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| 1 | A study of rock bolting failure modes显示文摘Rock bolting has advanced rapidly during the past 4 decades due to a better understanding of load transfer mechanisms and advances made in the bolt system technology. Bolts are used as permanent and temporary support systems in tunnelling and mining operations. A review of has indicated that three systems of reinforcement devices have evolved as part of rock bolt and ground anchor while the rock is not generally thought of as being a component of the reinforcement system. A classification of rock bolting reinforcement systems is presented, followed by the fundamental theory of the load transfer mechanism. The failure mode of two phases of rock bolting system is formularised. The failure modes of cable bolting are discussed using a bond strength model as well as an iterative method. Finally, the interfacial shear stress model for ribbed bar is introduced and a closed form solution is obtained using a tri-line stress strain relationship. | Cao Chen Jan Nemcik Ren Ting Naj Aziz | 2013 | International Journal of Mining Science and Technology2013，23，1： | 14 |
| 2 | Evolution and application of in-seam drilling for gas drainage显示文摘The presence of seam gas in the form of methane or carbon dioxide presents a hazard to underground coal mining operations.In-seam drilling has been undertaken for the past three decades for gas drainage to reduce the risk of gas outburst and lower the concentrations of seam gas in the underground ventilation.The drilling practices have reflected the standards of the times and have evolved with the development of technology and equipment and the needs to provide a safe mining environment underground.Early practice was to adapt equipment from other felds,with rotary drilling being the only form of drilling available.This form of drainage allowed various levels of gas drainage coverage but with changing emphasis,research and development within the coal industry has created specifc equipment,technology and practices to accurately place in-seam boreholes to provide effcient and effective gas drainage.Research into gas content determination established a standard for the process and safe levels for mining operations to continue.Surveying technology improved from the wire-line,single-shot Eastman survey instruments which was time-dependent on borehole depth to electronic instruments located in the drill string which transmitted accurate survey data to the drilling crew without time delays.This allowed improved directional control and increased drilling rates.Directional drilling technology has now been established as the industry standard to provide effective gas drainage drilling.Exploration was identifed as an additional beneft with directional drilling as it has the ability to provide exploration data from long boreholes.The ability of the technology to provide safe and reliable means to investigate the need for inrush protection and water drainage ahead of mining has been established.Directional drilling technology has now been introduced to the Chinese coal industry for gas drainage through a practice of auditing,design,supply,training and ongoing support.Experienced drilling crews can offer site specifc gas drainage drilling services utilising the latest equipment and technology. | Frank Hungerford Ting Ren Naj Aziz | 2013 | International Journal of Mining Science and Technology2013，23，4： | 12 |
| 3 | Influence of Temperature on Coal Sorption Characteristics and the Theory of Coal Surface Free Energy显示文摘 | Lei Zhang Naj Aziz Ting X Ren Zhongwei Wang | 2011 | Procedia Engineering2011，，： | 1 |
| 4 | The effect of surface profile, rock strength and pretension load on bending behaviour of fully grouted bolts显示文摘 | Hossein Jalalifar Naj Aziz Muhammad Hadi | 2006 | Geotechnical and Geological Engineering2006，，5： | 1 |
| 5 | Analytical study of steel bolt profile and its influence on bolt load transfer显示文摘 | Chen Cao Jan Nemcik Naj Aziz Ting Ren | 2013 | International Journal of Rock Mechanics and Mining Sciences2013，，： | 1 |
| 6 | Large excavations and their effect on displacement of land boundaries显示文摘A study to estimate land surface movement caused by large surface excavations in sedimentary strata is presented.In stratified or jointed strata the stress relief driven movement adjacent to large excavations can be significantly larger than expected.High lateral stresses measured in Australia and other places around the world indicate that the ratio of horizontal to vertical stress has been particularly high at shallow depths.The in situ strata is in compression and during excavation,stress is relieved towards the opening causing strata movement.Large excavations such as,open cut mines or highway cuttings,can initiate an extensive horizontal slide of surface layers towards the excavation.These ground movements can be damaging to surface structures such as water storage dams and large buildings.Based on stress measurements at shallow depths in Australian coal mines the study presented here calculates and models the extent of potential ground movement along the bedding surface adjacent to large excavations and provides a new prediction tool of land movement at the excavation boundary that can benefit the geotechnical practitioners in the mining industry. | Jan Nemcik Naj Aziz | 2012 | International Journal of Mining Science and Technology2012，22，5： | 1 |
| 7 | Influence of Temperature on Coal Sorption Characteristics and the Theory of Coal Surface Free Energy显示文摘 | Lei Zhang Naj Aziz Ting X Ren Zhongwei Wang | 2011 | Procedia Engineering2011，，： | 1 |
| 8 | Failure characterization of fully grouted rock bolts under triaxial testing显示文摘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. | Hadi Nourizadeh Ali Mirzaghorbanali Mehdi Serati Elamin Mutaz Kevin McDougall Naj Aziz | 2024 | Journal of Rock Mechanics and Geotechnical Engineering2024，16，3： | 0 |
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