Amount Of Explosive Research Articles

The fracture propagation law of axially symmetric intersecting precut hydraulic fracturing in mine rock-breaking

As a mine rock-breaking technique, hydraulic fracturing technology can reduce the amount of explosives used, which enhance safety and reduce environmental pollution in mines. After precutting along the borehole axis, hydraulic fractures will expand along the precutting direction within a certain range and reduce initiation pressure. These hydraulic fractures cut through the rock mass, reducing its integrity and weakening its mechanical properties. Hydraulic fracturing with axially symmetric intersecting precut fractures not only controls the multi-directional propagation of fractures but also increases the fractures within rock mass. The lattice method simulated the hydraulic fracturing process, focusing on the parameters like angles between precut fractures and the minimum horizontal principal stress, the maximum horizontal principal stress, and angles between intersecting precut fractures. Results indicate that the hydraulic fractures propagate along intersecting precut fractures, forming main and interconnected secondary fractures. The directional cutting effect is influenced by the number of secondary fractures. With the increase in the angle between precut fractures and the minimum horizontal principal stress, the maximum horizontal principal stress, the angle between precut fractures, the area of secondary fractures decreased, and the expansion extent of main fractures along the precut fractures increased, indicating better directional effects. The study identifies relationships between initiation time, initiation pressure, and parameters. These findings provide valuable technical guidance for designing on-site construction plans for hydraulic fracturing projects involving intersecting precut fractures.

Ensuring the protection of critical infrastructure energy facilities from explosions

Purpose. Analysis of the protection of critical energy infrastructure facilities, which are often destroyed under the influence of a shock wave, which affects the stability of Ukraine's energy systems. Determination of the state of security of critical infrastructure, which ensures the functionality, continuity of work, integrity and stability, which is reflected in the life support of the population. Methodology. To achieve this goal, a simulation of a detonation explosion and the distribution of shock waves within prismatic bodies simulating urban development using the ANSYS AUTODYN software product were carried out. In conditions of dense urban development, measures to ensure the protection of critical infrastructure facilities are selected based on the interaction of liquids, gases and solids, phase transitions, propagation of shock waves, etc. The results of the study were obtained. The calculated parameters of the shock wave distribution limit in 15 ms after detonation were determined, the pressure data corresponding to the measurement sensors T1 and T2 were recorded, it was determined that the values of the pressure of the blast wave at the manometric points T1 and T2 are the highest about 5 ms, аt the same time, the pressure on the underground structure is almost 50% less than on the ground. Protection of critical energy infrastructure facilities in the form of construction of underground transformer substations and their modernization in conditions of dense urban development is proposed. This is the optimal solution to eliminate problems, which arise with an increase in loads in city power grids and protect them from the action of a blast wave PCT. Originality. The dependencies of the pressure distribution on the shock wave in time for two variants of shading of critical energy infrastructure objects, namely underground location and ground location in the urban environment, are obtained. At the same time, the parameters of the materials of the structure and the characteristics and amount of explosives were taken into account. Practical value. The construction of underground transformer substations and their modernization in dense urban areas is the optimal solution for eliminating the problems that arise with an increase in loads in city power grids and protecting them from the effects of a blast wave.

Learning-enabled data transmission with up to 32 multiplexed orbital angular momentum channels through a commercial multi-mode fiber.

Multiplexing orbital angular momentum (OAM) modes enable high-capacity optical communication. However, the highly similar speckle patterns of adjacent OAM modes produced by strong mode coupling in common fibers prevent the utility of OAM channel demultiplexing. In this paper, we propose a machine learning-supported fractional OAM-multiplexed data transmission system to sort highly scattered data from up to 32 multiplexed OAM channels propagating through a commercial multi-mode fiber parallelly with an accuracy of >99.92%, which is the largest bit number of OAM superstates reported to date (to the best of our knowledge). Here, by learning limited samples, unseen OAM superstates during the training process can be predicted precisely, which reduces the explosive quantity of the dataset. To verify its application, both gray and colored images, encoded by the given system, have been successfully transmitted with error rates of <0.26%. Our work might provide a promising avenue for high-capacity OAM optical communication in scattering environments.

