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The stability analysis of man-made rock slopes is one of the oldest geomechanical problem, the solution of which has been given considerable attention for many years all over the world. The violation of slope stability is the cause of a landslide–a sliding displacement of rock masses down the slope according to the gravity influence. Landslides occur in any part of a slope due to an imbalance in rocks caused by: an increase in the steepness of the slope because of water washing; weakening of the strength of rocks during weathering or waterlogging by precipitation and groundwater; seismic impact etc. Largely one of the landslide causes is human activity. The main damaging factor of landslides is vast masses, falling asleep or destroying everything in its motion path. Therefore, the list of research papers on the prediction of the landslide occurrence and its consequences includes many hundreds, and their number will not decrease now. Most of them are connected with attempts to build some optimal surface in the body of the slope, along which, most likely, collapse will occur if the equilibrium state of the massif is disturbed. Numerous, sometimes very complex, methods for constructing this surface are used, which, in fact, are not far from the first, simplest approaches based on straight-line (broken) and circularly cylindrical shear surfaces. This paper presents a computer approach to assessing the landslide situation based on the Smoothed Particle Hydrodynamics method (SPH). The scientific and practical value of developing such a computational approach to studying the danger of slope massifs deformation lies in the fact that it does not require a priori assignment of possible places of landslide localization, as is needed in most methods for describing landslides. The proposed computer simulation approach provides researchers with a tool that helps them make scientifically based decisions to evaluate the critical characteristics of the mining. [ABSTRACT FROM AUTHOR]

The relevance of research is driven by the need to expand the possibilities of an explosion action controlling to obtain a rational rock mass fragmentation, the requirements to improve the safety of mining working, as well as the economic feasibility of reducing the loss of minerals and eliminating negative environmental factors of blasting. The paper presents some regularities of the radial air gap value influence for the TNT and ANFO charges on the yield of fractions during geo-environment explosive failure. The investigation were carried out experimentally on compositional models and numerically by the Smoothed Particle Hydrodynamics method (SPH). The article considers the methodological issues of combined application of compositional axisymmetric models and computer simulation for dynamic loading problems solving of the massive to identify patterns of stress localization and rock fragmentation. The research results made it possible to determine the dependences of the change in the middle rock piece and the yield of fines on the radial air gap value. In addition, the influence of the distance to the charge on the yield of the middle rock piece at different explosive densities was established. The developed research methodology makes it possible to determine numerically the influence of various factors on the nature of stress localization and to identify the trigger effect of the geo-environment explosive failure. The results comparison of processing physical experiments and computer simulation shows that the chosen approach ensures the reliability of the research results and turned out to be very useful for analyzing and better understanding the rock massive explosive failure mechanics. The results comparison for physical experiments processing and computer simulation shows that the chosen approach ensures the reliability of the research results and turned out to be very useful for analyzing and better understanding the rock massive explosive failure mechanics. [ABSTRACT FROM AUTHOR]

The article discusses the regularities of deformation and destruction of rock samples with a circular-shaped hole in its center during uniaxial compression tests. With an increase in the load, the appearance of microparticles in the hole, which were recorded instrumentally, was noted. Some experimental dependences of their number on the level of loading for various materials have been obtained. Some theoretical aspects of deformation and fracture of specimens with the formation of main cracks cutting the specimen in the diagonal direction are considered. The smoothed particle method (SPH) attempts to simulate the formation of particles in a sample's boring. [ABSTRACT FROM AUTHOR]

To solve an urgent problem in the coal industry - forecasting emergency hazardous phenomena in mine workings, taking into account the geodynamic activity of the coal seam, it is advisable to represent such a coal seam in the form of some energy-saturated medium, capable of collapsing under certain conditions and releasing a significant amount of kinetic energy into the array. Based on the results of computer calculations for a particular scheme of drilling and blasting operations, it is possible to identify the moment and place of the outburst origin and evaluate the consequences of filling the working space with crushed coal masses and methane. The paper proposes a new model for modeling the entire ejection process. The model integrates well-developed numerical approaches: the finite element method and Euler solver and the Smoothed Particle Hydrodynamics (SPH) method. The first explicitly simulates the deformation, destruction and destruction of a solid, and the second simulates the flows of an ejected mixture of coal, rock and gases, the third is convenient for simulating explosive charges. The interaction and behavior of geomaterials with different physical and mechanical properties in a coupled model under dynamic loading are illustrated. A simple example is presented to simulate a coal and gas outburst process to demonstrate the potential of a coupled model. The results obtained for various parameters of energy saturation can be applied to the study of the regularities of the occurrence and course of the outburst phenomena. At the same time, the capabilities of the SPH method were tested as part of a combined computational approach for computer calculation of the stress-strain state of a coal-bearing rock mass, taking into account the possibility of an outburst. The main task was to obtain adequate results of the consequences of drilling and blasting operations in a rock mass near an outburst-hazardous coal seam. [ABSTRACT FROM AUTHOR]

