Purpose. Comprehensive assessment of the fill slope stability for cyclical-and-continuous technology (CCT) conveyors applied to rocks of stripping at Pervomaiskiy quarry of PJSC "Severnyi GOK" to justify effective antilandslide measures. Methods.To study geomechanical stability of fill-up rock mass and slopes of the CCT line, the following methods are used: hydrogeological analysis, visual observation of the object, numerical modeling of the fill slope stability in the finite element analysis software Phase2. Findings.Calculations of the fill slope stability for the open belt conveyor gallery, the bases of the embankment mass and pit wall slopes show that the fill-up mass stability is conditioned by the complex effect of geological, hydrogeological and anthropogenic factors. The geometrical parameters of CCT facilities and physical-mechanical properties of the embankment rocks play a key role in ensuring the stable operation of the CCT line and its sustainability. The numerical modeling of different options to strengthen the slopes of the fill-up mass is carried out, the most effective techniques for these purposes turned out to be surcharges, different in geometry, and retaining prisms of rocks.Originality. The stability margins (SM) for the fill-up mass and slopes on cross-section profiles considering physical and mechanical properties of the complex-structured fill-up mass, its water content and loads of mining equipment are calculated. The areas most subjected to geomechanical deformations and displacements are identified. Practical implications.Based on the simulation results, anti-landslide measures are developed to ensure the stable operation of the CCT complex and stability of the embankment slopes and the pit walls. : cyclical-and-continuous technology (CCT), open pit slope stability, stability of fill-up rock mass, landslide, rock mass water content, stability margin, Mohr-Coulomb failure criterion Keywords ВВЕДЕНИЕНасыпные массивы вскрышных пород являются неотъемлемой частью технологии открытых горных работ. Создание значительных объемов дисперсных несвязных насыпных образований в виде внешних и внутренних отвалов коренных пород вскрыши, гид-ротехнических сооружений, путепроводов и прочих техногенных породных массивов требует постоянно-
Purpose. To analyze the current research regarding rock failure criteria and justify the analytical failure criterion for structurally heterogeneous materials in three dimensional stress-strain state.Methods. The study is based on an integrated approach with the use of analysis and synthesis of literature on the issues related to failure of the rock with heterogeneous structure, and application of analytical and empirical failure criteria to assess the strength of rocks. Findings.The analytical failure criterion is compared with the results of testing rocks in three dimensional stress-strain state. It is proposed to assess the degree of danger of the rock media failure for any point of homogeneous rock mass in the vicinity of mine working through the safety factor n , by comparing the value of equivalent stress e σ with tensile strength in uniaxial compression c R . Application of structural attenuation coefficient c k allows to pass from assessment of the rock sample strength to the evaluation of strength of the real structurally inhomogeneous rock mass.Originality. Failure criterion for structurally heterogeneous bodies with defects in the form of joint system which allows to adequately assess stability of the rock mass is proposed. Practical implications.Comparison of the analytical criterion with the results of laboratory testing of structurally heterogeneous materials in three dimensional stress state allows to predict rock failure in the massif with the accuracy of 94%. Keywords: failure criteria, structurally heterogeneous material, safety factor, tensile strength in uniaxial compression, equivalent stress, coefficient of the rock mass structural attenuation ВВЕДЕНИЕПри монотонном нагружении критерий разруше-ния представляет собой точечное условие потери несущей способности нагруженного твердого тела. Выбор адекватного критерия разрушения горных пород является одной из ключевых проблем в геоме-ханике. В случае одноосного напряженного состоя-ния критерий разрушения оценивается предельным (нормативным) значением напряжения, при котором теряется структурная целостность исследуемого тела. Это пределы прочности на одноосное сжатие, растя-жение и сдвиг. В геомеханике объектом исследова-ния, как правило, является объемное напряженно-деформированное состояние неоднородного массива горных пород, поэтому от выбора и применения кри-терия разрушения зависит точность геотехнических расчетов. Приоритет дается тем критериям, которые достаточно хорошо описывают поведение как одно-родного, так и неоднородного породного массива находящегося в объемном напряженном состоянии.Цель данной работы заключается в анализе суще-ствующих исследований критериев разрушения гор-ных пород и обосновании аналитического критерия разрушения для структурно неоднородных материа-лов, находящихся в объемном напряженно деформи-рованном состоянии.
