RISKS IDENTIFICATION OF THE GEOTECHNICAL SYSTEM STABILITY LOSS DUE TO GEOMECHANICAL AND HYDROGEOLOGICAL FACTORS

Abstract

Problem statement. The most dangerous of mining technologies is the construction of workings underground and their maintenance in good condition. Uncontrolled deformations of the rock mass, sudden rock falls, destruction of the lining and blockages of workings are emerged. Personnel injuries from these risk factors, directly related to geomechanical processes, reach half of the total number of victims. Therefore, the issue of risks identifying for geotechnical system stability loss due to geomechanical factor, taking into account the rocks water saturation (a factor that significantly affects the strength properties of rocks) is relevant and serves as the foundation for the development of efficient and safe mining technologies. The purpose of the article. To substantiate methods for risks identifying of the underground workings stability loss due to geomechanical and hydrogeological factors for the mining enterprises conditions. Research results. The potential risk of an emergency situation for each of the geotechnical system elements is proposed to be determined: by the parameters values at the current time, by the parameters deviation amplitude and by the parameters deviation speed from the equilibrium point during the previous period of time. For forecasting the stress-strain state of rocks, the methods of implementing geomechanical models, assessing risks and scenarios of situation development are improved. On the basis of rock deformations monitoring, the risks of longwall support stability loss due to roof collapse were established. To identify the risks arising from the influence of the rocks flooding factor on their strength, and, accordingly, on the mine workings stability, rock samples were studied. It was found that when rocks are watered, the risks increase linearly with an intensity of 0.62...0.71 for mudstones, 0.49...0.58 for siltstones, 0.25...0.37 for sandstones in the depth range of 400 ... 800 m. For automated safety systems, it is proposed to process these parameters using fuzzy logic methods. Scientific novelty. The method for risks identifying of the geotechnical system stability loss has been further developed, which is distinguished by: determining regularities of changes in risk indicators of the controlled object dangerous state by a statistically significant number of geomechanical and hydrogeological parameters of monitoring previous events or by trends and forecasts of further events; using fuzzy logic models that take into account the parameters deviations of each geotechnical system elements and the rate of change for these deviations over a period of time. Conclusions. The obtained dependencies determine the input conditions for identifying of the flooded rock massif stability and creating technologies for mine workings support. The investigations made it possible to answer a number of previously unresolved problems associated with the risks of the mine workings stability loss, to ensure higher efficiency and mining operations safety.