多孔台阶爆破破裂过程的模型试验研究

应用高速摄影仪和超动态应变仪研究模拟台阶爆破的水泥砂浆模型破裂过程，解决了三维模型爆破试验中装药结构、可靠起爆和同步实现等一系列技术问题.研究了水泥砂浆台阶爆破裂纹的起裂、扩展、分叉、止裂.实验发现，裂纹扩展速度一般为400～600 m/s；密集系数m影响台阶爆破炮孔间裂纹贯通时间，并随m增大而推迟，应变波持续作用时间和最大拉应变峰值随m增大，说明较大m提高了炸药能量利用率，使爆破微裂纹充分发育，爆破破碎块度合理.

Experimental investigation on fracture process of multi-hole bench blasting

The process of blasting fractures of cement mortar model for simulating bench blasting was analyzed with high speed camera and super dynamic strain measuring system.Solved a series of difficult experimental problems of such as explosive charge， reliable initiation and time synchronization with high speed camera for the three dimensions laboratory blasting model.Studied mechanical behavior of initial crack， propagation， bifurcation and interaction. The test indicates that the velocity of crack propagation is general 400～600 m/s. The time of crack transfixion between holes is longer along with density coefficient.The duration of strain wave and peak wave of tension strain increase  with m  .It indicates that the larger density coefficient improves energy utilization ratio of explosive， and the abundant small cracks are formed. Reasonable blasting fragment sizes are obtained.