基于XFEM的切槽炮孔定向断裂爆破数值模拟

 应用ABAQUS 扩展有限元（XFEM）模拟了切槽炮孔定向断裂爆破时爆生裂纹沿切槽方向和非切槽方向的起裂、扩展和止裂。结果表明：切槽方向爆生裂纹的起裂时间比非切槽方向早10 μs；裂纹扩展速度较非切槽方向具有明显的阶段性，可分为加速扩展、失稳扩展和减速扩展3 个阶段；裂纹的止裂时间比非切槽方向晚60 μs。在裂纹扩展阶段，切槽方向在失稳扩展阶段爆生裂纹的平均速度为1343 m/s，非切槽方向爆生裂纹的平均速度为600 m/s，仅为切槽方向爆生裂纹平均速度的44%，说明切槽有利于爆炸能量释放，增加爆生裂纹的扩展速度。切槽方向和非切槽方向爆生裂纹扩展的平均距离分别为124 mm 和45 mm，说明切槽对爆生裂纹的扩展有明显的导向作用。XFEM 能够正确模拟切槽爆破爆生裂纹的扩展，具有广阔的应用前景。

Numerical simulation of directional fracture blast in grooving borehole based on XFEM method

The blast- induced crack initiation, propagation and arrest along both grooving and non- grooving directions in grooving directional fracture blasting are simulated by using the extended finite element method (XFEM) in the ABAQUS software. The results show that, it is 10 μs earlier in the grooving direction for the charge explosion to initiate cracks than in the non-grooving direction; while the crack propagation in the non-grooving direction does not see clear stages, the crack propagation in the grooving direction is clearly in three stages: the accelerating crack propagation, the unstable crack propagation and the decelerating crack propagation; the crack arrest time along the grooving direction is 60 μs more as compared with that in the non-grooving direction. During the crack propagation stage, the average speed of the unstable propagation in the grooving direction is 1343 m/s, while, it is 44% less in the non-grooving direction with the average speed of 600 m/s. This indicates that the groove is benecial for releasing the blast energy, and increasing the crack speed to a higher level. The groove has obviously the guidance effect in the extension direction of cracks, for the average crack length in the grooving and non-grooving directions is 124 mm and 45 mm, respectively. The XFEM method shows a promising prospect in simulating the crack propagation in the grooving directional blast.