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    Wyświetlanie 1-13 z 13
    Tytuł:
    The analysis of selected methods of the yielding of a circular arch support made of V profiles
    Autorzy:
    Rotkegel, Marek
    Szot, Łukasz
    Fabich, Sławomir
    Powiązania:
    https://bibliotekanauki.pl/articles/1853839.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    wał
    podpora stalowa
    metoda elementów skończonych
    shaft
    circular support
    arch support
    Opis:
    Steel yielding arch support constructed of V profiles is commonly used to protect galleries and, in some cases, to reinforce or secure a shaft support. For this purpose, a closed, circular-shaped arch support is used, with arches overlapped by clamps that are typical for this type of construction. The support has high resistance to the impact of even (distributed over the entire surface of the support) load, however, as a result of significant deformation associated with a change in the radius of the curvatures, the support shows limited yielding capacity. This is due to the increase in resistance to slide on the locks, resulting from changes in the geometry of the ring caused by the rock mass. This article presents the results of research and analysis concerning the elements of the arch support with notches in arches. The research team tested the effect of the depth and location of the notches of the section’s flanges on the load impacting on the clamp’s bolts and the strength of the roof support. Moreover, the tests covered the influence of the number and location of clamps in a frictional joint on the change in the nature of work and yielding capacity. Finally, the research included both strength tests of the support’s elements, as well as strength analyses based on the finite element method.
    Źródło:
    Archives of Mining Sciences; 2020, 65, 3; 531-550
    0860-7001
    Pojawia się w:
    Archives of Mining Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimisation of selected parameters of the shield support base dedicated for the condition of a weak floor
    Autorzy:
    Rajwa, Sylwester
    Bock, Sven
    Powiązania:
    https://bibliotekanauki.pl/articles/2203341.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    modelowanie numeryczne
    eksploatacja węgla
    podpora hydrauliczna
    numerical modelling
    PFC3D
    shield support
    longwall mining
    Opis:
    In longwall coal exploitation, problems with the proper functioning of the powered shield support often occur. In many cases, it results from the insufficient load-bearing capacity of the ground (floor) and the inability to achieve the set or yield pressure of the shield support. The improper functioning of the shield support may also result from its construction and the lack of optimisation to work effectively on a weak mine floor. This paper presents an attempt to optimise the operating conditions of the base of two-legged shield support based on the field observations and results of the PFC3D numerical calculation. In the framework of the numerical calculations, the impact of the width of the base and the location of the hydraulic legs on the working conditions of shield support on a weak floor were analysed.
    Źródło:
    Archives of Mining Sciences; 2022, 67, 3; 509--529
    0860-7001
    Pojawia się w:
    Archives of Mining Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Welding supports of fine-grained steel mobile platforms
    Spawanie podpór podestów ruchomych ze stali drobnoziarnistej
    Autorzy:
    Silva, Abilio
    Szczucka-Lasota, Bożena
    Węgrzyn, Tomasz
    Jurek, Adam
    Powiązania:
    https://bibliotekanauki.pl/articles/1819220.pdf
    Data publikacji:
    2020
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    spawanie
    parametr spawania
    podpora
    platforma mobilna
    stal drobnoziarnista
    welding
    welding parameter
    support
    mobile platform
    fine-grained steel
    Opis:
    The article presents the process of welding of steel movable platform supports. There is a growing demand for the welding of difficult-to-weld fine grain steels used in civil engineering and transport. An example of this could be the use of high-strength movable platform supports. The recently used material in the production of movable platform supports are fine-grained steels due to their high tensile strength of 1000 MPa. The joints formed using them, however, are characterized by much lower strength than the native material. In this article, the most appropriate parameters were selected for welding the movable platform supports made of difficult-to-weld fine-grained steel S960 MC.
    Wzrasta zapotrzebowanie na spajanie trudno-spawalnych stali drobnoziarnistych stosowanych w inżynierii lądowej i w transporcie. Przykładem tego może być stosowanie wysokowytrzymałych podpór podestu ruchomego. Ostatnio stosowanym materiałem w produkcji podpor podestów ruchomych są stale drobnoziarniste z uwagi na ich dużą wytrzymałość na rozciąganie na poziomie 1000 MPa. Powstałe przy ich wykorzystaniu złącza cechują się jednak dużo niższą wytrzymałością od materiału rodzimego. W niniejszym artykule dobierano najwłaściwsze parametry do spawania podpór podestu ruchomego z trudno-spawalnej stali drobnoziarnistej S960 MC.
