Application of Long Expansion Rock Bolt Support in the Underground Mines of Legnica–Głogów Copper District

Skrzypkowski, Krzysztof; Korzeniowski, W.; Zagórski, Krzysztof; Dudek, P.

doi:10.1515/sgem-2017-0029

Cited by 20 publications

(15 citation statements)

References 8 publications

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“…Sci. 2019, 9, 3173 4 of 19 According to Equations (2) and (4), the RMD function is expressed as follows:…”

Section: Rmd Functionmentioning

confidence: 99%

“…For example, Zheng et al [2] applied borehole pressure relief technology to prevent rockburst in deep-buried mine roadways and achieved good results. Skrzypkowski et al [3,4] studied a new type of bolt support system, which had good energy absorption and rockburst prevention ability under the condition of tremor. However, in addition to finding reliable prevention and control measures, it is also important to establish an accurate rockburst prediction model in order to resist the occurrence of rockburst disasters [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

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Comprehensive Prediction and Discriminant Model for Rockburst Intensity Based on Improved Variable Fuzzy Sets Approach

Wang

et al. 2019

Applied Sciences

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Rockburst intensity prediction is one of the basic works of underground engineering disaster prevention and mitigation. Considering the dynamic variability and fuzziness in rockburst intensity prediction, variable fuzzy sets (VFS) are selected for evaluation and prediction. Here, there are two problems in the application of traditional VFS: (i) the relative membership degree (RMD) calculation process is complex and time-consuming, and the RMD matrix of all indexes can be only obtained by using the RMD function repeatedly; (ii) unreasonable weights of indicators have great impact on the synthetic relative membership degree (SRMD), so it is difficult to guarantee the correctness of the final prediction result. In view of the above problem, this paper established three simplified feature relationship expressions of RMD based on VFS principle and used the SRMD function to establish a BP neural network model to optimize SRMD. The improved VFS method is more efficient and the prediction results are more stable and reliable than the traditional VFS method. The main advantages are as follows: (1) the improved VFS method has higher computational efficiency; (2) the improved VFS method can verify the correctness of RMD at all times; (3) the improved VFS method has higher prediction accuracy; and (4) the improved VFS method has higher fault tolerance and practicability. because rockburst is a very complex nonlinear dynamic phenomenon, it needs many methods to combine and complement each other to accurately predict the intensity of rockburst. Therefore, it is still necessary to introduce new theories and methods to study the occurrence of rockburst and intensity classification prediction.Based on fuzzy mathematics, Chen [15] has proposed the variable fuzzy sets (VFS) method with relative membership degree (RMD) and synthetic relative membership degree (SRMD) at the core. This method establishes the corresponding VFS model according to the index classification level; then, the RMD function is established by using the VFS model corresponding to each level, and finally the method uses the SRMD function to combine the RMD values and weights of each index to get the final result. Compared with the fuzzy mathematics method, this method considers the dynamic variability and fuzziness of objective things, which improves the reliability of the prediction results [16]. Thus, the VFS method has been widely used in many multi-attribute decision-making problems, such as flood disaster risk assessment [16], surrounding rock stability assessment [17], water resources carrying capacity assessment [18], runoff prediction [19], and so on. Although the indexes and classification criteria are different in different evaluation types, the principle of the VFS method and the characteristics of RMD and SRMD functions are unchanged.Recently, the research of VFS mainly focuses on the application of the VFS method in different fields and the development of some new methods. For example, Guo et al. [20] applied the VFS model to landslide stability eva...

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“…Sci. 2019, 9, 3173 4 of 19 According to Equations (2) and (4), the RMD function is expressed as follows:…”

Section: Rmd Functionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comprehensive Prediction and Discriminant Model for Rockburst Intensity Based on Improved Variable Fuzzy Sets Approach

Wang

et al. 2019

Applied Sciences

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“…2, 3). For all free bolts, the diameter of smooth rod was 0.0183 m. A detailed description of used rock bolts can be found in the literature [22,23]. In order for laboratory studies to best satisfy mining conditions, dual bushings filled with concrete with a compressive strength of at least 75 MPa were used at the laboratory test facility.…”

Section: Laboratory Test Facilitymentioning

confidence: 99%

Laboratory testing of a long expansion rock bolt support for energy-absorbing applications

Skrzypkowski

2018

E3S Web Conf.

