摘要
为探究矸石集料的承载特性与破裂演化规律,采用液压伺服岩石力学试验系统与破碎矸石压实装置,开展了不同矸石粒径(0~5,5~10,10~15,15~20,20~25,25~30 mm)、轴向应力(2.5,5.0,7.5,10.0 MPa)、加载速率(0.05,0.10,0.50,1.00 mm/s)影响下破碎矸石集料压实试验,研究各因素对矸石集料压缩变形与分形特征的影响;基于PFC^(3D)数值软件建立考虑矸石形状与粒径分布的颗粒流模型,探讨了矸石集料承载过程中能量耗散、力链演化等规律,揭示颗粒形状与粒径级配对矸石集料压实力学特性的影响机制。试验结果表明:矸石集料压缩变形分为孔隙压密、结构调整和弹塑性变形3个阶段,随着轴向应力逐渐增大,矸石集料的大颗粒骨架破坏、中等颗粒滑动移位、小颗粒填充孔隙,颗粒间的接触方式由锐角接触转变为钝角或球面接触;不同加载速率下,矸石集料轴向应力与应变呈幂函数分布,轴向应力和加载速率与破碎矸石分形维数呈对数函数关系;相同载荷下大粒径矸石易发生挤压破碎,矸石颗粒克服变形消耗摩擦能,有利于强化整体的摩擦效应;矸石集料的力链长度随载荷的增大逐渐增长,覆盖范围逐渐增大,高应力范围自上而下逐渐扩展,随外载荷的增大,矸石颗粒网状结构断裂失效,岩块发生滑动、移位、重组,小粒径矸石颗粒具有弱化断裂失效的作用。
In order to explore the bearing characteristics and fracture evolution law of gangue aggregate,a hydraulic servo rock mechanics test system and a broken gangue compaction device are used to conduct a compaction test of crushed gangue aggregate.The test is under the conditions of different gangue particle sizes(0-5,5-10,10-15,15-20,20-25 and 25-30 mm),different axial stresses(2.5,5.0,7.5 and 10.0 MPa)and different loading rates(0.05,0.10,0.50 and 1.00 mm/s).Also,the effect of various factors on the compression deformation and fractal characteristics of gangue aggregate is studied.A particle flow model considering gangue shape and particle size distribution is established using the PFC^(3D) numerical software,the laws of energy dissipation and force chain evolution in the bearing process of gangue aggregate are discussed,and the effect mechanism on the compaction mechanical properties of gangue aggregate by the particle shape and particle size gradation are revealed.The test results show that the compression deformation of gangue aggregate can be divided into three stages:pore compaction,structural adjustment and elastic-plastic deformation.With the gradual increase of axial stress,the skeleton of large particles of gangue aggregate is destroyed,the sliding displacement of medium particles and small particles fill the pores.The contact mode between particles changes from acute angle contact to obtuse angle or spherical contact.Under different loading rates,the axial stress and strain of gangue aggregate shows a power function distribution,and the axial stress and loading rate demonstrate a logarithmic function relationship with the fractal dimension of broken gangue.Under the same load,large-size gangue is easy to crush.Gangue particles overcome deformation and consume friction energy,which is conducive to strengthening the overall friction effect.The length of force chain of gangue aggregate gradually increases with the increase of load,the coverage gradually increases,and the high stress range gradually expands from top to bottom.With the increase of external load,the mesh structure of gangue particles breaks and fails,and the rock blocks slide,shift and reorganize.Small particle size gangue particles can weaken the fracture failure.
作者
杨科
魏祯
何祥
周光华
陈登红
张继强
YANG Ke;WEI Zhen;HE Xiang;ZHOU Guanghua;CHEN Denghong;ZHANG Jiqiang(State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mine,Anhui University of Science and Technology,Huainan 232001,China;Institute of Energy,Hefei Comprehensive National Science Center,Hefei 230031,China;Ningxia Coal Company,China Energy Investment Group Co.,Ltd.,Yinchuan 751410,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2022年第3期1087-1097,共11页
Journal of China Coal Society
基金
国家重点研发计划资助项目(2019YFC1904304)
国家自然科学基金重点资助项目(52130402)
合肥综合性国家科学中心能源研究院资助项目(21KZS217)。
关键词
矸石集料
力学特性
粒径级配
分形维数
细观结构演化
gangue aggregate
particle size grading
fractal dimension
mechanical properties
mesostructure evolution
