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Date submitted2023-03-16
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Date accepted2023-12-27
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Date published2024-04-25
Comprehensive assessment of deformation of rigid reinforcing system during convergence of mine shaft lining in unstable rocks
Operation of vertical mine shafts in complex mining and geological conditions is associated with a number of features. One of them is a radial displacement of the concrete shaft lining, caused by the influence of mining pressure on the stress-strain state of the mine workings. A rigid reinforcing system with shaft buntons fixed in the concrete lining thus experiences elastoplastic deformations, their value increases with time. It results in deviation of conductors from design parameters, weakening of bolt connections, worsening of dynamic properties of geotechnical system “vehicle – reinforcing”, increase of wear rate of reinforcing system elements, increase of risks for creating an emergency situation. The article offers a comprehensive assessment of displacements of characteristic points of the bunton system based on approximate engineering relations, numerical modeling of the deformation process of the bunton system and laser measurements of the convergence of the inner surface of the concrete shaft lining. The method was tested on the example of the reinforcing system of the skip-cage shaft of the potash mine. Displacement of the characteristic points of the reinforcing system is determined by the value of radial displacements of the surface of the concrete shaft lining. Evaluation of the radial displacements was made using monitoring measurements and profiling data. The results obtained make it possible to justify the need and timing of repair works. It is shown that the deterioration of the reinforcing system at different levels occurs at different rates, defined, among other things, by mechanical properties of the rock mass layers located at a given depth.
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Date submitted2023-02-27
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Date accepted2023-10-25
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Date published2024-04-25
Microstructural features of chromitites and ultramafic rocks of the Almaz-Zhemchuzhina deposit (Kempirsai massif, Kazakhstan) according to electron backscatter diffraction (EBSD) studies
Microstructural features of the main rock-forming minerals of host ultramafic rocks (olivine, orthopyroxene) and chrome spinel from ores of the Almaz-Zhemchuzhina deposit were studied using the electron backscatter diffraction method. For ultramafic rocks, statistical diagrams of the crystallographic orientation of olivine and orthopyroxene were obtained, indicating the formation of a mineral association in conditions of high-temperature subsolidus plastic flow in the upper mantle. The main mechanisms were translation gliding and syntectonic recrystallization. Olivine deformation occurred predominantly along the (010)[100] and (001)[100] systems. The textural and structural features of chromitites reflect plastic flow processes, most pronounced in lenticular-banded ores. Microstructure maps in inverse pole figure encoding show differences in the grain size composition of the ores: areas consisting of disseminated chromitites are characterized by a finer-grained structure compared to lens-shaped segregations of a massive structure. Analysis of microstructure maps shows that during the transition from disseminated to massive ores, there is a widespread development of recrystallization, adaptation of neighbouring grains to each other, resulting in homogenization of crystallographic orientation in aggregates. The data obtained develop ideas about the rheomorphic nature of chromitite segregations in ophiolite dunites. It is assumed that the coarsening of the structure of massive chromitites is critically associated with an increase in the concentration of ore grains during solid-phase segregation within a plastic flow, when individual chrome spinel grains, initially separated by silicate material, begin to come into direct contact with each other.
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Date submitted2022-06-20
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Date accepted2022-10-07
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Date published2022-11-03
Evaluation of deformation characteristics of brittle rocks beyond the limit of strength in the mode of uniaxial servohydraulic loading
One of the most reliable methods for assessing the physical and mechanical properties of rocks as a result of their destruction are laboratory tests using hard or servo-driven test presses. They allow to obtain reliable information about changes in these properties beyond the limit of compressive strength. The results of laboratory tests of rich sulfide ore samples are presented, which made it possible to obtain graphs of their extreme deformation. Both monolithic samples and samples with stress concentrators in the form of circular holes with a diameter of 3, 5 and 10 mm were tested. It was revealed that during the destruction of the samples, the modules of elasticity and deformation decrease by 1.5-2 times, and in the zone of residual strength – by 5-7 times.