    Źródło:
    Welding Technology Review; 2020, 92, 6; 17--22
    0033-2364
    2449-7959
    Pojawia się w:
    Welding Technology Review
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Resistance of columns
    Autorzy:
    Eamon, C.
    Alsendi, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/129235.pdf
    Data publikacji:
    2017
    Wydawca:
    PWB MEDIA Zdziebłowski
    Tematy:
    podpora betonowa
    most
    analiza elementów skończonych
    obciążenie wybuchem
    podmuch
    concrete column
    bridge
    finite element analysis
    explosive load
    blast
    Opis:
    A large strain, large displacement finite element model that allows element separation and failure is constructed and validated based on existing results of reinforced concrete columns subjected to blast loads. In this approach, concrete is represented with the Johnson-Holmquist-Cook model while a plastic-kinematic relationship describes steel behavior. The model is used to predict the capacity of typical reinforced concrete bridge columns to resist an assumed blast load scenario, where changes in concrete strength, steel reinforcement ratio, and axial force on the column are considered. The effectiveness of a method of column protection is investigated, where existing columns are wrapped with a relatively inexpensive steel fiber reinforced polymer (SFRP) jacket. It was found that the use of SFRP can significantly enhance the resistance of the columns.
    Źródło:
    Builder; 2017, 21, 12; 66-69
    1896-0642
    Pojawia się w:
    Builder
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Reduced equations of slope-deflection method in structural analysis
    Autorzy:
    Husain, Muhammed Abbas
    Hasan, Zahraa Hameed
    Powiązania:
    https://bibliotekanauki.pl/articles/2106462.pdf
    Data publikacji:
    2021
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    analiza strukturalna
    konstrukcja słupowo-belkowa
    podpora mostu
    indeterminate structures
    slope-deflection
    structural analysis
    classical methods
    reduced equations
    Opis:
    This paper presents an update of the slope-deflection method, which is used in the analysis of statically indeterminate structures. In this study, new reduced equations are presented based on including both the effects of the member rotations and the fixed end moments in one term, rather than two terms, in order to simplify the application of the slope-deflection method. The reduced equations are developed, then three numerical examples with comprehensive cases of beams are solved by applying both the original and the proposed reduced equations. The analysis outputs indicated that the reduced equations are applicable for all cases that can be analyzed by the slope-deflection method, and give identical results compared with the original equations. It is found that the reduced equations require less computations when the structure has no support settlement, compared with the original equations, whereas the computations are approximately similar when the structure has a support settlement.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2021, 26, 4; 51--62
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Interaction principle of rock-bolt structure and rib control in large deformation roadways
    Autorzy:
    Yuan, Xun
    Yang, Shuangsuo
    Powiązania:
    https://bibliotekanauki.pl/articles/1853892.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    budowa dróg
    kopalnia węgla
    podpora betonowa
    rock-bolt structure
    fluctuation balance law
    large deformation roadway
    thick-board support
    Opis:
    Large deformation in roadways is an inevitable problem faced by many coal mines, and bolt installation is widely adopted to keep roadway stability. To provide a theoretical basis for bolt supporting scheme design in order to eliminate hazards associated with roadway failure, the interaction principle between bolts and the bolted strata should be studied thoroughly. This research attempts to investigate the above principle through theoretical analysis through a group of selected statistics from fifteen different coal mines. At the same time, the thick board support method was proposed and applied for controlling the ribs deformation in a particular coal mine. It is concluded that the interaction of the rock-bolt entity is subjected to the fluctuation balance law. When deformation increases, the bolted structure experiences periodic equilibrium variation. Both the supporting force needed to stabilise the surrounding rocks and the supporting capability of bolted strata show a trend of decrease in this process. The interaction principle of surrounding rocks and bolts is in essence the mechanical phenomenon caused by their mutual load transformation, and the load-carrying capacity varies with the bolted structure’s deformation, which is subjected to the following law: elastic roadway>plastic roadway> fractured roadway>broken roadway. The designed bolted thickness of the ribs should be more than 1/5 of roadway height to make full use of the self-stability of surrounding rocks. Finite Difference Method simulation and on-site monitoring data showed that the roof subsidence and ribs convergence of 2201 roadway in Shuguang coal mine was reduced by 83.7% and 88.6% respectively after utilising the proposed support method, indicating that the thick-board method was effective. Results of this research can lay a foundation for support design in large deformation roadways.
