Block Stone Research Articles

Theoretical aspects of block stone blasting method

Theoretical aspects of block stone blasting method

Research on the penetration performance of shaped charge jet into block stone concrete targets

Experiment and numerical simulation were conducted to investigate the penetration performance of shaped charge jet into block stone concrete targets. The experiment has shown that the jet undergoes deflection and other phenomena during its penetration of block stone concrete. Improvements have been made to the methods used by previous scholars for constructing aggregate particles, resulting in a particle model that more closely resembles the true shape of the aggregate. A novel method for judging the intersection of aggregate particles based on the Plucker coordinate system was proposed. In comparison with traditional methods, this method is not constrained by the shape of aggregate particles. By utilizing dynamic simulation software to replicate aggregate settlement during the production process of concrete targets, a 3D meso-scale model of concrete was successfully established. Numerical simulations were conducted according to the experimental settings, with the results demonstrating good consistency between the experimental and numerical simulations, thus confirming the reliability of the model and methodology presented in this article. Additionally, the numerical simulation results suggest that the aggregate content significantly influences the degree of interference, penetration depth, and damage zone range of the jet, while the impact position primarily affects the deflection of the jet. This article provides a numerical simulation method for future research on the penetration and damage mechanism of shaped charge jet considering the 3D meso-scale model of concrete.

Research of Fuel-air Thermal Tools for Extraction and Processing of Block Stone

The stages of development of thermal tools with intensifiers of combustion of fuel components are described. Studies for obtaining the manifestation of detonation in the free stream of thermal tools during combustion of fuel components have been performed. The design features of the development of gasoline-air thermal tools, which allow intensifying the combustion processes of fuel components, are presented. However, due to the simplicity of operation and organization of feeding fuel components with gasoline-air burners, their use as working bodies of mechanized equipment is urgent. Increasing the power of gasoline-air burners without considerable development of their overall dimensions and increasing the size of the burner flame is possible due to intensification of combustion processes. The use of gasoline-air burners as working bodies of mechanized thermal units is restrained by their relatively low power, the increase of which quickly increases their overall dimensions. Also, the thermal tools with supersonic flare for various technological operations, for rock destruction during slot excavations are considered. The experiments have shown that with the increase in the number of ejection windows, the size of the flare and the power of shock waves increase. To determine the heat transfer parameters of supersonic high-temperature gas jets, a special burner was developed with the possibility of using gasoline, diesel fuel and propane gas as fuel. Gasoline-air burners allow using detonation combustion in them to increase the productivity of thermal destruction of rocks, and to automate the start-up of the burners in operation. Experimental studies have shown that gasoline-air burners, with a combustion intensifier, allow using detonation combustion in them to increase the productivity of thermal destruction of rocks, to automate the start-up of thermal tools in operation

Study on the Influence of Matrix on Mechanical and Failure Characteristics of Miscellaneous Fill

Abstract The matrix has a great influence on the mechanical and failure characteristics of the miscellaneous fill. Based on the laboratory medium-sized triaxial test, the confining pressure tests of 100, 200, and 400 kPa were carried out on the miscellaneous fill under three kinds of matrix with block stone content of 30 %, and the influence of the matrix on the mechanical properties of miscellaneous fill was analyzed. A biaxial test with a confining pressure of 200 kPa was carried out on three kinds of matrix miscellaneous fill samples using the particle flow method, and the influence of miscellaneous fill on the failure characteristics was studied. The test results show that the relation curve of the miscellaneous fill (σ1–σ3)∼εa can be considered as a hyperbola. The miscellaneous fill whose matrix is clay and silty soil always shows shear shrinkage. When the confining pressure is 100 kPa, the miscellaneous fill in the sandy soil matrix shows the property of shrinkage first and then dilatancy. When the confining pressure is 200 kPa and 400 kPa, it shows shear shrinkage. Through numerical simulation, it is found that when the matrix is clay, the shear zone is obvious and the shear failure surface is stable. When the matrix is silty soil, the contact cracks become thinner and the shear bands increase. When the matrix is sandy soil, compared with clay matrix, the overall crack is finer and the shear fracture surface is irregularly distributed.

