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Theory,technology and application of grouted bolting in soft rock roadways of deep coal mines
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作者 Hongpu Kang Jianwei Yang +4 位作者 Pengfei Jiang Fuqiang Gao Wenzhou Li Jiafeng Li Huiyuan Chen 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第7期1463-1479,共17页
The grouted bolt,combining rock bolting with grouting techniques,provides an effective solution for controlling the surrounding rock in deep soft rock and fractured roadways.It has been extensively applied in numerous... The grouted bolt,combining rock bolting with grouting techniques,provides an effective solution for controlling the surrounding rock in deep soft rock and fractured roadways.It has been extensively applied in numerous deep mining areas characterized by soft rock roadways,where it has demonstrated remarkable control results.This article systematically explores the evolution of grouted bolting,covering its theoretical foundations,design methods,materials,construction processes,monitoring measures,and methods for assessing its effectiveness.The overview encompassed several key elements,delving into anchoring theory and grouting reinforcement theory.The new principle of high pretensioned high-pressure splitting grouted bolting collaborative active control is introduced.A fresh method for dynamic information design is also highlighted.The discussion touches on both conventional grouting rock bolts and cable bolts,as well as innovative grouted rock bolts and cables characterized by their high pretension,strength,and sealing hole pressure.An examination of the merits and demerits of standard inorganic and organic grouting materials versus the new inorganic–organic composite materials,including their specific application conditions,was conducted.Additionally,the article presents various methods and instruments to assess the support effect of grouting rock bolts,cable bolts,and grouting reinforcement.Furthermore,it provides a foundation for understanding the factors influencing decisions on grouted bolting timing,the sequence of grouting,the pressure applied,the volume of grout used,and the strategic arrangement of grouted rock bolts and cable bolts.The application of the high pretensioned high-pressure splitting grouted bolting collaborative control technology in a typical kilometer-deep soft rock mine in China—the soft coal seam and soft rock roadway in the Kouzidong coal mine,Huainan coal mining area,was introduced.Finally,the existing problems in grouted bolting control technology for deep soft rock roadways are analyzed,and the future development trend of grouted bolting control technology is anticipated. 展开更多
关键词 deep coal mine soft rock roadway grouted bolting rock bolt and cable grouting material high-pressure splitting grouting collaborative control technology
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Mechanical behavior and failure mechanisms of rock bolts subjected to static-dynamic loads
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作者 Hongpu Kang Guiyang Yuan +4 位作者 Linpo Si Fuqiang Gao Jinfu Lou Jinghe Yang Shuangyong Dong 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第3期281-288,共8页
This study explores the effects of dynamic and static loading on rock bolt performance a key factor in maintaining the structural safety of coal mine roadways susceptible to coal bursts.Employing a housemade load fram... This study explores the effects of dynamic and static loading on rock bolt performance a key factor in maintaining the structural safety of coal mine roadways susceptible to coal bursts.Employing a housemade load frame to simulate various failure scenarios,pretension-impact-pull tests on rock bolts were conducted to scrutinize their dynamic responses under varied static load conditions and their failure traits under combined loads.The experimental results denote that with increased impact energy,maximum and average impact loads on rock bolts escalate significantly under pretension,initiating plastic deformation beyond a certain threshold.Despite minor reductions in the yield load due to impactinduced damage,pretension aids in constraining post-impact deformation rate and fluctuation degree of rock bolts.Moreover,impact-induced plastic deformation causes internal microstructure dislocation,fortifying the stiffness of the rock bolt support system.The magnitude of this fortification is directly related to the plastic deformation induced by the impact.These findings provide crucial guidance for designing rock bolt support in coal mine roadway excavation,emphasizing the necessity to consider both static and dynamic loads for improved safety and efficiency. 展开更多
关键词 Rock bolt PRETENSION Static and dynamic load IMPACT
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Failure characterization of fully grouted rock bolts under triaxial testing
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作者 Hadi Nourizadeh Ali Mirzaghorbanali +3 位作者 Mehdi Serati Elamin Mutaz Kevin McDougall Naj Aziz 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第3期778-789,共12页