    Źródło:
    Archives of Mining Sciences; 2021, 66, 2; 227-248
    0860-7001
    Pojawia się w:
    Archives of Mining Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of behaviour of the steel arch support in the geological and mining conditions of the Cam Pha coal basin, Vietnam
    Autorzy:
    Nguyen, Phu Minh Vuong
    Rotkegel, Marek
    Van, Hoang Do
    Powiązania:
    https://bibliotekanauki.pl/articles/1853833.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    podpora stalowa
    analiza numeryczna
    górnictwo wietnamskie
    steel arch support
    profiles of steel arch support
    numerical analysis
    Vietnamese coal mining industry
    Opis:
    In recent years, the Vietnamese coal mining industry has observed a dynamic increase in both its production and efficiency. In Vietnam, the most precious type of coal is anthracite, which is found in the Quang Ninh province. Industrial anthracite deposits are estimated to be over 2 billion Mg. At present, coal deposits are extracted mostly by the underground method. Coal production is gradually increasing in the underground mines in the Quang Ninh area and it is expected to constitute about 75% of the country’s total coal production in 2030. This involves an increase in the number and length of underground workings. Cam Pha is the largest coal basin of Vietnam, located in the Quang Ninh province. So far, the yearly length of underground workings driven in underground mines in the Cam Pha basin is roughly 90÷150 km. About 84 % of these underground workings are supported by the steel arch support made of SWP profile. A similar situation can be observed in Russia, Ukraine, China, India and Turkey. In addition, the average length of repaired underground workings in the Cam Pha basin constitutes approximately 30% of the total length driven . The main cause was reported is loss of underground workings stability. This requires significant material and labour costs as well as the cost of replacing damaged elements. Addi-tionally, it disturbs the continuity of the mining operations.This article presents the results of the numerical modelling of the rock mass around underground wor-kings driven in typical geo-mining conditions for underground coal mines in the Cam Pha basin, supported by the steel arch support made of SWP and V profiles. As a result of the conducted analyses, the range of failure zone of the rock mass around underground workings and the distribution of reduced stress in the steel arch support elements were determined. The effort states of the steel arch support made of SWP22 profile and V21 profile were compared. The simulations considered different inclinations angle of coal seam, following the structure of the rock mass in the Cam Pha basin. The analysis was carried out using the based-finite difference method code, FLAC2D. Based on the obtained results, actions for improving the stability of underground workings driven in the underground mines of the Cam Pha basin were proposed.
    Źródło:
    Archives of Mining Sciences; 2020, 65, 3; 551-567
    0860-7001
    Pojawia się w:
    Archives of Mining Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Computer modelling of point supported laminated glass panes
    Modelowanie komputerowe podpartych punktowo płyt ze szkła laminowanego
    Autorzy:
    Woźniczka, Piotr
    Powiązania:
    https://bibliotekanauki.pl/articles/2174006.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    analiza nieliniowa
    modelowanie komputerowe
    podpora punktowa
    szkło laminowane
    teoria płyt cienkich
    computer modelling
    laminated glass
    nonlinear analysis
    point support
    thin plate theory
    Opis:
    In recent years significant progress has been made in structural application of glass elements in building industry. However, the issues related to computer modelling of glass panes, as well as analytical procedures allowing for taking into account the bonding action of PVB foil are not widely known in the engineering environment. In this paper results of numerical study of laminated glass plates are presented. The scope of the research covers over 40 cases of panes. Narrow (characterized by edge length ab > 2) and square (a/b = 1) panes made of two or three layer laminated glass have been taken into account. The paper deals mainly with point supported glass. However, selected results for linearly supported plates have been included as well for comparison. For each considered case an advanced computational model have been developed within the environment of Abaqus software. Pointwise supports have been modelled using methods of various complexity. The obtained results have been compared with the results of standard calculations using Wölfel-Bennison and Galuppi-Royer-Carfagni hypotheses. The analytical procedures proposed by CEN have been applied as well. As a result, recommendations for static calculations of laminated glass panes have been formulated. The computational procedure based on the hypothesis presented by L. Galuppi and G. Royer-Carfagni should be considered the most universal. The remaining methods may be applied only in limited scope. In order to estimate maximum principal stress in the support zone an advanced computer model has to be used. The support may be modelled in an exact or simplified manner.
