Geo-Technical Mechanics最新文献

{"title":"Metamorphism of coals, stages of transformation of coal seams and their hazardous properties","authors":"","doi":"10.15407/geotm2022.161.095","DOIUrl":"https://doi.org/10.15407/geotm2022.161.095","url":null,"abstract":"","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":"132079349","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":"Improvement of thermal-hydraulic efficiency of mining power equipment through the application of porous freon steam generators with high heat conductivity","authors":"","doi":"10.15407/geotm2023.164.045","DOIUrl":"https://doi.org/10.15407/geotm2023.164.045","url":null,"abstract":"In the article, various areas of technical application of porous freon steam generators in mining power equipment are described, and explanations why freon coolants can provide a positive energy effect in such facilities are given. The paper presents results of calculations of thermal-hydraulic efficiency of the porous once-through tubular steam generators with freon-12 as a model working fluid in the the laminar flow area and with boundary conditions of the first kind. The smooth-wall cylindrical channels with different diameters were used as the reference surfaces to be compared. The following mode and design parameters were taken as a calculation base: the liquid temperature and pressure on the saturation line at the entry into the channel were: Ts0= 110 °С; P0s = 39,9·105 N/m2.; temperature heads, i.e. a difference between the wall temperature and temperature of the liquid at the entry into the channel were: ΔT=Tw-Ts0 = 1 °C; 2 °C; 3 °C; 4 °C; 5 °C; the Reynolds numbers at the entry into the channel were: Reo = 100; 200; 500; 1000; 2000; 2300; the channel porosities were: θ = 0.7; 0.75; 0.8; 0.85; 0.9. The porous material was metal felt with the copper fiber diameter of 200 microns. The channel diameters were: d =3·10-3 m; 4·10-3 m; 5·10-3 m; 6·10-3 m; 7·10-3 m. On the basis of the performed computational studies, it was concluded that for the conditions of the same mass flow rates of the coolant, with laminar flow, and the same channel diameters, it is possible to achieve a significant reduction in the length of the porous once-through steam generator in comparison with the length of the smooth-wall once-through steam generator. Due to the significantly shorter length, differential pressure for pumping the coolant can be several tens of percent less in porous evaporation channels than in the similar smooth-walled channels. This computational study also made it possible to establish main regularities in dynamics of the energy efficiency coefficients and their dependence on the model mode and design parameters. It was shown, that positive dynamics of the efficiency coefficients of porous steam generators occurs with decrease of the channel diameter and temperature head, as well as with increase of the Reynolds number in the investigated region of coolant laminar flow.","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"289 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114041243","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":"Further improvements of the shock-wave control equipment","authors":"S. Skipochka, Victor Serhiienko, I. Krasovskyi","doi":"10.15407/geotm2021.159.038","DOIUrl":"https://doi.org/10.15407/geotm2021.159.038","url":null,"abstract":"The equipment for operational non-destructive testing by the shock-wave method developed by the Institute for Geotechnical Mechanics under the National Academy of Sciences of Ukraine, was successfully tested in mine conditions and confirmed the results of theoretical and experimental studies on the possibility of using the relaxation time of free oscillations of a metal-polymer anchor to assess the quality of its fastening. At the same time, some drawbacks of the equipment were identified, which can be eliminated by improving both the data processing unit and the sensor part. The areas of improvements, considered in this work, will improve the stability, speed, mobility and ergonomics of the equipment. It is possible to improve the data processing unit by implementing modern 32/64 bit ARM microprocessors with higher computing power and with greater variability of circuitry solutions. It is possible to develop a new circuit based on these microprocessors or to use available mini-solutions based on the ARM core. It will also improve the oscillator-receiver unit, potentially making it completely wireless. For both options, it will be necessary to develop software, which, due to the increased computing power, can be improved with additional algorithms for data processing. The increased speed and a larger number of I/O ports will also allow transferring the functionality of the analog part to the ARM microprocessor, which, in turn, will reduce the board size, and the freed space can be occupied by additional batteries to increase the battery life. The introduction of ARM microprocessors will also allow, thanks to a large number of libraries and circuits for wireless data transmission, the development of anchor vibration sensor with Wi-Fi/Bluetooth data transmission to the processing unit, which, in turn, will increase mobility and ease of use. For maximum ergonomics, it is possible to develop a combined design with an automatic stabilized hammer and oscillation sensor.","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"1 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":"121035304","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 thin-layer rubber-metal elements of machines and buildings considering the compressibility of the material","authors":"","doi":"10.15407/geotm2021.157.019","DOIUrl":"https://doi.org/10.15407/geotm2021.157.019","url":null,"abstract":"In some constructions with rubber-metal elements, the rubber is loaded in such a way that the hydrostatic stress is tens of times greater than the shear stress. In this case, ignoring the compressibility of rubber