粒子浆液射流冲击下岩石动态损伤及破坏效应

Dynamical response and failure effect of rock with particle slurry jet impact

粒子浆液射流破岩过程涉及大变形、高应变及强载荷,表现为钢粒-浆液-岩石之间非线性动态耦合问题。针对岩石损伤瞬时多变性及观测困难等问题,开展了粒子与浆液射流冲击下岩石的动态损伤机理及破坏效应研究。首先,基于光滑粒子动力学-有限元模拟(smoothed particle hydrodynamics-finite element method,SPH-FEM)耦合算法描述了粒子-浆液冲击破岩的建模方法;然后,结合JH-Ⅱ(Johnson-Holmquist-Ⅱ)模型与Rankine拉伸断裂软化模型建立了岩石损伤本构模型,对粒子浆液射流冲击破岩过程及损伤机理进行了动态模拟。研究结果表明:岩石的损伤破坏主要以纵向扩展为主,具有瞬时性与阶跃性特征,呈现出“从累积损伤到不断破坏”的循环过程;岩石破坏机理以剪切破碎和拉伸裂纹为主。同时,通过试验和数值模拟对比验证了破岩样本的形态,并分析了冲击速度、角度与粒子尺寸对破岩效应的影响规律。研究结果对于粒子浆液冲击钻井破岩理论的发展具有重要意义。

Particle slurry jet impact rock-breaking process involves large deformation,high strain and strong loads,which is characterized by the complex-nonlinear-dynamic-coupled problem among steel particles,slurry,and rock.Aiming at the problems of instantaneity and difficult observation of rock-breaking process,damage mechanism and failure effect of rock with particle slurry jet impact were studied.Based on the smoothed particle hydrodynamics-finite element method(SPH-FEM)coupled algorithm,a modeling method of particle slurry impact rock was described.Afterwards,a rock damage constitutive model was established by combining the Johnson-Holmquist-Ⅱ(JH-Ⅱ)model and the Rankine tensile fracture soft model,and dynamical simulation of particle slurry jet impact rock-breaking process was carried out.The results show that the damage of rock is mainly longitudinal propagation,with instantaneity and step property,which is a cycle process of“from damage accumulation to continuous fracture”;and the rock failure mechanism is mainly characterized by tensile crack,and shear powder.Meanwhile,the morphology of rock-breaking samples was compared and verified by experiments and numerical simulation,and influence laws of impact velocity,angle and particle size on rock-breaking effect were analyzed.This research has great significance for the development of particle slurry jet impact rock-breaking theory.