Numerical study on the fracturing mechanism of shock wave interactions between two adjacent blast holes in deep rock blasting  

作　　者：Yuan Wei Liu Shangge Wang Wei Su Xuebin Li Zonghong Li Jiaxin Wen Lei Chang Jiangfang Sun Xiaoyun 

机构地区：[1]School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043, China [2]Hebei Technology and Innovation Center on Safe and Effi cient Mining of Metal Mines, Shijiazhuang 050043, China [3]CCCC Second Highway Consultants Co., Ltd., Wuhan 430056, China [4]China National Uranium Co. Ltd., Beijing 100013, China

出　　处：《Earthquake Engineering and Engineering Vibration》2019年第4期735-746,共12页地震工程与工程振动（英文刊）

基　　金：National Science Foundation for Young Scientists of China under Grant No.51709176;National Natural Science Foundation of China under Grant No.51979170;Key Project of Hebei Natural Science Foundation under Grant No.F2019210243;Hebei Province Science Foundation for Young Scientists under Grant No.E2018210046;Open Project of State Key Laboratory of Advanced Electromagnetic Engineering and Technology under Grant No.AEET 2019KF005

摘　　要：With the application of electronic detonators, millisecond blasting is regarded as a signifi cant promising approach to improve the rock fragmentation in deep rock blasting. Thus, it is necessary to investigate the fracturing mechanisms of short-delay blasting. In this work, a rectangle model with two circle boreholes is modeled as a particles assembly based on the discrete element method to simulate the shock wave interactions induced by millisecond blasting. The rectangle model has a size of 12 × 6 m (L × W) and two blast holes have the same diameter of 12 cm. The shock waves are simplifi ed as time-varying forces applied at the particles of walls of the two boreholes. Among a series of numerical tests in this study, the spacing between two adjacent boreholes and delay time of millisecond blasting are considered as two primary variables, and the decoupling charge with a coeffi cient of 1.5 is taken into account in each case. The results show that stress superposition is not a key factor for improving rock fragmentation (tensile stress interactions rather than compressive stress superposition could aff ect the generation of cracks), whereas collision actions from isolated particles or particles with weakened constraints play a crucial role in creating the fracture network. The delay time has an infl uence on causing cracks in rock blasting, however, whether it works heavily depends on the distance between the two holes.With the application of electronic detonators, millisecond blasting is regarded as a significant promising approach to improve the rock fragmentation in deep rock blasting. Thus, it is necessary to investigate the fracturing mechanisms of short-delay blasting. In this work, a rectangle model with two circle boreholes is modeled as a particles assembly based on the discrete element method to simulate the shock wave interactions induced by millisecond blasting. The rectangle model has a size of 12 × 6 m(L × W) and two blast holes have the same diameter of 12 cm. The shock waves are simplified as time-varying forces applied at the particles of walls of the two boreholes. Among a series of numerical tests in this study, the spacing between two adjacent boreholes and delay time of millisecond blasting are considered as two primary variables, and the decoupling charge with a coefficient of 1.5 is taken into account in each case. The results show that stress superposition is not a key factor for improving rock fragmentation(tensile stress interactions rather than compressive stress superposition could affect the generation of cracks), whereas collision actions from isolated particles or particles with weakened constraints play a crucial role in creating the fracture network. The delay time has an influence on causing cracks in rock blasting, however, whether it works heavily depends on the distance between the two holes.

关 键 词：rock FRAGMENTATION MILLISECOND BLASTING shock wave DECOUPLING charge discrete element method 

分 类 号：P[天文地球]