Confining stresses serve as a pivotal determinant in shaping the behavior of grouted rock bolts.Nonetheless,prior investigations have oversimplified the three-dimensional stress state,primarily assuming hydrostatic st... Confining stresses serve as a pivotal determinant in shaping the behavior of grouted rock bolts.Nonetheless,prior investigations have oversimplified the three-dimensional stress state,primarily assuming hydrostatic stress conditions.Under these conditions,it is assumed that the intermediate principal stress(σ_(2))equals the minimum principal stress(σ_(3)).This assumption overlooks the potential variations in magnitudes of in situ stress conditions along all three directions near an underground opening where a rock bolt is installed.In this study,a series of push tests was meticulously conducted under triaxial conditions.These tests involved applying non-uniform confining stresses(σ_(2)≠σ_(3))to cubic specimens,aiming to unveil the previously overlooked influence of intermediate principal stresses on the strength properties of rock bolts.The results show that as the confining stresses increase from zero to higher levels,the pre-failure behavior changes from linear to nonlinear forms,resulting in an increase in initial stiffness from 2.08 kN/mm to 32.51 kN/mm.The load-displacement curves further illuminate distinct post-failure behavior at elevated levels of confining stresses,characterized by enhanced stiffness.Notably,the peak load capacity ranged from 27.9 kN to 46.5 kN as confining stresses advanced from σ_(2)=σ_(3)=0 to σ_(2)=20 MPa and σ_(3)=10 MPa.Additionally,the outcomes highlight an influence of confining stress on the lateral deformation of samples.Lower levels of confinement prompt overall dilation in lateral deformation,while higher confinements maintain a state of shrinkage.Furthermore,diverse failure modes have been identified,intricately tied to the arrangement of confining stresses.Lower confinements tend to induce a splitting mode of failure,whereas higher loads bring about a shift towards a pure interfacial shear-off and shear-crushed failure mechanism. 展开更多
关键词 Rock bolts bolt-grout interface Bond strength Push test Triaxial tests
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Stability analysis of tunnel face reinforced with face bolts
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作者 TIAN Chongming JIANG Yin +3 位作者 YE Fei OUYANG Aohui HAN Xingbo SONG Guifeng 《Journal of Mountain Science》 SCIE CSCD 2024年第7期2445-2461,共17页
Face bolting has been widely utilized to enhance the stability of tunnel face,particularly in soft soil tunnels.However,the influence of bolt reinforcement and its layout on tunnel face stability has not been systemat... Face bolting has been widely utilized to enhance the stability of tunnel face,particularly in soft soil tunnels.However,the influence of bolt reinforcement and its layout on tunnel face stability has not been systematically studied.Based on the theory of linear elastic mechanics,this study delved into the specific mechanisms of bolt reinforcement on the tunnel face in both horizontal and vertical dimensions.It also identified the primary failure types of bolts.Additionally,a design approach for tunnel face bolts that incorporates spatial layout was established using the limit equilibrium method to enhance the conventional wedge-prism model.The proposed model was subsequently validated through various means,and the specific influence of relevant bolt design parameters on tunnel face stability was analyzed.Furthermore,design principles for tunnel face bolts under different geological conditions were presented.The findings indicate that bolt failure can be categorized into three stages:tensile failure,pullout failure,and comprehensive failure.Increasing cohesion,internal friction angle,bolt density,and overlap length can effectively enhance tunnel face stability.Due to significant variations in stratum conditions,tailored design approaches based on specific failure stages are necessary for bolt design. 展开更多
关键词 Highway tunnels Tunnel face Face bolts Limit equilibrium method Slice method
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Numerical Optimization by Finite Element Method of Stainless Steel/Glass-Epoxy Composite Bolted Joint under Tension and Compression
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作者 Christian Schmitt Arnaud Kremeur +1 位作者 Pawel Lipinski Julien Capelle 《Engineering(科研)》 2024年第4期102-122,共21页
The aim of this study was to optimize the geometry and the design of metallic/composite single bolted joints subjected to tension-compression loading. For this purpose, it was necessary to evaluate the stress state in... The aim of this study was to optimize the geometry and the design of metallic/composite single bolted joints subjected to tension-compression loading. For this purpose, it was necessary to evaluate the stress state in each component of the bolted join. The multi-material assembly was based on the principle of double lap bolted joint. It was composed of a symmetrical balanced woven glass-epoxy composite material plate fastened to two stainless sheets using a stainless pre-stressed bolt. In order to optimize the design and the geometry of the assembly, ten configurations were proposed and studied: a classical simple bolted joint, two joints with an insert (a BigHead<sup>R</sup> insert and a stair one) embedded in the composite, two “waved” solutions, three symmetrical configurations composed of a succession of metallic and composites layers, without a sleeve, with one and with two sleeves, and two non-symmetrical constituted of metallic and composites layers associated with a stair-insert (one with a sleeve and one without). A tridimensional Finite Element Method (FEM) was used to model each configuration mentioned above. The FE models taked into account the different materials, the effects of contact between the different sheets of the assembly and the pre-stress in the bolt. The stress state was analyzed in the composite part. The concept of stress concentration factor was used in order to evaluate the stress increase in the highly stressed regions and to compare the ten configurations studied. For this purpose, three stress concentration factors were defined: one for a monotonic loading in tension, another for a monotonic loading in compression, and the third for a tension-compression cyclic loading. The results of the FEM computations showed that the use of alternative metallic and composite layers associated with two sleeves gived low values of stress concentration factors, smaller than 1.4. In this case, there was no contact between the bolt and the composite part and the most stressed region was not the vicinity of the hole but the end of the longest layers of the metallic inserts. 展开更多
关键词 bolted Joint Glass-Epoxy Composite CLEARANCE Hybrid Steel-Composite
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Flexural Property of String Beam of Pre-Stressed Glulam Based on Influence of Regulation and Control 被引量:2
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作者 Nan Guo Wenbo Wang Hongliang Zuo 《Structural Durability & Health Monitoring》 EI 2019年第2期143-179,共37页
Applying pre-stress in glulam beam can reduce its deformation and make full use of the compressive strength of wood.However,when the glulam with low strength and the pre-stressed steel with high strength form combined... Applying pre-stress in glulam beam can reduce its deformation and make full use of the compressive strength of wood.However,when the glulam with low strength and the pre-stressed steel with high strength form combined members,materials of high strength can’t be fully utilized.Therefore,this study puts forward the idea of regulating and controlling string beam of pre-stressed glulam.By regulating and controlling the pre-stress,a part of the load borne by the wood is allocated to the pre-stressed tendon,which is equivalent to completing a redistribution of internal force,thus realizing the repeated utilization of the wood strength and the full utilization of the strength of the high-strength pre-stressed tendon.The bending experiments of 10 beams under 5 working conditions are carried out.The failure mode,bearing capacity and deformation of the beams are analyzed.The results show that 90%of beams are deformed under compression.The ultimate load of the regulated and controlled beam is obviously larger than that of the unregulated beam,and the ultimate load of the beam increases with the increase of the degree of regulation and control.Compared with that of the unregulated beams,the ultimate load of beams regulated by 7.5%-30%increases by 25.42%-65.08%,and the regulated and controlled effect is obvious.With the increase of the regulation and control amplitude of pre-stress,the stiffness of string beam of pre-stressed glulam increases.In addition,with the increase of the regulation and control amplitude,the compression height of the beam increases before the failure,and it reaches the state of full-section compression at the time of failure,giving full play to the compressive property of the glulam.At the end of the experiment,the constitutive relation which can reflect the anisotropy of the wood is established combined with the experimental data.The finite element analysis of the beam under 7 working conditions is carried out by using ABAQUS finite element program,and the influence of the regulation and control amplitude on the stress distribution and ultimate bearing capacity of the beam is discussed. 展开更多
关键词 STRING BEAM of GLULAM FLEXURAL PROPERTY experimental study pre-stress regulation and control
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Pre-Stressed Rope Reinforced Anti-Sliding Pile 被引量:1
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作者 XU Jun WANG Chenghua 《Wuhan University Journal of Natural Sciences》 EI CAS 2006年第4期887-891,共5页
Pre-stressed rope reinforced anti-sliding pile is a composite anti-sliding structure. It is made up of pre-stressed rope and general anti-sliding pile. It can bring traditional anti-sliding pile's retaining performan... Pre-stressed rope reinforced anti-sliding pile is a composite anti-sliding structure. It is made up of pre-stressed rope and general anti-sliding pile. It can bring traditional anti-sliding pile's retaining performance into full play, and to treat with landslide fast and economically. The difference between them is that the pre-stressed rope will transfix the whole anti- sliding pile through a prearranged pipe in this structure. The working mechanics, the design method and economic benefit are studied. The results show that the pre-stressed rope reinforced anti-sliding pile can treat with the small and middle landslides or high slopes well and possess the notable advantage of technology and economic. 展开更多
关键词 pre-stressed rope anti-sliding pile composite anti-sliding structure
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Dynamic analysis of double-layer and pre-stressed multi-limb six-axis force sensor 被引量:1
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作者 王志军 He Jing +1 位作者 Cui Bingyan Li Zhanxian 《High Technology Letters》 EI CAS 2019年第2期189-196,共8页
