A.G. Novinkov, Cand. Sci. (Eng.), Sector Head S.I. Protasov, Cand. Sci. (Eng.), Dir., email@example.com Innovative Firm «KUZBASS-NIIOGR», Kemerovo, Russia P.A. Samusev, Cand. Sci. (Eng.), Assoc. Prof. KuzGTU, Kemerovo, Russia
At present, the regulatory methods are missing related to the assessment of seismic safety of the underground workings when conducting blasting on the earth surface. The need for such assessments occurs in the conditions of the location of underground mining workings near the coal pits, finishing mine fields by the open method, when the integrated highwall mining is used in the coal pits. The issues of seismic safety assessment can be complicated by the lack of the experimental data on vibration parameters, for example, if required, to give the answer at the design stage of new mines.
As a criterion of seismic safety, the condition is normally used when the maximum speed of oscillations is less than or equal to the permissible maximum speed for the workings of the defined type. In the present work, the forecast of maximum speed of oscillations is performed on the basis of the regression analysis of the experimental data taking into account the defined probability of non-exceedance, and the «quality» of the regression is estimated using statistical analysis of the residuals characterizing the random spread of the experimental data with respect to the regression line.
The paper also analyzes experimental data, including the results of monitoring the state of underground workings at seismic effects of different degree of intensity. It is shown that the spread of the observed oscillation velocities at which local damage or deformation of the mine workings took place, reaches high values. In the conditions of absence of such data for workings spreading in specific mining and geological conditions, it is recommended that the permissible maximum speed of oscillations be set considering the class of workings and the type of the support. In this case it is noted that the recommended values given in the literature refer to the workings spread in the massif without geological disturbances and anomalies; not having deviations from the regulatory requirements in terms of the state of the workings; in absence of the risk of groundwater breakthrough; in the absence of hazard of gas dynamic phenomena and negative factors. Otherwise, according to the requirements of the federal norms and regulations, seismic safe distance should be increased by 2 times. This requirement is equivalent to multiplying the maximum permissible vibration speed of oscillations by the decreasing factor that considers the regression parameter obtained based on the results of experimental data processing.
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