Livak O. Substantiation of parameters for reducing the strength of mountain rocks by the method of rapid cooling during their mechanical destruction.

Українська версія

Thesis for the degree of Candidate of Sciences (CSc)

State registration number

0424U000012

Thesis Registration Form

0424U000012.pdf

Applicant for

Specialization

  • 05.15.09 - Геотехнічна і гірнича механіка

16-02-2024

Specialized Academic Board

Д 08.188. 01

Institute of Geotechnical Mechanics named after MS Polyakova of the National Academy of Sciences of Ukraine

Essay

The paper establishes the main regularities of rock fracture under conditions of sharp cooling of the rock surface, determines the nature of the formation and development of the crack system both on the rock surface and in depth, theoretically and experimentally shows the influence of the formed crack system on the indicators of mechanical rock fracture, proposes constructive changes to diamond drill bits at the level of inventions that allow to increase the drilling efficiency, develops and implements methodological recommendations for treating the rock mass through a pilot hole to weaken significant rock objects. A model of rock fracture during cooling is proposed, according to which, along with the formation of macrocracks in the massif, a wave of micro fractures moves behind the cooling front. The existence of a micro fracture zone has been confirmed experimentally. It is established that the depth of penetration of the crack system deep into the massif, depending on the difference in heating and cooling temperatures at the same time, is described by a linear function with an angular coefficient in the range of 0.001-0.008, and the dependence of the increase in the degree of rock crushing on the temperature difference is parabolic. A dependence for determining the size of a cracking cell on the rock surface under abrupt cooling was obtained. It was found that the dependence of the cracking cell size on the difference in heating and cooling temperatures on the rock surface is described by a hyperbolic function, with the increase in the temperature difference of 200, 400, 600 °C, the cell size reaches 8.2, 1.9, and 0.83 mm for granite. The studies showed that with the increase in the temperature difference of heating-cooling, the drilling speed of the diamond crown increases linearly, with the temperature differences of 280, 430, 580 °C, the drilling speed increases by 1.4, 1.7, and 2.1 times respectively in relation to the drilling of untreated rock. On the basis of theoretical and experimental studies, the ways of realization of thermocyclic hardening in real mining processes related to the destruction and loosening of rocks are proposed. The results of the dissertation work in the form of methodological recommendations have been implemented at the National Technical University "Dnipro Polytechnic", Kryvyi Rih National University of the Ministry of Education and Science of Ukraine, and ANA-TEMS Limited Liability Company. The expected economic effect is 9 UAN per one meter of well when drilling with a diamond crown with a diameter of 59 mm, and 121 UAN per one meter when expanding the well from 105 mm to 300 mm.

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Research papers

Кожевников А.А., Крисан В.В., Вахалин Ю.Н., Третьяков О.А., Ливак О.В. Разрушение горных пород при резком охлаждении: монография. Днепропетровск: ТОВ «Лизунов Пресс», 2011. 52с.

Vasyliev D.L., Hankevych V.F., Moskalova T.V., Livak O.V. The character of disruption of the rocks surface during rapid cooling. Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, 2020. №5. P. 61-67. (Scopus).

Livak O.V. Effect of a preliminary thermocyclic treatment on the energy intensity of subsequent mechanical destruction of rocks. Modern engineering and innovative technologies. Karlsruhe. Germany, 2020. №14. P. 61-66.

Ганкевич В.Ф., Вахалин Ю.Н., Ливак О.В., Бабец В.В., Коцупей А.Н. Определение геометрических параметров сетки трещин на поверхности горных пород при термоциклическом воздействии. Науковий вісник НГУ, 2008. №8. С. 22-26.

Ганкевич В.Ф., Ливак О.В. Исследование процессов разрушения горных пород с использованием температурного фактора. Збагачення корисних копалин: Наук. – техн. зб., 2017. № 68 (109). С. 46-55.

Ганкевич В.Ф., Кравец В.И, Ливак О.В. Разупрочнение твердых пород тепловым воздействием. Збагачення корисних копалин: Наук. – техн. зб., 2017. №68 (109). С. 76-82.

Ганкевич В.Ф., Кравец В.И., Ливак О.В. Исследование температурных полей на поверхности горной породы при трении плоского элемента для термоциклического ослабления поверхностного слоя. Геотехнічна механіка: між від. зб. наук. праць ІГТМ HAH Укpaїни. 2017. № 135. С. 83-91.

Ганкевич В.Ф., Вахалин Ю.Н., Ливак О.В. Влияние термоциклического воздействия на энергетические и прочностные показатели разрушения горных пород. Збагачення корисних копалин: Наук. – техн. зб., 2018. №69 (110). С. 45-52.

Ганкевич, В.Ф., Вахалин Ю.Н., Ливак О.В. Экспериментальные исследования влияния термоциклической обработки на прочность горных пород. Збагачення корисних копалин: Наук. – техн. зб., 2019. №72 (113). С. 13-19.

Васильев Д.Л., Ливак О.В., Кравец В.И., Ганкевич В.Ф., Куц А.В. О предельных разрывных напряжениях как критерии разрушения горных пород при резком охлаждении. Геотехнічна механіка: між від. зб. наук. праць ІГТМ HAH Укpaїни. 2020. №150. С. 127-135.

Васильев Д.Л., Ганкевич В.Ф., Ливак О.В., Кравец В.И. К оценке температурных флуктуаций в зернах алмаза при бурении. Геотехнічна механіка: між від. зб. наук. праць ІГТМ HAH Укpaїни, 2021. №157. С. 172–179.

Мінєєв С.П., Антончик В.Є., Ганкевич В.Ф., Лівак О.В., Кіба В.Я., Куц О.В., Захарова Д.Р. Пошук методів підвищення продуктивності буріння свердловин у міцних гірських породах. Фундаментальні та прикладні проблеми чорної металургії. 2022. Вип. 36. С. 499-506.

Кожевников А.А., Вахалин Ю.Н., Ливак О.В., Дреус А.Ю. Анализ термического воздействия на горную породу при бурении алмазными коронками. «Форум гірників-2015»: матеріали міжнар. наук.-техн. конф., м. Дніпропетровськ, 30 вересня - 3 жовтня 2015 р. Національний гірничий університет, 2015. Т. 3. С. 21-25.

Hankevich V., Moskalova T., Kabakova L., Livak O. The feasibility evaluation of using cyclic thermal effect in the rock-cutting tools during drilling hard rock. E3S Web of Conferences. 2019, Vol. 109, 00026.

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