation about the failure process of the roadways in layered red shale strata was implemented to investigate the change regulation of stress and strain in the surrounding rock, according to the real rock mechanical parameters and in-situ stress data. Therefore, based on the composite failure law and existing support problems of red shale roadways, some effective methods and techniques were adopted, especially a kind of new wave-type bolt that was used to relieve rock expansion and plastic energy to prevent concentration of stress and excess deformation. The field experiment shows the superiorities in new techniques have been verified and successfully applied to safeguard roadway stability.
Highlights
As the mining depth increases, the in-situ stress increases rapidly, the original support technology and measures are invalid, the roadway repair rate is high and there are frequent roof falls, slabs, bottom heaves, etc. [1,2,3] after permanent roadway support, which requires multiple maintenances
The large deformation of the roadway severely restricts the production of soft rock mines [4,5,6]
Roadway support is a crucial step in the mining process, and it is the direction that many scholars have been studying [7,8,9]
Summary
Roadway in Gentle Dipping Strata of Keywords: high stressed soft rock roadway; wave-type bolt; support technology. Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
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