Materiały konferencyjne SEP 2023

3 and the aggressiveness of the mine water, which is used for diluting the mixture k rel . Evaluation criterion: with an increase in coefficients, the bearing capacity of the wall increases [7]. Cast wall (CW) has a monolithic structure, which helps to increase its load-bearing capacity. Therefore, when the CW is used, k str = 1.0. For the packed wall (PW), k str = 0.7, which is explained by irregular geometric shape of the packs with the mixture that form its structure. When the CW are used, irregularities in the relief of the load-bearing surfaces (roof and floor rocks) concentrate stress in some points of the wall, which provokes the occurrence of vertical cracks in it and their growth along entire height of the protection means, which negatively affects its bearing capacity. Therefore, for CS, k rel = 0.7. In the case of using PW, irregularities in the relief do not affect the strength limit of the wall, so, k rel = 1. This is explained by the fact that under a significant load, only the extreme upper and lower layers of the packs with the mixture, which support the subsequent layers, are destroyed. This contributes to the uniform distribution of stresses in the PWand increases its bearing capacity. Mineral composition of mine waters reduces compressive strength of concrete in the CW and PW by 10% ( k rel = 0.9) on average. Then, taking into account mine conditions, the compressive strength limit for the wall R compm is R comp m = R comp  k str  k rel  k w, (1) where R comp is the compressive strength limit of the wall concrete according to standard tests for different times of its hardening. Next, the limit of compressive strength of the wall with taking into account mine conditions R comp m is compared with the calculated maximum compressive stress in the protective- insulating wall σ comp calc . To ensure the normal operation of the longwall protection means at all time stages of deformation of the underworked roof, the condition R comp m  σ comp calc should be fulfilled. 3. CONCLUSIONS Based on the results of the work performed, the method of calculating the rational parameters of protective-insulating walls, in composition of which the cement-mineral mixtures are used, is improved by taking into account the strength of the host rocks and the speed of the longwall face advancing. The scope of the method application is cast and packed protective-insulating walls. The method made it possible to substantiate the correspondence of physical and mechanical properties of the GiSiV-Sh mixture (the intensity of concrete hardening over time) to geological and technological conditions of mining the Sokalsky coal seam n 7 b and rational parameters of the protection means - the width of the berm and wall. The dimensionless coefficients of the cast and packed walls weakening under the influence of their structure, the irregularities of relief of the underworked and overworked rocks, and the aggressiveness of the mine water used to dilute the mixture are also taken into account. A method is proposed for experimental studying of influence of the mining operations on the state of the roadway district. The method assumes to monitor the stress-strain state of the protection means of the roadway district and the degree of deformation of its supports with taking into account location of the longwall face and the mixture hardening time. Criterion for assessing the state of the protective-insulating wall is its relative vertical deformation under the pressure of the undermined roof at various stages of the mixture hardening. Measurements are carried out from the moment the roadway district drivage starts to its transition to the mode of permanent deformation behind the line of the stope. Therefore, the studies cover all