临近胶结充填体矿房爆破装药结构及振动规律分析

Analysis of Blasting Charge Structure and Vibration Law of Stope Near Cemented Filling Body

  • 摘要: 在采用空场嗣后充填法开采矿石过程中,为降低Ⅱ步骤回采矿房爆破落矿时,爆破冲击作用对Ⅰ步骤回采后进行胶结充填的矿柱造成的损伤,通过数值模拟方法,分析了不同厚度预留矿柱下空气间隔装药及砂石间隔装药两种装药结构在爆破过程中对临近胶结充填体的损伤情况。研究结果表明,两种装药结构在爆破过程中对紧邻胶结充填体侧的保留矿体的损伤范围及胶结充填体内损伤,随保留矿体厚度的变化情况基本一致。但与砂石间隔装药结构相比,空气间隔装药结构在粉碎区耗能较低,更多能量集中于裂隙区,炸药能量分布更均衡,破岩效能更优。此外,通过现场监测爆破振动数据,结合萨道夫斯基爆破振动衰减公式,对振动监测数据进行多元线性回归。得到爆破振动在充填体中X、Y、Z三个方向衰减系数分别为2.31、1.76、2.08,且回归曲线线性相关关系强,符合矿山实际,相关衰减系数可作为控制爆破过程中最大单响药量的理论依据。研究结论为井下回采爆破参数选择提供了理论依据,对井下安全开采具有一定指导意义。

     

    Abstract: In the process of mining with open stoping subsequent filling method, in order to reduce the damage caused by blasting impact during blasting and ore falling in the second step back mining room to the pillar of cemented filling after mining in the first step. Through the LS−DYNA software analyze the damage of two charge structures of air interval charge and sand−gravel interval charge to the adjacent cemented filling body during the blasting process under different reserved pillar thicknesses. The research results showed that the damage range of the retained ore body adjacent to the side of the cemented filling body and the change of the damage in the cemented filling body with the thickness of the retained ore body during the blasting process of the two charging structures were basically the same. However, compared with the sand−gravel interval charge structure, the air interval charge structure had lower energy consumption in the crushing zone, more energy was concentrated in the fracture zone, the explosive energy distribution was more balanced, and the rock breaking efficiency was better. In addition, throught the on−site monitoring of blasting vibration data, combined with the Sadov's formula for blasting vibration attenuation, the vibration monitoring data were subjected to multiple linear regression.The attenuation coefficients of blasting vibration in the XY、and Z directions of the filling body were 2.31, 1.76, and 2.08, respectively, and the regression curve had a strong linear correlation, which was in line with the actual situation of the mine, the relevant attenuation coefficient could be used as the theoretical basis for controlling the maximum single−shot charge in the blasting process.The research conclusion provides a theoretical basis for the selection of blasting parameters in underground mining, and has certain guiding significance for safe underground mining.

     

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