切缝药包爆破岩石爆生裂纹断面的SEM试验

SEM experiment of rock crack cross section morphology after explosion fracturing with slotted cartridge

利用电镜扫描(SEM)切缝药包爆破大理岩爆生裂纹断面形貌,从微观角度探究动载下岩石的定向断裂机理。通过对主裂纹和次裂纹断面上不同区域的观测,发现了河流状、台阶状、根状、鱼骨状、"雾区"状等典型断面形貌,定性的解释了爆炸荷载作用下典型断面形貌的形成机理。研究表明,爆炸荷载作用下,大理岩的微观破坏机制分为拉伸破坏和剪切破坏,爆炸近区多为拉伸破坏,中区、远区有剪切破坏出现;大理岩微观断裂机制是以脆性断裂为主,爆炸近区形成张拉脆性破坏区,远区有较少的塑性破坏;非切缝方向的沿晶断裂较多。

The research used scanning electron microscope（SEM） to scan the crack cross section morphology of marble after explosion fracturing with slotted cartridge.From micro perspective,the directional fracture mechanism of rock was explored under the dynamic load.Through observing the different areas of the main and secondary cracks＇ sections,the study concluded typical section morphology,such as river-like,step-like,root-like,fish bone-like,fog zone-like,etc.The formation mechanism of typical section morphology was qualitatively elaborated under the blast load.The results show that： the microscopic failure mechanism of marble under blast load falls into tensile failure and shear failure;tensile failure is mainly in near-blast zone;shear failure appears in the middle or far-blast zone;microscopic fracture mechanism of marble was mainly brittle fracture;tensile and brittle failure zone formed in near-blast zone;a little plastic failure could be found at far-blast zone;and intergranular fracture mainly appeared in the non-cutting direction.