Experimental data – driven algorithm to predict muckpile characteristics in jointed overburden bench using unmanned aerial vehicle and AI tools

ABSTRACT In the current investigation, an intriguing method called Firefly-XGBoost was put up to predict and integrate blast muck-pile results notably drop, throw, and lateral spread, which are instrumental in regulating and remedying the loading problems by loader as well as deceiving factors in type of loader selection. As a result, the particle swarm optimisation (PSO) algorithm and the firefly algorithm were relied on to shore up the efficacy of the XG Boost conventional model. A total of 164 blast experiments were executed in two different mines and the data collected from these trials data were used to train the model. This data includes specific features such as joints spanning height (JSH) as well as other blast characteristics such as the number of joint sets, decking length, total quantity of explosives, stemming length, decking length and firing pattern. The Firefly-XG Boost algorithm yielded better outcomes in terms of RMSE and R 2 values when compared to the XG Boost, and PSO-XG Boost algorithms. The developed model was found to be suitable in predicting muck-pile parameters for practical application.

Experimental Investigation of the Explosion Effects on Reinforced Concrete Slabs with Fibers

In today’s world, concrete structures are exposed to various influences, including explosive actions. With the increasing use of fiber-reinforced concrete (FRC), it is essential to investigate its response to blast effects. As there are few studies on this topic worldwide, this research is dedicated to the question of how blast effects affect the damage and properties of six different types of reinforced concrete (RC) slabs. These samples differ in concrete classes (C30/37 and C50/60) and in the type of fibers added (steel and polypropylene). Visual inspections and non-destructive measurements are carried out before and after blasting. The damaged area of the concrete surface is determined by visual inspection, while non-destructive measurements evaluate parameters such as the rebound value of the Schmidt hammer, the electrical resistivity of the concrete, the velocity of the ultrasonic wave, and the dynamic modulus of elasticity. Equal amounts of explosives are applied to five of the RC slabs to enable a comparative analysis of the resulting damage. Based on the comparison of the measured data from these five RC slabs, conclusions are drawn regarding the effects of the explosive impacts on conventionally reinforced concrete slabs compared to those with added fibers. In addition, one of the RC slabs with steel fibers is exposed to approximately three times the amount of explosives to assess the extent of increased damage and to evaluate the suitability of military standards in the calculation of explosive charges for blasting RC elements with fibers.

Prediction of rock fragmentation in a fiery seam of an open-pit coal mine in India

Spontaneous combustion of coal increases the temperature in adjoining overburden strata of coal seams and poses a challenge when loading blastholes. This condition, known as hot-hole blasting, is dangerous due to the increased possibility of premature explosions in loaded blastholes. Thus, it is crucial to load the blastholes with an appropriate amount of explosives within a short period to avoid premature detonation caused by high temperatures of blastholes. Additionally, it will help achieve the desired fragment size. This study tried to ascertain the most influencial variables of mean fragment size and their optimum values adopted for blasting in a fiery seam. Data on blast design, rock mass, and fragmentation of 100 blasts in fiery seams of a coal mine were collected and used to develop mean fragmentation prediction models using soft computational techniques. The coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE), mean square error (MSE), variance account for (VAF) and coefficient of efficiency in percentage (CE) were calculated to validate the results. It indicates that the random forest algorithm (RFA) outperforms the artificial neural network (ANN), response surface method (RSM), and decision tree (DT). The values of R2, RMSE, MAE, MSE, VAF, and CE for RFA are 0.94, 0.034, 0.027, 0.001, 93.58, and 93.01, respectively. Multiple parametric sensitivity analyses (MPSAs) of the input variables showed that the Schmidt hammer rebound number and spacing-to-burden ratio are the most influencial variables for the blast fragment size. The analysis was finally used to define the best blast design variables to achieve optimum fragment size from blasting. The optimum factor values for RFA of S/B, ld/B and ls/ld are 1.03, 1.85 and 0.7, respectively.