In order to adapt to the specific task, the six-axis dynamic contact force between end-effectors of intelligent robots and working condition needs to be perceived. Therefore, the dynamic property of six-axis force sen... In order to adapt to the specific task, the six-axis dynamic contact force between end-effectors of intelligent robots and working condition needs to be perceived. Therefore, the dynamic property of six-axis force sensor which is installed on the end-effectors of intelligent robots will have influence on the veracity of detection and judgment to working environment contact force by intelligent robots directly. In this paper, dynamic analysis to double-layer and pre-stressed multi-limb six-axis force sensor is conducted. First, the structure of the sensor is introduced, and the limb number is confirmed by introducing the related definitions of convex analysis. Then, based on vibration of multiple-degree-of-freedom system, a mechanical vibration simplified model of double-layer and pre-stressed multiple limb six-axis force sensor is set up. After that, movement differential equations of sensor and the response of analytical expression are deduced, and the movement differential equations is solved. Finally, taking the double-layer and pre-stressed seven limb six-axis force sensor as an example, numerical calculation and simulation of deriving result is conducted, which verify the correctness and feasibility of the theoretical analysis. 展开更多
关键词 six-axis FORCE sensor multi-limb pre-stressed mechanical vibration dynamic analysis
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Design and Preparation of High Elastic Modulus Self-compacting Concrete for Pre-stressed Mass Concrete Structures 被引量:1
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作者 祝雯 CHEN Yang +4 位作者 LI Fangxian ZHANG Tongsheng HU Jie 韦江雄 YU Qijun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2016年第3期563-573,共11页
Requirements of self-compacting concrete (SCC) applied in pre-stressed mass concrete structures include high fluidity, high elastic modulus, low adiabatic temperature rise and low drying shrinkage, which cannot be s... Requirements of self-compacting concrete (SCC) applied in pre-stressed mass concrete structures include high fluidity, high elastic modulus, low adiabatic temperature rise and low drying shrinkage, which cannot be satisfied by ordinary SCC. In this study, in order to solve the problem, a few principles of SCC design were proposed and the effects of binder amount, fly ash (FA) substitution, aggregate content and gradation on the workability, temperature rise, drying shrinkage and elastic modulus of SCC were investigated. The results and analysis indicate that the primary factor influencing the fluidity was paste content, and the main methods improving the elastic modulusof SCC were a lower sand ratio and an optimized coarse aggregate gradation. Lower adiabatic temperature rise and drying shrinkage were beneficial for decreasing the cement content. Further, based on the optimization of mixture, a C50 grade SCC (with binder amount of only 480 kg/ m3, fly ash substitution of 40%, sand ratio of 51% and proper coarse aggregate gradation (Vs.~0 mm: V10-16 ram: V16.20 mm= 30%: 30%:40%)) with superior workability was successfully prepared. The temperature rise and drying shrinkage of the prepared SCC were significantly reduced, and the elastic modulus reached 37.6 GPa at 28 d. 展开更多
关键词 self-compacting concrete pre-stressed mass structure high elastic modulus adiabatic temperature rise drying shrinkage
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Experimental study on seismic behavior of circular RC columns strengthened with pre-stressed FRP strips 被引量:1
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作者 Zhou Changdong Lu Xilin +1 位作者 Li Hui Tian Teng 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2013年第4期625-642,共18页
Bonding fiber reinforced polymer (FRP) has been commonly used to improve the seismic behavior of circular reinforced concrete (RC) columns in engineering practice. However, FRP jackets have a significant stress hy... Bonding fiber reinforced polymer (FRP) has been commonly used to improve the seismic behavior of circular reinforced concrete (RC) columns in engineering practice. However, FRP jackets have a significant stress hysteresis effect in this strengthening method, and pre-tensioning the FRP can overcome this problem. This paper presents test results of 25 circular RC columns strengthened with pre-stressed FRP strips under low cyclic loading. The pre-stressing of the FRP strips, types of FRP strips and longitudinal reinforcement, axial load ratio, pre-damage degree and surface treatments of the specimens are considered as the primary factors in the tests. According to the failure modes and hysteresis curves of the specimens, these factors are analyzed to investigate their effect on bearing capacity, ductility, hysteretic behavior, energy dissipation capacity and other important seismic behaviors. The results show that the initial lateral confined stress provided by pre-stressed FRP strips can effectively inhibit the emergence and development of diagonal shear cracks, and change the failure modes of specimens from brittle shear failure to bending or bending-shear failure with better ductility. As a result, the bearing capacity, ductility, energy dissipation capacity and deformation capacity of the strengthened specimens are all significantly improved. 展开更多
