Wyniki wyszukiwania - BazTech

1

Study on the effect of loading on the stress distribution in components chosen for the car scissor lift

Woźniak Marek, Morawski Jakub, Zakrzewski Sergiusz, Kądziela Arkadiusz, Siczek Krzysztof

Zeszyty Naukowe Politechniki Morskiej w Szczecinie

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2025

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nr 84 (156)

94--105

EN

This study aims to determine the effect of loading on stress distribution in components of the scissor lift during the pushing up or down of the car being analyzed. The FEM models of the lead screw and the lift arms are elaborated and implemented using both Autodesk Inventor and the Solid Edge software. The mathematical model for the lead screw is also developed. The models allowed for the obtaining of the von Mises stress values in the lead screw and in the lift arms. Such stress values in the middle of the FEM screw model coincided with those determined analytically. The obtained values are very sensitive to the level of refinement applied for the size of finite elements. The values of the von Mises stresses in both lower and upper arms varied depending on the lift. For a small value of the lift, they can be up to 35% higher than those in the lead screw. However, for the higher lift, the von Mises stress values in the arms may be equal to or smaller than those in the lead screw.

2

Wpływ współczynnika Fröhlicha na rozkład naprężeń w jednorodnym ośrodku gruntowym

Olszewska Magdalena, Kłakowicz Oliwier, Kozerski Mateusz, Mospinek Ewa, Sucharzewska Wiktoria, Żygadło Antoni

Przegląd Budowlany

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2025

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R. 96, nr 6

127--131

PL

Artykuł dotyczy wpływu współczynnika Fröhlicha na rozkład naprężeń pionowych w jednorodnym ośrodku gruntowym. Przedstawiono modyfikacje klasycznego modelu Boussinesqa oraz wyniki obliczeń numerycznych dla gruntów spoistych i niespoistych. Omówiono znaczenie współczynnika Fröhlicha jako parametru kalibracyjnego zależnego od rodzaju podłoża. Uwzględniono porównanie modeli literaturowych oraz ich zastosowanie w praktyce inżynierskiej. Wskazano różnice w strefie wpływu siły skupionej między analizowanymi podejściami. Podkreślono ograniczenia modelu Fröhlicha dla n ≠ 3 w kontekście teorii sprężystości. Model ten może być użyteczny jako narzędzie wspomagające w analizach lokalnych.

EN

The article concerns the influence of the Fröhlich coefficient on the distribution of vertical stresses in a homogeneous soil medium. Modifications of the classical Boussinesq’s model and results of numerical calculations for cohesive and non-cohesive soils are presented. The importance of the Fröhlich coefficient as a calibration parameter dependent on the type of subsoil is discussed. A comparison of literature models and their application in engineering practice is included. Differences in the zone of concentrated force influence between the analyzed approaches are indicated. Limitations of the Fröhlich model for n ≠ 3 in the context of the theory of elasticity are emphasized. This model can be useful as a supporting tool in local analyses.

3

Analiza wpływu rozdrobnionych odpadów gumowych na pionowy rozkład odkształceń w kompozytach związanych spoiwem

Walotek Konrad, Olma Anna, Szołtysik Joanna

Materiały Budowlane

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2025

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nr 7

230--234

4

Application of the numerical simulation method for the strength analysis of long-term portal crane components

Lipiec Sebastian, Zvirko Olha, Dzioba Ihor, Venhryniuk Oleh

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 4

126--139

EN

In this paper, the strength analysis of the material from two elements of a portal crane operated for about 33 years was carried out. The assessment was based on modelling and numerical simulation results using the finite element method of the load of three-point bending specimens. The constitutive relationships of the materials in the form of true stress-strain relationships were defined based on data from the uniaxial tensile test of the appropriate specimens. The iterative fitting method of the experimental and numerical relationship and the method that considers triaxiality and the Lode parameter were used. The accuracy of the defined stress-strain relationships was verified by comparing the load curves determined experimentally and numerically. Numerical modelling and simulation of the load of three-point bending specimens allowed obtaining stress distributions before the crack tip and the values of fracture toughness – J-integral. The results of the numerically calculated J-integral are similar to the experimental results. The trends in the stress component distributions indicate a high level of fracture toughness of the tested materials, ensuring a ductile nature of subcritical crack growth. The proposed methodology can be applied to other steels of operated structures.

