Analysis of Yielding Steel Arch Support with Rock Bolts in Mine Roadways Stability Aspect

2014 ◽  
Vol 59 (3) ◽  
pp. 641-654 ◽  
Author(s):  
Tadeusz Majcherczyk ◽  
Zbigniew Niedbalski ◽  
Piotr Małkowski ◽  
łukasz Bednarek
Keyword(s):  
Support System ◽  
Support Systems ◽  
Coal Mines ◽  
Rock Bolt ◽  
Rock Bolts ◽  
Mining Conditions ◽  
Arch Support ◽  
The Stability ◽  
Rock Bolt Support ◽  
Rockbolt Support

Abstract The result of the search for new technological solutions in the field of support for roadways in coal mines has in recent years been the widespread use of steel arch with rockbolt support systems. The efficiency of these systems is affected among other things by the option of installing rock bolts after the actual driving the mine roadway, the increased load capacity that these systems can support, and their resistance to dynamic weight. Large variation in the way that these steel arch support can be connected using different types of rock bolts necessitates mining research revealing the effectiveness of such solutions. Although the steel arch with rockbolt support system is used in the majority of European coal mines, it is still not possible to apply templates of schemes due to the diversity of geological and mining conditions. Therefore, throughout a period of several years, the authors of this article conducted research in situ under conditions of different schemes related to connecting arched support frames with rock bolts, with only selected results being presented in the article. The measurements of convergence, load supported by the system frame, load supported by the rock bolts, and the stratification of roof rocks were analyzed, carried out in two roadways with yielding steel arch support in which strand bolts were applied. The article also proposes the index for working maintenance nuw, used in preliminarily assessing the stability of a given working with a limited number of data concerning geomechanical conditions. Additionally considered are empirical methods used in Poland for designing steel arch with rock bolt support systems. The results of mine research indicate that strengthening yielding steel support with strand bolts through steel beams maintains the stability of a roadway, even when exposed to the exploitation stress. Aside from the impact of exploitation, deformations of the support system are negligible, despite the fact that the tensile forces acting on the rock bolts can reach values of up to 160 kN. Under favorable geological and mining conditions, support system frames can be spread up to 1.5 m apart when using rock bolts between them. The conducted measurement of convergence during a three year period revealed a compression amounting to a few centimeters. The results obtained by the research fully confirm the effectiveness of combined yielding steel arch with rock bolt support systems under different mining conditions.

scholarly journals Tests of steel arch and rock bolt support resistance to static and dynamic loading induced by suspended monorail transportation

2019 ◽  
Vol 41 (2) ◽  
pp. 81-92 ◽  
Author(s):  
Andrzej Pytlik
Keyword(s):  
Dynamic Loading ◽  
Coal Mines ◽  
Rock Bolt ◽  
Hard Coal ◽  
Maximum Speed ◽  
Arch Support ◽  
Roadway Support ◽  
Rock Bolt Support ◽  
Static And Dynamic Loading ◽  
Bolt Support

AbstractAt present, the suspended monorail systems constitute a very common means of transportation in the Polish hard coal mines. The main advantages of the suspended monorail include the independence of the route from the working floor surface irregularities and the possibility to transport cargo of significant mass and size.The masses and dimensions of machines and devices transported via monorail have increased considerably in recent times. This particularly concerns the transport of longwall system elements. In Poland, the maximum speed of suspended monorail travel is 2 m/s. Due to the fact that preparations are currently underway to increase the maximum speed above 2 m/s, it is necessary to inspect what influence it will have on work safety and mining support stability.Current operational experience and tests have shown that dynamic loads induced by the suspended monorail transportation have a significant influence on the roadway support stability, working protection durability and on the monorail operators. This is particularly true during the emergency braking of a suspended monorail by means of a braking trolley, where the overloads reach 3g.Bench tests of the selected steel arch and rock bolt support elements utilised in the Polish hard coal mines were conducted in order to determine the resistance of steel arch and rock bolt supports to static and dynamic loads.The article presents the results of the tests conducted on a steel arch support in the form of the sliding joints of an ŁP/V29 yielding roadway support, which is commonly employed in the Polish hard coal mines. Tests of elements of the threaded bolts with trapezoidal threads over the entire rod length were conducted as well.The conducted strength tests of steel arch and rock bolt support elements under static and dynamic loading have shown that dynamic loading has decisive influence on the support’s retaining of its stability. Support element stability decreases along with the increase of the impact velocity. This concerns both the steel arch support and the rock bolt support.

