Abstrakt
The dynamic characteristics of the hydraulic leg are essential for determining the safe working range of roof supports operating in seams threatened by rock mass tremors. The systematic increase in the support of the hydraulic legs due to deteriorating geological-mining conditions has increased their diameters, which currently exceed 0.32 m for the 1st hydraulic stage. Evaluation of the dynamic properties of the roof support and the hydraulic legs are carried out by the Central Mining Institute through calculation methods as an implementation of the Regulation of the Minister of Energy on occupational safety and health. However, the issue of validating the calculations concerning natural scale studies still needs to be addressed. There are significant limitations in this area due to the technical and metrological capabilities of the testing stations. This paper presents an attempt to evaluate bench testing of a hydraulic leg with 0.32 m of the 1st hydraulic stage diameter for the validation of computational and test methods. Results of previous studies affecting the evaluation of the research methods used are also cited. According to the authors, the optimal and economically justifiable direction is to undertake model tests using numerical analyses and to validate these results, based on the study of models of hydraulic legs that are in use at a reduced scale. The construction of testing stations to ensure adequate dynamic loading for the support of the largest diameter hydraulic legs is currently not economically viable. The problem presented, however, is important given the constantly deteriorating geological-mining conditions and the associated threat of rock mass tremors.
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