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Date submitted2022-04-29
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Date accepted2022-07-21
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Date published2022-11-10
Deep structure, tectonics and geodynamics of the Sea of Okhotsk region and structures of its folded frame
The use of the zonal-block model of the earth's crust for the construction of regional tectonic schemes and sections of the earth's crust based on a complex of geological and geophysical data makes it possible to consider the resulting maps and sections as tectonic models. The main elements of such models are blocks with an ancient continental base and interblock zones formed by complexes of island arcs, an accretionary prism, or oceanic crust. The developed geotectonic model of the Sea of Okhotsk region reflects the features of the deep structure, tectonics, and geodynamics. The Cimmerian Novosibirsk-Chukotka, Verkhoyansk-Kolyma, Kolyma-Omolon, and Amur folded regions and the Alpides of the Koryak-Kamchatka and Sakhalin-Sikhote-Alin folded regions are developed along the northern, western, and southern boundaries of the Sea of Okhotsk megablock with a continental crust type. From the east, the megablock is limited by oceanic basins and island arcs.
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Date submitted2021-09-29
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Date accepted2022-05-11
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Date published2022-07-13
Tensor compaction of porous rocks: theory and experimental verification
Compaction in sedimentary basins has been traditionally regarded as a one-dimensional process that ignores inelastic deformation in directions orthogonal to the active load. This study presents new experiments with sandstone demonstrating the role of three-dimensional inelastic compaction in cyclic true triaxial compression. The experiments were carried out on the basis of a triaxial independent loading test system in the Laboratory of Geomechanics of the Ishlinsky Institute for Problems in Mechanics of the Russian Academy of Science. The elastic moduli of the material were estimated from the stress-strain curves and the elastic deformations of the sample in each of the three directions were determined. Subtracting the elastic component from the total deformation allowed to show that inelastic compaction of the sandstone is observed in the direction of active loading, whereas in the orthogonal directions there is a expansion of the material. To describe the three-dimensional nature of the compaction, a generalization of Athy law to the tensor case is proposed, taking into account the role of the stress deviator. The compaction tensor and the kinetic equation to describe the evolution of inelastic deformation, starting from the moment of the load application are introduced. On the basis of experiments on cyclic multiaxial compression of sandstone, the identification and verification of the constructed model of tensor compaction were carried out. The possibility of not only qualitative, but also quantitative description of changes in inelastic deformation under complex cyclic triaxial compression is shown.
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Date submitted2021-12-16
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Date accepted2022-04-07
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Date published2022-07-13
The Upper Kotlin clays of the Saint Petersburg region as a foundation and medium for unique facilities: an engineering-geological and geotechnical analysis
- Authors:
- Regina E. Dashko
- Georgiy A. Lokhmatikov
The article reviews the issues concerned with correctness of the engineering-geological and hydrogeological assessment of the Upper Kotlin clays, which serve as the foundation or host medium for facilities of various applications. It is claimed that the Upper Kotlin clays should be regarded as a fissured-block medium and, consequently, their assessment as an absolutely impermeablestratum should be totally excluded. Presence of a high-pressure Vendian aquifer in the lower part of the geological profile of the Vendian sediments causes inflow of these saline waters through the fissured clay strata, which promotes upheaval of tunnels as well as corrosion of their lining. The nature of the corrosion processes is defined not only by the chemical composition and physical and chemical features of these waters, but also by the biochemical factor, i.e. the availability of a rich microbial community. For the first time ever, the effect of saline water inflow into the Vendian complex on negative transformation of the clay blocks was studied. Experimental results revealed a decrease in the clay shear resistance caused by transformation of the structural bonds and microbial activity with the clay’s physical state being unchanged. Typification of the Upper Kotlin clay section has been performed for the region of Saint Petersburg in terms of the complexity of surface and underground building conditions. Fissuring of the bedclays, the possibility of confined groundwater inflow through the fissured strata and the consequent reduction of the block strength as well as the active corrosion of underground load-bearing structures must be taken into account in designing unique and typical surface and underground facilities and have to be incorporated into the normative documents.
