Purpose. To substantiate changes in stress-strain state of rock mass in the process of long-pillar mining with the help of double-unit longwalls while evaluating stress of a mine field in terms of Lvivvuhillia SE mine. Methods. Analysis of the plans of mine workings has become a basis for the evaluation of physical and geometrical parameters of a support pressure area of the double-unit stopes depending upon mining and geological as well as engineering conditions for n7 b coal seam extraction. 3D model of the rock mass has been rendered using SolidWorks 2019 software. The geomechanical model of the rock mass is based upon the specified output data concerning actual operating schedule of 1018 and 1019 double-unit longwalls (numbers of the longwalls are changed as it has been required by the authorities of Lvivvuhillia SE) in terms of n7 b seam and support patterns of the development mine workings in Lvivvuhillia SE mine. Each component of the support was modeled as a separate part with the relevant geotech data. Behaviour of the expansion of the rock mass stress-strain state within the selected point has been analyzed by means of sections at the specified plane. Findings. Rendering algorithm of 3D model of rock mass in terms of long-pillar mining of a coal seam using double-unit longwalls has been developed. A geomechanical model of the rock mass has been substantiated depending upon the mining and geological mode of occurrence and engineering parameters of coal mining process. Originality. Nature of the support pressure area formation in front of a stope as well as along the extraction pillar length has been analyzed. It has been identified that if stopes are within one and the same plane, interconnection of their frontal support pressure areas as well as walls of the development workings take place. In this context, adjoining entry acts as the extra destressing technogenic cavity in addition to its proper functions. Practical implications. Output data to make recommendations concerning the efficient mining parameters and methods for rock pressure control have been identified relying upon the analysis of stress-strain state of rock mass in the process of the operation of double-unit longwalls. Visualization of the principles of formation of the stress-strain state of support pressure area and evaluation of the rock mass condition have shown that the maximum reduced stresses reach 70 MPa in terms of 18 m width of the support pressure area.
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© 2020. R. Dychkovskyi, Ia. Shavarskyi, P. Saik, V. Lozynskyi, V. Falshtynskyi, E. Cabana.