Laboratory Investigations into the Failure Mechanisms of New Yielding and Inflatable Rockbolts Under Axial and Shearing Loading Conditions

Li, Danqi; Ma, Shuqi; Lane, Martin; Chang, Ping; Crompton, Brendan; Hagen, Simon Alexander

doi:10.1007/s00603-022-03086-1

Cited by 23 publications

(7 citation statements)

References 38 publications

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“…Assuming that the PKS is a clamped plate [43], which is rectangular and bears a uniform load. Based on these assumptions, the following restrictions are imposed [36,37,44,45]:…”

Section: Construction Of Prediction Modelmentioning

confidence: 99%

Influence of the Primary Key Stratum on Surface Subsidence during Longwall Mining

Wang

Jin

2022

Sustainability

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The surface subsidence caused by mining influences the mine environment and construction safety. In this paper, strata movement and surface subsidence were combined. Based on elasticity and Winkler theory, a prediction method of surface subsidence was established with the primary key stratum as the research object. Using the Tingnan Coal Mine as an example, the mining subsidence of the second panel was predicted. Comparing the predicted results with the measured results, the causes of errors were analyzed and the field of application of the model was clarified. Besides, the geological and mining factors affecting surface subsidence were also analyzed. The results show that the mining subsidence is the surface manifestation of the strata movement. Surface subsidence is affected by the mining area, load, and flexural rigidity of the primary key stratum, foundation modulus of the goaf, and the rock mass. The research results have significance for the planning of the coal resources and the prevention of geological disasters.

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“…Assuming that the PKS is a clamped plate [43], which is rectangular and bears a uniform load. Based on these assumptions, the following restrictions are imposed [36,37,44,45]:…”

Section: Construction Of Prediction Modelmentioning

confidence: 99%

Influence of the Primary Key Stratum on Surface Subsidence during Longwall Mining

Wang

Jin

2022

Sustainability

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“…The plate fixing mechanisms vary reinforcement/support reactions of rock bolts. For improving the energy absorption capacity of the plate part, load bearing capacity and displacement limits should be improved together [26][27][28]. As the energy unit of Joule (J) is equal to N‧m, the are under load (N) and displacement (m) graphs can be used to calculate the energy absorption capacity.…”

Section: Introductionmentioning

confidence: 99%

Investigation of New Energy Absorbing Mechanisms Used to Fix Rock Bolt Plates

Komurlu

2023

Period. Polytech. Civil Eng.

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In this study, different plate fixing designs were tested in order to improve rock bolting performances. Instead of commonly used steel nuts, different plate fixing designs were investigated by both laboratory and site studies. In addition, the usability of nuts and energy absorbers made of the polyamide type engineering polymer was investigated to assess whether they are advantageous for the aim of supplying high-energy absorbing features. In this experimental study, deformation-controlled load tests were carried out to evaluate the bearing and energy absorption capacities of totally eight different groups of specimens. According to the findings from this study, use of the polyamide material with steel nuts as an energy absorber material, rather than using instead of steel nuts supplies good results. As another outcome, it has been determined that use of proper washers between steel nuts and polyamide absorbers can significantly improve the energy absorption performances. It has been evaluated that the energy absorption capacity of the bolt plates can be economically increased up to 10 times by using suitable polyamide energy absorbers placed between the plate and steel nut parts. It was concluded that the polyamides can be used to remarkably improve the rock bolting performances especially in the rock masses where the high energy absorption capacity property is needed, like those with rock bursting, squeezing and swelling problems.

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“…The excavation and unloading of coal mine roadways cause the stress readjustment of the surrounding rock, which, in turn, causes displacement of the roadway surrounding rock towards the excavation space. In order to prevent the destruction or even instability of the surrounding rock, it is necessary to implement active support for the surrounding rock of the roadway and restore its three-dimensional stress state, which provide support compensation stress that can achieve a new balance of internal stress in the surrounding rock [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

“…When the compensated stress is reduced from 0.2 MPa to 0.1 MPa, the acoustic emission counts do not increase significantly, indicating that the compensated stress of 0.1 MPa can also keep the coal sample stable. 3 When the compensated stress is reduced to 0 MPa, the acoustic emission counts increase sharply and become more and more involved in the process of pressure relief. After about 3 min, the coal sample becomes unstable and failure occurs, indicating that the coal sample without compensated stress cannot guarantee long-term stability.…”

mentioning

confidence: 99%

True Triaxial Test and Research into Bolting Support Compensation Stresses for Coal Roadways at Different Depths

Yang,

Lin,

Jiang

2023

Processes

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During the excavation and support construction process used in coal mine roadways, the stress path is the unloading of in situ stress and the compensation of support stress. The 150 mm × 150 mm × 150 mm coal mass samples were obtained in situ underground and prepared, the true triaxial loading–unloading–confining pressure restoring test method was used, and the mechanical response and deformation failure evolution characteristics of the coal seam during the excavation and support process of the shallow, medium depth, and deep coal roadways in the coal mine were simulated and studied. Based on the distribution law of the bolt and cable support stress field, the support compensation stress required for the stability of the surrounding rock after the excavation of the coal roadway with different burial depths was determined, and the corresponding roadways’ surrounding rock control technologies were proposed. This study’s results indicate that the compensation stress required for support in shallow coal roadways (with a burial depth of about 200 m) was much less than 0.1 MPa. A single rock bolt support can keep the surrounding rock of the roadway stable; the compensation stress required for support in the medium buried coal roadway (with a depth of about 600 m) is around 0.1 MPa, and the combined support of rock bolts and cables can meet the support requirements. Deep coal roadways under high stress (with a depth of about 1000 m) require support to provide compensation stress. Even if the compensation stress reaches 0.2 MPa, the surrounding rock of the roadway will experience varying degrees of creep. In this study, it was necessary to increase the support density and surface area of rock bolts and cables, the pre-tension forces of rock bolts and cables were improved, and in synergy with grouting modification, destressing and other technologies could control the large deformation of the surrounding rock of the roadway in 1000 m deep coal mines. This study’s results provide a theoretical basis for the selection of control technologies for use in coal roadways at different depths.

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Laboratory Investigations into the Failure Mechanisms of New Yielding and Inflatable Rockbolts Under Axial and Shearing Loading Conditions

Cited by 23 publications

References 38 publications

Influence of the Primary Key Stratum on Surface Subsidence during Longwall Mining

Influence of the Primary Key Stratum on Surface Subsidence during Longwall Mining

Investigation of New Energy Absorbing Mechanisms Used to Fix Rock Bolt Plates

True Triaxial Test and Research into Bolting Support Compensation Stresses for Coal Roadways at Different Depths

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