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Date submitted2021-03-18
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Date accepted2021-11-30
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Date published2021-12-27
Deformations assessment during subway escalator tunnels construction by the method of artificial freezing of soil for the stage of ice wall formation
- Authors:
- Evgenii M. Volokhov
- Diana Z. Mukminova
The work is devoted to the study of the processes of displacement and deformation of the surface during the escalator tunnels construction of the subway by the method of artificial freezing of soils. The features of the construction and freezing technology, the rocks characteristics in which the escalator tunnels made are considered. The data of specially organized, full-scale surveying observations of deformations on the earth surface are presented. The main factors influencing deformation processes in the frozen strata of a layered inhomogeneous rock mass with inclined tunneling are determined, the complexity of the predictive task and the need to simplify the design scheme are shown. The work is focused on the assessment of the least studied geomechanical processes of soil heaving-uplifts and deformations during the periods of active and passive freezing stages. When studying the displacements processes of the earth surface and rock mass, the finite element method and analysis of the obtained data using field observations of displacements were used. A simplified calculation scheme is proposed for modeling, which allows taking into account the uneven influence of frozen rocks of an inhomogeneous layered rock mass with a large inclined tunneling. The satisfactory convergence of the data of field surveying observations on the earth surface and the results of modeling geomechanical processes for the period of active and passive freezing stages is shown. The proposed calculation scheme is recommended for the prediction of deformation at the stages of underground construction, characterized by the development of the most dangerous tensile deformations of buildings and structures on the surface.
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Date submitted2021-04-11
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Date accepted2021-10-18
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Date published2021-12-16
Comprehensive assessment and analysis of the oil and gas potential of Meso-Cenozoic sediments in the North Caucasus
- Authors:
- Igor I. Bosikov
- Andrey V. Мaier
At the present stage, the development of the oil and gas industry in the Russian Federation is impossible without replenishing the raw material base, so the urgent task is to conduct investigations, prospecting and evaluation of oil and gas bearing capacity prospects in undiscovered areas. The purpose of the investigations is to analyze facies and thicknesses, choose the methodology of prospecting and exploration in reservoirs, make a comprehensive assessment of oil and gas bearing capacity prospects based on experimental investigations and construct a map of oil and gas bearing capacity prospects of the studied sediment structure. The methodology of the conducted investigations was to identify and trace zones of increased fracturing by qualitative interpretation of time seismic sections. Methods for qualitative interpretation of time seismic sections, the model of physical, chemical and geochemical criteria developed by I.A.Burlakov, gas and geochemical surveying and correlation analysis were used in the investigations. A number of prospecting criteria, established based on the analysis of reference seismic materials on well-studied areas in comparison with the results of well tests, were also used. Structural plan for forecast prospects of oil and gas bearing capacity in the studied area was made; zonal and local objects with prospects for oil and gas were identified. Graphical plotting of Eh and pH concentrations distribution and various gas and geochemical indicators allowed identifying zones of possible oil and gas accumulations and starting their detailed survey. Processing of gas and geochemical materials by means of software allowed efficient assessment of prospects for oil and gas bearing capacity of the investigated objects.
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Date submitted2021-03-31
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Date accepted2021-09-29
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Date published2021-10-21
Methodology of modeling nonlinear geomechanical processes in blocky and layered rock masses on models made of equivalent materials
- Authors:
- Boris Yu. Zuev
The research purpose is to develop a methodology that increases the reliability of reproduction and research on models made of equivalent materials of complex nonlinear processes of deformation and destruction of structured rock masses under the influence of underground mining operations to provide a more accurate prediction of the occurrence of dangerous phenomena and assessment of their consequences. New approaches to similarity criterion based on the fundamental laws of thermodynamics; new types of equivalent materials that meet these criteria; systems for the formation of various initial and boundary conditions regulated by specially developed computer programs; new technical means for more reliable determination of stresses in models; new methods for solving inverse geomechanical problems in the absence of the necessary initial field data have been developed. Using the developed methodology, a number of complex nonlinear problems have been solved related to estimates of the oscillatory nature of changes in the bearing pressure during dynamic roof collapse processes; ranges of changes in the frequency of processes during deformation and destruction of rock mass elements, ranges of changes in their accelerations; parameters of shifts with a violation of the continuity of the rock mass under the influence of mining: secant cracks, delaminations, gaping voids, accounting for which is necessary to assess the danger of the formation of continuous water supply canals in the water-protection layer.
