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基于數碼電子雷管的巖巷中深孔–孔內分段爆破破巖機制及應用

Rock breaking mechanism and the application of medium-deep hole–in-hole segmented blasting in rock roadway using digital electronic detonators

  • 摘要: 巖巷掘進中“速度的關鍵在掏槽”,針對目前掏槽爆破中破碎巖石難以拋擲、單循環進尺小、大塊率高等問題,提出了中深孔–孔內分段爆破技術. 采用數學建模,推導了中深孔–孔內分段爆破巖石拋擲所受的動、阻力公式;利用LS-DYNA進行數值模擬,分析了中深孔–孔內分段爆破應力波的傳播規律,并比較了不同分段比例下有效應力變化情況;將中深孔–孔內分段爆破應用于現場,對比了單循環進尺、炮孔利用率、孔痕率及大塊率等爆破效果指標. 結果表明,中深孔–孔內分段爆破巖石拋擲所受的阻力比普通楔形掏槽爆破的阻力小,動力作用時間短,能量損失少,更易爆破成腔. 提出了能夠使破碎巖石完全拋擲出腔的措施,并初步確定孔內分段的最優比例為0.6. 中深孔–孔內分段爆破增加了單循環進尺,提高了工作效率,具有良好的經濟社會效益.

     

    Abstract: “Cutting is the key to speed” in rock roadway excavation. With the aim of addressing the challenges related to broken rock disposal, low single-cycle penetration, and high block rate in the conventional straight hole and diagonal hole excavation blasting, the method of medium-deep holein-hole segmented blasting is proposed herein. The mathematical relations for the force and resistance required in the process of rock crushing and ejection in the groove of medium-deep hole-in-hole segmented blasting, as well as that for the expected value range of the key parameters of the cutting groove, were determined. LS-DYNA was used to numerically simulate the process of medium-deep hole-in-hole and ordinary wedge cut blasting. The nature of stress wave propagation during medium-deep hole-in-hole segmental blasting and the stress characteristics of the rock at the bottom of the hole were analyzed. Furthermore, the variation characteristics of the stress wave intensity were compared for different segmental proportions, and the optimal segmental proportions were determined. The results of theoretical analysis and numerical simulation were applied to the excavation site of the rock roadway, and the blasting effect indices, such as singlecycle footage, hole utilization rate, eye mark rate, and block rate, of the medium-deep hole-in-hole segmented blasting and the ordinary wedge blasting schemes were compared. The results showed that rock can be ejected from the cavity when the dynamic force is greater than or equal to the resistance during the rock crushing and ejection process and that the resistance to rock ejection in the medium-deep holeinhole segmented blasting is less than that in ordinary wedge cut blasting, and it is easier to blast into the cavity. Best practices for achieving the complete ejection of broken rocks from the cavity are proposed, and theoretical support for determining the parameters, such as the depth of the hole, is provided. As compared to ordinary wedge cut blasting, producing a large blasting cavity through medium-deep hole-in-hole segmented blasting is easier, which is more favorable for subsequent blasting. The optimal ratio of the hole-in-hole segmented blasting was initially determined to be 0.6. Medium and deep hole-inhole segmented blasting increases the single-cycle footage, improves the utilization rate of the hole, reduces the working time, reduces construction cost, and has excellent economic and socialadvantages.

     

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