周期荷载作用下煤的疲劳变形及能量演化特征
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摘要
为研究单向应力状态下周期荷载对煤疲劳破坏特性的影响,利用MTS815.02岩石力学试验系统进行了多级周期荷载试验.试验结果表明:(1)当周期荷载峰值应力低于煤样疲劳强度时,煤样变形具有初始和停滞两个发展阶段,耗散能呈L型演化规律;当周期荷载峰值应力超过煤样疲劳强度时,煤样变形具有初始、等速和加速3个发展阶段,耗散能呈U型演化规律;(2)对于煤样的疲劳破坏,环向变形和体积变形比轴向变形更为敏感;(3)常规单轴压缩试验时,煤样大致呈单斜面剪切破坏,局部伴随拉伸破坏;周期荷载试验时,煤样破坏后产生许多小碎块,偶尔可见较大块体;(4)只有当周期荷载峰值应力高于煤样的疲劳强度时,煤样内部微裂隙才开始大量萌生、扩展、贯通,这一过程将最终导致煤样发生疲劳破坏.
To research the coal' s fatigue failure characteristics under uniaxial state,the multi-level amplitude cyclic loading tests were conducted using MTS815. 02 rock mechanics test system.The results show that:( 1) When the peak stress of cyclic loading is less than the coal's fatigue strength,the coal's deformation exhibits the two phases: namely,primary and stagnation phases,and the dissipated energy curve is L-shaped. However,when the peak stress of cyclic loading exceeds the coal' s fatigue strength,the coal' s deformation exhibits the three phases: namely,primary,steady,and acceleration phases,and the dissipated energy curve is U-shaped;( 2) Compared with the axial deformation,the circumferential and volumetric deformations are more sensitive to coal' s fatigue failure;( 3) Coal sample mainly fails in the mode of a single inclined shear plane and accompanied by tensile failure in conventional uniaxial compression test. However,coal sample is mainly destroyed into many small fragments and sometimes accompanied by few large blocks in cyclic loading test;( 4) Only when the peak stress of cyclic loading exceeds the coal' s fatigue strength,the micro-cracks inside coal begin to massively initiate and propagate,and eventually result in the coal's fatigue failure.
To research the coal' s fatigue failure characteristics under uniaxial state,the multi-level amplitude cyclic loading tests were conducted using MTS815. 02 rock mechanics test system.The results show that:( 1) When the peak stress of cyclic loading is less than the coal's fatigue strength,the coal's deformation exhibits the two phases: namely,primary and stagnation phases,and the dissipated energy curve is L-shaped. However,when the peak stress of cyclic loading exceeds the coal' s fatigue strength,the coal' s deformation exhibits the three phases: namely,primary,steady,and acceleration phases,and the dissipated energy curve is U-shaped;( 2) Compared with the axial deformation,the circumferential and volumetric deformations are more sensitive to coal' s fatigue failure;( 3) Coal sample mainly fails in the mode of a single inclined shear plane and accompanied by tensile failure in conventional uniaxial compression test. However,coal sample is mainly destroyed into many small fragments and sometimes accompanied by few large blocks in cyclic loading test;( 4) Only when the peak stress of cyclic loading exceeds the coal' s fatigue strength,the micro-cracks inside coal begin to massively initiate and propagate,and eventually result in the coal's fatigue failure.
引文
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[17]邹俊鹏,陈卫忠,杨典森,等.循环荷载条件下原煤力学性质及损伤演化规律[J].煤炭学报,2016,41(7):1675-1682Zou Junpeng,Chen Weizhong,Yang Diansen,et al.Mechanical properties and damage evolution of coal under cyclic loading conditions[J].Journal of China Coal Society,2016,41(7):1675-1682
[18]杨永杰,王德超,李博,等.煤岩三轴压缩损伤破坏声发射特征[J].应用基础与工程科学学报,2015,23(1):127-135Yang Yongjie,Wang Dechao,Li Bo,et al.Acoustic emission characteristics of coal damage failure under triaxial compression[J].Journal of Basic Science and Engineering,2015,23(1):127-135
[19]马德鹏.岩石三轴卸围压破坏机理及前兆特征基础实验研究[D].青岛:山东科技大学,2016Ma Depeng.Basic experiment research of failure mechanism and precursory characteristics of rock under triaxial unloading confining pressure[D].Qingdao:Shandong University of Science and Technology,2016
[20]Lazan B J.Damping of material and members in structural mechanics[M].London:Pergamon Press,1968:41-46
[21]Xiao J Q,Ding D X,Jiang F L,et al.Fatigue damage variable and evolution of rock subjected to cyclic loading[J].International Journal of Rock Mechanics and Mining Sciences,2010,47(3):461-468
[22]张媛.循环荷载条件下岩石变形损伤及能量演化的实验研究[D].重庆:重庆大学,2011Zhang Yuan.Experimental research on characteristics of deformation and dissipated energy of rock under cyclic loading conditions[D].Chongqing:Chongqing University,2011
[2]章清叙,葛修润,黄铭,等.周期荷载作用下红砂岩三轴疲劳变形特性试验研究[J].岩石力学与工程学报,2006,25(3):473-478Zhang Qingxu,Ge Xiurun,Huang Ming,et al.Testing study on fatigue deformation law of red-sandstone under triaxial compression with cyclic loading[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(3):473-478
