地应力及岩石抗拉强度对双孔爆破的影响

为研究地应力和岩石抗拉强度对爆破效果的影响，本文利用颗粒流程序（PFC2D）开展数值模拟实验，用单孔爆破实验效果验证了模型的合理性。考虑炮孔间的相互影响，从裂纹形态、应力场及能量场三个角度来分析双孔爆破实验结果。结果表明:（1）双孔爆破在地应力为40~60 MPa时裂纹才会受到明显的抑制作用，当地应力小于40 MPa时，随着地应力的提高，平行于炮孔方向的裂纹受到的抑制作用较小，而垂直于炮孔连线方向的裂纹受到抑制作用较大。（2）地应力在0~5 MPa时，摩擦能和动能衰减最严重；地应力在20~40 MPa时，岩体内部应变能峰值最高。（3）抗拉强度每增长10 MPa，裂纹数量会减少约80%，同时，岩石抗拉强度对能量场的影响也较严重。

Study on the influence of in-situ stress and rock tensile strength on double hole blasting

In order to study the influence of in-situ stress and rock tensile strength on blasting effect, the numerical simulation experiment was carried out by using particle flow code (PFC2D), and the rationality of the model was verified by the experimental effect of single hole blasting. Considering the interaction between blast holes, the experimental results of double hole blasting were analyzed from the perspectives of crack shape, stress field and energy field. (1) When the in-situ stress of double hole blasting is 40 ~ 60 MPa, the crack will be obviously restrained. When the local stress is less than 40 MPa, with the increase of in-situ stress, the crack parallel to the blast hole direction will be restrained less, while the crack perpendicular to the blast hole connecting line will be restrained more. (2) When the in-situ stress is 0 ~ 5 MPa, the attenuation of friction energy and kinetic energy is the most serious; when the in-situ stress is 20 ~ 40 MPa, the peak value of strain energy in rock mass is the highest. (3) When the tensile strength increases by 10 MPa, the number of cracks will be reduced by about 80%. At the same time, the tensile strength of rock has a serious impact on the energy field.