Assessment of fracturing and blockiness of the Pshenychne gabbro deposit massif

Proper development of the deposit and the choice and use of effective technologies for block stone extraction are impossible without evaluating the structural indicators of the massif. It consists in studying the propagation of cracks in the array, orientation of the main crack systems, studying the anisotropic properties of stone, and predicting the yield of commercial stone blocks in the deposit. This allows both to increase the efficiency of block extraction and to reduce the loss of stone during its extraction, which increases the economic performance of field development. The assessment of fracturing and blockiness of the Pshenychne gabbro deposit was carried out based on the results of studying the core documentation of 11 exploration wells and the documentation of a pilot production quarry. Rose diagrams, pie charts, and fracturing plans were constructed in isolines, and crack systems common in the field were identified.

Réselő adapter rezgéstani vizsgálata kőzetvágás során

This paper deals with a dimensional rock sawing machine to optimize the production of small-volume dimension stone products in limestone. After cutting around the block stone, the rock material can be moved with the help of the machine. The finite element (FE) analysis of the adapter with simplified geometry treated as a solid model is to investigate the natural frequen-cies of the adapter to identify any potentially dan-gerous frequencies. In this study, the eigenvalue extraction used to calculate the natural frequen-cies is based on the Lanczos iteration methods. The natural frequencies of the concept design, es-timated by FE-modal analysis, provide an oppor-tunity to give sufficient stability against the low frequencies associated with the normal operating speed of the cutting at the final version.

NOVOUKRAINSKYI MASSIF: SOURCE OF ORIGINAL MAGMAS AND TIME OF FORMATION

NOVOUKRAINSKYI MASSIF: SOURCE OF ORIGINAL MAGMAS AND TIME OF FORMATION

Исследование и разработка компонентов газогенераторных составов на основе нитрата натрия для повышения безопасности при разрушении искусственных объектов

In the process of extraction of the piece stone and in the destruction of concrete and brick buildings in dense urban areas, the issue of safety and efficiency of work is very important. For reducing the percussive action during blasting operations, various methods and means are used. Currently, when extracting block stone, the substances are used that can create pressure in the hole due to the combustion reaction in the deflagration mode. The article is devoted to the research and development of gas-generating compositions based on the sodium nitrate to improve safety during the destruction of artificial objects. Sodium nitrate was chosen as an oxidizer, this is primarily due to the low cost of sodium nitrate, low sensitivity to mechanical and detonation effects, and a significantly lower content of harmful compounds in the combustion products compared to analogues. Magnesium and carbon (from a gas mask and walnut) were used as fuel. Tests for the flammability of mixtures and thermodynamic calculations of combustion parameters were carried out to determine the optimal ratio of the initial components. It was established that a sufficiently high efficiency and uniformity of combustion are observed at a ratio of the initial components of 60 % — NaNO3, 20 % — Mg, 20 % — C. X-ray phase analysis of solid combustion products was carried out. It is shown that the main products are magnesium oxide and sodium carbonate. Field experiments on the destruction of concrete blocks were carried out. The performed studies and field tests showed high efficiency and safety of the use of the developed gas generator composition for the destruction of artificial objects, which can be used for the directed destruction of artificial objects or rocks of medium strength with a coefficient of 8 on the scale of the professor MM. Protodyakonov. The destruction of the concrete block occurred without the scattering of individual stone fragments, the formation and propagation of a shock air wave.

Finite Element Analysis of a Cutting and Hauling Mining Adapter

Abstract A recently completed research focused on the development of a low-volume mining production and transportation prototype machine. By developing this new mining adapter, the number of machines used in the mine can be reduced. Its application in dimensional stone mining can reduce the expenses of mining companies. After the block stone has been cut around, the stone material can be moved with the machine. The cutting forces and power requirements are calculated for the chain speeds used in production. This paper shows the static stress analysis of two kinds of possible structures of the dimension stone mining adapter. Finite element analysis was used to determine the displacements and the effective stress distribution of the adapter.

