CC BY
1УДК 622.235
Isaev E.A.
Chief Miner Ahangarantement JSC (Akhangaran, Republic of Uzbekistan)
ARTIFICIAL ROCK REINFORCEMENT AND BLASTING OPERATIONS IN QUARRIES WITH DIFFICULT GEOMECHANICAL CONDITIONS
Аннотация: article discusses modern methods of artificial rock reinforcement in difficult geomechanical conditions of a quarry. The main factors affecting the stability of arrays, as well as injection, cementation, and polymer hardening technologies, are analyzed. Special attention is paid to the application of geotechnical solutions to prevent deformation processes and collapses. The research results confirming the effectiveness of various methods of rock stabilization, as well as their impact on the safety of mining operations and the economic feasibility of quarry operation, are presented. The factors influencing the efficiency and safety of explosive rock destruction, including the stress-strain state of the massif, fracturing and mechanical properties of rocks, are analyzed. Modern technologies and methods for optimizing blasting parameters are presented, aimed at reducing the negative impact on slope stability and minimizing seismic vibrations. Special attention is paid to the issues of improving safety, environmental sustainability and economic efficiency of mining operations.
Ключевые слова: rock reinforcement, geomechanical conditions, quarry, mass stability, injection hardening, explosion, polymer reinforcement, deformation processes, geotechnical solutions, mining safety.
Artificial reinforcement of rocks in quarries is aimed at ensuring the stability of slopes, preventing collapses and improving the safety of mining operations. In difficult geomechanical conditions, such as high fracturing, water saturation of rocks or the presence of tectonic disturbances, the use of specialized technologies and materials is required.
Key methods include:
- injection technologies (cement and polymer solutions) for filling voids and
cracks,
- anchor and bolt systems for slope stabilization and rock shear prevention,
- the use of geosynthetics to strengthen slopes and prevent erosion,
- drainage systems for groundwater drainage and reduction of hydrostatic pressure,
- the use of reinforcing meshes and structures to strengthen the surface of the
quarry.
Various technologies of injection hardening of soils are used to increase the strength characteristics of the foundations of mining facilities. The most effective methods are pressure injection, effective for sandy soils, and electrochemical fixation, suitable for dusty-clay water-saturated soils [1]. The pressure injection method is based on the introduction of a special injection solution into the soil mass under high pressure sufficient for partial hydraulic rupture of the soil structure. The injected compound penetrates into the pore space, filling it and forming a solid structural matrix. The method of electrochemical fixation is based on the electromigration of reagents under the influence of electric current, which initiates a complex of physico-chemical processes leading to the formation of strong bonds between soil particles [25].
Figure 1. Mechanical methods of strengthening slopes: The principle of strengthening unstable slopes by mechanical means.
Figure 1 is based on the redistribution of stresses in the rock mass. Perceiving the pressure of the collapse prism, fortifications and structures transfer it to a stable part of the array located outside the shear zone. A prerequisite for the use of mechanical methods for strengthening slopes is the presence of a strong, stable array behind the sliding surface (or zone) or at the base of the slope.
Soil fixation is a process of artificial modification of their physico-mechanical characteristics under natural conditions using various physico-chemical methods. This process is aimed at increasing the strength properties of the soil and reducing its deformation characteristics due to the formation of stable interparticle interactions. It should be noted that the method of fixation achieves the greatest efficiency in relation to water-permeable soils with high filtration capacity.
The main methods of soil hardening include cementation, silicatization, electrochemical fixation, thermal treatment, tarring, claymation and bituminization [6-7]. The most common technologies for strengthening foundations are injection methods that allow modifying the soil structure without destroying it.Effective reinforcement requires a preliminary analysis of geological conditions, modeling the behavior of rocks and constant monitoring of the slopes. Modern reinforcement methods reduce emergency risks, extend the life of the quarry and minimize the impact on the environment.
Blasting operations with complex geomechanical conditions in the quarry areas must take into account all factors, including not only the characteristics of rocks (fracturing, porosity, natural slope angles), the level of seismic activity, the presence of groundwater and surface water, as well as the impact and consequences of blasting operations on the surrounding conditions and slope stability. For safe and effective blasting operations, it is necessary to conduct comprehensive geological and geomechanical studies, use modern equipment and technologies, as well as develop modern blasting projects that minimize the risks of deformations and collapses. The use of optimal methods for initiating explosions, accurate calculation of the amount of explosives and controlled blasting operations can increase productivity, efficiency, reduce the cost of quarrying and ensure the safety of work.
Violations of the basic parameters of mining and blasting operations at the quarry site, often observed during operation, can have serious consequences for both safety and economics, depending on the location and scale of the industry. During complex geomechanical studies, several goals are pursued: planning stable slopes of the ledges of the quarry, assessing the stability of the slopes. In this case, the assessment is carried out by calculating the margin coefficient, which is the ratio of passive and active forces acting on the slopes. A margin factor value greater than one indicates sufficient stability, however, uncertainties related to geomechanical conditions can lead to instability even with a higher margin factor. In regulatory documents on slope design, high performance is achieved with reserve coefficients below 1.3 and 1.1 for static and dynamic loads, respectively [8-12].
Blasting operations are initially one of the most complex production processes, which in turn necessitates compliance with increased requirements to established standards and regulations. In some cases, when the procedure for performing certain types of specific work, such as specialized explosive work, is not regulated by the current regulatory documents, certain difficulties arise. In such cases, highly qualified specialists from specialized research institutes and design organizations are involved in the development and implementation of requirements for the production of blasting operations. Similar practices are used when carrying out mowing operations, when it is necessary to determine the critical slope angles, mining parameters and hazardous site mining modes.
Recently, mining companies have shown a special interest in excavation work during drilling and blasting operations in the extreme contour of the quarry. Firstly, it is obvious that an increase in the cost of mining in the contiguous zone, with an increase in the quality of execution and appropriate control, leads to an increase in the safety of mining operations, maintaining a stable condition of the slopes, and, consequently, to an increase in the economic efficiency of field development as a whole [13].
Modern developments in the explosive destruction of rocks during the extraction of solid minerals, obtained as a result of scientific research, laboratory
experiments and industrial operation, have led to the creation of high-precision electronic systems for the initiation (ESI) of borehole charges, which has significantly improved the efficiency of mining operations. However, the existing methods for calculating the parameters of drilling and blasting operations do not fully take into account the geomechanical properties of the rock mass, as well as their impact on the efficiency of rock destruction. For example, the presented methods are based on taking into account approximate values of the length of the face, the drilling, the distances between the blast wells in their rows, which in industrial conditions must be specified taking into account the block structure of the developed mountain range [14].
Artificial reinforcement of rocks in difficult geomechanical conditions of a quarry plays a key role in ensuring the safety and efficiency of mining operations. In conditions of high fracturing, slope instability, and exposure to hydrostatic forces, the use of modern reinforcement methods such as injection technologies, anchor systems, and geosynthetic materials can prevent mountain collapses and deformations.
An integrated approach to reinforcement, including preliminary geomechanical modeling, continuous monitoring and adaptation of the technologies used, ensures the stability of the quarry, reduces emergency risks and extends its service life. This not only contributes to the fulfillment of production tasks, but also minimizes environmental impacts, ensuring balanced and safe development of mineral resources.
Blasting operations in quarries with complex geomechanical conditions requires a comprehensive approach that takes into account the specifics of the geological structure, fracturing of rocks, the presence of tectonic faults and other factors affecting the safety and efficiency of operations. An integrated approach and the introduction of innovative technologies make it possible not only to increase the efficiency of blasting operations, but also to reduce their impact on the environment and the stability of mountain ranges.
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