[3]卢高明,李元辉,张希巍,等.周期荷载作用下黄砂岩疲劳破坏变形特性试验研究[J].岩土工程学报,2015,37(10):1886-1892Lu Gaoming,Li Yuanhui,Zhamg Xiwei,et al.Fatigue deformation characteristics of yellow sandstone under cyclic loading[J].Chinese Journal of Geotechnical Engineering,2015,37(10):1886-1892
[4]卢高明,李元辉.围压对黄砂岩疲劳破坏变形特性的影响[J].岩土力学,2016,37(7):1847-1856Lu Gaoming,Li Yuanhui.Influence of confining pressure on fatigue deformation properties of yellow sandstone[J].Rock and Soil Mechanics,2016,37(7):1847-1856
[5]Bagde M N,Petro2 V.Fatigue properties of intact sandstone samples subjected to dynamic uniaxial cyclical loading[J].International Journal of Rock Mechanics and Mining Sciences,2005,42(2):237-250
[6]Bagde M N,Petro2 V.Fatigue and dynamic energy behavior of rocksubjected to cyclical loading[J].International Journal of Rock Mechanics and Mining Sciences,2009,46(1):200-209
[7]Araei A A,Razeghi H R,Ghalandarzadeh A,et al.Effects of loadingrate and initial stress state on stress-strain behavior of rock fill materials under monotonic and cyclic loading conditions[J].Scientia Iranica,2012,9(15):1220-1235
[8]冯春林,吴献强,丁德馨,等.周期荷载作用下白砂岩的疲劳特性研究[J].岩石力学与工程学报,2009,28(增1):2749-2754Feng Chunlin,Wu Xianqiang,Ding Dexin,et al.Investigation on fatigue characteristics of white sandstone under cyclic loading[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(S1):2749-2754
[9]Jiang D Y,Fan J Y,Chen J,et al.A mechanism of fatigue in salt under discontinuous cycle loading[J].International Journal of Rock Mechanics and Mining Sciences,2016,86:255-260
[10]何明明,陈蕴生,李宁,等.单轴循环荷载作用下砂岩变形特性与能量特征[J].煤炭学报,2015,40(8):1805-1812He Mingming,Chen Yunsheng,Li Ning,et al.Deformation and energy characteristics of sandstone subjected to uniaxial cyclic loading[J].Journal of China Coal Society,2015,40(8):1805-1812
[11]王学滨,杜亚志,潘一山,等.弹性-脆性-损伤模型及其在岩石局部破坏研究中的应用[J].应用基础与工程科学学报,2012,20(4):642-653Wang Xuebin,Du Yazhi,Pan Yishan,et al.An elastic and brittle model with damage and application in study on rock localized failures[J].Journal of Basic Science and Engineering,2012,20(4):642-653
[12]赵凯.岩溶地区石灰岩疲劳特性试验研究及工程应用[D].北京:北京交通大学,2013Zhao Kai.Experimental study on fatigue characteristics of karst areas limestone and engineering application[D].Beijing:Beijing Jiaotong University,2013
[13]杨永杰,宋杨,楚俊.循环荷载作用下煤岩强度及变形特征试验研究[J].岩石力学与工程学报,2007,26(1):201-205Yang Yongjie,Song Yang,Chu Jun.Experimental study on characteristics of strength and deformation of coal under cyclic loading[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(1):201-205
[14]潘一山,杜广林,张永利,等.煤体振动方法防治冲击地压的机理研究[J].岩石力学与工程学报,1999,18(4):432-436Pan Yishan,Du Guanglin,Zhang Yongli,et al.On the mechanism of rockburst prevention by coal mass vibration[J].Chinese Journal of Rock Mechanics and Engineering,1999,18(4):432-436
[15]潘一山,杜广林,张永利,等.煤体振动后力学性质变化规律的试验研究[J].岩土工程学报,1998,20(5):41-43Pan Yishan,Du Guanglin,Zhang Yongli,et al.An experimental study on the mechanical properties of coal mass after vibrating[J].Chinese Journal of Geotechnical Engineering,1998,20(5):41-43
[16]任伟杰,杜广林,潘一山.振动对煤体裂隙分布和力学性能的影响[J].阜新矿业学院学报(自然科学版),1997,16(6):687-690Ren Weijie,Du Guanglin,Pan Yishan.The experimental study of rockburst prevention through vibration inducing crevasse in coalmass[J].Journal of Fuxin Mining Institute(Natural Science),1997,16(6):687-690
[17]邹俊鹏,陈卫忠,杨典森,等.循环荷载条件下原煤力学性质及损伤演化规律[J].煤炭学报,2016,41(7):1675-1682Zou Junpeng,Chen Weizhong,Yang Diansen,et al.Mechanical properties and damage evolution of coal under cyclic loading conditions[J].Journal of China Coal Society,2016,41(7):1675-1682
[18]杨永杰,王德超,李博,等.煤岩三轴压缩损伤破坏声发射特征[J].应用基础与工程科学学报,2015,23(1):127-135Yang Yongjie,Wang Dechao,Li Bo,et al.Acoustic emission characteristics of coal damage failure under triaxial compression[J].Journal of Basic Science and Engineering,2015,23(1):127-135
[19]马德鹏.岩石三轴卸围压破坏机理及前兆特征基础实验研究[D].青岛:山东科技大学,2016Ma Depeng.Basic experiment research of failure mechanism and precursory characteristics of rock under triaxial unloading confining pressure[D].Qingdao:Shandong University of Science and Technology,2016
[20]Lazan B J.Damping of material and members in structural mechanics[M].London:Pergamon Press,1968:41-46
[21]Xiao J Q,Ding D X,Jiang F L,et al.Fatigue damage variable and evolution of rock subjected to cyclic loading[J].International Journal of Rock Mechanics and Mining Sciences,2010,47(3):461-468
[22]张媛.循环荷载条件下岩石变形损伤及能量演化的实验研究[D].重庆:重庆大学,2011Zhang Yuan.Experimental research on characteristics of deformation and dissipated energy of rock under cyclic loading conditions[D].Chongqing:Chongqing University,2011