预裂爆破中柱状孔间应力场作用分析

Analysis of the stress field between the columnar holes in pre-split blasting

建立深孔预裂爆破柱状孔间应力作用力学模型,以塔吉克斯坦吉劳露天矿南部边帮1915平台现场参数为试验模拟基础,利用ANSYS/LS-DYNA建立分段空气间隔装药条件下三维双孔预裂爆破数值模型,分析了预裂爆破中柱状孔间不同部位处应力作用过程。研究表明:孔口部位主要以反射拉伸破坏为主,炮孔中部可近似看作是平行于炮孔轴线方向的应力波多重叠加导致破坏,炮孔底部采用加强装药后,应力大小及持续时间大大加强,有助于克服孔底夹制力,形成孔底贯通预裂缝。

A mechanical model of the stress action between cylindrical holes in deep hole pre-splitting blasting was established.Based on the field parameters of the 1915 platform on the southern side of the Jilao Open-pit Mine in Tajikistan,ANSYS/LS-DYNA was used to establish the three-dimensional double-hole pre-splitting blasting numerical model under the condition of segmented air-spaced charging.The stress process at different positions between the cylindrical holes in the pre-splitting blasting was analyzed.The research showed that the main part of the orifice was mainly reflected tensile failure,and the middle of the blast hole can be regarded as parallel to the multiple superposition of stress waves in the axial direction of the blast hole leads to damage.After the reinforced charge was used at the bottom of the blast hole,the stress size and duration were greatly enhanced,which helps to overcome the clamping force at the bottom of the hole and form a through-hole pre-crack.