Numerical Analysis of the Influence of Foundation Replacement Materials on the Hydrothermal Variation and Deformation Process of Highway Subgrades in Permafrost Regions

Affected by global warming, permafrost thawing in Northeast China promotes issues including highway subgrade instability and settlement. The traditional design concept based on protecting permafrost is unsuitable for regional highway construction. Based on the design concept of allowing permafrost thawing and the thermodynamic characteristics of a block–stone layer structure, a new subgrade structure using a large block–stone layer to replace the permafrost layer in a foundation is proposed and has successfully been practiced in the Walagan–Xilinji section of the Beijing–Mohe Highway to reduce subgrade settlement. To compare and study the improvement in the new structure on the subgrade stability, a coupling model of liquid water, vapor, heat and deformation is proposed to simulate the hydrothermal variation and deformation mechanism of different structures within 20 years of highway completion. The results show that the proposed block–stone structure can effectively reduce the permafrost degradation rate and liquid water content in the active layer to improve subgrade deformation. During the freezing period, when the water in the active layer under the subgrade slope and natural ground surface refreezes, two types of freezing forms, scattered ice crystals and continuous ice lenses, will form, which have different retardation coefficients for hydrothermal migration. These forms are discussed separately, and the subgrade deformation is corrected. From 2019 to 2039, the maximum cumulative settlement and the maximum transverse deformation of the replacement block–stone, breccia and gravel subgrades are –0.211 cm and +0.111 cm, –23.467 cm and –1.209 cm, and –33.793 cm and –2.207 cm, respectively. The replacement block–stone subgrade structure can not only reduce the cumulative settlement and frost heave but also reduce the transverse deformation and longitudinal cracks to effectively improve subgrade stability. However, both the vertical deformation and transverse deformation of the other two subgrades are too large, and the embankment fill layer will undergo transverse deformation in the opposite direction, which will cause sliding failure to the subgrades. Therefore, these two subgrade structures cannot be used in permafrost regions. The research results provide a reference for solving the settlement and deformation problems of subgrades in degraded permafrost regions and contribute to the development and application of complex numerical models related to water, heat and deformation in cold regions.

Experimental assessment of in-plane behavior of traditional Tibetan three-leaf walls

Multi-leaf masonry is a technique that can be dated back many centuries, but limited reports can be found on the seismic behaviors of three-leaf walls (TLWs). This study intended to understand better the seismic capacity of traditional Tibetan three-leaf walls (TTTLWs) constructed with stones and mud mortar by an in-plane cyclic shear loading test. A series of test results, including failure modes, hysteretic behavior, ductility, stiffness degradation, energy dissipation, and in-plane and out-of-plane bulge of tested walls were analyzed and discussed. And the experimental values of the shear strength and shear modulus were compared with the predicted values given by prediction models available in literature. Three types of failure modes were found on the wall specimens in this test: sliding of mortar joints, cracking of block stone at wall toe, and separation between external and inner leaves. The TTTLWs may be concluded to have a low shear strength of 0.118–0.162 MPa and medium shear modulus of 99–147 MPa compared with the published data of multi-leaf stone masonry. The shear strength of TTTLWs is controlled by the flexural failure, and can be predicted by the formulas recommended by ASCE.

Design and Mechanical Behavior of a Custom Adapter for Dimensional Stone Mining

The paper deals with the development of a dimensional rock sawing machine to optimize the production of small-volume dimensional stone products in limestone quarries by re-thinking the use of production and transport equipment. A low-volume mining production and transportation adapter to be developed for both production and transport can reduce the number of mining machines to be used in the mine. After cutting around the block stone, the rock material can be moved with the help of the machine. Cutting tests were performed to determine the winning properties of the limestone. The first objective of the paper was to calculate the cutting forces and cutting powers and eliminate the failure possibilities and vibrations. In this study, the eigenvalue extraction used to calculate the natural frequencies and mode shapes was based on the Lanczos iteration methods using the Abaqus software to identify any potentially dangerous frequencies. By taking the load cases from modelling of the extraction of limestone and the transport of block stones, the deformation and strength properties of the adapter were also examined using FE analysis for stress/displacement analysis. Drawing the conclusion from finite element analysis, the construction of the adapter can be developed and checked. The results can be used with great confidence, so the main dimensions of the concept serve as the basis for the dimensions of the adapter.