    W ostatnich latach dokonano znaczącego postępu w zakresie konstrukcyjnego wykorzystania w budownictwie elementów ze szkła. Równocześnie trwają prace nad drugą edycją norm europejskich, wśród których przewidziano przygotowanie odrębnej normy dotyczącej projektowania konstrukcji szklanych. Zgodnie z dokumentami opracowanymi przez odpowiedni komitet techniczny Europejskiego Komitetu Normalizacyjnego, wspomniana norma powinna obejmować swoim zakresem także nowoczesne procedury w zakresie obliczeń statycznych prętów i płyt ze szkła laminowanego. Tego typu elementy konstrukcyjne podparte w sposób punktowy lub w sposób liniowy są powszechnie stosowane w praktyce inżynierskiej ze względów architektonicznych i funkcjonalnych. Problematyka związana z modelowaniem komputerowym elementów ze szkła, jak również procedury analityczne pozwalające na uwzględnienie zespalającego działania folii PVB, nie są jednak powszechnie znane i stosowane w środowisku inżynierskim. W tej sytuacji w artykule przedstawiono wyniki weryfikacji wybranych procedur obliczeniowych dotyczących płyt ze szkła laminowanego. W przeprowadzonych analizach uwzględniono metody obliczeniowe oparte na hipotezach opracowanych przez E. Wolfela i S.J. Bennisona, a także przez zespół autorski L. Galuppi i G. Royer-Carfagni. Rozpatrywano również ścisłe rozwiązanie zagadnienia zginanego pręta ze szkła laminowanego wyprowadzone z modeli reologicznych przez K. Langosch. Otrzymane rezultaty porównano każdorazowo z wynikami zaawansowanych symulacji komputerowych. W celu możliwie dokładnego odwzorowania zachowania się danej płyty szklanej oraz zespalającej warstwy PVB stosowano bryłowe elementy skończone, natomiast obliczenia były prowadzone jako geometrycznie nieliniowe. Szczególną uwagę poświecono zagadnieniom związanym z analizą płyt podpartych w sposób punktowy. Naprężenia główne w strefie podporowej były wyznaczane dla modeli komputerowych o zróżnicowanym stopniu skomplikowania, w tym również dla przypadków w których uwzględniono dokładna geometrię danej rotuli. Omówiono propozycję uproszczonego sposobu modelowania strefy podporowej. Analizy były prowadzone dla dwóch grup płyt o zróżnicowanej geometrii. W zakresie rozwiązań poszczególnych płyt rozpatrywano elementy ze szkła dwu- oraz trójwarstwowego. W celach porównawczych w artykule przedstawiono również rezultaty uzyskane dla płyt podpartych w sposób przegubowo-liniowy. Na podstawie przeprowadzonych badan sformułowano wnioski w zakresie przydatności poszczególnych metod obliczeniowych.
    Źródło:
    Archives of Civil Engineering; 2022, 68, 3; 353--368
    1230-2945
    Pojawia się w:
    Archives of Civil Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Determination of the stress-strain state of rock mass and zone of inelastic deformation around underground mine excavation using modern methods of numerical modelling
    Autorzy:
    Ignatiev, Sergey A.
    Sudarikov, Aleksandr E.
    Imashev, Askar Zh.
    Powiązania:
    https://bibliotekanauki.pl/articles/2073903.pdf
    Data publikacji:
    2021
    Wydawca:
    Główny Instytut Górnictwa
    Tematy:
    rock support
    rock mass
    surrounding rock mass
    geomechanical process
    mathematical modelling
    zone of inelastic deformation
    podpora skalna
    górotwór
    górotwór otaczający
    proces geomechaniczny
    modelowanie matematyczne
    strefa deformacji niesprężystych
    Opis:
    The paper reviews methods and trends of numerical modelling of geomechanical processes around underground mine excavations. The most rational method of determining the additional stresses caused by the mine excavations is chosen. Mathematical modelling was performed for excavations of various cross sections and different strength of rocks. The dimensions of the inelastic deformation zone around the mine excavations have been identified. The area of the total fracture zone around the excavation, as well as the area of the roof fracture zone are calculated. The results of the fracture zone modelling are presented both as coordinates and in a graphical form. To simplify application of the modelling results, dependency plots of the obtained parameters were created and analytical dependencies of the fracture zone parameters were identified. The SURFER and KOMPAS software packages were used as the graphic tools to visualize the modelling results.
