Geo-Technical Mechanics最新文献

{"title":"Сurrent situation on determination of critical value of heat flow density","authors":"V. Nizhnyk, A. Borysova","doi":"10.15407/GEOTM2020.152.099","DOIUrl":"https://doi.org/10.15407/GEOTM2020.152.099","url":null,"abstract":"The physical process of energy transfer in the form of a certain amount of heat from a body with a higher temperature to a body with a lower temperature until the onset of thermodynamic equilibrium is a continuous process and is present in many areas of human activity. Determining the surface heat flux density makes it possible to measure and control the thermal processes of almost any object made of different materials, as well as substances in order to assess their condition. Based on a theoretical review, the article analyzes the current state to determine the critical value of the surface heat flux density depending on environmental conditions. Based on statistics and arrays of fire cards, it was concluded that every fourth fire in Ukraine can spread to adjacent buildings and structures, process equipment and natural ecosystems by spreading thermal energy with subsequent ignition. The authors consider the concept of heat flux and the concept of heat flux density, as well as define the essence of the concept of critical surface heat flux density as characteristics of heat flux. Scientists conducted a detailed analysis of literature sources, regulations and other sources of information related to this topic. Based on the research, the authors analyzed and found that the value of the surface heat flux density significantly depends on environmental conditions, namely the introduction of finely divided water into the space where the heat process and wind exposure. The authors found that to assess the value of the critical surface heat flux density, it is advisable to use the sign of flame combustion of substances and materials for the criterion base. However, to date there is no statistical base of critical values of surface heat flux density for various substances and materials, in particular those that can be used in the decoration of buildings and technological installations. The article analyzes modern approaches to determining the parameters of heat flux, as well as identifies some differences in these approaches, which allowed to formulate the purpose and relevance of further research, and identifies the main tasks to be achieved to achieve this goal.","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121242881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Calculation of rubber-metal silent-blocks under quasi-static loading","authors":"","doi":"10.15407/geotm2021.157.200","DOIUrl":"https://doi.org/10.15407/geotm2021.157.200","url":null,"abstract":"Abstract. In this paper, an algorithm for calculating rubber-metal silent blocks (hinges) under the action of a lateral quasi-static load is presented. Silent blocks of a welded type made of new brands of rubbers, which are widely used in vibration machines of various types as elastic links, are considered. A calculation is given for a very long hinge, for which the length is large compared to its outer diameter. In the calculation, it was assumed that there are no axial displacements, and the angular and radial displacements can be represented as a product of arbitrary functions of the radial coordinate and the sine and cosine of the angular coordinate, respectively. The relationship between these functions is obtained from the condition of rubber incompressibility. From the condition of the minimum total energy of the system, we have a linear inhomogeneous differential equation of the third order for one of these functions. By solving it under known boundary conditions, we obtain final expressions for the radial and angular displacement, and, consequently, for the displacement of the inner cage. With taking these expressions into account, a solution was also obtained for the hinge, the length of which cannot be considered infinite in comparison with its diameter. In this case, axial displacements should also be considered. Besides, it is assumed that the functions of the radial coordinate for the radial and angular displacement can be represented as a linear combination of the corresponding functions for the long hinge. The corresponding function for axial displacement can be found from the condition of volume constancy. The linear combination coefficients are obtained from a system of two linear algebraic equations, to which the minimum condition for the total energy of the system leads. The exact expression for the movement for the short hinge is rather cumbersome. But for the most common sizes of rubber-metal hinges, you can use a series expansion of the expression for displacement and thus get a fairly simple formula. By comparing the resulting expression with the expression for displacement of the long hinge, you can see that the formula for the infinitely long hinge can only be used if a certain condition is met that binds the dimensions of the hinge. At the end of the paper, an example of calculating a rubber-metal element ШРМ-102, which is under the action of a radial load, is given. The rubber layer in it is made of a new medium-filled rubber made of natural rubber. The obtained value of the displacement of the inner cage is in good agreement with the experimental data.","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117028099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Innovative approaches in organization of work on labour protection and industrial safety on the coal-mining enterprises of the «DTEK ENERGO» LTD","authors":"V. Myroshnychenko, D. Energo","doi":"10.15407/geotm2019.149.089","DOIUrl":"https://doi.org/10.15407/geotm2019.149.089","url":null,"abstract":"","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115971691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of