Rock deformation problems

Bulat, A.F.

doi:10.1007/s10778-005-0039-y

Cited by 14 publications

(8 citation statements)

References 23 publications

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“…Обработка результатов таких наблюдений по мнению авторов (Yasin, Umetsu, Tatsuoka, Arthur, & Dunstan, 1999) позволит установить не только характеристики развития деформационных процессов в трех плоскостях, но и определить взаимосвязь между деформациями на земной поверхности и в массиве; -методов визуального внутрискважинного контроля (Shevchenko & Zaitsev, 2014) и много-канальной сейсмоаккустики (Bulat, 2004), которые позволяют определить наличие и динамику раскрытия трещин в массиве и характеризуют напря-женно-деформированное состояние массива вокруг горных выработок;…”

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The rate of deformation development in the rock massif on the basis of surveying monitoring on the earth surface

Chetveryk¹,

Bubnova²,

Babiy³

2017

Min. miner. depos.

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Purpose. Basing on the instrumental surveying measurement, to determine the rate of tensile strain displacements in the rock mass, and to use the obtained data for controlling rock pressure and ensuring job safety.Methods. The rate of deformation development in different types of rocks was defined on the basis of statistical processing of the surveying monitoring results applying the theory of layer-by layer block rockfall. Findings.Results of the instrumental surveying monitoring of the rock mass and surface displacements were generalized, and on their basis, the rate of deformation displacement was determined. Interdependence between the rate of deformation displacement, velocity of the stope advance, depth of mining and height of sheeted zone was specified. Taking into account parameters of the dynamic displacement trench, the volume of destroyed rocks was determined, which manifested itself as rock pressure.Originality. It is for the first time when, on the basis of instrumental observations, the rate of the tensile strain displacement in the rocks with varying degrees of lithification was defined. The height of sheeted zone in the undermined mass was determined on the basis of the established interdependence between the rate of deformations displacements, stope advance velocity, and the step of the main roof rock fall. The value of the sheeted zone height determines the value of the rock pressure. Practical implications.The obtained data about the velocity of deformation displacement in the undermined rock mass allow to control rock pressure and improve efficiency of mining operations and their safety.

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Section: Introductionunclassified

The rate of deformation development in the rock massif on the basis of surveying monitoring on the earth surface

Chetveryk¹,

Bubnova²,

Babiy³

2017

Min. miner. depos.

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“…Over the last years, the international scientific journal International Applied Mechanics has published review articles on applications of engineering mechanics [1,6,7,10,15,21,27], offering in this way the specificity of modern solutions to problems in engineering to the circle of specialists in mechanics and related fields.…”

Section: Introductionmentioning

confidence: 99%

“…Introduction. Over the last years, the international scientific journal International Applied Mechanics has published review articles on applications of engineering mechanics [1,6,7,10,15,21,27], offering in this way the specificity of modern solutions to problems in engineering to the circle of specialists in mechanics and related fields.To guarantee high standards of safety for the nuclear reactors, different kinds of accidents are studied. Among the severe accidents postulated (accidents with a probability of occurrence lower than 10 -6 ), in-vessel steam explosions are studied for Pressurized Water nuclear Reactors (PWRs) [22][23][24].…”

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Influence of the projectile composition and shape during an impact

2006

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Slug impact is considered a potential risk for pressurized water reactors in the event of a severe accident. The German team of FZK investigates this issue through the reduced-scale experiments BERDA, whose goal is to quantify the maximum mechanical energy that the upper head of a PWR is able to withstand. As these tests are performed with a material different from the one that would intervene in a real accident, the French team of CEA studies the influence of the slug material with the SKIPPY mock-ups. In order to understand better the impact process, relevant theoretical study has been conducted with the EUROPLEXUS code Keywords: composition and shape of slugs, slug impact, upper head of pressurized water reactor, mechanical energy, experimental investigation, simulation 1. Introduction. Over the last years, the international scientific journal International Applied Mechanics has published review articles on applications of engineering mechanics [1,6,7,10,15,21,27], offering in this way the specificity of modern solutions to problems in engineering to the circle of specialists in mechanics and related fields.To guarantee high standards of safety for the nuclear reactors, different kinds of accidents are studied. Among the severe accidents postulated (accidents with a probability of occurrence lower than 10 -6 ), in-vessel steam explosions are studied for Pressurized Water nuclear Reactors (PWRs) [22][23][24]. Part of the reactor core is supposed to have molten and fallen into the lower head of the reactor. The contact between the hot molten material (called corium) and the cold water leads to violent evaporation of the water, thus causing a steam explosion. In case of a very energetic explosion, part of the molten material can be accelerated as a liquid slug towards the upper head of the reactor pressure vessel.The slug impact concerns both the upward acceleration of the corium slug and its crash against the upper head of the vessel. In some cases, the head may fail and fragments can be hurled against the concrete containment. If the missiles endanger the containment integrity, this process can lead to a release of radioactive products to the atmosphere. This kind of accident is generally called an α-mode accident [8,9,18].In Europe, slug impact is mainly studied by the German and French research centers FZK and CEA-Saclay. FKZ aims at the quantification of the maximum mechanical energy that the upper head can be able to withstand without failing. The investigation work is largely based on the German mock-ups BERDA, consisting in the simulation of a slug impact on reduced-scale replicas of the upper part of the reactor pressure vessel.As the BERDA tests are performed with a material different from corium because of the difficulties introduced by radioactive material handling, the influence of the slug material is investigated with the French mock-ups SKIPPY.In order to deepen the understanding of the impact process and to extrapolate the experimental results to other combinations of parameters, relevant theoret...

