scholarly journals Influence of anchorage length and pretension on the working resistance of rock bolt based on its tensile characteristics

2021 ◽  
Author(s):  
Jucai Chang ◽  
Kai He ◽  
Dongdong Pang ◽  
Dong Li ◽  
Chuanming Li ◽  
...  
Keyword(s):  
High Strength ◽  
Rock Bolt ◽  
Support Design ◽  
Anchorage Length ◽  
High Strength Bolt ◽  
Working Face ◽  
Key Factor ◽  
Roadway Support ◽  
Working Resistance ◽  
Surrounding Rock Deformation

AbstractIn coal mining roadway support design, the working resistance of the rock bolt is the key factor affecting its maximum support load. Effective improvement of the working resistance is of great significance to roadway support. Based on the rock bolt’s tensile characteristics and the mining roadway surrounding rock deformation, a mechanical model for calculating the working resistance of the rock bolt was established and solved. Taking the mining roadway of the 17102 (3) working face at the Panji No. 3 Coal Mine of China as a research site, with a quadrilateral section roadway, the influence of pretension and anchorage length on the working resistance of high-strength and ordinary rock bolts in the middle and corner of the roadway is studied. The results show that when the bolt is in the elastic stage, increasing the pretension and anchorage length can effectively improve the working resistance. When the bolt is in the yield and strain-strengthening stages, increasing the pretension and anchorage length cannot effectively improve the working resistance. The influence of pretension and anchorage length on the ordinary and high-strength bolts is similar. The ordinary bolt’s working resistance is approximately 25 kN less than that of the high-strength bolt. When pretension and anchorage length are considered separately, the best pretensions of the high-strength bolt in the middle of the roadway side and the roadway corner are 41.55 and 104.26 kN, respectively, and the best anchorage lengths are 1.54 and 2.12 m, respectively. The best anchorage length of the ordinary bolt is the same as that of the high-strength bolt, and the best pretension for the ordinary bolt in the middle of the roadway side and at the roadway corner is 33.51 and 85.12 kN, respectively. The research results can provide a theoretical basis for supporting the design of quadrilateral mining roadways.

scholarly journals Study on the Influence of Anchorage Length and Pretension on the Working Resistance of Rock Bolt Based on its Tensile Characteristics

2021 ◽  
Author(s):  
Jucai Chang ◽  
Kai He ◽  
Dongdong Pang ◽  
Dong Li ◽  
Chuanming Li ◽  
...  
Keyword(s):  
High Strength ◽  
Rock Bolt ◽  
Support Design ◽  
Anchorage Length ◽  
High Strength Bolt ◽  
Working Face ◽  
Key Factor ◽  
Roadway Support ◽  
Working Resistance ◽  
Surrounding Rock Deformation

Abstract In coal mining roadway support design, the working resistance of the rock bolt is the key factor affecting its support effect. Effective improvement of the working resistance is of great significance to roadway support. Based on the rock bolt’s tensile characteristics and the mining roadway surrounding rock deformation, a mechanical model for calculating the working resistance of the rock bolt is established and solved. Taking the mining roadway of the 17102 (3) working face at the Panji 3# Well Coal Mine of China as a research object, with a quadrilateral section roadway, the influence of pretension and anchorage length on the working resistance of high-strength and ordinary rock bolts in the middle and corner of the roadway is studied. The results show that when the bolt is in the elastic stage, increasing the pretension and anchorage length can effectively improve the working resistance. When the bolt is in the yield and strain-strengthening stages, increasing the pretension and anchorage length cannot effectively improve the working resistance. The influence of pretension and anchorage length on the ordinary and high-strength bolts is similar. The ordinary bolt’s working resistance is approximately 25 kN less than that of the high-strength bolt. When pretension and anchorage length are considered separately, the best pretensions of the high-strength bolt in the middle of the roadway side and the roadway corner are 41.55 and 104.26 kN, respectively, and the best anchorage lengths are 1.54 and 2.12 m, respectively. The best anchorage length of the ordinary bolt is the same as that of the high-strength bolt, and the best pretension for the ordinary bolt in the middle of the roadway side and at the roadway corner is 33.51 and 85.12 kN, respectively. The research results can provide a theoretical basis for supporting the design of quadrilateral mining roadways.

scholarly journals Study on the Influence of Anchorage Length and Pretension on the Working Resistance of Rock Bolt Based on its Tensile Characteristics

2021 ◽  
Author(s):  
Jucai Chang ◽  
Kai He ◽  
Dongdong Pang ◽  
Dong Li ◽  
Chuanming Li ◽  
...  
Keyword(s):  
High Strength ◽  
Rock Bolt ◽  
Support Design ◽  
Anchorage Length ◽  
High Strength Bolt ◽  
Working Face ◽  
Key Factor ◽  
Roadway Support ◽  
Working Resistance ◽  
Surrounding Rock Deformation