Self Cite

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Abstract. The main purpose of rock support and reinforcement in underground mining is to maintain excavations safe and open for their intended lifespan. The basic type of rock mass reinforcement method both in ore and hard coal mining is rock bolt support. Very often, existing bolt support systems are not always capable of providing a reliable controlled performance. Therefore, in recent years energy-absorbing bolts which are exposed to dynamic loading, for example from rock burst caused by high rock stresses, earthquakes, or blasting have appeared. In this article particular attention was paid to short and long expansion bolts. Quasi-static tests of expansion bolts were carried out at the laboratory test facility in simulated mining conditions, especially for the KGHM Po mines. In the underground mines of the Legnica-(LGOM) the main way to protect the room excavation is rock bolt support with a length from 1.2 m to 2.6 m. Rock bolt support longer than 2.6 m is considered as additional support of excavations and is increasingly being used to reinforce the roofs. The comparisons of energy-absorbing short and long expansion bolts with a length of 1.8m, 3.6m and 5.2m were presented. In addition, for elastic and plastic range of each bolts were determined.

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“…In recent decades, many scholars carried out lots of laboratory and numerical tests, complemented by theoretical analysis, to study the mechanism of anchored rock. In roadway support, the anchor housing is often installed in sections over a short section with one resin charge or using an expansion head [6,7]. Carranza-Torres [8] proposed a closed-form solution of rockbolt reinforcement around tunnels, and numerical analysis confirmed that the bolt plays an important role in increasing the tunnel confining pressure and controlling the surrounding rock deformation.…”

Section: Introductionmentioning

confidence: 99%

Experimental Research on Mechanical and Energy Characteristics of Reinforced Rock under Dynamic Loading

Xin-xi

Liu

Zhao

et al. 2019

Shock and Vibration

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The properties of anchored surrounding rock may vary considerably under complex geological and stress conditions, especially dynamic loading in deep mining. Therefore, comprehensive study of the reinforced mechanism is required to prevent failures associated with deep mining. In this paper, with sandstone as matrix and steel bar as bolt, the dynamic compression test of reinforced rock was carried out by using a 50 mm rod diameter split Hopkinson pressure bar (SHPB) test device. The mechanical and energy characteristics of reinforced rock under dynamic loading were analyzed. The results show that the dynamic strength of reinforced sample is greater than that of unreinforced sample and increases with the increase of the strain rate. The reflected energy and absorbed energy increase with the increase of incident energy, while the transmitted energy increases slightly. The higher the strain rate, the larger the energy dissipation rate and the higher the degree of fragmentation. It shows that the energy dissipation characteristic reflects the internal damage process to some extent. Compared with the results of unreinforced samples, the reflected energy of reinforced samples significantly increases and the absorbed energy will significantly decrease. It can be seen that the bolt can reduce absorbed energy of surrounding rock, thereby improving the stability of roadway surrounding rock. The results may provide reference for the stability of deep roadway and support design.

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Application of Long Expansion Rock Bolt Support in the Underground Mines of Legnica–Głogów Copper District

Cited by 20 publications

References 8 publications

Comprehensive Prediction and Discriminant Model for Rockburst Intensity Based on Improved Variable Fuzzy Sets Approach

Comprehensive Prediction and Discriminant Model for Rockburst Intensity Based on Improved Variable Fuzzy Sets Approach

Laboratory testing of a long expansion rock bolt support for energy-absorbing applications

Experimental Research on Mechanical and Energy Characteristics of Reinforced Rock under Dynamic Loading

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