Study on dynamic response of debris flow to pipeline with defect

Based on the Finite Element Method (FEM) and the Smooth Particle Hydrodynamics (SPH) coupling method, this paper established full-size multi-physical field coupling model of debris flow impacting pipeline. By simplifying mud into Bingham fluid, this paper studied the dynamic response law of pipeline with defect and intact pipeline (pipeline without defect) under the joint action of mud and block stone, established the displacement equations of the pipeline under impact, thus obtained the displacement, stress and strain characteristics of different pipeline positions at different impact moment. The results showed that numerical simulation of dispersing mud into SPH particles can well simulate the movement process of mud splashing and detour flow. The maximum displacement occurred in the middle part of the pipeline. For the intact pipeline, the main failure was caused by the instantaneous impact of the mud, however, for the pipeline with defect, the dominant failure factor changed from the mud impact to the stone impact. This study provided a new pathway and theoretical reference for disaster prevention and control of pipelines in debris flow section.

ИССЛЕДОВАНИЯ МАССИВА И ОСНОВНЫХ ПАРАМЕТРОВ СИСТЕМЫ РАЗРАБОТКИ СЛОЖНОСТРУКТУРНЫХ МЕСТОРОЖДЕНИЙ ОБЛИЦОВОЧНОГО КАМНЯ УЗБЕКИСТАНА

The scientific paper has investigated a range and parameters of the block stone mining system in Uzbekistan. Scientific researches, made by leading scientists in this field, have been closely reviewed. Methods of assessment of fracturing and blockiness of massif based on correlation between linear and area indices of natural separations in massif have been applied. A technological scheme of face orientation in relation to fracture systems has been developed. Possible technical productivity of stone blocks extraction using different methods of preparation for excavation has been determined. Rational areas of various methods of stone block preparation for excavation and optimum technological parameters are established.

Structural characteristics of soil-rock mixtures based on electrochemical impedance spectroscopy

Geotechnical problems in extremely complex environments have become increasingly prominent, which raises the need to explore more efficient solutions. Multidisciplinary approaches show a new perspective to deal with these problems. In this study, the electrochemical impedance spectroscopy (EIS) was introduced to illustrate the structural characteristics of soil-rock mixtures (SRM), aiming at deducing the relationship between physical property indices such as the mass ratio indices (e.g., water content, soil-rock ratio, and stone particle size) and volume ratio indices (e.g., porosity and saturation) and equivalent circuit at the macro and micro levels. A three-level equivalent circuit corresponding with the physical characteristic of SRM was established to describe the cementation state. It shows that the degree of cementation of SRM increases with increasing water content, rock content, and median size of block stone; meanwhile, the real impedance coefficient of the non-cemented part is lower than that of the cemented part. The corresponding relationship between the imaginary impedance and the specific gravity has segmental characteristics. The density first increases and then decreases with the increase of water content; the water content and saturation threshold are 16% and 80 ± 2%, respectively. Moreover, the saturation (Sr and n∙Sr) decreases with the increase in the real impedance coefficient. In addition, the characteristics of the propagation mode and interfacial contact characteristics of the charged material inside SRM were examined, and the macro and micro mapping of the cementation state of SRM and the basic mass transfer mode (i.e., migration, diffusion, and convection) were obtained. The mapping relationship proposed in this study reflects the micro-scale cementation characteristics and the macro-scale physical characteristics of the SRM system, which provides new insight into the multi-scale research of SRM.

Triaxial Discrete Element Simulation of Soil–Rock Mixture with Different Rock Particle Shapes under Rigid and Flexible Loading Modes

Three-dimensional scanning technology was used to construct the database of natural block stone shapes with different particle sizes. On the basis of Particle Flow Code 3D, a discrete element random model of soil–rock mixtures with different stone contents and shapes was established. A flexible boundary loading method of multisection wall was adopted to simulate the flexible film constraint mode of indoor triaxial test. Large-scale triaxial numerical simulation tests were carried out on the soil–rock mixture with different stone contents, stone shapes, and loading modes to analyze the macromechanics, microscopic deformation, and failure laws under various working conditions. Results showed that under the flexible loading mode, the stress curve of the samples with low stone content (0%–20%) has no obvious peak value and the deformation is mainly shear shrinkage. The stress curve of the samples with high stone content (40%–60%) showed the obvious peak value, and the dilatancy was prominent. Under the action of vertical load, the specimen bulged and formed multiple fork shear bands. Compared with the flexible loading mode, the rigid loading mode showed that the strength of the specimen increased in the rigid loading mode, and the cohesion and internal friction angle improved overall, but the friction energy was basically the same. During shearing, no obvious bulging was noted at the edge of the sample, and the shear bands were K-shaped and diagonal. The shape of block stone had significant influence on the strength, friction energy, and shear band shape of the soil–rock mixture.

