深厚冲积层大直径千米立井冻土掘进爆破参数优化

Optimization of Blasting Parameters for Frozen Soil Excavation in Large-diameter Vertical Shaft with Deep Alluvium

理论研究和室内试验在深层冻土爆破参数设计中存在着限制,结合赵固二矿西风井冻土掘进的施工特点,开展爆破参数优化现场实验。以掘进速度、安全、质量为评价依据,对炸药选择、钻眼机具、炮眼布置和深度、装药参数和起爆顺序等参数进行优化分析。结果表明:通过合理设置中空孔、一二级掏槽孔、辅助孔和周边孔的孔距与间排距,调整装药参数和雷管段位等手段,使得爆后土体均匀无大块,将爆破进尺由1.9 m提高至2.8 m,炮孔利用率由67.9%提高至93.3%;同时将爆破振动控制在安全范围以内,实测井壁最大振动速度为8.39 cm/s,保证了施工安全性;通过经济效益比较分析,优化后的爆破方案较之前显著提高了施工效率,缩减掘进工期44.5 d,大大节约了施工成本和冻结成本。

There are limitations in the design of blasting parameters for deep frozen soil in theoretical research and laboratory test.Combined with the construction characteristics of frozen soil excavation in the west wind shaft of Zhaogu No.2 Mine,the field experiment of blasting parameters optimization was carried out.Based on the excavation speed,safety and quality,the optimization of the parameters such as explosive selection,drilling equipment,blast hole arrangement and depth,charging parameters and detonation sequence were analyzed.The results show that by properly setting the empty holes and layouting the hole spacing and row spacing of the first and second cutting holes,the auxiliary holes and the perimeter holes,and adjusting the charging parameters and the detonator segments,the frozen soil mass were uniform and free of large blocks after blasting.The excavation footage was increased from 1.9 m to 2.8 m,and the blast hole utilization rate was increased from 67.9% to 93.3%.At the same time,the blasting vibration was controlled within the safe range,and the measured maximum vibration velocity of the shaft wall was 8.39 cm/s,which ensured the construction safety.Through comparative analysis of economic benefits,the optimized blasting scheme significantly improved the construction efficiency,reduced the excavation construction period by 44.5 days,and greatly saved the costs of construction and freezing.