5

Wpływ sposobu obciążenia na nośność i morfologię uszkodzeń połączeń ścian wykonanych z ABK

Galman Iwona

Materiały Budowlane

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2024

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nr 7

110--112

6

Numerical simulation on effect of coal pillar width on stability of retained roadway: A case study of Khe Cham Coal Mine, Vietnam

Le Quang Phuc, Le Tien Dung

Journal of Sustainable Mining

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2024

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Vol. 23, iss. 1

1--9

EN

When extracting coal seams in Vietnam underground mines, coal pillars are often left unmined for the protection of retained roadways in the longwall mining method. During longwall mining operations, coal pillars are often placed where high-stress concentrations occur in the abutment pressure zone of adjacent panels, especially when extracting seams under hard-to-cave main roof conditions. The instability of coal pillars under the loading of the main roof may cause the roadway to collapse, threatening the safe operation of a coal mine. This paper presents a detailed numerical investigation of the effect of coal pillar width on the stability of retained roadway under hard-to-cave main roof conditions, which has not been fully understood in previous studies. The results indicate that as the width of the coal pillar increases, the peak stress gradually moves from the virgin coal side to the pillar side, and an elastic zone will gradually be formed in the center of the pillar. A pillar width of less than 40 m coal pillars is easily destroyed under the great pressure caused by the hard main roof. A pillar width greater than 40 m creates a safe condition and has enough bearing capacity to maintain the stability of retained roadways. Based on these results, this paper proposes to use an improved longwall mining method where the coal pillars should be mined together with the adjacent panel to reduce coal loss in pillars.

7

Pomiary światłowodowe DFOS w diagnostyce konstrukcji sprężonych

Piątek Bartosz

Inżynier Budownictwa

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2024

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nr 3

49--54

8

Numerical study of the possibility of using adhesive joints for indirect measurements for stress distribution

Kisała Piotr, Wiśniewski Paweł

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

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2024

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T. 14, nr 2

51--55

EN

The article covers the subject of examining adhesive joints usage in indirect stress distribution measurements, taking into account contemporary methods of stress distribution measurements, including testing with fiber optic stress sensors. Numerical methods, in particular the finite element method, were used to calculate the stress distribution. The research carried out is described taking into account the following order – firstly, preliminary assumptions regarding sample models and simulation parameters were presented, then the course of the simulation was described, and finally, an analysis of the obtained results was carried out. A control simulation was carried out on a base-glue-fiber sample, which, due to difficulties in assessing the stress characteristics, was retaken in order to calculate the strain convertible to stress. The final results, together with the coefficients defining the measure of compatibility of the characteristics, are presented in the form of graphs and a table.

PL

Artykuł poświęcono badaniu możliwości wykorzystania połączeń klejowych do pomiarów pośrednich rozkładu naprężenia, biorąc pod uwagę współczesne metody badania rozkładu naprężenia, w tym badania przy pomocy światłowodowych czujników naprężenia. Do obliczenia rozkładu naprężenia wykorzystano metody numeryczne, a w szczególności metodę elementów skończonych. Przeprowadzone badania opisano uwzględniając następujący porządek – po pierwsze zaprezentowano wstępne założenia dotyczące modeli próbek i parametrów symulacji, następnie opisano przebieg symulacji, a ostatecznie przeprowadzono analizę uzyskanych wyników. Kontrolną symulację przeprowadzono na próbce podstawa-klej-światłowód, która z powodu trudności w ocenie charakterystyki naprężenia została powtórzona w celu obliczenia odkształcenia możliwego do przeliczenia na naprężenie. Ostateczne wyniki wraz z współczynnikami określającymi miarę zgodności charakterystyk zostały przedstawione w formie wykresów oraz tabeli.

9

Study on crack growth resulting from spacing and alignment of two circular holes : a phase field approach

Alfat Sayahdin

Computer Assisted Methods in Engineering and Science

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2024

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Vol. 31, no. 4

431--447

EN

This study investigates the effects of spacing and alignment between two circular holes on crack growth simulation. Key aspects analyzed include: (a) crack growth behavior, (b) von Mises stress distribution, and (c) energy profiles, all through variations in the spacing and alignment of the holes. The material is assumed to be homogeneous and isotropic, with the following non-dimensional properties: Young’s modulus E = 70, Poisson's ratio ν = 0.35, which correspond to the real values E = 70 GPa, ν = 0.35, and ɣ = 2800 J · m–2. Additionally, the body force is neglected (f(x; t) = 0). The numerical method used in this research is the adaptive finite element method, which is considered highly robust for solving the phase field model for crack growth. Notable findings include: (a) spacing between the two holes did not significantly alter the crack path, while alignment differences had a significant impact; (b) during the cracking process, the highest stress occurs at the crack tip and the lowest at the crack center; and (c) the time for cracking in materials with two holes varies with spacing and alignment, and elastic and surface energy curves help predict total damage.