Optimization Study of Water Interval Charge Structure Based on the Evaluation of Rock Damage Effect in Smooth Blasting

In tunnel smooth blasting, optimizing the water interval charging structure of peripheral holes is of great significance in improving the effect of smooth blasting and reducing the unit consumption of explosives. Addressing the issue of a single traditional evaluation standard, this paper proposes a composite index evaluation method for rock blasting damage in different zones, and the best charging structure is optimized according to the evaluation results. Taking Liyue Road Tunnel Light Smooth Blasting Project in Chongqing as the Research Background, the numeric models were established with ten kinds of charge structures, the charge structures and explosive quantity were optimized according to the evaluation results, and then the field tests were conducted. The results show that when the length of the water medium at the bottom of the hole is 20 cm, the damage range of the retained rock mass can be controlled while ensuring rock fragmentation. If the length of the water medium at the orifice and in the center of the hole is more than 30 cm, it will affect the superposition effect of the blast stress wave, resulting in under-excavation; in the preferred charge structure, the ratio of the length of the upper and lower explosives reaches 1:3, and the ratio of the length of the water medium is 2:2:1, which achieves a better rock-breaking effect in the field test.

DETERMINATION OF THE AMOUNT OF LOAD ON PROTECTIVE STRUCTURES OF CIVIL DEFENSE AGAINST THE INFLUENCE OF A SHOCK WAVE ACCORDING TO DBN V.2.2-5:2023

The main types of explosions and their differences between each other are considered, as well as the difference in excess pressure in the air shock wave is shown. The definition of the calculated load on various load-bearing elements depending on the type of building, its location and structural inhomogeneities of building structures according to DBN B.2.2-5:20023 [1] is given. One of the extreme effects, the danger of which must be taken into account when designing protective structures of civil protection, is an external explosion, which can be caused by both man-made and military factors. The explosion generates a whole complex of loads and impacts. The pressure at the front of the air shock wave, as well as the duration of the compression and rarefaction phases, depend on the amount of explosives and the distance to the center of the explosion or cloud boundary. In general, a detonation explosion is characterized by the possibility of significant pressure on the front of the air shock wave and the short duration of the action (tenths and even hundredths of a second). The air shock wave, when interacting with the structure, affects its above-ground and underground parts. This process is complex: at the beginning of the interaction process, the air shock wave affects the external structures of the above-ground part of the building and the surface of the soil in front of the building, causing a compression wave in it, which, in turn, affects the front outer face of the underground part. Further, the air shock wave, passing through the structural inhomogeneities of building structures in the form of window and door openings, affects the internal load-bearing and non-load-bearing structures of the building, as well as the covering of the underground part. At the same time, compression waves in the soil affect the side and rear walls of the underground part.

Deformation behavior of super-austenitic stainless steel sandwich panels subjected to air blast and underwater explosion

Super-austenitic stainless steel is a class of high alloy steels with enhanced toughness, outstanding strength, and corrosion resistance. In this article, the structural integrity of super-austenitic stainless steel square sandwich panels subjected to surface and underwater explosions is investigated through numerical simulations, and the results are validated with experiments. Abaqus Explicit Solver is used to predict the face deformation and core crushing failure modes of the sandwich panels. Simulations are performed for three levels of impulse load by varying the explosive quantity. The fluid-structure interaction is established by CONWEP and UNDEX algorithms for air blasts and underwater explosions respectively. The dynamic deformation behavior of the sandwich panel is modeled using the Johnson-Cook (JC) plasticity model incorporating strain rate and temperature effects. Good agreement is witnessed between the numerical predictions and experimental observations. An increment in deformation of the face sheet, cell wall buckling, and core compaction is observed with the increase in the impulse. From a series of air and underwater explosion simulations, the advantage of using sandwich structures for blast mitigation is demonstrated. In addition, the significance of numerical simulations to limit experiments and predict the deformation of the sandwich panels is presented.

