Горный информационно-аналитический бюллетень (научно-технический журнал), 2015, № 4 (спецвып.13)
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Горная промышленность. Металлургия
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Горная книга
Год издания: 2015
Кол-во страниц: 68
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Артикул: 700864.0001.99
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Представлены результаты научных исследований по проблемам освоения георесурсов Российского Дальнего Востока и Азиатско-Тихоокеанском региона. Представленные научные работы основаны накомплексном научном подходе к таким вопросам, как использование
подземных пространств мегаполисов, внедрение новых и новейших безотходных технологий добычи, переработки и обогащения полезных ископаемых в условиях Азиатско-Тихоокеанского региона, основанных на
принципах полноты и комплексности освоения георесурсов, обеспечения
сейсмо- и ударобезопасности, а также других актуальных вопросов в
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ГОРНЫЙ ИНФОРМАЦИОННОАНАЛИТИЧЕСКИЙ БЮЛЛЕТЕНЬ № 4 СПЕЦИАЛЬНЫЙ ВЫПУСК 13 ОСВОЕНИЕ ГЕОРЕСУРСОВ В АЗИАТСКОТИХООКЕАНСКОМ РЕГИОНЕ
УДК М 15 622.271; 553.068.5; 553.981.2; 658.5:622.32 М 15 Книга соответствует «Гигиеническим требованиям к изданиям книжным для взрослых» СанПиН 1.2.1253-03, утвержденным Главным государственным санитарным врачом России 30 марта 2003 г. (ОСТ 29.124—94). Санитарно-эпидемиологическое заключение Федеральной службы по надзору в сфере защиты прав потребителей и благополучия человека № 77.99.60.953.Д.014367.12.14 Под общей редакцией канд. техн. наук, действительного члена РАЕН А.В. Андреева Макаров В.В., Ксендзенко Л.С., Голосов А.М., Опанасюк Н.А., Андреев А.В., Макишин В.Н., Маликов А.С., Хрулев Е.А., Миробян А.А., Николайчук Н.А., Белов А.В., Каулин М.И., Гребенюк И.В., Обжиров А.И., Лушпей В.П., Видоменко В.В., Жуков А.В., Жукова Ю.А., Михалков А.В., Умаров М.С., Ким Кен Чжу Освоение георесурсов в Азиатско-Тихоокеанском регионе. Отдельные статьи: Горный информационно-аналитический бюллетень (научно-технический журнал). — 2015. — № 4 (специальный выпуск 13). — 68 с. — М.: Издательство «Горная книга» ISSN 0236-1493 Представлены результаты научных исследований по проблемам освоения георесурсов Российского Дальнего Востока и АзиатскоТихоокеанском региона. Представленные научные работы основаны накомплексном научном подходе к таким вопросам, как использование подземных пространств мегаполисов, внедрение новых и новейших безотходных технологий добычи, переработки и обогащения полезных ископаемых в условиях Азиатско-Тихоокеанского региона, основанных на принципах полноты и комплексности освоения георесурсов, обеспечения сейсмо- и ударобезопасности, а также других актуальных вопросов в этой области. УДК 622.3:33.24 © Приморское отделение РАЕН, 2015 © Издательство «Горная книга», 2015 ISSN 0236-1493 © Дизайн книги. Издательство «Горная книга», 2015
УДК 62-75 © В.В. Макаров, Л.С. Ксендзенко, А.М. Голосов, Н.А. Опанасюк, 2015 О МЕХАНИЗМЕ ЯВЛЕНИЯ РЕВЕРСИВНОГО ДЕФОРМИРОВАНИЯ ОБРАЗЦОВ СИЛЬНО СЖАТЫХ ГОРНЫХ ПОРОД* На реверсивный характер линейных деформаций при сжатии образцов горных пород, по-видимому, впервые было обращено внимание в 1958 году в работе (Seldenrath & Gramberg 1958). При поиске деформационных предвестников реверсивные деформации были установлены также в работе (Tomashevskaya & Khamidullin 1972), где была выдвинута гипотеза дилатансионного расширения. Причиной реверсивного деформирования в работе (Tazhibaev 1986) были названы остаточные напряжения. Однако ни одна из рассмотренных гипотез не объясняет все имеющие место аномальные эффекты с единых позиций, как было показано в (Guzev & Makarov 2007). Ключевые слова: сжатие горных пород, линейные деформации, обратимая деформация, акустические и математические методы. UDC 62-75 © Makarov V.V., Ksendzenko L.S., Golosov A.M., Opanasiuk N.A. ABOUT THE MECHANISM OF A HIGH STRESSED ROCK SAMPLES REVERSIBLE DEFORMATION PHENOMENA* Attention to the reversible character of linear deformations of rock samples was presented, apparently, for the first time in (Seldenrath & Gramberg 1958). The authors did not research the mechanisms of the origination of the deformation anomalies, but already in subsequent works such attempts have begun to be undertaken. So the reversible character of the deformations of rocks was contacted with a barrel-shaped straining of samples at uniaxial compression (Tomashevskaya & Khamidullin 1972). In the works of other researchers, residual stresses were proposed in the capacity of reasons for deformation anomalies of various types (Tazhibaev 1986). However, these hypotheses are not supported by critics on closer examination (Guzev & Makarov 2007). In this paper, based on specially developed complex research methods, including on deformation, acoustical and mathematical methods, the authors analyse deformation anomalies of reversible types in samples of rocks at uniaxial compression, define the mechanism of their origin, and develop a mathematical model of the phenomenon. Key words: high stressed rock, linear deformations, reversible deformation, acoustical and mathematical methods. * The paper was supported by grant numbers № 13-06-0113-м_a from the “Scientific Fund” of FEFU and Ministry of the Russian Federation Grant ГК5.2535.2014К.