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Date submitted2021-01-20
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Date accepted2021-03-29
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Date published2021-09-20
Analysis of the causes of engineering structures deformations at gas industry facilities in the permafrost zone
Construction of oil and gas infrastructure facilities on permafrost soils is the most important task of increasing the raw material base of the entire fuel and energy industry in Russia. Permafrost soil is a complex, multicomponent system, state of which depends on many factors. Buildings and structures built under such conditions, on the one hand, have a complex thermal effect on permafrost soils, and on the other hand, they perceive the consequences of changes in the characteristics of such soils. This situation leads to the fact that buildings and structures on permafrost soil during their life cycle are subject to complex and poorly predictable deformations. Article presents the results of a study for various degradation processes of permafrost soils that can be implemented at construction sites of industrial facilities. Analysis of the deformations causes for engineering structures at the gas industry in the permafrost zone is carried out. Series of reasons causing such deformations have been investigated. Comprehensive criterion for assessing changes in permafrost-geological conditions of industrial sites is proposed. It is suggested to apply the method of calculating the individual characteristics for the temperature regime of the territory to monitor and assess the conditions of heat exchange and predict changes in the geocryological conditions of permafrost soil.
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Date submitted2020-07-30
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Date accepted2021-03-02
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Date published2021-04-26
Experimental study of thermomechanical effects in water-saturated limestones during their deformation
Stability control of elements of stone constructions of various structures is a prerequisite for their safe operation. The use of modern methods of non-destructive diagnostics of the stress-strain state of such constructions is an effective, and in many cases the only way to control it. Studies of thermal radiation accompanying the processes of solid bodies deformation allowed to justify and develop a method that allows to obtain non-contact information about changes in the stress-strain state in various types of geomaterials, including limestones. However, studies of the water saturation influence of rocks on the thermal radiation parameters recorded in this way are currently superficial. Taking into account the water saturation degree of rocks is necessary when monitoring the mechanical condition of stone structures that are in direct contact with water. The main purpose of this work is to study the dependences of changes in the intensity of thermal radiation from the surface of limestone samples with different humidity under conditions of uniaxial compression. The obtained results showed the expected significant decrease in the mechanical properties (uniaxial compressive strength and elastic modulus) of water-saturated samples in comparison with dry ones. At the same time, a significant increase in the intensity of thermal radiation of limestone samples subjected to compression with an increase in their water saturation was recorded, which makes it necessary to take into account the revealed regularity when identifying changes in the stress state of stone structures established according to non-contact IR diagnostics in real conditions.
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Date submitted2020-11-11
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Date accepted2021-03-02
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Date published2021-04-26
Oil and gas content of the understudied part in the northwest of the Timan-Pechora oil and gas province according to the results of basin modeling
Comprehensive interpretation of the results for regional seismic operations and reinterpretation of archived seismic data, their correlation with the drilling data of more than 30 deep wells, including Severo-Novoborsk parametric well, made it possible to clarify the structural maps and thickness maps of all seismic facies structures developed in the territory and water area in the junction of the north of Izhma-Pechora depression and Malozemelsko-Kolguevsk monocline of Timan-Pechora oil and gas province. Data obtained were used at basin modeling in TemisFlow software in order to reconstruct the conditions of submersion and transformation of organic substance in potential oil and gas bearing formations. Modeling made it possible to get an idea of the time and conditions for the formation of large zones of possible hydrocarbons accumulation, to establish space-time connections with possible sources of generation, to identify the directions of migration and on the basis of comparison with periods of intense generation, both from directly located within the operation area and outside them (taking into account possible migration), to identify zones of paleoaccumulation of oil and gas. Work performed made it possible to outline promising oil and gas accumulation zones and identify target objects for further exploration within the site with an ambiguous forecast and lack of industrial oil and gas potential.
