The purpose of this study was to investigate the effect of bolt profile on load transfer mechanism of fully grouted bolts in jointed rocks using analytical and numerical methods. Based on the analytical method with de...The purpose of this study was to investigate the effect of bolt profile on load transfer mechanism of fully grouted bolts in jointed rocks using analytical and numerical methods. Based on the analytical method with development of methods, a new model is presented. To validate the analytical model, five different profiles modeled by ANSYS software. The profile of rock bolts T3 and T4with load transfer capacity,respectively 180 and 195 kN in the jointed rocks was selected as the optimum profiles. Finally, the selected profiles were examined in Tabas Coal Mine. FLAC analysis indicates that patterns 6+7 with2 NO flexi bolt 4 m better than other patterns within the faulted zone.展开更多
Roof bolt support system has been widely applied in the No.7, 9 seam in Caozhuang coal mine. However, it has not been able to be applied in the No.10-2 seam since the small interburden （2 m） between No.9 and No.10-2...Roof bolt support system has been widely applied in the No.7, 9 seam in Caozhuang coal mine. However, it has not been able to be applied in the No.10-2 seam since the small interburden （2 m） between No.9 and No.10-2 seam. The No.9 and No.10-2 seams are contiguous seams. The No.9 seam has been mined out and the No.10-2 seam will be mined under the gob of the No.9 seam. The roof strata of the No.10-2 seam may have been weakened and fractured due to the shear failure caused by the No.9 seam mining activities. The steel beam sets spaced at 0.8 m have been used to support the entry of the No.10-2 seam. In order to speed up the advance rate and cut entry development cost, a test area, using roof bolt in conjunction with truss-system, was successfully conducted. This paper presents the support system design, application of designed system, and the test results. Test results provide a cheaper, quicker, and safer way to support entry for the No.10-2 seam.展开更多
Following a small-scale wedge failure at Yukon Zinc＇s Wolverine Mine in Yukon, Canada, a vibration monitoring program was added to the existing rockbolt pull testing regime. The failure in the 1150 drift occurred aft...Following a small-scale wedge failure at Yukon Zinc＇s Wolverine Mine in Yukon, Canada, a vibration monitoring program was added to the existing rockbolt pull testing regime. The failure in the 1150 drift occurred after numerous successive blasts in an adjacent tunnel had loosened friction bolts passing through an unmapped fault. Analysis of blasting vibration revealed that support integrity is not compromised unless there is a geological structure to act as a failure plane. The peak particle velocity（PPV） rarely exceeded 250 mm/s with a frequency larger than 50 Hz. As expected, blasting more competent rock resulted in higher PPVs. In such cases, reducing the round length from 3.5 m to 2.0 m was an effective means of limiting potential rock mass and support damage.展开更多
文摘The purpose of this study was to investigate the effect of bolt profile on load transfer mechanism of fully grouted bolts in jointed rocks using analytical and numerical methods. Based on the analytical method with development of methods, a new model is presented. To validate the analytical model, five different profiles modeled by ANSYS software. The profile of rock bolts T3 and T4with load transfer capacity,respectively 180 and 195 kN in the jointed rocks was selected as the optimum profiles. Finally, the selected profiles were examined in Tabas Coal Mine. FLAC analysis indicates that patterns 6+7 with2 NO flexi bolt 4 m better than other patterns within the faulted zone.
文摘Roof bolt support system has been widely applied in the No.7, 9 seam in Caozhuang coal mine. However, it has not been able to be applied in the No.10-2 seam since the small interburden （2 m） between No.9 and No.10-2 seam. The No.9 and No.10-2 seams are contiguous seams. The No.9 seam has been mined out and the No.10-2 seam will be mined under the gob of the No.9 seam. The roof strata of the No.10-2 seam may have been weakened and fractured due to the shear failure caused by the No.9 seam mining activities. The steel beam sets spaced at 0.8 m have been used to support the entry of the No.10-2 seam. In order to speed up the advance rate and cut entry development cost, a test area, using roof bolt in conjunction with truss-system, was successfully conducted. This paper presents the support system design, application of designed system, and the test results. Test results provide a cheaper, quicker, and safer way to support entry for the No.10-2 seam.
文摘Following a small-scale wedge failure at Yukon Zinc＇s Wolverine Mine in Yukon, Canada, a vibration monitoring program was added to the existing rockbolt pull testing regime. The failure in the 1150 drift occurred after numerous successive blasts in an adjacent tunnel had loosened friction bolts passing through an unmapped fault. Analysis of blasting vibration revealed that support integrity is not compromised unless there is a geological structure to act as a failure plane. The peak particle velocity（PPV） rarely exceeded 250 mm/s with a frequency larger than 50 Hz. As expected, blasting more competent rock resulted in higher PPVs. In such cases, reducing the round length from 3.5 m to 2.0 m was an effective means of limiting potential rock mass and support damage.