    Źródło:
    Journal of Sustainable Mining; 2021, 20, 3; 220--227
    2300-1364
    2300-3960
    Pojawia się w:
    Journal of Sustainable Mining
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    On the resistance of concrete hollow thin-walled high piers to rock collisions
    Autorzy:
    Huang, Yao
    Powiązania:
    https://bibliotekanauki.pl/articles/27312168.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    podpora betonowa
    filar mostowy
    element cienkościenny
    zderzenie
    skała
    siła uderzenia
    uszkodzenie
    odporność na kolizje
    concrete pier
    thin-walled element
    rock
    collision
    collision force
    damage
    collision resistance
    Opis:
    Concrete hollow thin-walled high piers (CHTWHPs) located in mountainous areas may be destroyed by the huge impact force of accidental rocks. The study focuses on analyzing the effects of rock impact on the pier, including its impact force, pier damage, dynamic response, and energy dissipation characteristics. The results show that: (1) Increasing the impact height led to a decrease in the peak impact force. Specifically, 15.5% decrease in the peak collision force is induced when the height of rock collision rises from 10 m to 40 m. (2) The damage mode of the pier’s collision surface is mainly oval damage with symmetrical center, radial damage on the side surface, and corner shear failure on the cross section. (3) The peak displacement of bridge pier increases with the increase of collision height. As the collision height increased from 10 m to 40 m, the bridge pier’s peak displacement also increased, rising by 104.2%. (4) The concrete internal energy gradually decreased with increasing collision height, dropping by 36.9% when the height of rock collision rises from 10 m to 40 m. The reinforcement internal energy showed an increase of 78%. The results of this study may provide reference for the rock collision resistance design of CHTWHPs.
    Źródło:
    Archives of Civil Engineering; 2023, 69, 3; 187--197
    1230-2945
    Pojawia się w:
    Archives of Civil Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of spatial form of underground galleries on geometry and structural design of old mine support constructions
    Wpływ formy przestrzennej podziemnych wyrobisk na kształtowanie geometrii struktur konstrukcyjnych historycznych obudów górniczych
    Autorzy:
    Wieja, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/119011.pdf
    Data publikacji:
    2017
    Wydawca:
    Polskie Towarzystwo Geometrii i Grafiki Inżynierskiej
    Tematy:
    brick lining
    geometry
    mine support
    steel support
    shape
    timber crib
    underground space
    timber post
    underground gallery
    obudowa murowa
    geometria
    obudowa górnicza
    podpora stalowa
    kształt
    kaszyca drewniana
    przestrzeń podziemna
    Opis:
    This study examines the geometry of old mine support structures, starting from simple props and chock supports to polygonal supports to refined truss or basket supports. The focus is on spatial structures of mine supports, geometry of their structural components’ crossprofiles and the locking (anchor) systems. The purpose of the present study is to define the geometric and spatial relations between the actual shape of structural elements and the manmade underground spatial structure.
    W artykule przedstawiono analizę geometrii historycznych ustrojów konstrukcyjnych obudów górniczych począwszy od prostych obudów typu stojakowego i kasztowego, poprzez obudowy poligonalne, aż do wyrafinowanych konstrukcji typu kratownicowego i koszykowego. Analiza obejmuje struktury przestrzenne obudów oraz geometrię przekrojów elementów konstrukcyjnych i systemu ich wiązań tzw. zamków. Istotą opracowania jest zdefiniowanie relacji geometrycznych oraz przestrzennych pomiędzy kształtem ustrojów konstrukcyjnych obudów a antropogeniczną podziemną strukturą przestrzenną.