scholarly journals Long-term Analysis of the Effects of Production Management in Coal Mining in Poland

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3146 ◽  
Author(s):  
Izabela Jonek-Kowalska
Keyword(s):  
Coal Mining ◽  
Production Management ◽  
Coal Mines ◽  
Work Productivity ◽  
Policy Implications ◽  
Productivity Improvement ◽  
Mining Conditions ◽  
The Stability ◽  
Efficiency And Productivity

The primary aim of this article is to examine financial efficiency and work productivity, as well as their determinants, in selected Polish coal mines in 1998–2015. To achieve this goal, after introducing a justification for the choice of subject and the literature studies, the research methodology is presented, and research results are subsequently described and analyzed. Next, based on the main conclusions, model regularities and policy implications regarding efficiency and productivity improvement in Polish coal mining enterprises are established. The research for this study was conducted in five Polish coal mines, which were chosen on the basis of criteria aimed at ensuring the results’ comparability and the stability of organizational and mining conditions in the analyzed research period.

scholarly journals Adjustment of the Yielding System of Mechanical Rock Bolts for Room and Pillar Mining Method in Stratified Rock Mass

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2082 ◽  
Author(s):  
Krzysztof Skrzypkowski ◽  
Waldemar Korzeniowski ◽  
Krzysztof Zagórski ◽  
Anna Zagórska
Keyword(s):  
Numerical Modeling ◽  
Impact Energy ◽  
Laboratory Tests ◽  
Ore Deposits ◽  
Rock Bolt ◽  
Rock Bolts ◽  
Damage Area ◽  
Rock Bolt Support ◽  
The Impact ◽  
Bolt Support

The article presents a novel yielding mechanism, especially designed for the rock bolt support. Mechanical rock bolts with an expansion head and equipped with one, two, four and six dome bearing plates were tested in the laboratory conditions. Furthermore, in the Phase2D numerical program, five room and pillar widths were modeled. The main aim of numerical modeling was to determine the maximal range of the rock damage area and the total displacements in the expanded room. The models were made for a room and pillar method with a roof sag for copper ore deposits in the Legnica-Głogów Copper District in Poland. Additionally, in the article a load model of the rock bolt support as a result of a geomechanical seismic event is presented. Based on the results of laboratory tests (load–displacement characteristics), the strain energy of the bolt support equipped with the yielding device in the form of dome bearing plates was determined and compared with the impact energy caused by predicted falling rock layers. Based on the laboratory tests, numerical modeling and mathematical dynamic model of rock bolt support, the dependence of the drop height and the corresponding impact energy for the expanded room was determined.

scholarly journals Investigation of rock bolting for tunnels based on an efficient CATIA-ABAQUS model

2019 ◽  
Vol 295 ◽  
pp. 03002
Author(s):  
Hui Lee ◽  
Wei-zhong Chen ◽  
Xian-jun Tan ◽  
Qiao-chu Yang ◽  
Xiao-gang Wang
Keyword(s):  
Knowledge Engineering ◽  
Axial Stress ◽  
Great Influence ◽  
Vertical Displacement ◽  
Rock Bolt ◽  
Rock Bolts ◽  
Distribution Features ◽  
The Stability ◽  
Logarithmic Relationship ◽  
Abaqus Model

As a widely used reinforcement method in tunnel engineering, the accuracy of models in numerical analysis has a vital influence on the reliability of the analysis results. To solve the problem of hard modeling for complicated models, this paper proposes to build models of different characteristics automatically by the means of Enterprise Knowledge Language (EKL) of CATIA, combining knowledge engineering template with parameterization. Furthermore, the stability of surrounding rocks and the distribution features of plastic areas were studied in different cases by CATIA-ABAQUS model. Besides, the effects and contributions of several parameters, including the rock-bolt diameter and interval between rock-bolts have been studied. It was found that: (1) Rock-bolt has a notable effect on the stability of the surrounding rocks. Increasing the diameter of rock-bolts contributes to significantly reduce the plastic area and the vertical displacement. With the increase of the quantity and the diameter of anchors, the degree of influence gradually weakens, showing the logarithmic relationship; (2) When the quantity and diameter of rock-bolts are constant, in the case in which the intervals between rock-bolts are various, the plastic area of surrounding rocks and the axial stress of rock-bolts are larger than that of the same distance, while the vertical displacement are uniform. (3) The excavation process has a great influence on the axial stress of rock-bolts and the redistribution of stresses in the surrounding rock.

