分层起爆抛掷爆破效应实验及数值模拟研究

Experimental and Numerical Simulation Study of Layered Initiation Rock and Soil Throwing Blasting

摘要: 基于装药在介质内部爆破技术，采用上、下两层分段抛掷爆破模型试验研究岩土中快速成坑效应，依据柱状装药岩土爆破理论设计分层装药爆破参数，通过改变上层装药长度、孔深及最小抵抗线获得不同尺寸的V型坑，结合下层装药二次爆破获取最终爆炸成坑，在此基础上，采用ANSYS/LS-DYNA结合SPH-FEM算法模拟了孔口堵塞分层延时起爆条件下的爆破过程，研究岩土内受力及运动特征。结果表明：下层装药量、与V型坑底距离、V型坑夹角直接影响爆破效果。约100˚夹角V型地形下方爆破时，下层装药上顶面距离V型坑底25至30 cm时，抛掷效果和开口长度较好，清理工作量相对较少；当下层装药上顶面与V型坑底距离加大时，水平开口直径和抛掷量都会下降；爆腔膨胀后，靠近临空面一侧岩体向外运动，在临空面最外层和堵塞段产生斜向明显拉裂。

Abstract: Based on pharmaceutical internal blasting technology, segment blasting model test is conducted to study the rapid cratering effect in rock and soil. The layered charging blasting parameters are de-signed according to the theory of rock and soil blasting initiated by cylindrical charging. V-shaped pits of different shapes are obtained by changing the upper charging length, hole depth and hole opening clearance. Combined with the secondary blasting of lower charging, the final explosion cratering is obtained. Based on the ANSYS/LS-DYNA combined with SPH-FEM algorithm, the blasting process under the condition of orifice blockage and layered delayed initiation, and the stress and motion characteristics in rock and soil are studied. The results show that during blasting at about 100 angle V terrain, the top surface of the lower charge is 25 to 30 cm from the V pit bottom, the throwing effect and opening length are better, and the cleaning workload is relatively less; when the distance between the upper top surface of the lower charge and the V-shaped pit bottom in-creases, the length of the horizontal opening and the throwing amount will decrease; after the explosion cavity expands, the rock mass on the side close to the free face moves outward, resulting in oblique obvious tensile cracks in the outermost layer and blocking section of the free face.