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“…It is now clear that he underestimated the difficulty of the latter problem. Recently, A. F. Bulat [45] has neatly achieved a real breakthrough in solving this formidable problem.…”

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Superposition Method in Thermal-Stress Problems for Rectangular Plates

Meleshko

2005

Int Appl Mech

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The classical two-dimensional biharmonic problem for a rectangular domain is considered. Some historical aspects of the problem are elucidated. The superposition method turns out to be efficient in solving thermoelastic-equilibrium problems in a rectangle. The relationship between the mathematical and engineering approaches to these problems is studied. A few typical examples are given Keywords: biharmonic problem, thermoelastic stresses in rectangle, infinite systems of linear algebraic equations Introduction. Nowadays, the needs of technology provoke interest in thermal-stress problems for various structures. Thermal stresses in structural members were intensively studied in the mid-20th century because of important practical problems that arose in designing new steam and gas turbines, jet and rocket engines, and nuclear reactors [1,6]. Members of such structures are subject to nonuniform and often nonstationary heating that causes temperature gradients and unequal thermal expansion of isolated components. Such nonuniform thermal expansion cannot proceed freely in an elastic body and induces thermal stresses. The magnitude and behavior of thermal stresses must be known to allow comprehensive strength analysis of structures.Thermoelasticity became an independent division of elasticity theory quite a long time ago-linear equations incorporating the thermal effect were derived independently by Duhamel [47] and Neumann [68]. In these fundamental works, they not only set up the governing equations of thermoelasticity, but also solved elementary one-dimensional problems for thermal stresses. The general formulation of the stress problem was discussed in the recent publications [42,43]. Thermoelastic problems were addressed in fundamental courses on elasticity theory due to S. P. 15, 16, and drills therein] and in fundamental treatises due to A. E. H. Love [23, Sect. 74], N. I. Muskhelishvili [31, Sect. 62], and A. I. Lur'e [ 22, Ch. 1, Sect. 13, Ch. 3, Sect. 7, Ch. 4, Sect. 4]. Moreover, these problems were discussed in monographs of Soviet and foreign authors [1,6,12,13,21,24,26,32,34], which include detailed bibliographies on the subject. In this variety of publications, A. D. Kovalenko's textbooks [14,15,17] stand out due to their concise format, clear formulations of problems and methods of their solution, wide coverage of almost all divisions of static and dynamic thermoelasticity, and in-deep analysis of the possibilities for practical application of results. It is not surprising that the first textbook was translated into English [54].It is often possible to analyze the thermostressed state of an elastic body under plane-strain conditions: the plane strain of an extended body of constant cross section where thermal processes do not depend on the longitudinal coordinate and (generalized) plane stress state of a thin, simply connected, isotropic plate of constant thickness. Two-dimensional quasistatic problems of thermoelasticity for a known temperature field and no surface mechanical loads on the boundary of t...

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Rock deformation problems

Abstract: Studies into the stress-strain state of rock mass are reviewed. The solutions of a wide range of applied problems are analyzed and methods used to solve them are generalized. Important areas of further research in rock mechanics are pointed out.

Cited by 14 publications

References 23 publications

The rate of deformation development in the rock massif on the basis of surveying monitoring on the earth surface

The rate of deformation development in the rock massif on the basis of surveying monitoring on the earth surface

Influence of the projectile composition and shape during an impact

Superposition Method in Thermal-Stress Problems for Rectangular Plates

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