scholarly journals Reinforcement of Underground Excavation with Expansion Shell Rock Bolt Equipped with Deformable Component

2017 ◽  
Vol 39 (1) ◽  
pp. 39-52 ◽  
Author(s):  
Waldemar Korzeniowski ◽  
Krzysztof Skrzypkowski ◽  
Krzysztof Zagórski
Keyword(s):  
Rock Mass ◽  
Construction Materials ◽  
Rock Bolt ◽  
Loading Test ◽  
Rock Bolts ◽  
Disk Spring ◽  
Static Loading Test ◽  
Two Phases ◽  
Rock Bolt Support ◽  
Ultimate Loading Capacity

AbstractThe basic type of rock mass reinforcement method for both preparatory and operational workings in underground metal ore mines, both in Poland and in different countries across the world, is the expansion shell or adhesive-bonded rock bolt. The article discusses results of static loading test of the expansion shell rock bolts equipped with originally developed deformable component. This component consists of two profiled rock bolt washers, two disk springs, and three guide bars. The disk spring and disk washer material differs in stiffness. The construction materials ensure that at first the springs under loading are partially compressed, and then the rock bolt washer is plastically deformed. The rock bolts tested were installed in blocks simulating a rock mass with rock compressive strength of 80 MPa. The rock bolt was loaded statically until its ultimate loading capacity was exceeded. The study presents the results obtained under laboratory conditions in the test rig allowing testing of the rock bolts at their natural size, as used in underground metal ore mines. The stress-strain/displacement characteristics of the expansion shell rock bolt with the deformable component were determined experimentally. The relationships between the geometric parameters and specific strains or displacements of the bolt rod were described, and the percentage contribution of those values in total displacements, resulting from the deformation of rock bolt support components (washer, thread) and the expansion shell head displacements, were estimated. The stiffness of the yielded and stiff bolts was empirically determined, including stiffness parameters of every individual part (deformable component, steel rod). There were two phases of displacement observed during the static tension of the rock bolt which differed in their intensity.

Laboratory Method for Evaluating the Characteristics of Expansion Rock Bolts Subjected to Axial Tension / Laboratoryjna Metoda Badania Charakterystyk Kotew Rozprężnych Poddanych Rozciąganiu Osiowemu

2015 ◽  
Vol 60 (1) ◽  
pp. 209-224 ◽  
Author(s):  
Waldemar Korzeniowski ◽  
Krzysztof Skrzypkowski ◽  
Łukasz Herezy
Keyword(s):  
Rock Mass ◽  
Laboratory Method ◽  
Operating Conditions ◽  
Rock Bolt ◽  
Test Facility ◽  
Geometrical Parameters ◽  
Rock Bolts ◽  
Axial Tension ◽  
Rock Bolt Support ◽  
Bolt Support

Abstract Rock bolts have long been used in Poland, above all in the ore mining. Worldwide experience (Australia, Chile, Canada, South Africa, Sweden, and USA) provides evidence of rock bolt supports being used for loads under both static and dynamic conditions. There are new construction designs dedicated to the more extreme operating conditions, particularly in mining but also in tunneling. Appreciating the role and significance of the rock bolt support and its use in Polish conditions amounting to millions of units per year, this article describes a new laboratory test facility which enables rock bolt testing under static load conditions. Measuring equipment used as well as the possibilities of the test facility were characterized. Tests were conducted on expansion rock bolt supports installed inside a block simulating rock mass with compression strength of 80 MPa, which was loaded statically as determined by taking account of the load in order to maintain the desired axial tension, which was statically burdened in accordance with determined program load taking into consideration the maintenance of set axial tension strength at specified time intervals until capacity was exceeded. As an experiment the stress-strain characteristics of the rock bolt support were removed showing detailed dependence between its geometrical parameters as well as actual rock bolt deformation and its percentage share in total displacement and deformation resulting from the deformation of the bolt support elements (washer, thread). Two characteristic exchange parts with varying intensity of deformation /displacement per unit were highlighted with an increase in axial force static rock bolt supports installed in the rock mass.

scholarly journals Application of a FBG-Based Instrumented Rock Bolt in a TBM-Excavated Coal Mine Roadway

