摘要
以Johnson-Holmquist modelⅡ(JH-2)脆性材料本构模型来表征岩石的力学特性,利用光滑粒子流(SPH)和有限元(FEA)耦合算法建立高压水射流冲击破岩过程的数值模型,很好地模拟水射流损伤破岩过程中岩石失效、裂纹扩展以及不同位置岩石单元的损伤程度随时间变化的过程。此外,模拟分析射流冲击速度、入射角以及平移速度对岩石损伤场的影响。研究结果表明:岩石的损伤破坏、裂纹扩展是剪切和拉伸共同作用引起的,且近射流冲击点的损伤破坏由剪切作用主导,而放射性裂纹和层状裂纹的扩展主要由拉伸作用主导;岩石单元的损伤值随时间呈阶跃性变化,且射流冲击损伤破岩过程为微秒量级;射流冲击损伤破岩的入射角存在一个有效范围,当入射角大于70o时损伤破岩效果较好;射流冲击速度较低时以表面冲蚀岩石为主,射流冲击速度达到一定值才能使岩石损伤破坏,出现放射性裂纹和层状裂纹;射流平移速度与冲击速度相比很小,对岩石的损伤场影响不明显。
A constitutive model, Johnson-Holmquist model II （JH-2） for brittle material was adopted to characterize the mechanical properties of rock. And the numerical model of rock breaking with high-pressure water jet impacting was established with coupling Smoothed Particle Hydrodynamics （SPH） method and finite element analysis （FEA） method. It well simulated the rock failure, cracks propagation and the variations of rock element damage in different positions. Moreover, the effects of impact velocity, incidence angle and translation velocity of water jet on rock damage field were investigated. The results show that rock damage, failure and cracks propagation are caused by shear and tensile action combinations. The damage and failure zone of rock near the jet impacting point is mainly due to shear action; however, the radial and spall cracks propagation are dominated by tensile action. The damage of rock element represents a step changing with time, and the response of rock damage and failure process under water jet impacting is within microseconds. The incidence angle of water jet impacting rock has an effective range, and better damage effect can be obtained when the incidence angle is more than 70~. The surface erosion of rock is primary with low impact velocity of water jet, actual damage and failure of rock as radial and spall cracks occurrence can be achieved only when impact velocity of water jet reaches a certain value. The effect of water jet translation velocity on rock damage field is not remarkable because the translation velocity of water jet is much smaller than its impact velocity.
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2015年第1期287-294,共8页
Journal of Central South University:Science and Technology
基金
国家高科技研究发展计划(863计划)项目(2012AA062104)
国家自然科学基金面上资助项目(51375478)
江苏高校优势学科建设工程资助项目(SZBF2011-6-B35)~~
