With rampant growth and improvements in drilling technology, drilling of blast holes should no longer be viewed as an arduous sub-process in any mining or excavation process. Instead, it must be viewed as an important...With rampant growth and improvements in drilling technology, drilling of blast holes should no longer be viewed as an arduous sub-process in any mining or excavation process. Instead, it must be viewed as an important opportunity to quickly and accurately measure the geo-mechanical features of the rock mass on-site, much in advance of the downstream operations. It is well established that even the slightest variation in lithology, ground conditions, blast designs vis-a-vis geologic features and explosives performance, results in drastic changes in fragmentation results. Keeping in mind the importance of state-of-the-art measurement-while-drilling （MWD） technique, the current paper focuses on integrating this technique with the blasting operation in order to enhance the blasting designs and results. The paper presents a preliminary understanding of various blasting models, blastability and other related concepts, to review the state-of-the-art advancements and researches done in this area. In light of this, the paper highlights the future needs and implications on drill monitoring systems for improved information to enhnnrp th~ hl^tin~ r^HIt~展开更多
The repair of reinforced concrete(RC)beams with carbon fiber reinforced polymers(CFRP)is experimentally investigated in this study.The four T-section reinforced reactive powder concrete beams with many locations of ci...The repair of reinforced concrete(RC)beams with carbon fiber reinforced polymers(CFRP)is experimentally investigated in this study.The four T-section reinforced reactive powder concrete beams with many locations of circular opening were repaired by CFRP and investigated under pure torsion.The repairing beams were tested to obtain the effect of the amount of CFRP laminate on beams cracking and ultimate torque behavior,angle of twist and failure modes.The results obtained from the adopted repairing technique showed a significant effect of external high strength CFRP laminates on effectively restore of section solid of 85%of crack torsional strength effectively restored.In addition,the results show that effectively restoring of section opening by 82%-80%of crack torsional strength,and the adopted repairing technique gives a good strength to the beams.展开更多
An experimental study was conducted to investigate the behavior of composite concrete beams damaged and cracked under pure torsion, and then repaired by external strengthening. This was achieved using high strength Ca...An experimental study was conducted to investigate the behavior of composite concrete beams damaged and cracked under pure torsion, and then repaired by external strengthening. This was achieved using high strength Carbon Fiber Reinforced Polymer (CFRP) laminates bonded with epoxy four composite modify reactive powder concrete (MRPC) I-beams. Different types of section (Solid & with opening) were tested to obtain the effect of amount of CFRP laminate on beams ultimate torque behavior, angle of twist and failure modes. The results obtained showed that a significant effect of external high strength CFRP laminates on effectively restore of section solid, the range of 89.8% to 91.2% of ultimate torsional strength effectively restored as well as effectively restoring of section opening by 83.48% - 86.67% of ultimate torsional strength. The repaired beams give high efficiency in ultimate torsional strength, and indicate that the adopted technique gives a good torsional strength.展开更多
文摘With rampant growth and improvements in drilling technology, drilling of blast holes should no longer be viewed as an arduous sub-process in any mining or excavation process. Instead, it must be viewed as an important opportunity to quickly and accurately measure the geo-mechanical features of the rock mass on-site, much in advance of the downstream operations. It is well established that even the slightest variation in lithology, ground conditions, blast designs vis-a-vis geologic features and explosives performance, results in drastic changes in fragmentation results. Keeping in mind the importance of state-of-the-art measurement-while-drilling （MWD） technique, the current paper focuses on integrating this technique with the blasting operation in order to enhance the blasting designs and results. The paper presents a preliminary understanding of various blasting models, blastability and other related concepts, to review the state-of-the-art advancements and researches done in this area. In light of this, the paper highlights the future needs and implications on drill monitoring systems for improved information to enhnnrp th~ hl^tin~ r^HIt~
文摘The repair of reinforced concrete(RC)beams with carbon fiber reinforced polymers(CFRP)is experimentally investigated in this study.The four T-section reinforced reactive powder concrete beams with many locations of circular opening were repaired by CFRP and investigated under pure torsion.The repairing beams were tested to obtain the effect of the amount of CFRP laminate on beams cracking and ultimate torque behavior,angle of twist and failure modes.The results obtained from the adopted repairing technique showed a significant effect of external high strength CFRP laminates on effectively restore of section solid of 85%of crack torsional strength effectively restored.In addition,the results show that effectively restoring of section opening by 82%-80%of crack torsional strength,and the adopted repairing technique gives a good strength to the beams.
文摘An experimental study was conducted to investigate the behavior of composite concrete beams damaged and cracked under pure torsion, and then repaired by external strengthening. This was achieved using high strength Carbon Fiber Reinforced Polymer (CFRP) laminates bonded with epoxy four composite modify reactive powder concrete (MRPC) I-beams. Different types of section (Solid & with opening) were tested to obtain the effect of amount of CFRP laminate on beams ultimate torque behavior, angle of twist and failure modes. The results obtained showed that a significant effect of external high strength CFRP laminates on effectively restore of section solid, the range of 89.8% to 91.2% of ultimate torsional strength effectively restored as well as effectively restoring of section opening by 83.48% - 86.67% of ultimate torsional strength. The repaired beams give high efficiency in ultimate torsional strength, and indicate that the adopted technique gives a good torsional strength.
