针对露天台阶剥离爆破块度大、根底多等不良爆破效果，采用炮孔底部与中部两段水介质间隔装药结构进行露天台阶爆破效果优化。从理论上分析了空气介质与水介质间隔装药爆破的炮孔压力，通过试验优化了水介质间隔装药结构的单耗，在选定的最优单耗基础上利用ANSYS/LS-DYNA数值仿真软件，建立3组不同水介质间隔装药结构的三维模型，通过分析得到最优的水介质间隔装药结构，并与空气介质间隔装药结构进行爆破对比试验。结果表明：水介质间隔装药结构爆破可以显著提高炮孔压力，从而改善岩石破碎效果；上、下部水介质间隔均为1 m的装药结构爆破作用于岩体的应力更大且持续时间长，其爆破效果最优；优选的水介质间隔装药结构块度指标均表现出良好的占比情况。研究结果能够为水介质间隔装药结构露天台阶爆破提供参考。

Aiming at the unfavorable blasting effects of the open-air step stripping blasting，such as large blocks and many root bottoms，the blasting effect of the open-air step was optimized by adopting the two-stage charge structure of water medium interval at the bottom of the blast hole and the middle part.To obtain the optimal two-stage charge structure of water medium interval in step stripping blasting of the open-pit mine，the blast hole pressure of the air-medium and water-medium interval charging were discussed from theoretical analysis，the unit consumption of water medium interval charge structure in Wujiata open-pit mine was optimized by experiments.On the basis of the selected optimal unit consumption，three groups of three-dimensional models of different water medium interval charge structure were established by using ANSYS/LS-DYNA numerical simu-lation software.The optimal water medium interval charge structure was selected by analyzing the stress change curve of rock mass，rock mass damage range，and free surface tensile crack area ratio at the bottom of the blast hole，the middle of the lower charge，and the upper position of the blast hole.The blasting effect was evaluated from the index of boulder yield by the blasting comparative experimental with the charge structure of air medium interval.The research results show that blasting with a charge structure of a water medium interval can significantly increase the blasting pressure and improve the rock-crushing effect.The optimal unit consumption of water medium interval charge structure blasting in Wujiata open-pit mine is 0.33~0.34 kg/m³，saving 0.03~0.04 kg/m³ unit consumption of explosives than before. The blasting of a charge structure with an upper water medium interval of 1 m and the lower water medium interval of 1 m has more stress on the rock mass and has a long duration，the damage is evenly distributed along the blast hole，the range is regular，and the free surface tensile crack area accounts for the highest proportion，and its blasting effect optimal.The blasting fragmentation indexes of the optimal water medium interval charge structure all show a good proportion.The research results can provide a reference for the application of water medium interval charge structure in open-pit step blasting.