Structural Investigations and Rheology of Convergence of Thick-Wall Shells from Al–Mg Alloy

Abstract—The deformation behavior of thick-walled hollow cylindrical shells made of the AMg6 alloy (Al–6.1% Mg–0.6% Mn–0.1% Ti–0.2% Si, wt %) loaded according to an 8-point initiation scheme of an attached explosive is considered. The intensity of explosive loading was regulated by the amount of explosives. It has been established that, different scenarios for their convergence are observed depending on the intensity of the impact and the geometric characteristics of the shells. The conditions for the formation of spallation internal layers were determined, the evolution of the structure during high-speed deformation along the radius and along the length of the shells and the change in hardness along the radius of the shells were studied. X-ray photography of the dynamics of shell deformation processes was carried out at different time intervals. The speeds of movement of the outer and inner layers of the shells and the speed of their deformation for different amounts of explosives were determined.

Anti-explosion performance and dynamic response of an innovative multi-layer composite explosion containment vessel

An innovative multi-layer composite explosion containment vessel (CECV) utilizing a sliding steel plate-aluminum honeycomb-fiber cloth sandwich is put forward to improve the anti-explosion capacity of a conventional single-layer explosion containment vessel (SECV). Firstly, a series of experiments and finite element (FE) simulations of internal explosions are implemented to understand the basic anti-explosion characteristics of a SECV and the rationality of the computational models and methods is verified by the comparison between the experimental results and simulation results. Based on this, the CECV is designed in detail and a variety of FE simulations are carried out to investigate effects of the sandwich structure, the explosive quantity and the laying mode of the fiber cloth on anti-explosion performance and dynamic response of the CECV under internal explosions. Simulation results indicate that the end cover is the critical position for both the SECV and CECV. The maximum pressure of the explosion shock wave and the maximum strain of the CECV can be extremely declined compared to those of the SECV. As a result, the explosive quantity the CECV can sustain is up to 20 times of that the SECV can sustain. Besides, as the explosive quantity increases, the internal pressure of the CECV keeps growing and the plastic deformation and failure of the sandwich structure become more and more severe, yielding plastic strain of the CECV in addition to elastic strain. The results also reveal that the laying angles of the fiber cloth's five layers have an impact on the anti-explosion performance of the CECV. For example, the CECV with fiber cloth layered in 0°/45°/90°/45°/0° mode has the optimal anti-capacity, compared to 0°/0°/0°/0°/0° and 0°/30°/60°/30°/0° modes. Overall, owing to remarkable anti-explosion capacity, this CECV can be regarded as a promising candidate for explosion resistance.

Research on dynamic response and deformation evolution of a rectangular recycled aggregate concrete-filled steel tubular column under small-equivalent loads and weak disturbances

To study the dynamic response and deformation evolution of the rectangular recycled aggregate concrete-filled steel tubular (RRACFST) column under small-equivalent loads and weak disturbances, the measuring methods of blasting and the arrangement of measuring points were precisely handled. Three contact explosion tests were conducted on the RRACFST column to obtain their failure modes, dynamic strains, and accelerations. The research results indicate that the range of 20-30g TNT equivalent represents the starting point and critical point of plastic deformation for the RRACFST column. When the explosive quantity increases incrementally under small-equivalent loads and weak disturbances, the radius and size of the explosion crater do not exhibit a linear relationship. The methods of explosive treatment under small-equivalent loads and weak disturbances adhere to the core principles of precision and quantification, meeting engineering requirements. This study provided a theoretical basis and experimental basis for the safety study of RRACFST columns structure under explosion load.

Acceleration of metal plates by hybridization of electrical and chemical energy for potential application in high-velocity impact welding

Vaporizing foil actuator welding is employed to connect dissimilar metals by utilizing the energy of an electrical explosion as the driving force for flyer plate acceleration. Herein, the electrical and chemical energies of explosives were combined to increase flyer plate velocity. A metal foil or wire mesh was used as an actuator, and a small amount of explosives was placed on the foil. Uniform acceleration of the flyer plate on the actuator was recorded using a high-speed video camera. The electrical energy applied to the actuator was measured synchronously by filming. The explosion of chemical explosives was successfully initiated owing to the electrical explosion of the actuator. In all experiments, the combination of the electrical explosion and chemical reaction improved the acceleration of the samples, facilitating higher velocities. The impact of the actuator type (mesh or foil) and the electric discharge parameters on the performance was studied. While foil actuators were more efficient in experiments on electric explosions alone, mesh actuators were superior when the chemical explosive was added. Explosions of the mesh actuator could initiate low density pentaerythritol tetranitrate (PETN) (the space-filling rate of PETN was approximately 30%). An explosive force of 0.3 g of PETN was converted into a driving force, imparting the flying plate with a velocity greater than 210 m/s. Electrical energy consumption for PETN initiation may be assumed to have an insignificant impact on flyer plate acceleration. In future, the proposed method may be used to connect heavier and thicker materials without expensive high-performance capacitors.