关键词 experimental study circular reinforced concrete column pre-stress fiber reinforced polymer axial loadratio seismic behavior active confinement
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Experimental study on the shear performance of quasi-NPR steel bolted rock joints 被引量:3
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作者 Manchao He Shulin Ren +3 位作者 Haotian Xu Senlin Luo Zhigang Tao Chun Zhu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第2期350-362,共13页
Quasi-NPR(negative Poisson’s ratio)steel is a new type of super bolt material with high strength,high ductility,and a micro-negative Poisson’s effect.This material overcomes the contrasting characteristics of the hi... Quasi-NPR(negative Poisson’s ratio)steel is a new type of super bolt material with high strength,high ductility,and a micro-negative Poisson’s effect.This material overcomes the contrasting characteristics of the high strength and high ductility of steel and it has significant energy-absorbing characteristics,which is of high value in deep rock and soil support engineering.However,research on the shear resistance of quasi-NPR steel has not been carried out.To study the shear performance of quasi-NPR steel bolted rock joints,indoor shear tests of bolted rock joints under different normal stress conditions were carried out.Q235 steel and#45 steel,two representative ordinary bolt steels,were set up as a control group for comparative tests to compare and analyze the shear strength,deformation and instability mode,shear energy absorption characteristics,and bolting contribution of different types of bolts.The results show that the jointed rock masses without bolt reinforcement undergo brittle failure under shear load,while the bolted jointed rock masses show obvious ductile failure characteristics.The shear deformation ca-pacity of quasi-NPR steel is more than 3.5 times that of Q235 steel and#45 steel.No fracture occurs in the quasi-NPR steel during large shear deformation and it can provide stable shear resistance.However,the other two types of control bolts become fractured under the same conditions.Quasi-NPR steel has significant energy-absorbing characteristics under shear load and has obvious advantages in terms of absorbing the energy released by shear deformation of jointed rock masses as compared with ordinary steel.In particular,the shear force plays a major role in resisting the shear deformation of Q235 steel and#45 steel,therefore,fracture failure occurs under small bolt deformation.However,the axial force of quasi-NPR steel can be fully exerted when resisting joint shear deformation;the steel itself does not break when large shear deformation occurs,and the supporting effect of the jointed rock mass is effectively guaranteed. 展开更多
关键词 Energy absorption bolt Quasi-NPR(Negative Poisson’s ratio)steel bolted rock joints Shear test Shear performance
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A hardening load transfer function for rock bolts and its calibration using distributed fiber optic sensing 被引量:2
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作者 Assaf Klar Ori Nissim Itai Elkayam 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第11期2816-2830,共15页
Confinement of rock bolts by the surrounding rock formation has long been recognized as a positive contributor to the pull-out behavior,yet only a few experimental works and analytical models have been reported,most o... Confinement of rock bolts by the surrounding rock formation has long been recognized as a positive contributor to the pull-out behavior,yet only a few experimental works and analytical models have been reported,most of which are based on the global rock bolt response evaluated in pull-out tests.This paper presents a laboratory experimental setup aiming to capture the rock formation effect,while using distributed fiber optic sensing to quantify the effect of the confinement and the reinforcement pull-out behavior on a more local level.It is shown that the behavior along the sample itself varies,with certain points exhibiting stress drops with crack formation.Some edge effects related to the kinematic freedom of the grout to dilate are also observed.Regardless,it was found that the mid-level response is quite similar to the average response along the sample.The ability to characterize the variation of the response along the sample is one of the many advantages high-resolution fiber optic sensing allows in such investigations.The paper also offers a plasticity-based hardening load transfer function,representing a"slice"of the anchor.The paper describes in detail the development of the model and the calibration/determination of its parameters.The suggested model captures well the coupled behavior in which the pull-out process leads to an increase in the confining stress due to dilative behavior. 展开更多
关键词 Rock bolts Distributed fiber optic sensing Pull-out tests Load transfer function Hardening model
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Numerical modeling on strain energy evolution in rock system interaction with energy-absorbing prop and rock bolt 被引量:1
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作者 Yang Hao Chunhui Liu +4 位作者 Yu Wu Hai Pu Yanlong Chen Lingling Shen Guichen Li 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第10期1273-1288,共16页
