1.Tianjin University;2.Shenzhen Municipal Design and Research Institute
National Key Research and Development Program(No. 2018YFC0407002); National Natural Science Foundation of China(No. 51974197)
The explicit dynamic FEM-based code AUTODYN was used to study the effect and law of barrier holes on blast-induced stress wave propagation and attenuation, as well as the dynamic response of adjacent underground opening and ground. First of all, by comparing with the results of blasting model test, the effectiveness and accuracy of AUTODYN in simulating the process of underground opening explosion and stress wave propagation are verified. Then, the effects of barrier hole parameters on peak particle velocity(PPV) of the adjacent chamber and ground, and the vibration-isolation rate of measuring points before and after barrier holes, were analyzed through the numerical simulation method，to investigate the influence law of barrier hole parameters on vibration reduction effect. The simulated results indicated that barrier hole diameter, hole spacing, the distance between hole and explosion center, and hole row have effects on PPVs of adjacent underground opening and ground and the vibration-isolation rate of measuring points before and after barrier holes. With increasing barrier hole diameter and barrier hole row, or decreasing barrier hole spacing and distance between barrier hole and explosion center, PPVs on the adjacent underground opening and ground show a decreasing trend and vibration-isolation rate of measuring points before and after barrier holes shows a great increasing trend, that is, the vibration reduction effect of barrier hole increases. In addition, with the change of barrier hole parameters, the vibration-isolation rates of the measuring points before and after barrier hole and the measuring points before and after rock mass between barrier holes show great differences. The former is obviously larger than the latter, and the difference between the two increases first and then decreases with the increase of hole diameter, and decreases rapidly with the increase of the distance between hole and explosion center, and doesn’t change significantly with the increase of barrier hole row. The change of barrier hole spacing could affect the relative position of the measuring point and the barrier hole, thus determining the vibration-isolation rate of the measuring point. These research results can provide a certain reference for the arrangement of barrier holes and disaster prevention and reduction in actual blasting projects.