Damage behavior of concrete members subjected to underwater contact explosion

In order to investigate the damage mechanism of dams subjected to underwater contact explosion, firstly, an experimental program was conducted with six concrete slabs and two explosive quantities. The test results showed that the diameter and depth of the crater on the front and back surface of the concrete slab increased with increasing explosive quantity with radial and circular cracks generated. Three different concrete material models were tested and it was found the CDP model was most suitable in simulating concrete subjected to underwater explosion. The calibrated models were used to conduct parametric studies to study the effect of explosive quantity, slab thickness, and transferring medium (water or air). Numerical analysis results showed that the diameter and depth of the crater on both the front and back surface of the concrete slab decreased with increasing slab thickness and decreasing explosive quantity. In addition, the damage caused by the air contact explosion was smaller and more concentrated in the detonation center compared with underwater contact explosion. Finally, a gravity dam and an arch dam were modeled to study the effect of detonation depth and water level on the damage distribution pattern of the dams. Based on the results, recommendations were provided for the anti-explosion protection design of hydraulic structures.

Blasting vibration hazard classification and prediction research

This paper explores the hazard classification method of blasting vibration on nearby buildings. The ratio of the self-vibration frequency f0 of the protected buildings to the main vibration frequency f of blasting vibration and the ratio of the actual measured peak blasting vibration velocity to the permissible vibration velocity of blasting safety regulations are used as two indicators of the blasting vibration hazard classification method, the blasting vibration hazard index calculation formula was proposed, and the blasting vibration hazard was classified into four levels according to the blasting vibration hazard index. An open pit mine blasting project was used for monitoring, the collected data were processed by random forest method. After processing, bursting heart distance, the total explosive quantity required for one blast, the hole distance meter delay, and the row distance meter delay was selected as the input parameters; the optimal kernel function parameter gamma and c were applied to the SVR (Support Vector Regression) model by changing the search step to expand the parameter search, and improved GS-SVR (Grid Search-Support Vector Regression) model was constructed, through which peak blasting vibration velocity and vibration frequency values were predicted. The results show: improved GS-SVR is effective in predicting peak blasting vibration velocity, with the lowest relative error of 0.15% and the average error of 7.96%; the minimum relative error for the prediction of vibration frequency is 0.03% and the average error is 2.54%. The measured data in the literature of related scholars verified that the blasting vibration hazard classification method is scientific and feasible. It can provide reference and reference for blasting vibration hazard classification and prediction of similar blasting projects.

2014 takeover of the SBU headquarters in Lugansk as an example of the operation of the Russian special services

The author analyzes the seizure of the SBU headquarters in Lugansk in 2014 by pro-Russian demonstrators. The author presents well-documented evidence that the Luhansk SBU was selected by the Russian secret services as a “trigger” of the uprising in the Donbas, due to the accumulation of a huge amount of ammunition, weapons and explosives, thanks to which the separatists could immediately start creating military structures after the attack. In the author’s opinion, the infiltration of the Ukrainian SBU and the Ministry of the Interior was facilitated by the existence of branched clientelist networks within them, enabling politicians hostile to the new prowestern government to steer state institutions in the name of the strategic interests of the Russian Federation.