The interaction mechanism between coal and rock masses with supporting materials is significant in roadway control, especially in deep underground mining situations where dynamic hazards frequently happened due to hig... The interaction mechanism between coal and rock masses with supporting materials is significant in roadway control, especially in deep underground mining situations where dynamic hazards frequently happened due to high geo-stress and strong disturbed effects. This paper is to investigate the strain energy evolution in the interaction between coal and rock masses with self-designed energy-absorbing props and rock bolts by numerical modeling with the finite difference method. The interaction between rock and rock bolt/prop is accomplished by the cables element and the interface between the inner and outer props. Roadway excavation and coal extraction conditions in deep mining are numerically employed to investigate deformation, plastic zone ranges, strain energy input, accumulation, dissipation,and release. The effect on strain energy input, accumulation, dissipation, and release with rock deformation, and the plastic zone is addressed. A ratio of strain energy accumulation, dissipation, and release with energy input a, β, γ is to assess the dynamic hazards. The effects on roadway excavation and coal extraction steps of a, β, γ are discussed. The results show that:(1) In deep high geo-stress roadways, the energyabsorbing support system plays a dual role in resisting deformation and reducing the scope of plastic zones in surrounding rock, as well as absorbing energy release in the surrounding rock, especially in the coal extraction state to mitigate disturbed effects.(2) The strain energy input, accumulation is dependent on roadway deformation, the strain energy dissipation is relied on plastic zone area and disturbed effects, and strain energy release density is the difference among the three. The function of energyabsorbing rock bolts and props play a key role to mitigate strain energy release density and amount, especially in coal extraction condition, with a peak density value from 4×10^(4) to 1×10^(4)J/m^(3), and amount value from 3.57×10^(8) to 1.90×10^(6)J.(3) When mining is advanced in small steps, the strain energy accumulation is dominated. While in a large step, the released energy is dominant, thus a more dynamic hazards proneness. The energy-absorbing rock bolt and prop can reduce three times strain energy release amount, thus reducing the dynamic hazards. The results suggest that energy-absorbing props and rock bolts can effectively reduce the strain energy in the coal and rock masses, and prevent rock bursts and other hazards.The numerical model developed in this study can also be used to optimize the design of energyabsorbing props and rock bolts for specific mining conditions. 展开更多
关键词 Strain energy Coal and rock mass Energy-absorbing prop and rock bolt Strain energy evolution
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Stress Analysis of New Type Pre-Stressed Anchor Bearing Plate Combining Stamping with Welding Forming and Its Anchorage Zone
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作者 Daosen Chen Nianchun Deng +1 位作者 Zanzhi Wang Haining Zuo 《World Journal of Engineering and Technology》 2017年第4期33-41,共9页
An anchor bearing plate transfers the anchoring force from anchor plate to the concrete and the pre-stress is formed in the concrete structure. Currently, the main type of anchor bearing plate is cast iron. It is brit... An anchor bearing plate transfers the anchoring force from anchor plate to the concrete and the pre-stress is formed in the concrete structure. Currently, the main type of anchor bearing plate is cast iron. It is brittle during transportation and tension process. This paper presents a new type of anchor bearing plate combined stamping with welding forming. The structure of the new type anchor bearing plate is introduced. The stress states of the anchor bearing plate and anchorage zone under work are studied. Various specifications of anchor bearing plate are studied by ANSYS finite element analysis software following the AASHTO specification. The analysis results are compared with the results of the same type of OVM round-shaped anchor plate. The study results show that the new pre-stressed anchor plates combined stamping with welding forming are feasible and more sturdy which can meet the engineering demand. 展开更多
关键词 pre-stressed Concrete Structure Finite Element Analysis ANCHOR BEARING Plate Stress of ANCHORAGE Zone
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Strength characteristics of rock anchored by NPR bolt with different preloads
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作者 SUN Xiao-ming CUI Li +2 位作者 ZHANG Yong WANG Lei JIANG Ming 《Journal of Mountain Science》 SCIE CSCD 2023年第3期834-844,共11页