دراسة أثرية لکتلة حجرية من عهد الملک رمسيس الثالث Archaeological study of a stone block from the reign of the King Ramses III

يتناول هذا البحث نشر کتلة من الحجر الجيرى، عثر عليها فى قرية شنشور- مرکز أشمون بمحافظة المنوفية محفوظة- حاليا– بالمخزن المتحفي بتل اليهودية، کفر الشوبک فى محافظة القليوبية، تحتوي على تسعة أسطر أفقية من الکتابة الهيروغليفية المنقوشة نقشا غائرا. وتهدف الدراسة إلى نشر الکتلة، ونسخ نصوصها الهيروغليفية وترجمتها، والتعليق الخطى واللغوي عليها، فضلا عن تحديد ماهيتها، التي ربما کانت تمثل جزء من لوحة هبة أو وقف أقامها الملک رمسيس الثالث لتخصيص قطعة أرض زراعية إلى دائرة أملاک المعبود رع في الدلتا، وکذلک توضيح القيمة التاريخية للإقليم الرابع من أقاليم مصر السفلى الذي کان يشغل أجزاء کبيرة من محافظة المنوفية، حيث لم يکشف به إلا عن القليل من الآثار التي ترجع لعصر الملک رمسيس الثالث، وذلک على الرغم من کثرة آثاره بالدلتا. هذا فضلا عن القيمة الحضارية لما يحويه النقش من ألقاب مهمة استخدمت فى الإدارة المحلية خلال عصر الدولة الحديثة کــــــ العمدة أو المشرف على مدينة خنتي نفرت، والتي تقع داخل نطاق الأقليم الثانى من أقاليم مصر السفلى في موقع القرية الحالية المسماة شنبارى شرق مدينة أوسيم محافظة الجيزة؛ مما قد يشير إلى المکان الأصلي للکتلة الحجرية قبل أن تنقل في فترة لاحقه إلى قرية شنشور مکان اکتشافها. ومما يؤسف له أن الکتلة الحجرية عثر عليها مصادفة، وليس عن طريق حفائر أو مسح أثرى، ومن ثم غياب السياق الأثري، مما يعد إشکالية کبيرة. Archaeological Study of a Block Stone from the Reign of the King Ramses III Abstract: This research tackles a block of limestone found at the village of Shanshor - Ashmoun in Menoufia Governorate. It is kept at the museum storage in Tal Al-Yahodia, Kafr Al-Shobak in Qalyubia Governorate. It contains nine horizontal lines of sunken hieroglyphic inscription. This study aims to publish, copy, translate and make comments on its hieroglyphic texts. The study will specify the type of object that may represent part of a gift or endowment stela which was set up by King Ramses III to allocate a plot of agricultural land to the deity Ra's property. Then clarify the historical value of the region the fourth, which used to occupy large parts of the Governorate of Menoufia, where only a few monuments dating to the era of King Ramses III were revealed, despite several monuments in the Delta. This paper looks at the cultural value, including important titles used in the local administration's inscription during the New Kingdom, such as “supervisor of the city of Khenti Nefert”; which may indicate the block stone's original location before it was transferred to the village of Shanshor. Unfortunately, the block stone was found by chance, not by excavations or archaeological surveys, and thus became very problematic due to the absence of the archaeological context.