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Bin Tang ◽  
Hua Cheng ◽  
Yongzhi Tang ◽  
Zhishu Yao ◽  
Chuanxin Rong ◽  
...  
Keyword(s):  
Monitoring System ◽  
Coal Mine ◽  
Electromagnetic Interference ◽  
Coal Mines ◽  
Work Conditions ◽  
Rock Bolt ◽  
Rock Bolts ◽  
Axial Forces ◽  
Underground Coal Mines ◽  
Fbg Sensors

Rock bolts have been widely applied with roadway excavation in underground coal mines to prevent roadway collapse and improve the stability of roadway surrounding rocks. Overloading and failures of rock bolts could result in accidents or casualties in coal mine roadways. Consequently, monitoring axial forces and work conditions of rock bolts plays an increasingly important role in ensuring safe operations of underground coal mines. Conventional mechanical or electronic rock bolt monitoring systems are typically affected by electromagnetic interference, corrosive groundwater, and dusty circumstance in underground working sites. This work proposed a FBG-based instrumented rock bolt. Quasi-distributed FBG sensors were installed on a slotted rock bolt and encapsulated by epoxy resin that was used to fix FBG sensors on the rock bolt and protect FBG sensors from damage. The FBG sensors were calibrated before the in situ application. Monitoring results indicated that the axial forces of rock bolts installed on the roof of the roadway were higher than that of others, and the maximum axial forces of each rock bolt were typically detected near the middle portion of rock bolts. A real-time and accurate rock bolt monitoring system was established by integrating instrumented rock bolts to the existing monitoring system of the coal mine.

scholarly journals Combined support mechanism of rock bolts and anchor cables for adjacent roadways in the external staggered split-level panel layout

2021 ◽  
Author(s):  
Adrian Batugin ◽  
Zhiqiang Wang ◽  
Zehua Su ◽  
Shermatova Sayyora Sidikovna
Keyword(s):  
Mechanical Properties ◽  
Side Wall ◽  
Rock Bolt ◽  
Rock Bolts ◽  
Thick Coal Seam ◽  
Support Mechanism ◽  
Anchor Cable ◽  
Side Rock ◽  
Air Intake ◽  
The Stability

AbstractUsing the spatial structure of the external staggered split-level panel layout, a combined support technology for adjacent roadways was developed and analyzed for a rock bolt and anchor cable mechanism. The influence of the side rock bolt and anchor cable parameters on the mechanical properties of the anchorage body and the support stress distribution of the lateral coal body were revealed using the FLAC3D software. The optimal support parameters of the side rock bolts and anchor cables were subsequently determined, and the support effect of gob-side entry in a mining scenario was verified. The results show that the support of the side rock bolts and anchor cables improves the mechanical properties and stress state of the anchorage body, producing a good protective effect on the coal body of the air-intake entry roof and side wall. This is beneficial to the stability of the side wall and the realization of the suspension effect for roof rock bolts and anchor cables, which in turn makes the surrounding rock maintenance of the gob-side entry to a thick coal seam more favorable.

IMPLEMENTASI METODE VIKOR DALAM PENERIMAAN JURNALIS PADA KORAN WASPADA MEDAN

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Soraya Rahma Hayati ◽  
Mesran Mesran ◽  
Taronisokhi Zebua ◽  
Heri Nurdiyanto ◽  
Khasanah Khasanah
Keyword(s):  
Decision Making ◽  
Decision Support ◽  
Decision Support System ◽  
Decision Support Systems ◽  
Support System ◽  
Support Systems ◽  
Knowledge Based ◽  
Computer Based ◽  
Support Decision Making ◽  
Made In

The reception of journalists at the Waspada Daily Medan always went through several rigorous selections before being determined to be accepted as journalists at the Waspada Medan Daily. There are several criteria that must be possessed by each participant as a condition for becoming a journalist in the Daily Alert Medan. To get the best participants, the Waspada Medan Daily needed a decision support system. Decision Support Systems (SPK) are part of computer-based information systems (including knowledge-based systems (knowledge management)) that are used to support decision making within an organization or company. Decision support systems provide a semitructured decision, where no one knows exactly how the decision should be made. In this study the authors applied the VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) as the method to be applied in the decision support system application. The VIKOR method is part of the Multi-Attibut Decision Making (MADM) Concept, which requires normalization in its calculations. The expected results in this study can obtain maximum decisions.Keywords: Journalist Acceptance, Decision Support System, VIKOR

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