目的研究水平边界条件下深孔微差爆破的作用机理．方法采用动态非线性有限元法对单个水平自由面深孔微差爆破进行数值模拟．根据模拟结果分析岩块运动和槽腔内岩块的破坏方式．结果孔底部分的岩石主要以冲击压缩破坏为主，而自由面附近的岩石主要以层裂破坏为主．结论掏槽孔的爆破作用和微差时间的确定是影响微差爆破的重要因素，使用含定向裂纹的弹塑性模型可较好地描述脆性岩石本构行为 Aim To study the mechanism of deep-hole millisecond blasting under horizontal boundary conditions. Methods The dynamic nonlinear finite element method is used to simulate the deep horizontal hole micro-scale blasting in a single horizontal free surface. According to the simulation results, the rock mass movement and the failure mode of the rock mass in the groove are analyzed. As a result, the rock at the bottom of the hole is dominated by impact compression and failure, whereas the rocks near the free surface are dominated by delamination. Conclusions The blasting effect and the determination of the microsecond time are the important factors that influence the microtactic blasting. The elastoplastic model with directional crack can describe the constitutive behavior of the brittle rock well