相邻炮孔爆生裂纹相互作用试验研究

Experimental Study on Blasting Crack Interaction between Adjacent Boreholes

为了研究爆炸载荷作用下的相邻炮孔间爆生裂纹相互作用机理,采用新型数字激光动态焦散线试验系统,通过改变炮孔间距,调整药包装药结构,研究了不同间距、不同装药结构下爆生裂纹相向扩展作用机理。结果表明:2炮孔均为普通药包时爆生裂纹随机分布,切缝药包与普通药包相互作用时前期爆生裂纹独立扩展,后期相互吸引互为自由面。2炮孔均为切缝药包相互作用时,炮孔间距较小情况下爆生裂纹在炮孔中心轴线方向贯穿呈“直线型”分布,间距较大时裂纹在炮孔中心轴线方向呈“牵手型”分布。随着炮孔间距增大,裂纹相遇时能量损耗较大,动态应力强度因子峰值和裂纹速度峰值较小,振幅较低,炮孔周围形成的粉碎区面积及次裂纹长度越小,分形维数也越小。

In order to study the interaction mechanism of explosive cracks between adjacent holes under explosive load,a new digital laser dynamic caustic line experiment system was used to study the mechanism of explosive cracks growing each other under different spacing and different charge structure by changing the spacing of holes and adjusting the structure of charge package.The results show that the explosive cracks in the two holes are randomly distributed in the case of the ordinary drug package,and the explosive cracks expand independently in the early stage when the slit drug package interacts with the ordinary drug package,and attract each other as a free surface in the later stage.When the two holes are interacted with slit charge,the explosion-induced cracks are distributed in a"straight line"in the direction of the central axis of the holes.When the spacing is large,the crack distribution in the direction of the central axis of the gun hole is"hand-in-hand".With the in-crease of hole spacing,the energy loss of crack encounter is larger,the peak value of dynamic stress intensity factor and crack velocity are smaller,and the amplitude is lower.The area of crushing zone formed around the hole and the length of secondary crack are smaller,and the fractal dimension is smaller.