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Date submitted2021-02-05
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Date accepted2021-03-30
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Date published2021-04-26
Assessment of negative infrastructural externalities when determining the land value
- Authors:
- Elena N. Bykova
The work forms and substantiates the concept of land value, based on a new institutional theory. The infrastructural component of the cost of land in the presented concept determines, on the one hand, the efficiency of the use of natural resources, properties, demand for land on the market, on the other hand, the costs, which are determined not only by capital investments in construction of engineering infrastructure, but also by losses associated with restrictions on activities within zones with special conditions for territory use, creation of unfavorable conditions for economic activity, small contours, irregularities and others on a specific land plot, which are external negative infrastructural externalities that create losses of rights holders of land plots that are not compensated by the market, falling within the boundaries of these zones. Methods for assessing the impact of such negative infrastructural externalities on the cost of land encumbered by zones in different conditions of land market activity have been developed and tested, based on an expert-analytical approach (depressed market); the ratio of market values of land plots encumbered and unencumbered by a specific zone, and qualimetric modeling (inactive market); modeling by introducing into the model the factor of presence of zones with special conditions for territory use, based on the grouping of zones according to similar regulations for use, or by introducing the parameters of this factor (active market). Methods for taking into account spatial deficiencies and compensating for restrictions and prohibitions on activities on the territory of land plots with an individual market assessment are proposed.
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Date submitted2020-02-19
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Date accepted2020-04-17
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Date published2020-10-08
Decrease in coal losses during mining of contiguous seams in the near-bottom part at Vorkuta deposit
- Authors:
- Oleg I. Kazanin
- Valeriy V. Yaroshenko
The problem of formation of extended zones with high rock pressure (HRP) from safety pillars at the boundaries of extraction pillars formed due to the mine layout of complex geometry is considered at the example of JSC Vorkutaugol mines. A detailed analysis of the remaining reserves of the near-bottom part of the deposit was carried out to estimate losses and the impact of HRP zones from the Chetvertyi protective seam to mining operations on the Troinoi upper seam along with the possibilities for the reduction of sizes of HRP zones at the account of expanding the underworked space. Due to research on the near-bottom part of the Vorkuta deposit, within the framework of the accepted layout, a zone at the Komsomolskaya mine and two zones at the Zapolyarnaya-2 mine were singled out, at which losses at the boundaries of the extraction pillars amount up to 13-22 % of the total resources of the mine field. The high volume of losses in these pillars indicates the relevance of research on the priority extraction impact of protective seams on the efficiency and safety of mining operations in the working area of underworked and HRP zones. Based on the analysis of foreign and Russian experience in the pillar cleaning-up at the boundaries of working areas and the methodical guidelines and instructions, a technological scheme was developed that allows increasing the coal mining recovery factor in the near-bottom part of the Vorkuta deposit from 0.75 to 0.9 without fundamental changing of the ventilation and transport networks and also without purchasing any additional mining equipment. The conducted economic calculations confirmed the effectiveness of implementing the new technological scheme for cleaning-up reserves at the boundaries of extraction districts. The economic effect is from 0.079 to1.381 billion rubles of additional profit from coaxial extraction pillars, depending on the mining and geological conditions and the size of the pillars.
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Date submitted2020-05-07
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Date accepted2020-05-24
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Date published2020-06-30
Study of the technogenesis of the Degtyarsky mine by audio-magnetotelluric express sounding
- Authors:
- Vadim A. Davydov
The audio-magnetotelluric express sounding was performed at four sections crossing the mine field of the currently not functioning Degtyarsky mine. Field measurements were carried out by a universal broadband receiver “OMAR-2m” with active electromagnetic field sensors developed at the Institute of Geophysics UB RAS. Based on the obtained data, deep sections of the electrophysical parameters of the medium – apparent resistivity and effective longitudinal conductivity – are drawn. The nature of the geoelectric structure of the section allows mapping of the major lithochemical contamination plume and identifying the tectonic disturbance zones that drain aggressive mine waters. The mine waters of the Degtyarsky mine are a source of dangerous technogenic pollution. Despite the neutralization of surface runoff, underground routes of acidic water migration occur along tectonic cracks, primarily in the zone of the regional Serovsko-Mauksky fault. Tectonic zones in the mine area contain contaminated fissure-vein water, which is transited at a depth of 70 to over 200 m. Discharging ascending springs of such waters can be located at a great distance from controlled hydrological objects and pollute sources of drinking and household water supply. Urban development in the western and eastern parts of Degtyarsk does not fall within the distribution zone of polluted water. The southern part of the city is located beyond the watershed of the mine water flow area, but a danger of local contamination by tectonic disturbance zones remains possible. The worst environmental situation is observed in the northern outskirts of Degtyarsk, which falls into the area of heavy pollution of underground and surface waters. Besides, acidic fumes from the flooded Kolchedanny quarry can affect the health of city residents when emitted to the atmosphere.