10

Three-dimensional Analysis of a Tunnel Excavation in a Jointed Rock Mass

Zabuski Lesław

Archives of Hydro-Engineering and Environmental Mechanics

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2024

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Vol. 71, nr 1

123–-134

EN

A tunnel at a shallow depth, lying between several and 55 meters, was excavated in a jointed rock mass. Models of the rock mass and tunnel were elaborated basing on the data from an object in Carpathian flysch (Poland). The tunnel behaviour was analysed by using FLAC3D program and Coulomb-Mohr criterion and ubiquitous model of the rock mass with 10 combinations of the joint systems orientation (with respect to the tunnel axis). The tunnel shape is horse-shoe and its height equals 4.5 m. In each tunnel cross-section, 16 rock bolts and 20 cm shotcrete layer (with the strength increasing with time) were mounted. In cases of unfavourable orientation of joint system and unstable conditions, rock bolting of the tunnel heading face was installed and modelled. The numerical analysis was carried out for each excavation step, equal to 1.5 m. The entire deformation process and stress redistribution were registered starting with the cross-section in originally intact rock mass (i.e. before the tunnel heading face reached it), to the section located far from the face, in already supported and stabilized tunnel. The results obtained show the effect of discontinuities orientation on the stress distribution and displace ment magnitude. The first signs of tunnel approaching heading face appear in a cross-section situated in a distance of 7 to 9 m from it. The processes of stress and displacement redistribution are long-range and occur in a distance of many meters from the already excavated tunnel face. The important result of the analysis was the determination of the ground response curves representing decompression and support loading as a function of the excavation advance. These results allow for better design of a proper support system of the tunnel.

11

Fracture Mechanism of Hard Main Roof and Determining the Width of Coal Pillars when Extracting Flat-lying Coal Seams

Le Quang Phuc, Dao Van Chi, Nguyen Phi Hung, Vu Thai Tien Dung

Inżynieria Mineralna

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2023

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no. 2, vol. 1

271--280

EN

In underground coal mining, the stability of roadways and gob-side entry depends on the coal pillar width. An unreasonable width of the coal pillar will cause the roadway to be in a dangerous zone of influence of the abutment pressure, leading to severe roadway deformation. This paper studies the fracture mechanism of the hard main roof and reasonable coal pillar width to protect the stability of gob-side entry driving. The research results show that when mining a coal seam under a hard main roof, the console of the main roof on the edge of the coal seam has the form of hinge structure. The great load of the roof layers and the rotation of the console are the main causes leading to the variation of the stress field in the coal seam. According to the development law of the stress field, after the main roof completes the collapse process, the peak of the maximum stress will move deep into the solid coal seam, and on the edge of the coal seam it will form a low-stress zone. Research results from the case of Seam #11 of Khe Cham coal mine, Vietnam show that the gob-side entry will be well stabilized when the narrow coal pillar between it and the boundary of the gob is 4–5 m.

12

Wpływ rodzaju szyny na wartość lokalnych pionowych naprężeń ściskających w środniku belki podsuwnicowej

Chybiński Marcin, Polus Łukasz, Kurzawa Zdzisław

Przegląd Budowlany

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2022

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R. 93, nr 11-12

35--41

PL

W pracy przeprowadzono numeryczne analizy rozkładu naprężeń w środniku belki podsuwnicowej. W celu oceny wpływu rodzaju szyny na wartość naprężeń wykonano analizy numeryczne dla różnych rodzajów szyn zamocowanych w sposób sztywny. Wartości lokalnych pionowych naprężeń ściskających wywołanych oddziaływaniem przekazywanym przez koło suwnicy otrzymane z analiz numerycznych zostały porównane z wielkościami obliczonymi wg normy PN-EN 1993-6.

EN

In this paper, numerical analyses of the stress distribution in the crane runway beam web were conducted. The analyses were carried out for different crane rail types rigidly fixed to the flange, to evaluate their impact on the stress value. The values of the vertical compressive stress generated by the wheel load obtained from the numerical analyses were compared with the ones calculated using the PN-EN 1993-6 standard.

13

Characteristics of stress distribution of a multi layered cylindrical pressure vessel

Somadder Somnath, Das Palash, Islam Md. Ashraful

Journal of Mechanical and Energy Engineering

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2022

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Vol. 6, No 2

1--6

EN

The operation of a multilayer pressure vessel subjected to thermomechanical loads is very significant. The cylindrical pressure vessel is widely used in industrial engineering: for example, to hold a variety of different types of liquid. On thick-walled cylinders, various loading circumstances such as internal overpressure, external overpressure, heat, bending, twisting, and combinations of these load characteristics are applied. Researchers have developed a number of strategies for enhancing the strength of cylinders, including the use of multilayer cylinders and increasing the thickness of the walls. This paper presents the results of an analytical and numerical analysis of a three-layer cylinder. The Abaqus FEA software is used to determine temperature, displacement, and stress distribution of a multilayer cylinder considering the effect of centripetal and centrifugal heat flow. From the numerical analysis, it is observed that centrifugal heat flux is more hazardous than centripetal heat flux for a multi-layered cylinder under thermo-mechanical loading.

