摘要
为全面揭示煤岩长历时蠕变破坏机制,开展了长历时煤岩单轴压缩分级蠕变声发射试验,分析了不同应力水平下煤岩蠕变变形和声发射规律,在此基础上,把临界幂律灾变函数引入理想黏弹塑性体,并与Burgers体串联,建立煤岩灾变蠕变模型。结果表明:煤岩单轴蠕变经历减速、稳定和加速蠕变3个阶段,声发射参数的变化规律能很好地反映煤岩蠕变3个阶段的变形特征;减速蠕变阶段内声发射事件较活跃,稳定蠕变阶段内低应力水平下声发射活动比中应力水平多,当从稳定蠕变阶段到加速蠕变阶段时,煤岩突然宏观脆性破坏,应变发生突变,声发射突然增大,呈现灾变破坏特征;高应力水平下的减速和稳定蠕变阶段煤岩内部裂隙充分且均匀发育,最终导致煤岩发生粉碎性的灾变破坏,这一破坏特征不同于单轴压缩破坏的剪切破坏;煤岩灾变蠕变模型能全面体现煤岩减速、稳定和加速蠕变阶段,已有几种非线性蠕变模型预测高应力水平蠕变试验结果相关系数最大为0.74,而灾变蠕变模型预测的相关系数大于0.97。岩石蠕变试验数据拟合结果表明灾变模型能够很好地描述各类岩石蠕变过程,临界幂律指数β对灾变破坏起控制作用,随着β的不断增大,岩石蠕变也从渐进式破坏转变为灾变破坏,从而验证了此煤岩灾变蠕变模型的正确性和适用性。
In order to comprehensively reveal the long-term creep failure mechanism of coal rock,the long-term uniaxial compression graded creep acoustic emission test of coal rock was carried out,and the creep deformation and acoustic emission laws of coal rock under different stress levels were analyzed.On this basis,the critical power-law catastrophe function was introduced into the ideal viscoelastic-plastic body which was connected in series with the Burgers body to establish the coal rock catastrophic creep model.The research results show that the uniaxial creep of coal rock goes through three stages:deceleration,stability and acceleration creep,and the variation of acoustic emission parameters under different stress levels can well reflect the three stage deformation characteristics of coal rock creep.In the deceleration creep stage,the acoustic emission events are more active.In the stable creep stage,the acoustic emission activity at low stress level is more than that at medium stress level.When transitioning from the stable creep stage to the accelerated creep stage,the coal rock suddenly undergoes macroscopic brittle failure,the strain changes abruptly,and the acoustic emission suddenly increases,presenting the characteristics of catastrophic failure.During the deceleration and stable creep stages under high stress levels,the internal cracks of the coal rock are fully and uniformly developed,leading to the ultimate crushing catastrophic failure of the coal rock,which is different from the shear failure of uniaxial compression failure.The established coal rock catastrophic creep model can fully reflect the deceleration,stability and acceleration creep stages of coal rock.Several nonlinear creep models have predicted the maximum correlation coefficient of high stress level creep test results to be 0.74,while the correlation coefficient predicted by the catastrophic creep model is greater than 0.97.The fitting results of rock creep test data show that the catastrophic model can well describe the creep process of all kinds of rocks,and the critical power-law indexβplays a controlling role in the catastrophic failure.With the increasing ofβ,the rock creep also changes from progressive failure to catastrophic failure,thus verifying the correctness and applicability of the coal rock catastrophic creep model.
作者
许刚刚
谷拴成
王晓东
冯龙飞
刘小宇
XU Ganggang;GU Shuancheng;WANG Xiaodong;FENG Longfei;LIU Xiaoyu(College of Architecture and Civil Engineering,Xi’an University of Science and Technology,Xi’an 710054,China;CCTEG Xi’an Research Institute(Group)Co.,Ltd.,Xi’an 710077,China;College of Sciences,Xi’an University of Science and Technology,Xi’an 710054,China)
出处
《西安科技大学学报》
CAS
北大核心
2024年第2期366-378,共13页
Journal of Xi’an University of Science and Technology
基金
国家自然科学基金项目(52004326)
中煤科工西安研究院(集团)有限公司科技创新项目(2019XAYZD05,2020XAYJS02)。
关键词
煤岩
蠕变试验
声发射
加速蠕变
灾变
非线性
coal rock
creep test
acoustic emission
accelerated creep
catastrophe
nonlinear
作者简介
第一作者:许刚刚,男,河南平顶山人,副研究员,E-mail:xugg111@163.com;通信作者:谷拴成,男,陕西扶风人,教授,博士生导师,E-mail:gushuanchengxakj@163.com。