Abstract In coal mining roadway support design, the working resistance of the rock bolt is the key factor affecting its maximum support load. Effective improvement of the working resistance is of great significance to roadway support. Based on the rock bolt’s tensile characteristics and the mining roadway surrounding rock deformation, a mechanical model for calculating the working resistance of the rock bolt is established and solved. Taking the mining roadway of the 17102 (3) working face at the Panji 3# Well Coal Mine of China as a research site, with a quadrilateral section roadway, the influence of pretension and anchorage length on the working resistance of high-strength and ordinary rock bolts in the middle and corner of the roadway is studied. The results show that when the bolt is in the elastic stage, increasing the pretension and anchorage length can effectively improve the working resistance. When the bolt is in the yield and strain-strengthening stages, increasing the pretension and anchorage length cannot effectively improve the working resistance. The influence of pretension and anchorage length on the ordinary and high-strength bolts is similar. The ordinary bolt’s working resistance is approximately 25 kN less than that of the high-strength bolt. When pretension and anchorage length are considered separately, the best pretensions of the high-strength bolt in the middle of the roadway side and the roadway corner are 41.55 and 104.26 kN, respectively, and the best anchorage lengths are 1.54 and 2.12 m, respectively. The best anchorage length of the ordinary bolt is the same as that of the high-strength bolt, and the best pretension for the ordinary bolt in the middle of the roadway side and at the roadway corner is 33.51 and 85.12 kN, respectively. The research results can provide a theoretical basis for supporting the design of quadrilateral mining roadways.

Coal Seam Roadway Bolt Support Design Method Based on the Supporting Theory of Broken Rock Zone

2013 ◽  
Vol 734-737 ◽  
pp. 535-539
Author(s):  
Hai Yuan Liu ◽  
Zhi Gang Wang ◽  
Ji Li ◽  
Lang Bai
Keyword(s):  
Theoretical Foundation ◽  
Design Method ◽  
Field Application ◽  
Surrounding Rock ◽  
Support Design ◽  
Roadway Support ◽  
The Stability ◽  
Comprehensive Classification ◽  
Classification Index ◽  
Surrounding Rock Deformation

broken rock zone is the main reason for the convergence of surrounding rock deformation, and its thickness not only is a reflection of many factors which influence the stability of surrounding rock, but also is the results of the interaction of many factors, a comprehensive classification index. Roadway support design based on classification result of broken rock zone, has a solid theoretical foundation, and the field application effect is remarkable.

Research on Supporting Technology of Roadway Driving along Next Goaf of Second Mining Strip Pillar

2012 ◽  
Vol 446-449 ◽  
pp. 1657-1660
Author(s):  
Wei Dong Lv ◽  
Nan Nan Zhao
Keyword(s):  
Abutment Pressure ◽  
High Strength ◽  
Main Roof ◽  
Surrounding Rock ◽  
Control Effect ◽  
General Stability ◽  
High Strength Bolt ◽  
Mining Face ◽  
The Stability ◽  
Surrounding Rock Deformation

For roadway driving along next goaf of strip pillar second mining, being influenced by the abutment pressure of previous coal mining face and main roof breaking rotary deformation, the surrounding rock deformation is serious and the control effect of ordinary bolt supporting on the general stability of roadway driving along next goaf is poorer. According to the concrete geological and technique condition of the 2351 second mining strip pillar in Daizhuang Colliery, adopting the united support pattern combined high strength bolt of levorotatory continuous thread and anchor of low relaxation prestress, the safety of the roadway can be ensured and the stability of the roadway surrounding rocks can be improved. It is of significant reference meaning for bolting support of roadway driving along next goaf of second mining strip pillar under similar condition.

Comparison and Application of High Prestress and Intensive Support System in Close, Soft and Cracked Roadway Support

2012 ◽  
Vol 524-527 ◽  
pp. 29-35
Author(s):  
Bin Hu ◽  
Hong Pu Kang ◽  
Jian Lin
Keyword(s):  
Support System ◽  
High Strength ◽  
Support Effect ◽  
Test Results ◽  
Support Design ◽  
Main Factors ◽  
Roadway Support ◽  
Roadway Deformation

Based on the analysis of support effect under original support design at Hongmiao Colliery, the paper summarized the main factors causing the destruction of roadways under neighboring gob areas, and pointed that the low pre-tension of the former support system and the irrationality of auxiliary support components were the main reasons for the failure of roadway support. The high prestress and intensive bolt-cable support system was recommended to reinforce roadways of this type, and the industrial on-site trial had been carried out in the transportation roadway of the Panel One of 5-2s Block, located at District 5. The test results showed that such measures as full encapsulation with high pre-tension for bolts and cables and auxiliary components with larger section and high strength could be used to effectively control roadway deformation. They provided an effective approach for the support of roadways under similar conditions.