sedimentation conditions on the coal structure and properties","authors":"","doi":"10.15407/geotm2022.160.051","DOIUrl":"https://doi.org/10.15407/geotm2022.160.051","url":null,"abstract":"","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125211340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of the properties of solid particles added to a structured suspension on its dynamic sedimentation stability","authors":"","doi":"10.15407/geotm2022.163.096","DOIUrl":"https://doi.org/10.15407/geotm2022.163.096","url":null,"abstract":"The research paper analyzes previous studies of the influence of two natural relatively pure aluminum oxides on rheological properties of structured suspensions. The results of the research show that the content of these materials in the mineral part of coal contributes to a decrease in viscosity inversely proportional to the ash content of coal to a certain fractional degree. The analysis showed that the effect of additions of mineral particles, their size and concentration on the dynamic or static sedimentation stability of structured suspensions has never been studied. The aim of the research paper is to study the effect of additions of mineral particles of polydisperse granulometric composition of different nature on the dynamic sedimentation stability of a structured suspension of high-ash coals. The solution of the problem is carried out by comparison of the forces of attraction and repulsion, which are characterized by an ion-electrostatic and van der Waals nature, with the forces , which arise when a fluid flows around two particles of different density and size, with taking into account the turbulent component and speed deficits proportional to the hydraulic sizes of interacting particles. As a result of the research, the authors developed and specified the hypothesis of the mechanism of aggregative stability of a structured suspension in dynamics. It takes into account the heterogeneity of the properties of particles of the solid phase, which made it possible to establish the value of the average flow velocity in a circular tube, at which the aggregative stability of a structured suspension is disturbed. It is found that the particle size, the nature of the solid material and its mineral inclusions, their surface potential, and rheological characteristics are the main factors, which determine the aggregative stability of structured suspensions. The influence of rheological characteristics of the structured suspension and the radius of the pipeline on the flow velocity, at which its aggregative stability was disturbed, was studied for the case when the solid phase was represented by particles with different density and fineness. In addition, the minimum possible ratio of the Archimedes parameters of the interacting particles, at which the effect of pseudo-homogeneity occurred, was evaluated.","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133586986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using the BOW-TIE method in analysis of aerological risks of coal mines","authors":"","doi":"10.15407/geotm2021.156.165","DOIUrl":"https://doi.org/10.15407/geotm2021.156.165","url":null,"abstract":"The coal industry in Ukraine remains one of the most dangerous industries. It is characterized by a wide range of accidents and emergencies, a high level of industrial injuries and occupational morbidity. The aim of improving production safety is not only to reduce the risk of injury and occupational morbidity (cases of high probability and insignificant), but also mine accidents, which occur relatively rarely, but are characterized by much more significant consequences. It is necessary to develop and use a risk analysis method that would take into account all aspects of the occurrence and course of a possible accident and would forecast in detail the elimination of its consequences. Ukraine still does not have an comprehensive legal and methodological support for assessing and managing emergency risks, and international standards on these issues, adapted to Ukrainian conditions, are not always brought to practical use. Risk assessment, especially aerological analysis, of a coal mine is a rather complicated process associated with the use of working methods in conditions of insufficient information, there are not enough specialists familiar with the methods of expert assessment, therefore, risk assessment methods well-known abroad are not used in the coal industry of Ukraine in full measure. One of these methods is the BOW-TIE diagram, which allows to simply and visually assess the advancing of a hazard from the place of the risk occurrence to the event that causes undesirable consequences, to determine the stages at which it is necessary to take emergency measures, the nature and reliability of such measures. The article presents the methods for constructing the BOW-TIE diagrams with different level of detail, routes of hazards advancing, establishment of risk control barriers, “brainstorming” during the analysis of aerological risks in order to reduce them to the acceptable level. Examples of using the BOW-TIE diagram are given. The use of foreign developments in domestic practice indicates the promising nature of this approach and the need to continue the work with the aim of wider introduction of this method at coal enterprises in Ukraine. Key words: coal mine, aerological risk, hazard, unwanted outcome, BOW-TIE method.","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131681396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The concept of risk-based technical solutions for the protection of ore and non-ore mine