中空孔对直眼掏槽爆破效果的影响数值模拟
Numerical Simulation of Influence of Hollow Hole on Blasting Effect of Parallel Cut
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摘要: 为了研究中空孔对直眼掏槽爆破效果的影响,运用非线性动力分析平台ANSYS/LS-DYNA,建立有、无中空孔2种直眼掏槽爆破的三维数值模型,比较分析掏槽爆破过程中爆炸应力场演化历程以及岩体破坏特征。模拟结果表明:由于中空孔处发生了应力波反射,中空孔附近产生明显的应力集中效应,中空孔模型孔壁处测点的等效应力峰值为107.0 MPa,无中空孔模型中心区域测点的等效应力峰值为20.3 MPa;有中空孔时槽腔内岩体被充分破坏,空孔与掏槽孔之间形成贯穿裂隙,且空孔附近形成了层裂现象,而无中空孔时槽腔中间岩体破碎长度差、炮孔利用率低。Abstract: To study the influence of hollow hole on blasting effect of parallel cut, two three-dimensional parallel cut models with or without hollow hole were established by using the nonlinear dynamic analysis platform ANSYS/LS-DYNA. The evolution history of explosive stress field and the failure characteristics of rock mass were compared and analyzed. The results indicated that the stress concentration was occurred around hollow hole obviously due to the reflection of stress wave. The peak equivalent stress of the measuring point on borehole wall is 107.0 MPa for the model with hollow hole. The peak equivalent stress of the measuring point on middle zone is 20.3 MPa for the model without hollow hole. Rock mass in cut cavity can be fully destroyed with hollow hole. Penetrating cracks are formed between cutting holes and hollow holes. The phenomenon of spallation is formed at the wall of hollow hole. Poor fragmentation length of rock mass in the middle of cut cavity and small utilizing rate of blasting holes are formed for the model without center empty.