can lead to large errors in calculating the elastic and strength parameters of rubber parts. The elastic elements, for which consideration of the material compressibility is essential, include thin-layer rubber-metal elements, whose dimensions in plan are much larger than the thickness. Such rubber-metal elements are used for vibration and seismic protection of heavy machines, buildings and structures. In this paper, the compression of a thin-layer cylindrical rubber-metal element is considered with taking into account the compressibility of the material. In the calculation, it was assumed that the hydrostatic stress is constant over the thickness of the rubber layer, and also that the rate of change of the displacement components in the middle surface of the layer can be neglected in comparison with the corresponding speed in the direction normal to the layer. These assumptions were substantiated as a result of the analysis of the geometry of deformation and equilibrium conditions of a thin layer of rubber bonded to metal reinforcement. As a result of applying these assumptions to the solution of the problem set, a boundary value problem is obtained for an ordinary inhomogeneous linear differential equation of the second order. The corresponding homogeneous equation is solved using a power series, the coefficients of which are expressed in terms of the previous ones using a recurrent formula. Finally, a formula with a modified Bessel function of the first kind is obtained for the hydrostatic stress. The analysis of the obtained formula leads to some simplifications for different values of the dimensionless parameter, which connects the bulk modulus and shear modulus, and the radius of the cylindrical element and its thickness. The resulting axial load on the rubber element is represented by the force that would be perceived by the element in case of uniaxial deformation, i.e. if displacements in cross-sections were prohibited and compression would be performed only due to the change in volume, multiplied by a certain coefficient less than one, which takes into account the decrease in the stiffness of the element due to shear deformation. The paper also presents the results of experimental studies carried out by the authors for thin-layer cylindrical rubber-metal elements made of medium-filled rubber 2959. An example of calculating the axial load on a thin-layer element considering the compressibility of rubber is given. The obtained axial load value coincides with the experimental results with a sufficient accuracy value. Keywords: thin-layer rubber-metal element, rubber compressibility, hydrostatic stress, axial load.","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"86 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":"121272569","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":"Ye Individual risk: possible standardization of estimation","authors":"Anatoliy F. Bulat, T. Bunko, I. Yashchenko, I. Kokoulin, S. A. Holovko","doi":"10.15407/geotm2019.149.003","DOIUrl":"https://doi.org/10.15407/geotm2019.149.003","url":null,"abstract":"","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"1 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":"129049951","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":"Geomechanical risks at underground gypsum mining","authors":"","doi":"10.15407/geotm2021.156.088","DOIUrl":"https://doi.org/10.15407/geotm2021.156.088","url":null,"abstract":"In the focus of the article is estimation of geomechanical risks during exploitation of gypsum mines. Underground extraction of gypsum is performed mainly with the use of room-and-pillar system of mining. This method provides long-term exploitation of large mine workings. The maintenance of workings in operation condition for decades is associated with existence of geomechanical risks. They potentially reduce stability of the mine workings. This negatively affects safety of personnel being underground. The long-term consequences are related to the deterioration of the ecological state of the environment. The main geomechanical processes that cause risks in the operation of gypsum mine workings are identified in the publication. Gypsum mine differs by supports installed only in a few sectors. In these conditions, the most dangerous are formation of the block structure of rock mass and stratification of the roof. Uncontrolled development of these processes can cause an emergency situation. Evolution of karst formation above the mine workings can cause caves on the day surface. Great water inflows are also a significant threat. The cases are known when separate sections in the mine field and entire mines were flooded . An approximate gradation of negative consequences as a result of the influence of each geomechanical process is presented. It is shown that a significant factor for the occurrence of geomechanical risks is the changed physical and mechanical properties of the rock mass. In this case, simulation can be used in order to quantify geomechanical risk. Its application for estimating risk of roof falls with known variation of calculated parameters is shown. The result of the simulation is the curve of probability distribution of safety factors of roof. The probability of unacceptable parameter values is calculated. The possible consequences of a gradual decrease of safety factor are taken into account. A quantitative estimate of the magnitude of geomechanical risk for a concrete project was obtained. This methodology is universal. It can be used to assess operational reliability of engineering objects under significant impact of unstable factors of natural origin. Keywords: geomechanical process, geomechanical risk, gypsum mine, safety factor, simulation.","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"69 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":"116897116","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":"Resource-saving and environmental protection in nuclear-grade