This study compares the strength characteristics of rocks anchored by NPR bolts and ordinary bolts with varied preloads,based on the mechanical properties of NPR bolts(with a negative Poisson’s ratio).The results sho... This study compares the strength characteristics of rocks anchored by NPR bolts and ordinary bolts with varied preloads,based on the mechanical properties of NPR bolts(with a negative Poisson’s ratio).The results show that the uniaxial compressive stress-strain curve of ordinary anchored rocks exhibits noticeable abrupt changes.After reaching peak strength,the bolt breaks,whereas the stress-strain curve of NPR-anchored rocks is smoother.The NPR bolt enters the stage of continuous resistance after reaching maximal strength and does not break.As the preload increases,the strength of the anchored rock grows linearly.A calculation equation for the strength of the anchored rock is proposed based on the preload.The theoretical equation fits the test results well,and the fitted parameters show that NPR bolts can better increase the strength of the rock.The concept of dynamic toughness UC of anchored rock is proposed to reflect the comprehensive mechanical properties of anchored rock,including strength and plasticity.As the preload increases,the UC of ordinary anchored rock first decreases and then increases,while the UC of the NPR anchored rock does not change significantly with the preload when the strain is small,and the UC increases with the increase of the preload when the strain is large. 展开更多
关键词 NPR bolt Anchored rock Rock bolt Uniaxial compression PRELOAD Strength characteristics
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Technical problems and non destructive testing of rock bolt support systems in mines
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作者 Andrzej Staniek 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第1期124-135,共12页
The problem of proper assessment of the technical functionality of rock bolt support systems is still valid.Many research centers have undertaken eforts to diagnose and monitor the technical state of such a support sy... The problem of proper assessment of the technical functionality of rock bolt support systems is still valid.Many research centers have undertaken eforts to diagnose and monitor the technical state of such a support system used in mines and tunneling.With that aim the method of quality assessment of grouted rock bolts was invented and a relevant apparatus was constructed.The method concerns non-destructive identifcation of discontinuity of a resin layer(grout)surrounding rock bolts.The method is based on an impact excitation of a rock bolt and uses modal analysis procedures.Assuming that the installed rock bolt acts as an oscillator,diferent lengths and positions of grouting discontinuity alter its modal parameters.The extraction of these modal parameters,of which a resonant frequency is seen as the most valued,enable the relevant identifcation of grout discontinuity.After constructing a prototype version and validating the results for known cases of resin discontinuity in an experimental coal mine,the apparatus fulflling ATEX requirements was developed.Subsequently that version was also verifed both in laboratory conditions and in an experimental coal mine.As necessary for proper identifcation of discontinuity length,the reference data base was developed and elaborated consisting of a very large number of fnite element models(FE models),namely discontinuity cases.The models encountered diferent rock bolt lengths and diameters,diferent rock strata parameters and diferent positions and lengths of resin layers.Then the method was used in a working coal mine to monitor a technical state of rock bolt support system mounted to reinforce long underground openings.The data base was utilized as reference for investigated rock bolts. 展开更多
关键词 ROCK Rock bolt SAFETY Modal analysis MINING
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Influence of Non-uniform Parameter of Bolt Joint on Complexity of Frequency Characteristics of Cylindrical Shell
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作者 Qiansheng Tang Houxin She +1 位作者 Chaofeng Li Bangchun Wen 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2023年第2期206-219,共14页
Bolt connection is one of the main fixing methods of cylindrical shell structures.A typical bolted connection model is considered as a tuned system.However,in the actual working conditions,due to the manufacturing err... Bolt connection is one of the main fixing methods of cylindrical shell structures.A typical bolted connection model is considered as a tuned system.However,in the actual working conditions,due to the manufacturing error,installation error and uneven materials of bolts,there are always random errors between different bolts.To investigate the influence of non-uniform parameters of bolt joint,including the stiffness and the distribution position,on frequency complexity characteristics of cylindrical shell through a statistical method is the main aim of this paper.The bolted joints considered here were simplified as a series of springs with random features.The vibration equation of the bolted joined cylindrical shell was derived based on Sanders’thin shell theory.The Monte Carlo simulation and statistical theory were applied to the statistical analysis of mode characteristics of the system.First,the frequency and mode shape of the tuned system were investigated and compared with FEM.Then,the effect of the random distribution and the random constraint stiffness of the bolts on the frequency and mode shape were studied.And the statistical analysis on the natural frequencies was evaluated for different mistuned levels.And some special cases were presented to help understand the effect of random mistuning.This research introduces random theory into the modeling of bolted joints and proposes a reference result to interpret the complexity of the modal characteristics of cylindrical shells with non-uniform parameters of bolt joints. 展开更多
关键词 bolted joint Random mistuning Shell vibration Mode shape Statistical analysis