Study on seismic and shock absorption performance of Yi Ci Hui stone pillar

The rigid block structure composed of multiple blocks of stones will sway during an earthquake. The rocking and rocking impact dissipates the seismic force and has good shock absorption performance. The seismic and seismic performance of Yi Ci Hui stone pillar with multi-layer block stones was studied. The results showed that: only the acceleration increases to a certain value, the rocking amplitude of the multi-layer stacked stone pillar occurs; with the continuous increase of the earthquake acceleration, the rocking amplitude of the stone pillar will rapidly decay or even be stationary. Stacking stone pillar can effectively take advantage of high compressive strength of block stone, and only produce compressive stress in the pillar root section to avoid stress failure of stone pillar. The energy reaction of the multi-layer stone pillar is mainly kinetic energy, which reaches the maximum when the stone pillar begins to shake, and then decreases rapidly. The total strain energy reaches the peak value when the stone pillar shakes, and then remains unchanged. The rocking and shaking of stacked stone pillars causes the impact of rock interface edge to dissipate seismic energy, which makes the rocking amplitude and kinetic energy of stone pillar gradually decrease, and the total strain energy is basically unchanged, which effectively plays the role of seismic shock absorption.

ПЕРСПЕКТИВИ ВИКОРИСТАННЯ ПРИРОДНЬОГО БЛОЧНОГО КАМЕНЮ В ЯКОСТІ НЕСУЧОЇ БУДІВЕЛЬНОЇ КОНСТРУКЦІЇ

Purpose. Research of reinforcement methods of natural block stone and possibilities of its application as a load-bearing building structure. Methods. The study used such general logical methods as generalization, analysis and synthesis, analogy, abstraction and modelling. Results. Disadvantages of traditional technology of mining of raw materials for concrete production and the factors that increase the final cost of concrete structures are considered. Advantages and disadvantages of natural block stone in comparison with reinforced concrete building structures on the example of foundation blocks are considered. In order to reduce the cost, improve performance and give the production more flexibility, it is proposed to make such blocks of natural stone blocks with low decorative value. The analysis of known methods of reinforcement of natural stone is made, and the scheme of reinforcement of the block is developed. In order to develop effective reinforcement of such blocks, it is proposed to place the longitudinal reinforcement in the holes drilled in the block before its removal from massif, and fill them with self-expanding cement. Known methods of strengthening the inclined sections of reinforced concrete beams without transverse reinforcement are considered. To strengthen the inclined sections of the natural stone block, it is proposed to use a similar system of external reinforcement of reinforced concrete beams with carbon fiber-based tapes, which are glued with epoxy resins. Scientific novelty. For the first time in the general case, it is proposed to use natural block stone, reinforced with internal and external reinforcement, as a load-bearing structural element of the prefabricated ferro-stone foundation. Practical significance. Preliminary calculation of the minimum allowable distance from the inner wall of the holes for reinforcement rods to the outer surface of the unit without taking into account the inhomogeneities and defects that may occur in the rock, and additional loads during operation of such a unit was made. The obtained result is determined by the pressure of the cement mortar, which expands itself. If this distance is reduced, the whole wall may be destroyed. The issues that need to be solved to substantiate the proposed method of manufacturing foundation blocks, which will use all the benefits of natural stone and reduce the cost of manufacturing foundation blocks, are formulated.

Influence of Meso-Structure Parameters on Wave Propagation in Soil-Rock Mixture

The macro mechanical properties of soil-rock mixture are closely related to the meso-structure features of block stones, namely, content, size, and shape. To promote the engineering application of soil-rock mixture, it is important to explore the meso-structure of the mixture, and evaluate its constitutive properties. The previous studies have shown that the wave propagation in the mixture is highly sensitive to the rock content and compaction. To clarify the meso-structure features of soil-rock mixture, this paper establishes a discrete element model of the mixture based on Particle Flow Code (PFC), investigates the wave propagation features in the model with different meso-structure parameters, and analyzes how the meso-structure parameters affect the wave propagation. The results show that: With the growing rock content, the first wave amplitude increased, while the take-off time shortened; With the growing feature size of block stone, the first wave amplitude gradually decreased, while the take-off time gradually lengthened; The soil-rock mixture containing spherical block stones had the highest first wave amplitude and shortest take-off time, while the mixture containing rectangular block stones had the lowest first wave amplitude and longest take-off time. With the growing rock content, the maximum amplitude, dominant frequency, and spectral area all exhibited an increasing trend; With the growing feature size of block stone, the maximum amplitude, dominant frequency, and spectral area all exhibited a decreasing trend.