Evaluation of blast wave parameters within the near-explosion zone in the process of rock breaking with borehole charges

Соболев, Валерий Викторович; Kulivar, V.V.; Kyrychenko, O.L.; Kurliak, Anton; Balakin, О.O.

doi:10.33271/nvngu/2020-2/047

Cited by 3 publications

(2 citation statements)

References 7 publications

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“…Деякий об'єм породи, що знаходиться на незначній відстані від зарядної порожнини, буде стиснуто у нормальному та розтягнуто у тангенціальному напрямках [15]. На фронті цієї зони хвиля механічних напружень перевищить модуль об'ємного стискання середовища, тому порода поблизу заряду розбивається, створюючи зону пластичних деформацій, так звану зону зминання [16]. Далі після утворення зони зминання та з віддаленням від місця розташування заряду ВР, стискаючі напруження від дії ударної хвилі швидко спадають і на деякій відстані стають менше, а ніж міцність породи на стискання.…”

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New method for determining parameters of drilling and blasting for horizontal and inclined mine workings

Kononenko,

Khomenko,

Kosenko

2023

Coll. res. pap. nat. min. univ.

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Purpose. Development of a new methodology for calculating the parameters of drilling and blasting (D&B) for horizontal and inclined mine workings, taking into account the pressure of the explosion products, the compressive strength of rocks, their structural structure, fracturing and compaction under the action of rock pressure. The methodology of research. Using the well-known laws of the theory of elasticity and the main provisions of the quasi-static-wave hypothesis of the mechanism of destruction of a solid medium by an explosion, a method has been developed for determining the D&B parameters for excavating, which is based on the principle of placing groups of blast-holes in the areas they occupy in the working face and their location behind outside the fender circuits. To establish the suitability of the developed new methodology for calculating the parameters of the D&B, it was tested in the conditions of a real object. Findings. A methodology has been developed for calculating the parameters of the D&B in the excavating, which is based on the principle of placing groups of blast-holes in the areas they occupy in the working face and their location behind outside the fender circuits. The first stage of the methodology includes the calculation and design of straight cuts, the distance between the blast-holes in which is determined by the radius of the crush zone. The second stage of the methodology includes the calculation of: specific and total costs of explosive (EX) per slaughter, the value of the line of least resistance (LLR) for the blast-hole along the radius of the zone of intensive grinding, the areas of groups of holes, the number of blast-holes, the calculated and actual distance between the blast-holes, the actual value of the charge per blast-hole, actual specific and total costs of EX for working face. Approbation of the developed methodology was carried out in the conditions of an operating ore mine during excavating using a bulk emulsion explosive (EЕ) Ukrainit-PP-2, for which the D&B parameters were calculated according to the developed method. On the basis of test blasts, good results were obtained for blasting the bottom of the working, uniform ore crushing and a high utilization rate of blast-holes. The originality. The parameters of the location of blast-holes in the working face are implemented according to the power-law pattern of change in the LLR depending on the diameter of the blast-hole, the pressure of the explosion products, the compressive strength of the rocks, their structural structure, fracturing and compaction under the action of rock pressure. Practical implications. The developed method for determining the D&B parameters for horizontal and inclined mine workings makes it possible to rationalize the uniform arrangement of blast-holes in the working face and to save resources when performing drivage up to 18%.

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unclassified

New method for determining parameters of drilling and blasting for horizontal and inclined mine workings

Kononenko,

Khomenko,

Kosenko

2023

Coll. res. pap. nat. min. univ.

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“…Відомо, що в результаті підривання заряду ВР за рахунок високого тиску продуктів вибуху, що виділилися з надзвуковою швидкістю, у конденсованому середовищі утворюється ударна хвиля [13]. У межах радіусу дії ударної хвили формується зона стискання [14], в якій порода зазнає руйнування до ультрадисперсних частинок і виникає зона зминання. Причиною одного з можливих, а може й головного механізму руйнування гірської породи в цій зоні вибуху можуть бути термопружні напруження.…”

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Mathematical simulation of rock mass destruction zones by explosion

Kononenko¹,

Khomenko²,

Sadovenko³

et al. 2023

Coll. res. pap. nat. min. univ.

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Purpose. Improving the parameters of the rock mass destruction zones by a blasting, depending on the pressure of the explosion products in the charging cavity and the physical and mechanical properties of rocks by combining analytical and numerical mathematical simulation. The methodology of research. Using the theory of elasticity and the main provisions of the quasi-static wave hypothesis of the mechanism of destruction of a solid medium under the action of an explosion, an analytical simulation of the parameters of the formation of crush zones and grinding of a rock mass around the charging cavity under its explosive load was carried out. After the change in the stress-strain state of the massif under the action of the explosion, numerical simulation of the crushing zones, intensive grinding and cracking by the finite element method was carried out. To establish the suitability of the obtained analytical models for calculating the radii of the indicated zones, the results of analytical and numerical simulation were compared. Findings. Analytical models have been developed for the radii of the zones of crushing, intense grinding and cracking, which are formed around the charging cavity in the rock mass under its explosive load, taking into account the pressure of the explosion products, the tensile-compressive strength of the rocks, their structural structure, and fracturing. Numerical simulation of the destruction of rocks around the charging cavity established the power-law dependences of the change in the radii of the crushing zones and the grinding of the massif depending on the diameter of the charging cavity, the pressure of the explosion products, and the compressive strength of the rocks. By comparing the results of analytical and numerical simulation for rigid boundary conditions of a homogeneous non-fractured massif, the discrepancy between the radii of the indicated zones is found to be 4, 8 and 6%, respectively. The originality. The radii of the zones of crushing, intense grinding and cracking, established by mathematicalsimulation, formed during the explosive destruction of the rock mass, change according to a power law dependence on the diameter of the explosive charge, the pressure of the explosion products in the charging cavity, the strength of the rocks in tension-compression, the coefficients of the rock structure, structural weakening and compaction, determine the increase in the accuracy of estimating the parameters of the destruction of the rock mass up to 50%. Practical implications. Based on mathematical models of the radii of the zones of crushing, intense grinding and cracking, which are formed in the rock mass around the charging cavity under the action of an explosion, improved parameters of drilling and blasting operations are determined for mine workings, special-purpose cavities and breaking of the massif.

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