To summarize and formalize the estimates of landslide risk levels based on the proposed classification of relevant environmental or man-made risks in the regions of Ukraine and local territories, including a gully-ravine network and manmade slopes of technology-related objects that represent certain environmental or man-made risk for residential areas. Methods. To achieve the objective, the following methodological approaches have been applied: analysis of the literature regarding state-of-the-art research on the issues of landslide phenomena assessment and prediction at regional and local levels, zonal-statistical analysis of orographic data for the each region of Ukraine with calculations of the relief integral coefficients, methods for comprehensive evaluation of natural and man-made slopes stability with the con-sideration of their geometry, water saturation, geoclimatic conditions and technogenic impacts; methods of geomechanical assessment, environmental evaluation and forecasting of landslide risk in natural geosystems and man-made slopes based on the stability factor, and scientific generalization of landslide risks using mathematical models developed by the authors and proposed criteria for watering extent and soil deformation in natural and man-made slopes. Findings. The five-level scale for evaluating landslide risk for natural and man-made slopes has been substantiated in terms of their stability control. The proposed landslide risk scale makes it possible to forecast reliably the geomechanical state of the rock mass depending on the values of the slope stability factor in changing geoclimatic conditions and substantiate effective anti-landslide engineering measures. Landslide risk classification of natural slopes according to the stability factor value has been proposed. The scale is recommended for assessing the stability of man-made slopes comprised of solid and bulk rocks and for forecasting the environmental risk from landslides resulting from emergency situations Originality. It has been proved that the number of landslides per unit of precipitation in a region with certain relief is a constant value. The dependences for determining the critical amount of precipitation that will cause a single landslide within the gully-ravine network depending on the specific area of the landslide-prone site and on the relief have been obtained. Practical implications. The five-level classification scale of landslide risk for natural and technogenic slopes in respect to annual precipitations and relief coefficient has been substantiated. That helps forecast landslides and determine the level of environmental and technogenic risk inflicted therefrom.
Railway operation can result in the significant environment contamination with heavy metals. The aim of the study was to broaden the knowledge about the railway transport as a source of heavy metals. Railway ballast stones and herbicides were chosen as the objects of the research since these contamination sources on railways are hardly investigated. The location of sampling the ballast stones was a passenger station, which is characterized by the high traffic intensity. The three most common glyphosate-based herbicides and two combination system herbicides of burn-down with other active agents were chosen for the analysis. The heavy metal content in the railway ballast stones was detected by means of XRF, in the herbicides-by means of MP-AES. The railway ballast stones did not contain a sufficient amount of Cd, Co, Mo, Pd, Sn and W for detection. Pb and As were detected at the low concentration of less than 35 ppm only in several samples. The research results showed that the investigated railway ballast contained a significant amount of Fe, Mn, Cu, Cr and Ni. According to the absolute content of HMs in the contaminated ballast layer, they can be arranged in the following sequence: Fe > Mn > Cu > Cr > Ni > Zn > Pb > As. The content of Fe in the contaminated ballast stones was strongly correlated with that of Ni (r = 0.972), Cr (r = 0.954) and Mn (r = 0.943). These metals are components of the railway steel. Therefore, their source can be the abrasion of rails and wheels. All the investigated herbicides contained Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn. The highest content of Cd, Cr, Ni and Pb was detected in the "Anti field bindweed" herbicide, which can be related to its complicated composition. Compared to the heavy metal content in the ballast stones, the herbicides can be considered a negligible source of these pollutants.
Purpose. To identify development regularities related to a stress-strain state and stability of the open pit walls while mining the steeply inclined iron-ore body at various stages of mining considering deterministic and stochastic components of the rock mass structural heterogeneity. Methodology. Numerical 3D simulation of the rock stress-strain state; application of the strength reduction procedure to determine a safety factor, taking into account the rock mass heterogeneity based on a stochastic model. Findings. The distribution of maximum shear deformations and displacements within the rock mass, making up the pit wall, has been obtained. Potential slide surfaces and safety factors have been determined at various stages of the inclined ore body mining. The effect of the rock mass structure on the pit wall stability has been estimated. A comparison of calculations based on the 3D and 2D models has been carried out. The correction coefficient has been obtained, which allows using the 2D model for multivariate calculations. The relationship of safety factor versus the overall slope angle has been developed. Originality. It has been proved that pit walls retain their stability (the stability factor (SF) is not less than 1.27) while mining the steeply inclined ore body with the transverse panels from top to bottom within each newly cut layer, despite the increasing depth of mining. It is shown that modeling of the real geological structure of a three-dimensional rock mass area factors into the decrease in (by 7%) the safety factor in comparison with the results of the homogeneous model. A probabilistic-statistical approach has been proposed to consider the heterogeneity of the rock mass and avoid unreasonably optimistic forecasts of the pit wall stability. It is shown that 3D modeling gives SF, which differs by 8% from the values obtained in the 2D model. This allows substantiating the correction coefficient to improve the 2D modeling results. Practical value. The regularity of changes in the pit wall stability has been determined depending on the overall pit slope angle in terms of mining-geological and mining-technical conditions of the Kachar deposit, taking into account the real rock heterogeneity.
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