Studying the performance of fully encapsulated rock bolts with modified structural elements

Chen, Jianhang; Zhao, Hongbao; He, Fulian; Zhang, Junwen; Tao, Kangming

doi:10.1007/s40789-020-00388-z

Cited by 51 publications

(19 citation statements)

References 24 publications

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“…Wu et al (2018) studied the tensile behavior of rock masses reinforced by fully grouted bolts and reinforced rock masses, and proposed an empirical method to predict the strength of rock masses reinforced by fully grouted bolts. Other research results are as the works of Chen et al (2021), Batugin et al (2021), andSmith et al (2019).…”

Section: Introductionmentioning

confidence: 90%

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

Chang

Pang

et al. 2021

Int J Coal Sci Technol

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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 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.

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Section: Introductionmentioning

confidence: 90%

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

Chang

Pang

et al. 2021

Int J Coal Sci Technol

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“…With the construction of large-scale intelligent mines, the double-roadway layout system will be chosen for more working faces. The research on controlling gob-side entry retaining roadways, gob-side entry driving roadways and rock surrounding the roadways has achieved many results, while there is less research on controlling of stability of the coal pillar and its supporting structures in the double-roadway layout system under the disturbance of roadway driving, working face mining, and repeated mining (Qi and Fourie, 2019;Zhang et al, 2020b;Meng et al, 2020;Chen et al, 2021a;Chen et al, 2021b). Wu et al (2019c) proposed the strengthening effect of high-intensity support and grouting on coal pillars in mining roadways.…”

Section: Introductionmentioning

confidence: 99%

Study on the Stability of Coal Pillars Under the Disturbance of Repeated Mining in a Double-Roadway Layout System

et al. 2021

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The double-roadway layout system, which is extensively applied in large mines, has the potential to significantly balance excavation-mining and improve mine ventilation and transportation capacity. However, the coal pillar in the double-roadway layout system is easily destabilized due to the disturbance of repeated mining, which has a significant impact on the safety and reliability of coal mines. This paper takes the coal pillar and its supporting structure of the double-roadway layout system as the research object, establishes a UDEC trigon numerical calculation model, and systematically corrects the input parameters, while explaining the excavation method of roadways and the simulation method of the supporting structure element. The numerical simulation results show that under the conventional support intensity conditions, the internal damage of the coal pillar during the excavation period is about 20%, while the internal damage to the coal pillar develops to 55% throughout the first-panel mining. During the disturbance of repeated mining, the damage in the coal pillar increased to 90%, and the coal pillar was already in a state of failure. Under the combined control of rock bolts and counter-pulled anchor cables, the coal pillar damage does not change significantly during the excavation and first-panel mining. During the disturbance of repeated mining, the damage of the coal pillar is reduced to 63%. There is a certain low damage area in the coal pillar, which can ensure the stability of the coal pillar and its supporting structure as a whole. Furthermore, the on-site monitoring results show that the maximum value of the floor-to-roof and rib-to-rib convergence of a W1310 tailgate during the repeated mining disturbance stage is 730 and 620 mm, respectively. The findings of this study give an approach to—as well as estimated values for the design of, including its “small structure” control technical parameters—the double-roadway layout system.

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“…However, experimental tests proved that in the fully grouted rock reinforcing system, failure of the system usually occurred at the bolt/grout interface [14]. is was caused by the low shear strength of the interface [15]. e shear behaviour of the cement grout has a significant role in determining the shear strength of the bolt/grout interface [16].…”

Section: Introductionmentioning

confidence: 99%

“…To study the shear behaviour of cement grout, researchers commonly used triaxial tests and direct shear tests. For triaxial tests, Hyett et al [17] studied the performance of Portland cement grout with the confining pressure ranging from 5 MPa to 15 MPa. e results showed that the larger the confining pressure, the higher the strength of the cement grout.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Shear Behaviour of Cement Grout

Chen

Zhang

Zhao

et al. 2021

Advances in Materials Science and Engineering

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Cement grout is widely used in civil engineering and mining engineering. The shear behaviour of the cement grout plays an important role in determining the stability of the systems. To better understand the shear behaviour of the cement grout, numerical direct shear tests were conducted. Cylindrical cement grout samples with two different strengths were created and simulated. The numerical results were compared and validated with experimental results. It was found that, in the direct shear process, although the applied normal stress was constant, the normal stress on the contacted shear failure plane was variable. Before the shear strength point, the normal stress increased slightly. Then, it decreased gradually. Moreover, there was a nonuniform distribution of the normal stress on the contacted shear failure plane. This nonuniform distribution was more apparent when the shear displacement reached the shear strength point. Additionally, there was a shear stress distribution on the contacted shear failure plane. However, at the beginning of the direct shear test, the relative difference of the shear stresses was quite small. In this stage, the shear stress distribution can be assumed uniform on the contacted shear failure plane. However, once the shear displacement increased to around the shear strength point, the relative difference of the shear stresses was obvious. In this stage, there was an apparent nonuniform shear stress distribution on the contacted shear failure plane.

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Studying the performance of fully encapsulated rock bolts with modified structural elements

Cited by 51 publications

References 24 publications

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

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

Study on the Stability of Coal Pillars Under the Disturbance of Repeated Mining in a Double-Roadway Layout System

Numerical Simulation of the Shear Behaviour of Cement Grout

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