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Method for Evaluating Bolt Competitive Failure Life Under Composite Excitation
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作者 Guangwu Yang Long Yang +3 位作者 Han Zhao Haoxu Ding Bing Yang Shoune Xiao 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2023年第4期372-384,共13页
In this study,the competitive failure mechanism of bolt loosening and fatigue is elucidated via competitive failure tests on bolts under composite excitation.Based on the competitive failure mechanism,the mode predict... In this study,the competitive failure mechanism of bolt loosening and fatigue is elucidated via competitive failure tests on bolts under composite excitation.Based on the competitive failure mechanism,the mode prediction model and“load ratio-life prediction curve”(ξ-N curve)of the bolt competitive failure are established.Given the poor correlation of theξ-N curve,an evaluation model of the bolt competitive failure life is proposed based on Miner’s linear damage accumulation theory.Based on the force analysis of the thread surface and simulation of the bolt connection under composite excitation,a theoretical equation of the bolt competitive failure life is established to validate the model for evaluating the bolt competitive failure life.The results reveal that the proposed model can accurately predict the competitive failure life of bolts under composite excitation,and thereby,it can provide guidance to engineering applications. 展开更多
关键词 bolt Competitive failure life Evaluation model Mode prediction model Composite excitation
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Numerical simulation study on shear resistance of anchorage joints considering tensile-shear fracture criterion of 2G-NPR bolt
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作者 Shulin Ren Zhigang Tao +2 位作者 Manchao He Mengnan Li Qiru Sui 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第4期186-202,共17页
2G-NPR bolt (the 2nd generation Negative Poisson’s Ratio bolt) is a new type of bolt with high strength, high toughness and no yield platform. It has signifcant efects on improving the shear strength of jointed rock ... 2G-NPR bolt (the 2nd generation Negative Poisson’s Ratio bolt) is a new type of bolt with high strength, high toughness and no yield platform. It has signifcant efects on improving the shear strength of jointed rock mass and controlling the stability of surrounding rock. To achieve an accurate simulation of bolted joint shear tests, we have studied a numerical simulation method that takes into account the 2G-NPR bolt's tensile–shear fracture criterion. Firstly, the indoor experimental study on the tensile–shear mechanical properties of 2G-NPR bolt is carried out to explore its mechanical properties under diferent tensile–shear angles, and the fracture criterion of 2G-NPR bolt considering the tensile–shear angle is established. Then, a three-dimensional numerical simulation method considering the tensile–shear mechanical constitutive and fracture criterion of 2G-NPR bolt, the elastoplastic mechanical behavior of surrounding rock and the damage and deterioration of grouting body is proposed. The feasibility and accuracy of the method are verifed by comparing with the indoor shear test results of 2G-NPR bolt anchorage joints. Finally, based on the numerical simulation results, the deformation and stress of the bolt, the distribution of the plastic zone of the rock mass, the stress distribution and the damage of the grouting body are analyzed in detail. The research results can provide a good reference value for the practical engineering application and shear mechanical performance analysis of 2G-NPR bolt. 展开更多
关键词 Anchorage joints 2G-NPR bolt Tensile-shear fracture criterion Shear behavior Numerical simulation
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Research on Bolt Support Technology in Soft Coal Seam Roadway
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作者 Xinyuan Ma Wenzhong Zhou +2 位作者 Shuai Zhao Mingxuan Jiang Zihao Yu 《World Journal of Engineering and Technology》 2023年第2期370-380,共11页
In order to solve the problem of surrounding rock control in soft coal seam roadway, taking the centralized return airway of No. 2 coal seam in Liangdu Coal Industry as the research background, the mechanical con... In order to solve the problem of surrounding rock control in soft coal seam roadway, taking the centralized return airway of No. 2 coal seam in Liangdu Coal Industry as the research background, the mechanical conditions of roadway surrounding rock were analyzed by means of field investigation, rock mechanics experiment and numerical simulation. The design principles of roadway support in soft coal seam were put forward: high strength anchor cable support, high preload support and high stiffness support. The bearing capacity of surrounding rock was strengthened by anchor cable support, and the deformation and failure of surrounding rock were effectively controlled. Through the numerical simulation method, the deformation and plastic failure range of roadwaysunder different support schemes are compared and analyzed. The support scheme of centralized transportation roadway is studied and determined, and the field test is carried out, which effectively controls the deformation of surrounding rock of roadway in weak coal seam. 展开更多
关键词 Roadway Support High Preload High Strength bolt Support Support Design
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