    Źródło:
    Journal Biuletyn of Polish Society for Geometry and Engineering Graphics; 2017, 30; 63-72
    1644-9363
    Pojawia się w:
    Journal Biuletyn of Polish Society for Geometry and Engineering Graphics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Anti-overturning safety performance investigation for single column pier bridge
    Autorzy:
    Ji, Yongcheng
    Liu, Wenchao
    Li, Wei
    Wang, Pixiang
    Powiązania:
    https://bibliotekanauki.pl/articles/2174020.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    podpora jednokolumnowa
    most dźwigarowy
    stateczność przeciwwywrotna
    modelowanie metodą elementów skończonych
    przewrócenie
    obciążenie krytyczne
    obrót
    single column pier
    girder bridge
    anti overturning stability
    finite element modelling
    overturn
    ultimate load
    rotation
    Opis:
    Under eccentric load, a single column pier bridge often overturns. In order to study the anti overturning performance of a single column pier bridge, taking the accident bridge in Wuxi as an example, a finite element model is established based on ABAQUS. According to the model simulation results, the relationship between the ultimate rotational load and overturning load of the accident bridge is obtained, and the ratio of the latter to the former is 1.75. Based on the model, the stress state, displacement state, and support state of the accident bridge under dead load, highway class I vehicle load, and accident vehicle load are obtained. Whether the strength and stability of the accident bridge under each load meet the service requirements is analyzed. In order to explore the differences among China, United States, and Japan specifications, the lateral stability of accident bridges is checked. It is found that the safety of the United States and Japan specifications is conservative, but the utilization rate of bridge traffic capacity is low. The safety of China specifications is slightly lower, but it can maximize the bridge’s traffic capacity and judge the ultimate overturning state of the bridge more accurately. The research results can provide technical references for the design and application of a single-column pier bridge.
    Źródło:
    Archives of Civil Engineering; 2022, 68, 3; 221--240
    1230-2945
    Pojawia się w:
    Archives of Civil Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Experimental studies of static and dynamic steel arch support load capacity and sliding joint temperature parameters during yielding
    Autorzy:
    Pytlik, Andrzej
    Powiązania:
    https://bibliotekanauki.pl/articles/1853806.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    nośność statyczna
    wyrobisko
    podpora stalowa
    yielding steel arch support
    support shackle torque
    static and dynamic load capacity
    support work
    arch acceleration in sliding joints
    joint sparking and heating temperature during yielding
    Opis:
    Difficult geological and mining conditions as well as great stresses in the rock mass result in significant deformations of the rocks that surround the workings and also lead to the occurrence of tremors and rock bursts. Yielding steel arch support has been utilised in the face of hard coal extraction under difficult conditions for many years, both in Poland and abroad. A significant improvement in maintaining gallery working stability is achieved by increasing the yielding support load capacity and work through bolting; however, the use of rock bolts is often limited due to factors such as weak roof rock, significant rock mass fracturing, water accumulation, etc. This is why research and design efforts continue in order to increase yielding steel arch support resistance to both static and dynamic loads. Currently, the most commonly employed type of yielding steel arch support is a support system with frames constructed from overlapping steel arches coupled by shackles. The yield of the steel frame is accomplished by means of sliding joints constructed from sections of various profiles (e.g. V, TH or U-type), which slip after the friction force is exceeded; this force is primarily dependent on the type of shackles and the torque of the shackle screw nuts. This article presents the static bench testing results of ŁP10/V36/4/A, ŁP10/V32/4/A and ŁP10/V29/4/A yielding steel arch support systems formed from S480W and S560W steel with increased mechanical properties. The tests were conducted using 2 and 3 shackles in the joint, which made it possible to compare the load capacities, work values and characteristics of various types of support. The following shackle screw torques were used for the tests: Md = 500 Nm – for shackles utilised in the support constructed from V32 and V36 sections. Md = 400 Nm – for shackles utilised in the support constructed from V29 sections. The shackle screw torques used during the tests were greater compared to the currently utilised standard shackle screw torques within the range of Md = 350-450 Nm. Dynamic testing of the sliding joints constructed from V32 section with 2 and 3 shackles was also performed. The SD32/36W shackles utilised during the tests were produced in the reinforced versions and manufactured using S480W steel. Since comparative testing of a rock bolt-reinforced steel arch support system revealed that the bolts would undergo failure at the point of the support yield, a decision was made to investigate the character of the dynamics of this phenomenon. Consequently, this article also presents unique measurement results for top section acceleration values registered in the joints during the conduction of support tests at fullscale.Filming the yield in the joint using high-speed video and thermal cameras made it possible to register the dynamic characteristics of the joint heating process at the arch contact point as well as the mechanical sparks that accompanied it. Considering that these phenomena have thus far been poorly understood, recognising their significance is of great importance from the perspective of occupational safety under the conditions of an explosive atmosphere, especially in the light of the requirements of the new standard EN ISO 80079-36:2016, harmonised with the ATEX directive.
    Źródło:
    Archives of Mining Sciences; 2020, 65, 3; 469-491
    0860-7001
    Pojawia się w:
    Archives of Mining Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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