zirconium and hafnium production","authors":"","doi":"10.15407/geotm2023.164.135","DOIUrl":"https://doi.org/10.15407/geotm2023.164.135","url":null,"abstract":"The development of efficient and environmentally friendly technological processes for processing zircon concentrate is an urgent problem in the technology of producing reactor-pure zirconium and hafnium used in nuclear power. The review presents the environmental, technical and economic characteristics of zircon decomposition processes using existing industrial technologies and provides data on the environmental safety of each technology. It is shown that current industrial technologies do not meet the criteria of sustainable development and allow emissions of toxic reagents into the environment. New applications of particularly pure zirconium and hafnium compounds which have emerged in recent decades, with impurity content of 10-3–10-5%, require less corrosive reagents than chlorine and fluorine, new resource-saving processes and equipment. Today, technical zirconium oxide with a purity of 98% is the main industrial product of zircon processing, but it allows for losses of hafnium, scandium and silicon. This is equivalent to financial losses of over USD 150 million per year. Based on the analysis of promising halogen-free technologies, a new integrated zircon processing technology is proposed which allows producing scarce hafnium, scandium and silicon compounds along with reactor-pure zirconium and its high-purity chemical compounds. The chemicals consumed in the zircon processing process are utilized in the production of mineral fertilizers, eliminating environmental pollution. The use of the highly efficient refining extraction process in a nitric acid environment using centrifugal extractors with an available tributilphosphate extractant allows us to obtain reactor metals with a purity of 99.95%. The production of high-purity zirconium, hafnium, scandium and silicon oxides meets the demand for non-nuclear products, which expands the volume of integrated zircon processing and meets the growing market demand for new functional materials. The integrated approach to zircon processing can reduce the cost of zircon by producing by-products, recycling consumed reagents and eliminating non-recyclable solid and liquid waste. This will ensure environmental protection even with relatively small volumes of reactor-pure metal production.","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"26 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":"117147116","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":"Estimation of parameters of hydrogeomechanical influence of extraction works on emergency degasation well","authors":"I. Sadovenko, V. Tymoshchuk, A. Zahrytsenko, N. Dereviahina","doi":"10.15407/geotm2019.144.199","DOIUrl":"https://doi.org/10.15407/geotm2019.144.199","url":null,"abstract":"","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"11 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":"115273040","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 influence of production factors on working capacity and adaptation to working conditions","authors":"","doi":"10.15407/geotm2021.156.138","DOIUrl":"https://doi.org/10.15407/geotm2021.156.138","url":null,"abstract":"The purpose of the study is to assess and predict the adaptation of workers of coke-chemical production to working conditions. An assessment is presented to the influence of harmful production factors on the body of workers of coke-chemical production in the process of adaptation to working conditions. The level of influence on the body of harmful production factors was estimated with using a method of multidimensional mathematical analysis of experimental data - solid correlation analysis. For this, intrasystem and intersystem links of physiological systems (PhS) were determined. With using the method of mathematical analysis, the diagnosis was carried out and the evaluation criteria were specified making possible to evaluate and predict the current state of health and level of efficiency of physiological systems. Quantitative criteria are specified for identifying the groups of \"risk\" and disability depending on the share of participation in professional and production activities, age and experience. Analysis of the systemic interaction of the PhS showed the predominance of intrasystem links over intersystems. The factor disperse analysis showed that the PhS stress indicators reflecting the condition of the body's functions were worsened with an increase in not only age, but also professional experience. Indicators of the age - length of service categories of the surveyed workers completely repeat a set of compensatory connections formed in the studied age groups, which made it possible to assume the existence of a single regulatory mechanism that ensures the sustainable functioning of the body as a biological system. It is shown that the low level and premature performance decrement, the exhaustion of functional reserves of the body's adaptation to the effects of a complex of harmful factors of the production environment significantly reduce occupational fitness of workers in the system \"Man - labor factors - health\". Keywords: working conditions, adaptation, factor analysis, diagnosis, intersystem and intrasystems links.","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"175 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":"115167410","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":"Simulation of work of combined support system in complex mining-and-geological conditions","authors":"V. Serhiienko, V. Amelin, Valerii Trypolskyi","doi":"10.15407/geotm2022.161.116","DOIUrl":"https://doi.org/10.15407/geotm2022.161.116","url":null,"abstract":"","PeriodicalId":222378,"journal":{"name":"Geo-Technical Mechanics","volume":"29 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":"115333635","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}