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Date submitted2020-05-06
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Date accepted2020-05-24
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Date published2020-06-30
Revisiting the evolution of deformation zones under platform conditions in the case study of the Kungur Ice Cave (Cis-Urals)
- Authors:
- Nataliya V. Lavrova
Observations in mining tunnels and caves allow to identify composition and development specifics of fault structures under subsurface conditions at various stages of geological history. Basing on the existing formation model of Kungur Ice Cave karst system, author examines the transformations of deformation zones, occurring in the mass of interlaid sulfate and carbonate rocks under platform conditions. Morphologic specifics of vertical structures – organ pipes, developed within one of the gypsum-anhydrite units, are defined by evolution stages of disjunctive faults, penetrating the entire rock mass of the Ice Cave. Point infiltration of surface waters and formation of a single channel, where rock softening and taluses from overlapping deposits gradually occur, are currently considered to be the initiators of pipe formation. At a later stage a sink forms on the surface, increasing the amount of water coming to the karsting mass. However, the size of debris in the talus, incommensurate with the pipe head, rounded arches of separate pipes, fragments of feeder channels, characteristic for artesian conditions of underground water circulation, faceted rock debris from overlapping deposits, specifics of wall structure all define the priority of pipe formation over grottos and cave galleries. Plastic properties of gypsum sediments and processes of their hydration define secondary modifications of pipe walls up to complete filling of the voids and formation of secondary pillars with subsequent renewed formation of vertical channels – significantly smaller in diameter and formed by infiltration waters when subject to corrosion.
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Date submitted2019-03-13
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Date accepted2019-09-19
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Date published2020-02-25
Specifying the technical state limit value of the pump pulp without disassembling
The northern part of the territory of the Republic of Sakha (Yakutia) is rich in vast deposits of diamonds. These deposits are developed by the mining company “Almazy Anabara”, which is engaged in the extraction of diamonds at seasonal processing plants using various technological equipment. One of the key types of equipment is the pulp pump of a foreign company “KETO”. The work of pulp pumps of this company in the enrichment of diamond-containing raw materials is accompanied by intensive hydroabrasive wear of their impellers, the service life of which usually does not exceed three months. In practice, untimely replacement of a worn impeller can lead to emergency breakdowns of sealing elements and bearings, which is explained by super-permissible deflections of the shaft of pumping equipment arising from a significant unbalance of the rotor. The main cause of breakdown of slurry pumps at “Almazy Anabara” seasonal processing plants is the inability to quickly identify their ultimate technical condition, the key sign of which is the maximum wear of the impeller. The seasonal beneficiation plants of “Almazy Anabara” currently need a simple and at the same time reliable diagnostic sign of pulp pumps reaching their ultimate technical state, the identification of which can be quickly performed without disassembling and using complex equipment, which is very important when operating pumping equipment in short wash season on the Far North.
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Date submitted2019-07-13
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Date accepted2019-08-31
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Date published2019-12-24
Method for predicting the stress-strain state of the vertical shaft lining at the drift landing section in saliferous rocks
The article proposes a method for predicting the stress-strain state of the vertical shaft lining in saliferous rocks at the drift landing section. The paper considers the development of geomechanical processes in the saliferous rock in the landing area, the support is viewed as a two-layer medium: the inner layer is concrete, the outer layer is compensation material. With this in view, the paper solves the problem of continuum mechanics in a spatial setting, taking into account the long-term deformation of salts and the compressibility of the compensation layer. Long-term deformation of saliferous rocks is described using the viscoplastic model of salt deformation into the numerical model, and the crushable foam model to simulate the deformation of the compensation layer. This approach considers all stages of the deformation of the compensation layer material and the development of long-term deformations of saliferous rocks, which makes it possible to increase the reliability of the forecast of the stress-strain state of the vertical shaft lining.
