单向压应力对砂岩漏斗爆破过程的影响

Influence of Unidirectional Compressive Stress on the Crater Blasting of Sandstone

针对深部高应力条件下岩石爆破问题,开展不同单向压应力条件下的砂岩漏斗爆破实验,研究了静应力对漏斗爆破过程中裂纹网形成与扩展的影响.提出了爆破漏斗破坏分区的概念,即块状破坏区、过渡区、片状剥落区.分别分析了静应力对爆破漏斗三个破坏区的影响,进而阐明了不同静应力条件下岩石爆破破坏的特征.结果表明:静应力促进平行其自身方向裂纹的形成,抑制垂直其自身方向裂纹的形成,进而改变了裂纹网的形态;静应力促进平行其自身方向爆破漏斗破坏区的形成,对片状剥落区的影响最大,块状破坏区与过渡区次之,对垂直其自身方向的破坏区影响较小;当应力强度比达到0.15时,需要考虑静应力对爆破效果的影响.

Considering the problems related to rock blasting under deep high in-situ stress,we conducted crater blasting tests on sandstone specimens under different unidirectional compressive stresses.The influence of static stress on the formation and propagation of crack network in the process of crater blasting was analyzed.The concept of failure zones formed in blasting crater,namely,block failure zone,transition zone and flaky spalling zone was put forward.The influence of static stress on the three failure zones in blasting crater and the characteristics of rock blasting failure under different static stress conditions were elucidated.The results show that static stress promotes the formation of cracks parallel to its own direction and inhibits the formation of cracks perpendicular to its own direction,thus changing the shape of the crack network.The static stress promotes the formation of blasting crater failure zone parallel to its own direction,and has the greatest influence on flaky spalling zone,followed by block failure zone and transition zone,and has little effect on the failure zone perpendicular to its own direction.When stress-strength ratio reaches 0.15,the influence of static stress on blasting effect needs to be considered.