14

Material dynamic behavior in cutting zone of Inconel 718 and its infuence on cutting process

Hao Zhaopeng, Cheng Gang, Li JiNing, Fan Yihang

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 3

art. no. e146

EN

The nickel-based superalloy Inconel 718 is widely used in aerospace and other fields due to its excellent performance. However, the alloy elements are presented in the form of compounds with high hardness, such as TiC, NbC, MoC, TiN and so on, which lead to complex cutting deformation in machining Inconel 718. In this study, the cutting experiments and the fast tool-drop test were carried out to obtain the chip root. Combining the split Hopkins pressure bar (SHPB) test, a scanning electron microscope (SEM) was used to observe the metallographic micrographs of the specimens and analyzed the plastic dynamic behavior of the material in the cutting area. The soft and hardening mechanism in the dynamic deformation process was described. The stress distribution model of material in the cutting area was proposed and the influence of stress distribution on cutting deformation, side fow and tool wear during the cutting process were also given.

15

Experimental investigation of bonding behavior of anchoraged timber-to-timber joint

Ghoroubi Rahim, Mercimek Ömer, Sakin Shaimaa, Anil Özgür

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 1

art. no. e7, 2022

EN

The comprehensive experimental study examining the general load–displacement behavior, stress distributions and shear stress–shear-displacement behaviors in the connection area when wood structural elements are combined with adhesive or adhesive with mechanical anchorages have been found in very limited number of studies in the literature. Therefore, an experimental study was planned. In this study, the general load–displacement behavior of the timber connection regions which are connected by adhesive and mechanical anchorages together with adhesive, with varying lengths of 180, 240 and 350 mm are investigated experimentally. Besides, the effect of changing the number and location of mechanical anchorages used in the connection area on the general load–displacement behavior and shear stress–shear-displacement behavior was also investigated. Using the load–displacement graphs obtained as a result of the experimental study, a generalized material model is proposed for the shear stress–shear-displacement interfacial adhesion surface for wood–wood junction points. This material model, which is proposed for wood–wood connection points with mechanical anchors, is a model that can be useful and can be used in the analysis of structural systems containing such connections using finite element software. It is thought that the overall capacity and load–displacement behavior of structural systems containing such connection points can be calculated more realistically using the proposed interfacial material model.

16

Effect of Nanoindentation Rate on Plastic Deformation in Cu Thin Films

Chocyk Dariusz, Zientarski Tomasz

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no. 1

170--179

EN

The paper investigates the nanoindentation process with different rates in the Cu (001) of FCC system. The indentation process was done using molecular dynamics simulation based on the embedded atom method theory and Morse potential. Simulation process of indentation used a rigid spherical indenter with the diamond structure. To structure characterization we applied the adaptive common neighbour and the dislocation extraction analysis. It was found that the range of the linear change of the indentation force depends on the rate of response of the system. The initial range of the linear dependence of stress evolution also depends on the rate of indentation. Moreover, the average total normal stress in the system is only compressive. After linear changes, we observe oscillating changes in stress evolution. During indentation, for the range of linear changes of stress, dislocations aggregated only around the indenter surface. The creation of dislocations is directly connected with the structural changes. The structure analysis revealed the formation of HCP and BCC structure in the Cu (001) of FCC systems and a correlation with the creation of dislocations.

17

Stress Distribution Around Mechanized Longwall Face at Deep Mining in Quang Ninh Underground Coal Mine

Bui Manh Tung, Le Tien Dung, Vo Trong Hung

Inżynieria Mineralna

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2021

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no. 2

167--176

EN

Quang Ninh underground coal mines are currently in the phase of finishing up the mineral reserves located near the surface. Also, in this phase, a number of coal mines have opened and prepared new mine sites for the extraction of the reserves at greater depth. Several mines have mined at -350 m depth and are driving opening excavations at -500 m depth below sea level. The mining at greater depth faces many difficulties, such as a significant increase in support and excavation pressures. The longwall face pressure is mostly manifested in great magnitude that causes support overloaded and jumped and face spall/roof fall. This paper, based on the geological condition of the Seam 11 Ha Lam coal mine, uses the numerical program UDEC for studying the impact of mining depth on stress distribution around the longwall face. The results show that the deeper the mining is, the greater the plastic deformation zone is. The peak front abutment stress moves closer to the coal wall, mainly concentrating on the immediate roof and top coal. The top coal is greatly broken, and its bearing capacity is decreased. Some solutions to the stability of roof strata are proposed, and a proper working resistance of support is determined. Additionally, the paper suggests that the starting depth for deep mining in Quang Ninh underground coal mines should be -350 m below sea level.

