• 论文
主办单位:煤炭科学研究总院有限公司、中国煤炭学会学术期刊工作委员会
准静态应变率下的煤岩非线性力学特性
  • Title

    Nonlinear mechanical properties of coal rock under quasi-static strain rate

  • 作者

    刘晓辉郝齐钧吴世勇张茹余洁

  • Author

    LIU Xiaohui1,2 ,HAO Qijun2 ,WU Shiyong3 ,ZHANG Ru4,5 ,YU Jie2

  • 单位

    西华大学 流体与动力机械教育部重点实验室西华大学 能源与动力工程学院雅砻江流域水电开发有限公司四川大学 水利水电学院四川大学深地科学与工程教育部重点实验室

  • Organization
    1. Key Laboratory of Fluid and Power Machinery,Ministry of Education,Xihua University,Chengdu  610039,China; 2. School of Energy and Power Engi- neering,Xihua University,Chengdu  610039,China; 3. Yalong River Hydropower Development Company,Ltd. ,Chengdu  610051,China; 4. Sichuan College of Water Resources and Hydropower,Chengdu  610065,China; 5. MOE Key Laboratory of Deep Earth Science and Engineering,Sichuan University,Chengdu 610065,China
  • 摘要

    为研究开挖扰动下煤岩的非线性力学特征,利用MTS815伺服刚性试验机对芙蓉白皎煤矿煤岩进行10-5~10-2 s-1准静态应变率下的单轴压缩试验,分析准静态应变率下煤岩的应力-应变曲线、抗压强度、弹性模量、泊松比等力学特性的变化规律,基于煤岩显著的非线性力学特征,修正并验证黏弹性损伤本构模型的合理性。研究表明:① 煤岩单轴压缩荷载作用下具有明显的压密、线弹性、塑性屈服、峰后破坏4个阶段;煤岩力学特性应变率相关性突出,随着应变率的增加,压密阶段缩短,线弹性阶段增长,屈服阶段应力强化特征及峰后破坏阶段应力软化特征趋于明显。② 由于原生裂隙的闭合和扩展,煤岩受载作用下,各阶段均呈现显著的非线性力学特征,随着应变率的增加,压密阶段和线弹性阶段表现出的明显非线性特征呈减弱趋势。③ 准静态应变率10-5 s-1~10-2 s-1范围内,抗压强度随应变率增加由8.83 MPa增加至12.57 MPa,增长率42.35%;弹性模量随应变率增加总体呈现先增加后减小的变化趋势,在10-5~10-4 s-1应变率区间,弹性模量由1 644 MPa增加至1 825 MPa,随后在10-4~10-2 s-1应变率区间内减小,变化趋势发生明显转折;泊松比在准静态应变率下随应变率增加而呈现逐渐减小的变化趋势,从1.53下降到0.71,减小53.59%;整个准静态应变率范畴下,煤岩的力学特征参数(抗压强度、弹性模量、泊松比)均表现出显著的非线性变化趋势,均在临界应变率10-3 s-1附近发生转折。④ 利用一个损伤体和一个Maxwell模型并联方式,综合考虑准静态应变率下煤岩的非线性变化特征后,引入材料常数a对胡克定律进行修正,推导得出准静态应变率下煤岩的非线性损伤演化本构方程,并结合煤岩单轴压缩试验对其合理性进行验证。

  • Abstract
    In order to study the nonlinear mechanical characteristics of coal rock under excavation disturbance,the uniaxial compression test of quasi-static strain rate of 10-5 -10-2 s-1 was carried out by MTS815 servo rigidity testing ma- chine on the coal rock of Fu Rong,Bai Jiao Coal Mine,China. The variation of mechanical properties such as stress- strain curve,compressive strength,elastic modulus and Poisson’s ratio of coal rock under quasi-static strain rate were analyzed. Based on the significant nonlinear mechanical characteristics of coal rock,the viscoelastic damage constitu- tive model was modified and verified. The research shows that ① Under uniaxial compression loading,the coal rock has four stages,such as compaction,linear elasticity,plastic yield and post-peak damage. The strain rate correlation of coal rock mechanical properties is outstanding. With the increase of strain rate,the compaction phase is shortened,the linear elastic phase is increased,and the stress strengthening characteristics in the yielding stage and the stress soften- ing characteristics in the post-peak failure stage tend to be obvious. ② Due to the closure and expansion of the primary fissures,each stage of the loading coal rock presents remarkable nonlinear mechanical characteristics. With the in- crease of strain rate,the obvious nonlinear characteristics of the compaction stage and the linear elastic stage show a weakening trend. ③ In the range of quasi-static strain rate 10-5 -10-2 s-1 ,the compressive strength increases with the strain rate from 8. 83 MPa to 12. 57 MPa,the growth rate is 42. 35% . The modulus of elasticity generally increases first and then decreases with the increase of strain rate. In the range of 10-5 -10-4 s-1 strain rate,the elastic modulus increases from 1 644 MPa to 1 825 MPa,followed by 10-4 -10-2 s-1 is reduced within the strain rate interval,and the trend of change is obviously turning. The Poisson’s ratio shows a decreasing trend with the increase of strain rate un- der the quasi-static strain rate,which decreases from 1. 53 to 0. 71,and decreases value by 53. 59% . The mechanical characteristics parameters (compressive strength,elastic modulus,Poisson’s ratio) of coal rock under the whole quasi- static strain rate category all shows significant nonlinear changes,and all of them turn around the critical strain rate of 10-3 s-1 . ④ Using a damage body and a Maxwell model in parallel,considering the nonlinear variation characteristics of coal rock under quasi-static strain rate,the material constant a is used to modify the Hooke’s law,and the constitu- tive equation of nonlinear damage evolution of coal rock under quasi-static strain rate is derived. The constitutive equa- tion’ rationality is verified with the combination of the uniaxial compression test of coal rock.
  • 关键词

    煤岩准静态应变率力学特征非线性本构方程

  • KeyWords

    coal rock;quasi-static strain rate;mechanical properties;nonlinear;constitutive equation

  • 基金项目(Foundation)
    国家重点研发计划资助项目(2016YFC0600702);四川省教育厅重点科研基金资助项目(18ZA0457);四川大学水力学与山区河流开发保护国家重点实验室开放基金资助项目(SKHL1718)
  • DOI
  • Citation
    LIU Xiaohui,HAO Qijun,WU Shiyong,et al. Nonlinear mechanical properties of coal rock under quasi-static strain rate [J]. Journal of China Coal Society,2019,44(5):1437-1445.
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主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会

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