粒子射流冲击下破岩应力分析与破岩区域

由于粒子射流冲击破岩的复杂性和破岩过程的短暂性，粒子射流冲击作用下岩石的力学特性与损伤破坏研究是一个难点问题。考虑粒子射流返流的影响，基于空腔膨胀理论建立了粒子射流耦合冲击作用下的岩石应力和破岩区域的数学模型，采用数值计算和仿真模拟相互验证的研究方法，分析了粒径和射流冲击速度对单粒子射流冲击作用下岩石的应力分布和破岩区域的影响规律。针对多粒子连续射流耦合冲击破岩过程，给出了破岩区域的计算方法，采用数值计算和实验验证相结合的研究方法，得到了垂直射流和旋转射流状态下的破岩区域规律。结果表明：粒子射流耦合冲击破岩过程中，呈一定角度的旋转射流破岩区域要比垂直射流破岩区域大，粒径的增加对破岩区域影响较小，当射流冲击速度为200 m/s和粒径为1.0 mm时，8°和20°射流冲击破岩区域分别是喷嘴出口直径的1.7和1.9倍。

Rock-breaking stress analysis and rock-breaking region under particle-waterjet impact

Due to the complexity of rock breaking by particle-waterjet impact and the transient rock breaking process, there is always a difficulty in studying the rock mechanical properties and failure damage under particle waterjet impact. Considering the influence of particle jet backflow, based on the cavity expansion theory, a mathematical model of rock stress and rock breaking region under the coupling impact of particle waterjet is established. The influence law of particle size and jet velocity on rock stress distribution and rock-breaking region under single particle jet impact is analyzed by mutual verification between numerical analysis and simulation. According to the rock breaking process by multi-particle waterjet under coupling continuous impact, this study proposes the calculation method of rock breaking region. The rock breaking region laws under the condition of vertical jet and rotating jet are obtained through numerical calculation and experimental verification. The results show that the rock-breaking area with rotating jet at a certain angle is larger than that with vertical jet during rock breaking under particle-waterjet coupling impact. The increase of particle diameter has little influence on the rock-breaking area. When the waterjet impact velocity is 200 m/s and the particle size is 1.0 mm, the rock breaking area impacted by 8° and 20° waterjet is 1.7 and 1.9 times greater than the diameter of nozzle outlet respectively.