Underground mining of coal seams often causes problems associated with the imbalance of the natural coal-methane system. In some cases, during anthropogenic action on the coal seam, an extremely large amount of methane is released, which leads to disasters—methane explosions or emissions of coal and gas, in other cases, very little free methane is released, which greatly complicates the commercial production of coal mine methane. Dynamic impact is one of the tools for managing the conditions of coal seams. As a result of explosive action, extended cracks can form in the coal seam for it degassing. The aim of the work is to consider the type of failure to find ways to optimize the explosive impact on the coal seam. This may contribute to the development of a drilling and blasting passport, depending on the objectives of this impact. To this goal, the work uses a joint model of a gas-saturated coal seam to describe the hierarchical relationship between explosive damage to the coal seam and gas evolution [1]. Based on this model, using the numerical simulation by the smoothed particle hydrodynamics method (SPH) [2, 3], the development of the fracture zone is studied and the stress-strain state of the formation near the face before and after the explosion is determined. The obtained patterns help to predict the reaction of coal to a dynamic effect. This is of great importance for the technology of preliminary degassing of coal seams and for the technology of provoking controlled emissions of coal and gas. [ABSTRACT FROM AUTHOR]

A process of the development of rocks discontinuous displacement, which can occur under man's impact in fractured rock massif in the gravitational field in the vicinity of steep sides of deep pits and slopes is considered. The shift of the rock mass manifests itself in the formation of a characteristic spatial structure. In this regard, the problem of finding a characteristic surface that determines the movement of collapsing rock mass in a stress-strain rock massif is very relevant. To evaluate the consequences of the behavior of the fractured slope structure on the formed shear surface, a new computational approach is proposed. The calculations carried out represent quite accurately the processes of deformation and fracture development in the vicinity of the quarries faces and edges, without specifying a priori the most probable location of the rock displacement surface appearance in the massif. It is shown that the identified line of movement is closest to the brachistochrone, which corresponds to the physics of the motion of material points in the gravitational field. [ABSTRACT FROM AUTHOR]

The mechanism of blasting failure of coal is considered for which a combined model of gas-saturated coal is used, which describes the relationship between explosive damage to the coal seam and the subsequent emission of gas. Based on this model, the numerical method of Smoothed-particle hydrodynamics (SPH) is studied the development of zones of failure and stress-strain state of the seam at the vicinity of the well charge after the explosion. In better patterns, help predict coal reaction to explosive dynamic impact. This may be considerable interest for the development of the technology of preliminary degassing coal seams, as well as the theoretical description of the processes occurring in the occurrence of carbon and gas emissions. In this regard, the mechanism for the preparation of gas-producing failure of the packing of the thrust ("bend") of coal with an explosive impact on the coal seam is considered. The investigation includes the study of the formation of cracks in the far from the explosive well zone, modeling the filling of induced cracks of the methane, which is initially in an coal in solvent state, and the time estimate of the initial development of the induced cracks due to the pressure of free methane in the crack. It is established, what depending on the mechanical and diffusion parameters of coal, the start time of the development of the fracture may vary from some tens seconds to many hours. The results of the study may be useful in the development of the theory of explosive effects on the coal seam used in practice in the combination of measures to reduce the risk of sudden outbrust of coal and gas. [ABSTRACT FROM AUTHOR]

The article presents some results of studies of the effect of the design of charges on the yield of fine fractions during blasting operations in open pits during mining. The data obtained serve to formulate recommendations for conducting experimental research in an industrial environment. These data are also useful for determining the influence of the design features of the charge, such as the size of the air gap and the decompaction of the explosive on the intensity of fragmentation and the nature of the stress localization in the rock destroyed by the explosion energy during the extraction of valuable crystalline raw materials and flux limestones. The relevance of research is due to the need to expand the capabilities of controlling the action of the explosion to obtain rational fragmentation of the rock mass, as well as the economic feasibility of reducing the loss of minerals, and eliminating the negative factors of blasting. A research methodology has been developed and tested using composite simulation models for blast-hole charges and within the blasted block. In this work, the Smoothed Particle Hydrodynamics method (SPH) is used for computer simulation. As the practice of calculating dynamic problems of geomechanics has shown, this method is a convenient tool for simulate the entire blasting process, starting from the detonation of the explosive charge, the expansion of detonation products, the action of the explosion energy on the rock, the rock failure, and ending with fragmentation and scattering of fragments. The simulation results show that the chosen method is useful for analyzing and better understanding the mechanics of rock massive failure and crack propagation. [ABSTRACT FROM AUTHOR]

With the aim of expanding the possibility of controlling the action of an explosion and reducing the technogenic impact and losses of minerals, work was carried out to study the effect on the completeness of detonation of various modifications of the structure of components of industrial explosives. It was found that at the nanolevel, the combined treatment with low and high frequency electromagnetic fields has the greatest effect on the change in the size of the mosaic structure block and the defectiveness of ammonium nitrate. At the submicron level, physicochemical treatment using ultrasound and surfactants is most effective. At the macro level, to optimize the parameters of blasthole breaking, studies are carried out using simulation compositional models with color highlighting of the blast zones. Some numerical simulation results are presented. [ABSTRACT FROM AUTHOR]