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|The current British Standard on rock reinforcement components used in coal mining (BS7861:1996) employs the axial double embedment tensile PET) test to determine the main system load transfer performance criteria, in terms of bond strength and stiffbess. This test involves measurement of load/displacement characteristics of a tendon fully grouted into internally threaded thick-walled steel tubes. Part 1 of the Standard covers rock bolting systems and Part 2 covers birdcaged cable bolting systems. Both parts are highly prescriptive, defining a specific design of bar (AT) and cable bolt (birdcaged). In 2000, it was agreed by the UK Rockbolt Research Liaison Committee that Part 1 of the Standard should be revised to allow further industry innovation of bolts and resins. Amongst other aspects, it was recognised that the double embedment test was limited by its inability to examine load transfer between the bolt and the host rock and the UK Health and Safety Executive commissioned an RMT research project to develop a new test to replace the DET test. The new test, the Laboratory Short Encapsulation Pull (LSEP) test has now been incorporated into a draft revision of BS7861 Part1 which has been issued for industry wide consultation. In 2003, it was agreed to begin revision of Part 2 of the Standard to encompass the many types of long tendon reinforcement which were, by then, being used in the UK coal mining industry. These included flexible bolts, deformed strands and tensionable systems encapsulated with resin, cementitious grout and combinations of the two. A second RMT research project was funded by the HSE to examine adapting the Laboratory Short Encapsulation Pull Test for the revised long tendon Standard. This project is nearing completion and a revised Part 2 of the Standard is being drafted. This paper presents some of the results of the two research projects, describes the laboratory tests and acceptance criteria developed and discusses the implications of the research on improving the understanding of reinforcement performance and its characterisation. In particular it shows how the new test can reveal very different load transfer characteristics to the double embedment test, as it takes the load transfer at the holefrock wall into account.|
Additional chapters/articles from the SME-ICGCM book 24th International Conference on Ground Control in Mining (ICGCM) 24th
|Keynote Address at the 23rd International Conference on Grou||Analysis and Design of Rib Support (ADRS) a Rib Support Desi||Evaluation of the Impact of Standing Support on Ground Behav||Half a Career Trying to Understand Why the Roof Along the Lo||Forecasting Roof Falls with Monitoring Technologies - A Look||Analysis of Seismic Source Parameters of Roof Falls in Time||A System to Provide Early Warning on Impending Goaf||Outcomes of the Landmark Longwall Automation Project with Re||Application of Phenolic Foam in Longwall Mining||Multiple Seam Mining Interactions: Case Histories from the H||Analysis of Entry Stability Associated with Multi-seam Minin||Failure Mechanics of Multiple Seam Mining Interactions||Engineering Classification of Ultra-close Multiple Seam Roof||Definition of Ultra-close Multiple-seams and its Ground Pres||Depillaring and Roof Bolting Practices at Quinsam Coal Mine||Seam Structure - An Important Criterion for Coal Pillar Desi||Mitigating Longwall Subsidence Effects on a Large Industrial||Impacts of Longwall Mining on Hydrology, Soil Moisture, and||Basics on the Dimensioning and the Extraction of Shaft Safet||Modeling the Arc-effect of a Coal Mine Roof||Recent Advances in Numerical Simulation of Cutter Roof Failu||Test Method for Assessing Water Degradation Potential of Coa||Geotechnical Strata Characterisation Using Geophysical Boreh||A Method for Quantitative Void/Fracture Detection and Estima||Implication of Highly Anisotropic Horizontal Stresses on Ent||Ground Control of a Mine Stope in Weak Rocks Subjected to Hi||Analysis of Highwall Mining Stability - The Effect of Multip||Highwall Mining in a Multiple-seam, Western United States Se||The Slope Stability Assessment in the Wall Overlooking the S||Numerical Modeling as a Tool to Predict Pillar Condition and||Development and Testing of a New Roof Prop||Stability Mapping System||Using Foaming Grout to Stabilize a Ventilation Raise in Very||Roof Control and Roadway Support Design in the #9 Coal Seam,||Non-confirmation Mathematics for Wall Rock Classification fo||The Influence of the First Layer Thickness of Immediate Roof||Studies on Distribution Pattern of and Methane Migration Mec||Development of a New Roof Bolt Technology to Improve Gate- R||Improved Pull out Strength of Fully Grouted Roof Bolts throu||Experimental and Numerical Methodology Assessment of Load Tr||An Investigation into the Support Systems in South African C||Investigation of Fully Grouted Roof Bolts Installed Under In||Development of the Laboratory Short Encapsulation Pull Test||A Resin Quality Testing Procedure for Collieries||Determination of Load Transfer Characteristics of Gloved Res||Fully Grouted Torque Tension Bolts Successfully Support Pitt||Shear Bond Characteristics in Grouted Cable Bolts||Overcoring Techniques to Assess in Situ Corrosion of Galvani||Development of a Laboratory Facility for Testing Shear Perfo||Mechanical Response of Split-Set Rock Bolts in Squeezing Gro||Mechanisms of Rib Sloughing and Methods of Controlling Thick||Supporting Method of the Bolted Strata in Large Deformation||Assessment of Ground Conditions Near a Mine Portal Using Gro||Detection of Abandoned Mines and Air Passages/Burning Center||Detecting Abandoned Coal Mine Entries by High Resolution Ear|