摘要
含水率对煤体力学特性具有重要影响,为深入探讨三轴加载条件下含水率在煤体力学中的作用机制,选择平顶山矿区代表性煤样并设置不同含水率水平的试验组,开展了不同含水煤样的单轴压缩试验和不同围压条件下的含水煤样三轴压缩试验,并对不同含水煤样进行应力-应变关系、抗压强度等方面的综合性能测试。结果表明:不同围压条件下,含水煤体的应力-应变曲线呈现相同趋势。三轴加载条件下,含水煤体轴向方向的应力-应变曲线与单轴加载时的煤体轴向方向的应力-应变曲线形式相同。相同含水率条件下,不同围压的试验煤样出现应力峰值时的轴向应变略有不同,整体呈现围压越大,其出现应力峰值对应的轴向应变越小。整个加载过程中,试验煤样轴向应变始终为正值,即煤体轴向方向发生轴向压缩变形,与此同时,试验煤样径向产生膨胀变形。单轴/三轴加载条件下,随着含水率增加,峰值强度整体呈降低,含水率与峰值强度呈一元二次函数关系。随着围压增加,峰值强度整体呈下降趋势。随着含水率增加,岩石软化系数整体呈现降低趋势。含水率与软化系数呈一元二次函数关系。研究结果为平顶山矿区煤炭资源的合理开发和利用提供了科学依据。
Water content has an important influence on the mechanical properties of coal.To further explore the mechanism of water content under triaxial loading conditions,representative coal samples in Pingdingshan mining area were selected and experimental groups with different water contents were set up.Uniaxial compression tests of coal samples with different water contents and triaxial compression tests of coal samples with different confining pressures were carried out,and comprehensive performance tests of stress-strain relationship and compressive strength of coal samples with different water contents were carried out.The results show that under different confining pressure conditions,the stress-strain curve of water-bearing coal shows the same trend.Under triaxial loading,the stress-strain curve in the axial direction of water-bearing coal body is the same as that under uniaxial loading.In the condition of same water content,the axial strain of the test coal samples with different confining pressures is slightly different at the stress peak.Generally,the larger the confining pressure has,the smaller the axial strain is at the stress peak.During the whole loading process,the axial strain of the test coal sample is always positive,that is,the axial compression deformation of the coal body occurs in the axial direction,and at the same time,the radial expansion deformation of the test coal sample occurs.In uniaxial/triaxial loading conditions,with the increase of water contents,the peak strength typically decreases,and water content and peak strength are connected in a quadratic function.The research result provides a scientific basis for coal resource development and utilization in Pingdingshan mine area.
作者
孙矩正
焦继红
寇建新
SUN Juzheng;JIAO Jihong;KOU Jianxin(Pingdingshan Tian’an Coal Industry Co.,Ltd.,Pingdingshan 467000,China)
出处
《煤炭工程》
北大核心
2024年第9期152-158,共7页
Coal Engineering
关键词
三轴加载
含水率
力学特征
峰值强度
软化系数
triaxial loading
water content
mechanical characteristics
peak strength
softening coefficient