workings","authors":"S. Skipochka, O. Krukovskyi, V. Serhiienko","doi":"10.15407/geotm2023.164.079","DOIUrl":"https://doi.org/10.15407/geotm2023.164.079","url":null,"abstract":"The subject of the research presented in the article is the fastening and protection of mine workings for the extraction of ore and non-ore minerals for the construction industry. The purpose of the work is the development of the concept of risk-oriented technical and technological solutions for the protection of underground mine workings to dramatically increase the efficiency and safety of extraction of ore and non-ore minerals at deposits of a complex structure. The work uses the well-known mixed method of risk assessment, which assumes that underground mining production is accompanied by three main interrelated indicators: occupational safety of miners, environmental safety, and financial and economic risks. The method involves building a matrix of consequences and probabilities by ranking them. The technical-technological solutions for fastening and protection of workings of iron ore and uranium mines and underground enterprises for the extraction of non-metallic raw materials are analyzed. Their shortcomings are identified and the associated risks of operation and long-term preservation of underground enterprises are assessed. The concept of technical and technological solutions for improving the safety, environmental and economic performance of mines is proposed, which should be the basis of the new regulatory and technical documentation for the protection of workings. In particular, for ore mines, this concerns the transition to new technologies of anchorage, special conditions for lining junctions, introduction of bookmarks in particularly dangerous areas, control and reduction of water inflows. For mines producing non-metallic raw materials, the effectiveness of a complete transition from drilling and blasting technology to a mining machinermed one has been practically. If there are thick seams, it is recommended to work them out in separate layers, leaving a gap between them. It is advisable to divide the zones of geological disturbances into small areas, which are outlined with barrier pillars. Emphasis is placed on the mandatory implementation of comprehensive monitoring of the condition of the roof of the structures and their lining on the active and decommissioned areas. Depending on the degree of risk of collapse in large-scale mine workings and its impact on ground objects, the feasibility of using stowing is determined. Research results can be used to implement measures to improve miners' labor safety, environmental safety, and economic performance of ore and non-ore mines.","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133623311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Problems of dumping technology in the inundated open pit space in conditions of surface deformation","authors":"","doi":"10.15407/geotm2022.162.144","DOIUrl":"https://doi.org/10.15407/geotm2022.162.144","url":null,"abstract":"","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"7 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120926970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Justification of the parameters of rotary-vibration drilling of small-diameter boreholes in rocks based on a submersible cavitation hydrovibrator","authors":"S. Minieiev, L. Vasyliev, Мyкola Trohymets, Vira Maltseva, M. Polushyna","doi":"10.15407/geotm2022.162.076","DOIUrl":"https://doi.org/10.15407/geotm2022.162.076","url":null,"abstract":"The article presents the results of laboratory studies of the rotary-vibration drilling method of blast-holes and boreholes of small diameter based on a submersible cavitation hydro-vibrator. A generator that operates in the mode of intermittently stalled cavitation was used as a source of vibration load to the rock-breaking tool. The authors of this article developed and described the design of a submersible cavitation hydro-vibrator at the level of the patent of Ukraine for the invention. In addition, a bench design for laboratory studies of the parameters of a rotary-vibration drilling method was developed and described at the level of a patent of Ukraine for a utility model. It is established that the optimal mode of operation of the cavitation generator is ensured by its cavitation parameter in the range of 0.16-0.2. The geometrical parameters of the cavitation generator in the submersible cavitation hydro-vibrator are determined: the diameter of the critical section is 2.0 mm, the opening angle of the diffuser is 20º, and the outlet diameter is 10.0 mm, and the length of the post-diffuser channel is 200 mm. It is established that under the action of pressure pulses of the washing liquid, which is passed through the cavitation vibrator in the optimal mode, the additional deepening of the rock-breaking tool into the rock sample reaches up to 0.6 mm per rotation. Thus, the drilling speed of small-diameter blast-holes and boreholes (up to 55 mm) with the ЕБГП‑1М drilling rig of the Konotop Machine-Building Plant with the optimal mode of the rotation frequency of the rock-breaking tool, which equals 315 min-1 (5.25 s-1), can be increased by 3∙10-3 m/s, from 23∙10-3 m/s up to 26∙10-3 m/s, which is 13%. Keywords: the rotary-vibration drilling method, cavitation generator, submersible cavitation hydro-vibrator, mining rock.","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116616342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Method of roof-bolting support of mining with the periodic strength of anchor-rock structure","authors":"O. Krukovskyi, V. Krukovska, V. O. Khvorostian","doi":"10.15407/geotm2019.144.053","DOIUrl":"https://doi.org/10.15407/geotm2019.144.053","url":null,"abstract":"","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123192071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}