|
Abstract To address the control challenge of bolt instability induced by blasting construction under hard coal seam conditions, No. 6-5 Face of Liujia Mine was taken as the engineering background, a comprehensive approach combining discrete element numerical simulation and on-site monitoring was adopted to systematically study the response laws of anchor rod shear stress and displacement to blasting vibration. The study revealed that: ①due to the hard coal seam and the enhancement effect of stress wave propagation, under the original "waist eye + bottom eye" blasting scheme, the vibration velocity of the anchor rod frequently approached the warning threshold and the cutting effect was poor; ② the shear stress and displacement at the anchor rod node showed a significant nonlinear positive correlation with the peak boundary vibration velocity; ③ a composite vibration reduction control technology of "vibration reduction empty hole + millisecond delay detonation" was proposed. Field application showed that this scheme could maintain the long-term pre-tightening force of the anchor rod within a stable range of 26.7 ~ 41.8 kN, which was higher than the design value, and the active support performance was good. The research results provided technical reference for vibration reduction in hard coal seam blasting.
|