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Date submitted2019-01-10
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Date accepted2019-03-02
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Date published2019-06-25
Modeling of the welding process of flat sheet parts by an explosion
- Authors:
- M. A. Marinin
- S. V. Khokhlov
- V. A. Isheyskiy
The list of materials subject to explosive welding is very extensive and amounts to several hundred combinations of various alloys and metals, and the variety of explosive welding schemes has more than a thousand options. In almost all technical solutions, the process involves the sequential creation of physical contact of the materials to be welded and their connection due to plastic deformation of the contacting surfaces. The strength of such a connection depends on the mode of the welding process. With the correct selection of the parameters of the mode, it is possible to obtain a high-quality connection of the required strength. However, the experimental selection of such options is a very laborious and costly process. Computer simulation and application of mathematical models for solving dynamic problems of explosion mechanics simplifies the search for optimal parameters and allows to predict the expected result in the shortest possible time. The article discusses the issues of modeling of explosive welding of metals, calculations related to the parameters of the process of formation of the weld using the Ansys Autodyn software package. A model is presented for analyzing the deformation process of explosion welding of a plate and its connection with a matrix. The main parameters of explosion welding (velocity, pressure, time) are determined. The adequacy of the obtained values was evaluated in the systems aluminum – copper and copper – steel. It also provides a comparative analysis of simulation results and field experiments. Based on numerical calculations, a conclusion was substantiated on the suitability of the model obtained for a preliminary analysis of the main welding parameters at the preparatory stage.
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Date submitted2018-11-23
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Date accepted2019-01-03
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Date published2019-04-23
Structural model and tectonic evolution of the fault system in the Southern part of the Khur area, Central Iran
- Authors:
- A. Sohrabi
- A. Nadimi
- I. V. Talovina
- H. Safaei
In the southern part of the Khur area, there is faults system with predominantly North-West strike. This network of tectonic disturbances is one of the most important fault systems in Central Iran which crosses Paleozoic metamorphic rocks, Cretaceous limestones, and Eocene volcanic rocks. Interpretation of satellite imagery ETM+ (Enhanced Thematic Mapper plus, Landsat) and field observations showed the presence of left-lateral shifts along with fault system. This formed the structure of the branch faults at the northeast end of the main fault. Another feature associated with shear dislocations is the rotation of blocks in the northeastern and southwestern segments of the area under study. There are several basins and positive structures within the area such as a series of uplifts and thrusts, indicating the presence of compressional and extensional tectonics. Another part of the work is devoted to the study of the correlation between active faults and earthquakes. Processing of satellite images, field observations, records of micro-earthquakes within a radius of 17 km made it possible to analyze the earthquakes parameters and the position of tectonic disturbances, and, as a result, confirm the presence of active faults in the region. In addition, we have identified three successive stages of the Khur area tectonics: rifting, contraction, change of convergence and uplift direction.
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Date submitted2018-08-29
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Date accepted2018-10-25
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Date published2019-02-22
The study of the effect of temperature on the ability of metals to accumulate energy during their plastic deformation
The subject of research is the surface layer of highly loaded parts, friction units of mining machines and equipment. The article presents a theoretical analysis of the factors that determine the ability of the material of the surface layer of parts to accumulate energy in the process of plastic deformation. It is suggested that the activation character of the accumulation of energy by metals. Based on the theory of diffusion, it was shown that the mobility of atoms, as well as the accumulated energy, are determined by the ratio of the test temperature to the melting temperature.
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Date submitted2018-01-23
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Date accepted2018-02-25
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Date published2018-06-22
Influence of post-welding processing on continuous corrosion rate and microstructure of welded joints of steel 20 and 30KHGSA
- Authors:
- A. M. Shchipachev
- S. V. Gorbachev
Welded joints of structure steels have lower corrosion resistance in comparison to base metal. To increase corrosion resistance of welded joints and heat-affected zone they use longtime and energy-consuming methods of thermal and mechanic processing. The article covers the possibility of using the superplasticity deformation (SD) effect for processing of welded joints. The effect of SD is that metals and alloys with a small grain size (of the order of 10 μm) under conditions of isothermal deformation at a certain temperature acquire the ability for unusually large plastic deformations while reducing the deformation resistance. Grain-boundary sliding during superplasticity provides a high degree of structural homogeneity. If the metal does not have the small grain size, then during isothermal deformation at appropriate temperature the SD effect will not be fully manifested but will cause relaxation of residual micro and macro strains, recrystallization, which can be used during processing of welded joints to ensure their full strength. There have been carried out the investigation of processing methods impact - SD, thermal cycling and influence of post-welding treatment on corrosion rate and microstructure of steels 20 and 30KhGSA. It is shown that after deformation in superplasticity mode there is low corrosion rate and more favorable microstructure in the studied samples of steel. Post-welding processing of welded joints in SD mode provides low tool loads and low energy costs.