scholarly journals Analysis of Strata Behavior Process Characteristics of Gob-Side Entry Retaining with Roof Cutting and Pressure Releasing Based on Composite Roof Structure

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Manchao He ◽  
Xingen Ma ◽  
Bin Yu
Keyword(s):  
Mechanical Analysis ◽  
Theoretical Research ◽  
Support Design ◽  
Process Characteristics ◽  
Roof Structure ◽  
Weak Interlayer ◽  
Roadway Support ◽  
Degree Equation ◽  
Roadway Deformation ◽  
Working Resistance

In order to explore the characteristics of rock pressure distribution with roof cutting and pressure releasing under different composite roof structures and optimize the support design of entry retaining, the mechanical analysis and numerical simulation are used to analyze the structure characteristics of composite roof and the effect of roof cutting under composite roof in this paper. Besides, taking the 8304 working face of Tashan Coal Mine as an example, the results of theoretical research are verified by field-monitoring data of hydraulic supports, working resistance, and roadway deformation. The results show that the weak interlayer in the composite roof is easily damaged under the external force and the distribution of the layer has a key effect on the roof characteristics. When the weak interlayer is located at the middle of the roof cutting layer range, the demand of the roadway support strength is the highest; when the weak interlayer is located at the top of the roof cutting layer range, the demand of the roadway support strength is the lowest. Furthermore, with the increase of the height of the weak interlayer in the roof cutting layer range, the stress concentration peak of the coal wall side decreases first and then rises, then descends again, and the trend can be fitted by the curve of a three-degree equation.

Constant-amplitude fatigue behavior of M24 high-strength bolt of end-plate flange connection

Structures ◽  
2021 ◽  
Vol 34 ◽  
pp. 2041-2053
Author(s):  
Jinfeng Jiao ◽  
Zhanxiang Liu ◽  
Qi Guo ◽  
Yong Liu ◽  
Honggang Lei
Keyword(s):  
Fatigue Behavior ◽  
High Strength ◽  
Constant Amplitude ◽  
Flange Connection ◽  
End Plate ◽  
High Strength Bolt

Analysis of Material Behaviour in Experimental and Simulative Setup of Joining by Forming of Aluminium Alloy and High Strength Steel with Shear-Clinching Technology

2014 ◽  
Vol 966-967 ◽  
pp. 549-556 ◽  
Author(s):  
Martin Müller ◽  
Réjane Hörhold ◽  
Marion Merklein ◽  
Gerson Meschut
Keyword(s):  
High Strength ◽  
Cost Effective ◽  
Metallic Materials ◽  
Material Behaviour ◽  
Transportation Sector ◽  
Reference Process ◽  
Key Factor ◽  
Mechanical Clinching ◽  
Safety Parameters ◽  
Systematic Development

In transportation sector the reduction of moving masses without the decrease of safety parameters is a key factor for future economic success. One possible approach for this is the use of different metallic materials in composite construction. Therefore, it is essential to establish a reliable component connection by means of suitable and cost-effective joining technologies. Mechanical joining technologies such as self-piercing riveting and mechanical clinching have proven to be effective methods for joining lightweight materials like aluminium and ductile steels. As these technologies require formability or pre-holing of the joining partners, the field of application is limited by the mechanical properties of the joining partners. Great potential for joining hot stamped steels, which have a very low elongation at fracture and therefore a low formability, offers the shear-clinching technology. For a systematic development of the shear-clinching technology, detailed investigations of the process are required. This paper presents an analysis of the material behaviour during the shear-clinching process and the reference process – clinching with pre-hole.

The Adaptation Analysis of the Fully Mechanized Coal Mining Face of Huopu Mine’s Third Soft Coal Seam

2014 ◽  
Vol 1049-1050 ◽  
pp. 335-338 ◽  
Author(s):  
Fa Quan Liu ◽  
Xue Wen Geng ◽  
Yong Che ◽  
Xiang Cui
Keyword(s):  
Coal Seam ◽  
Coal Mining ◽  
Geological Condition ◽  
Soft Coal ◽  
Working Face ◽  
Mining Face ◽  
Soft Coal Seam ◽  
Working Resistance

To get the maximum coal in front of the working face of the 17# coal seam, we installed a longer beam which is 1.2m in length in the leading end of the original working face supports ZF3000/17/28, and know that working face supports’ setting load and working resistance are lower .We changed the original supports with shield supports ZY3800/15/33 that are adaptable in the geological condition and got the favorable affection.

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