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采用新型数字激光动态焦散线实验系统,对缺陷介质双孔定向断裂控制爆破裂纹扩展的动态行为进行了研究。结果表明,预制斜裂纹阻断了爆生主裂纹的扩展,最终两条主裂纹分别与翼裂纹形成相互勾连的形状。爆生主裂纹尖端以张拉应力场为主,其断裂为近似I型断裂。当爆生主裂纹运动到预制裂纹附近时,主裂纹端部应力场与预制裂纹尖端奇异应力场相互叠加,在预制裂纹尖端形成较强的拉剪应力场,且受已有主裂纹面的影响,预制裂纹扩展表现为弯向主裂纹面的弯曲断裂。研究结果可为含节理岩体定向断裂控制爆破提供理论依据。
The dynamic behavior of controlled crack propagation in two-hole directional fracture of a defective medium was studied by using a new digital laser dynamic caustic experiment system. The results show that the precast slanting crack intercepts the expansion of the main crack and the final two main cracks are connected with the wing crack respectively. The main crack tip of the burst is dominated by the tensile stress field and its fracture is approximate type I fracture. When the main crack propagates to near the prefabricated crack, the stress field at the tip of the primary crack and the singular stress field at the tip of the prefabricated crack are superposed on each other, and a strong tensile shear stress field is formed at the prefabricated crack tip and is affected by the existing primary crack surface , The preformed crack growth is manifested as bending fracture to the main crack surface. The results can provide a theoretical basis for the controlled blasting of directional fractures with jointed rock mass.