18

Large amplitude forced vibrations of restrained beams resting on elastic point supports

Fakhreddine Hatim, Adri Ahmed, Chajdi Mohcine, Rifai Said, Benamar Rhali

Engineering Transactions

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2021

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Vol. 69, iss. 3

225--242

EN

The present paper concerns the study of geometrically non-linear forced vibrations of beams resting on two different types of springs: rotational and translational. Assuming that the motion is harmonic, the displacement is extended as a series of spatial functions determined by solving the linear problem. Hamilton’s principle and spectral analysis are used to reduce the problem to a non-linear algebraic system solved using a previously developed approximate method. The effects of the nature of the added springs and their location on the non-linear behaviour of the beam are examined. A multimode approach is used in the forced case to obtain results over a wide range of vibration amplitudes. This leads to examining the non-linear forced dynamic response for different positions of each spring and different levels of excitations. Following a parametric study, the non-linear forced mode shapes and their associated bending moments are presented for different levels of excitations and for different vibration amplitudes to give an estimation of the stress distribution over the beam length.

19

An Influence of Geometrical Parameters of the Lock of the Blade-Disc Joint on Stress in the FEA and DIC Methods

Kozakiewicz Adam, Grzejszczak Olga

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no. 1

209--217

EN

In this paper, an assessment of strength properties of the existing blade-disc dovetail joint was presented, taking the parametric optimization of its geometry. A sensitivity of the analysis was carried out to determine the relationship between the selected geometric parameters and strength properties of the structure questioned. The results from experiments and computer simulations were compared. In addition, the fatigue life of the structure was analyzed for different materials and using the change of speed ranges and parameterization of geometry.

20

Front Stress Distribution Under the Impact of Cutting Height to Caving Height Ratio in Extra-thick Longwall Top Coal Caving Technology

Bui Manh Tung, Nguyen VanQuang, Nguyen Phi Hung, Vo Ngoc Dung, Do Hoang Hiep

Inżynieria Mineralna

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2020

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no. 2, vol. 1

123--129

EN

The extraction with higher cutting height for extra-thick seam is the new research orientation in longwall caving technology. Due to the increase of top coal thickness and of cutting height which leads to the change of cutting/caving height ratio, the rule of roof failure (including top coal caving) and the distribution of stress around the face alter correspondingly. This paper is based on the geological conditions of face 8102 of Tashan-DaTong mine, employing the numerical model by UDEC2D code, analysing the effect of cutting/ caving height ratio on the law of stress distribution ahead of the face. When the ratio of cutting/caving height decreases and the cutting height increases, the results of the research have shown that: (i)- peak stress redistributes further ahead of the face and its value manifestly drops; (ii)- the plastic deformation ahead of face significant increases and the zone of plastic strain also expands. It is therefore concluded that the variation of cutting/caving height ratio results in the redistribution of roof pressure, which contributes to the control of roof failure and face stability.

PL

Przy bardzo grubych pokładach, eksploatacja z dużą wysokością to nowy kierunek badań w technologii zawału stropu węgla. Ze względu na grubość warstwy stropu węglowego i zwiększoną wysokość urabiania prowadzi do zmiany stosunku urabiania do odzyskania, co również zmienia regułę zapalenia skał stropowych i zmienia stan rozkładu naprężeń wokół ściany. W artykule, przedstawiono wyniki analizy wpływu stosunku urabiania do uzyskania opierając się na prawie rozkładu obciążenia przed ścianą. Analiza ta została oparta na warunkach geologicznych kopalni 8102 TaSan-DaTong wykorzystując model numeryczny UDEC2D. Wyniki badań pokazują, że wraz ze spadkiem stosunku urabiania do odzyskania, oznacza to wzrost wysokości urabiania, położenie maksymalnego naprężenia jest daleko od ściany, maksymalna wartość naprężeń znacznie spada, zniszczenie plastyczne przed ścianą i stropem gwałtownie rośnie, zwiększa się strefa odkształcenia plastycznego. Dlatego zmiana stosunku urabiania do odzyskania może zmienić stan rozkładu ciśnienia stropowego, co jest korzystne dla procesu niszczenia stropu i kontrolowania stabilności ściany.