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Date submitted2017-10-29
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Date accepted2017-12-31
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Date published2018-04-24
Risk assessment of accidents due to natural factors at the Pascuales – Cuenca multiple-use pipeline (Ecuador)
- Authors:
- Dzh. Zambrano
- S. V. Kovshov
- E. A. Lyubin
The natural aspects of the accident risk at the Pascuales – Cuenca multiple-use pipeline (Ecuador) are analysed in the paper. The Russian Methodological recommendations for the quantitative analysis of accident risks at hazardous production plants of oil trunk pipelines and oil product trunk pipelines issued in 2016 are used as a methodological framework due to relatively poorly defined evaluation mechanism for natural factors of accidents at oil trunk pipelines in the most widespread international accident risk assessment methodologies. The methodological recommendations were updated to meet the environmental conditions of oil pipelines of Latin America. It was found that the accidents due to natural factors make up approximately 15 % of cases at oil trunk pipelines in Ecuador. Natural geographical features of the areas surrounding the main Ecuadorian Pascuales–Cuenca oil trunk pipeline and its relatively short length allow defining three zones along the line in terms of the accident risk: lowland coastlines, high plateaus, and foothills. Calculations and analysis revealed that the maximum predicted specific frequency of accidents is characteristic of the lowland seaside area. The evidence showed that physical and chemical properties of soils and significant seismic activity are the root causes of failures.
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Date submitted2016-11-03
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Date accepted2016-12-27
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Date published2017-04-14
Evolution of mineral forms of rare element accumulation in ore-bearing granites and meta-somatites of Verkhneurmiysk ore cluster (Priamur region)
It has been attempted to expand existing understanding of accessory mineralization evolution of rare metal-granite series at post-magmatic stage of their development and formation of associated hydrothermal deposits. Composition and distribution of rare elements of Verkhneurmiysk ore cluster have been examined from the position of mineralogy: the study focused on accessory and ore minerals Sn, W, Nb, Ta, Bi, Y, rare earth elements in rare metal Li-F granites and associated metasomatites. It has been discovered that accessory magmatic and hydrothermal mineral complexes share the same geochemical features, are formed under the leading role of abovementioned elements and consistently follow each other over time. It has been traced how mineral forms of accumulation of Sn, W, Nb, Ta, Y and rare earth elements evolve in the processes of magmatic crystallization and post-magmatic metasomatism in the time series: rare metal granites → zwitters → tourmalinites → chloritites. Mineral rocks of each stage were noted to inherit mineralogical and geochemical distinctions from the rocks of the previous stage. A significant number of minerals, forming in the course of two-three stages, have been discovered, as well as omnipresent magmagene-hydrothermal minerals. For a number of accessory minerals of rare metal granites post-magmatic generations have been identified. Special diversity among accessories of rare metal granites and zwitters was observed in tungsten, tin and bismuth minerals.
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Date submitted2016-09-06
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Date accepted2016-11-15
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Date published2017-02-22
Modelling of fiberglass pipe destruction process
The article deals with important current issue of oil and gas industry of using tubes made of high-strength composite corrosion resistant materials. In order to improve operational safety of industrial pipes it is feasible to use composite fiberglass tubes. More than half of the accidents at oil and gas sites happen at oil gathering systems due to high corrosiveness of pumped fluid. To reduce number of accidents and improve environmental protection we need to solve the issue of industrial pipes durability. This problem could be solved by using composite materials from fiberglass, which have required physical and mechanical properties for oil pipes. The durability and strength can be monitored by a fiberglass winding method, number of layers in composite material and high corrosion-resistance properties of fiberglass. Usage of high-strength composite materials in oil production is economically feasible; fiberglass pipes production is cheaper than steel pipes. Fiberglass has small volume weight, which simplifies pipe transportation and installation. In order to identify the efficiency of using high-strength composite materials at oil production sites we conducted a research of their physical-mechanical properties and modelled fiber pipe destruction process.