Geomechanical assessment of the stability of internal dump on worked up foundation of the open pit edge

Purpose. Evaluation of the stability of the internal rock dump on the worked up pit edge of Pervomaiskiy quarry of SevGOK taking into consideration geometry, rock physical and mechanical properties and seismic impacts from blasting operations. Methodology. To study geomechanical stability of the pit edge while mining operations, the data of engineering and geological surveys, technological schemes for conducting open mining operations, surveying data were used. For numerical simulation of the internal dump slope stability and the pit edge slope stability, the finite element analysis software Phase2 by Rocscience Inc. is used. Findings. Geomechanical assessment of the stability of the quarry internal dump constructed on the southwestern pit edge taking into consideration complex structure, rock properties and seismic effects from blasting operations has been carried out. For a three-tier dump, safety factors were calculated taking into consideration seismic impacts from blasting operations at a quarry in the range of 0.00625-0.1 g, which corresponds to a magnitude of 3-7 earthquake. The potential effect of extinguished underground mine workings on the stability of the internal dump was assessed. Originality. It is established that the maximum potential displacement of the massif near the extinguished underground workings in the pit edge reaches the value Uxy = 7.6-22.0 m, and a large-scale subsidence area of rocks up to 50-60 m in diameter and up to 4 m in depth can form on the surface of the internal dump. Seismic impacts from blasing operation at the quarry can be as a trigger factor for geomechanical disturbances. Practical value. The results of numerical simulation of the stability of internal dump on worked up the pit edge foundation can be considered in mining development projects to ensure the safety of the open mining technology and internal dumping operations

Вивчення залежності росту Bromopsis inermis holub від різного поливу та кількості важких металів у ґрунті

Зворигін, К. О. Вивчення залежності росту Bromopsis inermis holub від різного поливу та кількості важких металів у ґрунті = Study of the dependence of growth of Bromopsis inermis holub from different watering and the amount of heavy metals in the soil / К. О. Зворигін, С. А. Красовський, О. С. Ковров // Зб. наук. пр. НУК. – Миколаїв : НУК, 2022. – № 2 (489). – С. 89–95.Мета. Визначити вплив важких металів та об’єм поливу на біометричні показники Bromopsis inermis holub. з подальшою можливістю використання досліджуваної рослини у якості фіторемедіатора відвалів відходів вуглевидобування. Методика. полягає у визначенні впливу солей важких металів (Pb, Cd, As) із різними концентраціями та об’єму поливу цих солей на ростові показники рослини B. inermis. Аналіз залежності впливу від концентрації та об’єму розчину на довжину кореневої системи та пагонів. Результати. Дослідження показали, що рослина росте краще не тільки як при збільшенні поливу, але і при додаванні розчинів з різними концентраціями ГДК важких металів. У середньому при 10 мл поливу та додаванні 10 ГДК свинцю, кадмію та миш’яку паростки збільшують свою довжину на 20-25% порівняно з поливом 5 мл води та додаванням 1 ГДК. Помітно, дані контрольних зразків поступаються 5 мл 1 ГДК на 5-10%. Це дозволяє зробити висновок про те, що B. inermis чудово росте за допомогою важких металів і це не пригнічує його зростання. Крім цього навіть з мінімальними умовами поливу, що відображають посушливі місця Донбасу, цю рослину можна використовувати як фіторемедіатор. Наукова новизна. Встановлено адаптивні ростові властивості B. inermis щодо важких металів, які є основним компонентом відвалів відходів вуглевидобування Західного Донбасу. Результати дослідження дають змогу у майбутньому використовувати цю рослину для початкового етапу біологічної рекультивації відвалів. Практична значимість. Результати дослідження дають змогу розробити ефективний метод біологічного етапу рекультивації відвалу шляхом застосування фіторемедіації за рахунок створення рослинного покриву досліджуваною рослиною B. inermis. Рослина являється «рослиною піонером», що в свою чергу дає можливість спростити біологічний етап рекультивації та в майбутньому покращити біологічні процеси на території відвалу відходу вуглевидобування.Purpose. To determine the influence of heavy metals and the volume of irrigation on the biometric indicators of Bromopsis inermis holub. with the further possibility of using the studied plant as a phytoremediator of coal miningm waste dumps. Method. Consists in determining the influence of salts of heavy metals (Pb, Cd, As) with different concentrations and the volume of irrigation of these salts on the growth indicators of the B. inermis plant. Analysis of the influence of the concentration and volume of the solution on the length of the root system and shoots. Results. Studies have shown that the plant grows better not only when watering is increased, but also when solutions with different concentrations of MPC of heavy metals are added. On average, with 10 ml of watering and the addition of 10 MPC of lead, cadmium and arsenic, sprouts increase their length by 20-25% compared to watering with 5 ml of water and adding 1 MPC. Noticeably, the data of the control samples are inferior to 5 ml of 1 MPC by 5-10%. This allows us to conclude that B. inermis grows excellently with the help of heavy metals and this does not suppress its growth. In addition, even with minimal irrigation conditions, reflecting the arid places of Donbas, this plant can be used as a phytoremediator. Scientific novelty. The adaptive growth properties of B. inermis, in relation to heavy metals, which are the main component of coal mining waste dumps in Western Donbass, have been established. The results of the research make it possible to use these plants in the future for the initial stage of biological reclamation of landfills. Practical importance. The results of the study make it possible to develop an effective method of the biological stage of landfill reclamation, by using phytoremediation, due to the creation of a plant cover by the researched plant B. inermis. The plant is a “pioneer plant”, which in turn makes it possible to simplify the biological stage of reclamation and in the future to improve biological processes on the territory of the coal mining waste dump

Determining the Influence of Physical Nonlinearity of Soil Strength Properties on the Estimated Base Resistance

The paper has examined the potential of using nonlinear models of strength in determining the initial critical load on soil, as well as the standardized and estimated base resistance, which makes it possible to reduce labor intensity in the process of determining the strength properties of soils.Based on the analysis and generalization of results from theoretical studies into geomechanical processes using analytical mathematical methods, the formula modifications have been derived that are intended for determining the initial critical load on soil, as well as the standardized and estimated base resistances.We have established interrelation between strength, in particular specific cohesion, and the angle of internal friction, which are included in the strength conditions by Mohr-Coulomb and A. Shashenko, thereby making it possible to improve the procedure for calculating external loads on soil.The dependences of critical loads on base on the mean pressure under the sole of the foundation haven been analyzed in the range of pressure Р=100...500 kPa using the strength conditions by Mohr-Coulomb and A. Shashenko.It has been established that when using generally accepted estimation formulae to determine the critical loads on base, it is required that the pressure range should be taken into consideration at which the properties of soil strength were determined. In this case, using the Shashenko failure criterion to determine critical loads on base makes it possible to properly consider the impact exerted by the mean pressure on them under the sole of the foundation.In contrast to dependences used currently in the Ukrainian, Belarusian, Russian regulatory documents, as well as in other countries' standards, the resulting formulae make it possible to take into consideration the dependences of soil strength properties on the mean pressure on soil under the sole of the foundation. The results obtained make it possible to improve the reliability of determining the initial critical load on soil, as well as the standardized and estimated base resistances. This is achieved by taking into consideration the nonlinearity of the Mohr limiting circles' envelope using the strength condition by A. Shashenk