Особливості використання гуми як конструкційного матеріалу під час створення вузлів стикування систем термостатування

Explosive bolts are widely used as actuating devices in the spacecraft separation systems. Explosive bolt body is divided into parts as a result of engagement of the pyromixture placed inside. Activated explosive bolts have negative mechanical effect on the interface elements and sensitive electronic devices installed nearby owing to explosive behavior of the pyromixture combustion, generating shock front with high pressure and velocities, impacts and collisions of the structural units. Cumulative effect of the above factors on the separated objects is called pyroshock. For separation systems with increased requirements to external actions and cleanliness, authors developed a shear explosive bolt or pyrobolt, divided into parts, cutting the body walls in segments, which are set in motion by action of the pressure of gases, released as a result of pyrocartridge activation. The basic sources of pyroshock for these shear explosive bolts with segments are: combustion of pyromixture, internal impacts of structural units against the bolt body; cutting of body wall in segments, release of preliminary deformed interface after activation. Structural solutions are presented to reduce the pyroshock per each of the components. Vibration impulsive loading during pyromixture combustion is reduced by optimization of explosive quantity, finding its minimum to provide the reliable activation of the device. To reduce the impact on the explosive bolt elements and shock front interface the rubber gasket is installed in the path of shock wave distribution, partially disseminating and absorbing its kinetic energy. Damper, made of easily deformable aluminum alloy, is also installed to decrease the internal impact of the rod against the explosive bolt body. Functional testing of the device, using the pendulum suspension and measuring separation speed and vibration impulsive loading, showed that body parts of the shear explosive bolt with segments are separated without significant impact loads and discharge of high-temperature gases and debris, providing reliable separation of compartments and units without damaging the sensitive equipment. Obtained values of the mechanical momentum, I = 0,4÷0,7 N•s and shock load spectrum – g-load 1950 g at the frequency range up to 5000 Hz, meet the up-to-date requirements to pyrotechnical devices. Key words: explosive bolt, pyroshock, shock wave, pyrocartridge, high-temperature gases, damper.

Research on The Damage Law of Reinforced Concrete Beams Caused by Cuboid Explosives under Contact Explosion

In order to study the damage law of cuboid explosives to reinforced concrete beams under contact explosion, the damage effect of reinforced concrete beams under the action of different length-to-width ratios, explosive heights and explosive equivalents of cuboid explosives is studied by LS-DYNA numerical simulation.The results show that when the amount of explosives and the height of explosives remain unchanged, and the ratio of length to width is 1:1, the volume of concrete damage is the largest. When the amount of explosives and the length-to-width ratio remain unchanged, the volume of concrete damage decreases with the increase in height. When the length-width-height ratio of the explosive is constant, the damage volume increases linearly with the increase of the explosive equivalent. The damage degree of beam is divided into three grades: Reinforced concrete beam is slightly damaged when the damage volume ratio is η <3%. Reinforced concrete beam is moderately damaged when the damage volume ratio is 3%< η <7%. Reinforced concrete beam is serious damaged when the damage volume ratio is η>7%.

Study on damage effect of caisson wharves subjected to underwater explosion

This study aimed at investigating the destructive effect of explosion shock waves on caisson wharves in shallow water. First, underwater explosion tests were conducted on caisson wharves, full-size finite-element models of caisson wharf-water-explosive were established, and the accuracy of the models was verified by comparison. The destruction pattern and damage characteristics of the caisson wharf structure were then studied, and the effects of different explosion depths and different explosive quantities on the dynamic response of caisson wharves were analyzed. The results show that the destruction pattern of shock waves on the caisson wharf is manifested as plastic damage at the joint of the reinforced concrete (RC) box wall, shear destruction at the lower edge of the explosion loading wall, and integral displacement of the superstructure. When the scaled distance remains unchanged and the explosion depth and explosive quantity increase, the bottom reflection effect strengthens, turning the bending damage on the explosion loading wall into shear damage. By strengthening the performance of the RC box wall joints, explosion loading wall, and superstructure joints, and taking measures to reduce the reflection effect, the anti-explosion capacity of caisson wharves can be effectively improved.

Laboratory Explosion Accidents: Case Analysis and Preventive Measures

This paper collected 22 cases of explosion accidents in laboratories in China in the past 10 years, analyzed the causes of the accidents, and put forward measures of preventing and mitigating the hazards of explosion accidents by identifying the explosion hazards in laboratories, assessing the explosion risks, minimizing the explosion hazards, and preparing for possible explosion accidents. Specific preventive measures are the DATS principles: keep the Distance as far as possible, use the minimum Amount of explosives, shorten the residence Time, and use appropriate Shielding.