1. Experimental research into the regularity of THE HIGH STRESSED rock samples FIELD near to the source of macrofailure Based on previous researches, a two-phase model of the macrocrack formation, consisting of a period of scattered microcracking followed by a stage of formation of the source of macrofailure and then macrodefect development, has been assumed (Lockner et al. 1991). The source field is often modelled by inhomogeneity in the form of a soft inclusion, calling the formation round it an area of consolidation at the expense of disproportionation of stress (Brace et al. 1966). Modern methods of researches applying servocontrolled rigid loading devices allow measurements to be taken directly before failure, and multichannel measurement systems – to research the behaviour of the sample as a whole, including around the site of the failure source. The technique of multidot deformation research of samples of strongly compressed rocks provides uniaxial loading of samples by the servocontrolled rigid loading machine MTS-816. This uses resistance strain gauges as a way of taking local measurements of deformations, both in the central part of the sample, and on its height. Thus the «cross» design of the resistance strain gauge allows measurements to be taken of both the longitudinal and lateral strains in a single position, which eliminates the possibility of the joining of individual measurements of the different processes. The conditions of loading, face conditions and sizes of the samples at compression are accepted, taking into account the effect of contacts of end faces with a load machine (Guzev & Makarov 2007). Research was conducted on samples of various rocks, including dacites, rhyolite, diorite, and granite-porphyry. Resistance strain gauges were attached at equal intervals on the whole of the sample, with from four to eight pairs in each row and from one (in the middle) to three rows in height. The special circuit design of their fastening has been developed to preserve the wire leading-outs on the sample. The readings from the resistance strain gauges were fixed by means of a computer program on the multichannel device UIU-2000. This research was carried out at the Geodynamics Laboratories at FEFU. In Fig. 1b, the schema of the sensors displacement is shown during tests. In total, 4 series on 10 samples were tested. The tests were carried out at uniaxial compression of samples under the multidot schema of measurements with from 8 to 48 sensors (Fig. 1).
a b c Fig. 1.Schema of measurements (a, b) of a sample of dacite, source position (triangle on a, b) and change of AE intensity (c) The source position was fixed according to acoustic tests using a complex «Interjunis». The change of AE intensity during the time of loading is shown in Fig. 1c. It can be seen from Fig. 1c that the cracking begins at a level of loading of 224 MPa, which corresponds to the moment of the deflection of the stress strain curves from a linear relation. The position of the source of failure concerning pairs of deformation gauges is shown in Fig. 1a-b). The basic results of the tests on the laws of the deformation of rock samples in a prefailure state using the newest equipment can be reduced to the following. In a prefailure stage of loading, a series of anomalous deformation effects which can be used as precursors is observed. First, this flattening out of the deformation curves with reduction by it fields of modules of deformations by 1.5—3 and more times can be seen in Fig. 2a. It is displayed especially clearly in the field of the source, as shown in Fig. 2b. In this part, there are two anomalous deformation effects where, apart from the already noted effect of significant (repeated) decreases of the module of deformation, there are naturally fixed sharp augmentations of the increments of lateral deformation, which are comparable in size or even exceeding the increments of
а b Fig 2. Laws of deforming of rock samples: a – dacite in a prefailure stage of loading: linear strains, the central part; – character of linear strains in source parts of the rhyolite sample longitudinal strain. The first anomalous effect can be considered to be within the limits of the model of «soft inclusion», as already mentioned above.
2. Source model of «defective heterogeneity» with reference to rocks samples at axial compression Modelling source areas by «soft inclusion» is good knowing in geomechanics (Rice 1980). The inclusion can be ideal soft at the rock module of deformation Е = 0. It is a case of a circular hole in a semiplane with evenly distributed symmetrical load on a part of its border. This problem is considered by the author in (Makarov 2013), where the character of the displacements of a contour of the hole is shown as in Table 1. The second deformation anomaly of the source part, consisting of large lateral strains, as a rule, exceeding the longitudinal increments of deformation, indicates a shear-rupture of a developmental character in the mesodefect part of the source, leading to the wedge action of such defects (Odintsev 1996). Within the frame of the «soft inclusion» model, this effect cannot be considered directly, as the Poisson's ratio of a continuous material cannot exceed 0.5. Properties of the source parts of the sample are formed at the expense of defects of the shearrupture type, where the wedge action of a shift element (Odintsev 1996) prevails. Therefore research on mechanisms of deformation anomalies should be divided into two stages, caused by the presence of two source deformation anomalies: longitudinal and across the direction of loading. Table 1 Size of displacements of a contour of a section of a round hole in a semiplane at the attitude of symmetrically applied load to depth В/Н = 5.0 (R – hole radius) Displacements ϴ, degree u/R v/R 90 0 –1,321 60 -0,011 -0,827 30 0,610 -0,142 0 1,029 -0,071 -30 0,567 0,018 -60 -0,012 0,664 -90 0 1,104 Direct overseeing by deformations of fields of rocks testify that it is lower and nearer to the source (Fig. 3a and 3b respectively) also. On the border of the source and the surrounding material, the condition of a continuity of displacements is met, so it is logical to expect deformation anomalies not only in the source area, but also in the adjoining parts of the rock.
The procedure considered above allows making such supervision, the results of which are shown in Fig. 3. The gauges located immediately under the source part of the sample have fixed the negative increments of the deformations, similar to the results described in (Guzev et al. 2005). At augmentation of strains, there is an original reversal of linear strains in this connection, and this can be called a phenomenon of reversive linear deforming in the immediate vicinity of source areas of the rock sample at uniaxial compression. The size of the negative increments of longitudinal strain in this case exceeds the size of the negative increments of lateral deformation (Fig.3a).The reversive deforming of that part of the sample which also adjoins the source areas has a different character from the source parts of the sample in a direction perpendicular to the direction of action of the load (Fig. 3,b). In this case, by contrast, the size of the negative increments of lateral deformation exceeds the size of the negative increments of longitudinal strain. Sometimes only negative increments of lateral deformation are identified. Thus, the results of complex acoustic, deformation and theoretical tests allow us to formulate a hypothesis of the conditionality of reversive linear strains of rocks samples in immediate proximity to source parts specificity of deforming of defective heterogeneity to what can present the source. a b Fig. 3. Reversive character of linear strains in the direction of an axis of the sample (a) and perpendicular to it (b)
3. Experimental reproduction of reversive deformations near to source areas The laws of deformation of heterogeneous rock samples in a kind of «soft inclusion» were researched using an expressly developed procedure that enables the building of a preliminarily relaxed field in the centre of the sample, its division in height in some parts and installation on their borders metal thresholds, serving by the supports for indicators of hour type. Gauges of hour type settle down on special posts (Guzev & Makarov 2007). For the experiments, samples of strong low-porosity granite were collected. The samples were loaded in two stages: first, deformations of the monolithic sample were measured at loading to 0.8σl-ts, (where σl-ts is the long-term strength) and the sample was then unloaded. Then it was lead up to a long-term strength and, after unloading, the deformations were measured at cyclic loading to σl-ts. The loading of samples of strong granite to strains close to a long-term strength shows that anomalous deformation effects in this case are absent (Fig. 4a). After reachingσl-ts and then unloading, the samples were loaded again to strains of 0.8σl-ts. The appearance in this case of reversible anomalies at the top of the sample (Fig. 4a) is positioned. At a cyclic load, the anomalous character of the deformations is conserved. a b Fig. 4. Reversive character of deforming of samples of rocks in conditions of axial compression: a– relative tests of the monolithic and preliminarily broken granite samples, b – character of deforming of separate parts of the sample
Note also that in all situations that demonstrate a reversive («negative») deformation anomaly, on the next fields of the sample on its height a «positive» deformation anomaly is also formed. This fully explains the cause of the reversal of deformations in the area near the source in a longitudinal direction (reversive anomaly of the first type) and confirms the hypothesis of defective heterogeneity. The modelling of cross-wise reversal of deformations in nearsource areas (reversive anomaly of the second type) can be done by building on local fields of the sample of holding apart efforts of sufficient size to reflect the holding apart action shear-rupture of defects in the area of the source. This effect is modelled to the full by thin cuts (thickness 0.2 – 0.3 mm) made by a cutting tool in the material of rocks well enough giving in to cutting, by introducing the cutting tool in the rock (wedge effect). The size of the deformations depends on the distance to a cut, its depth and length. The optimum depth of a cut is 3 mm, and it is rational to make the cuts at a distance of 3 mm from the gauge. Experimental reproduction of the reversive deformation effects shown in Fig. 3b is done by making imitation shear-rupture fractures in a preliminarily loaded sample. From the experiments, it is determined that anomalous longitudinal and lateral deformations of the reversive type arise close to these imitation fractures (Fig. 5b). Fig. 5. Reversive deformations of the second type: a — the experiment schema, b – deformations of rock samples at compression and the subsequent drawing of a cut, c – wedge effect of cutting
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