煤岩突出中单个煤壳失稳前兆阶段的能量分析
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摘要
在不计突出前兆阶段煤壳动能的条件下,建立了地应力、瓦斯压力与渗流耦合作用下孔隙介质球对称力平衡方程;根据球对称性质使弹性与塑性阶段应变Lode参数相同,满足单一曲线的物理关系条件,将单轴本构模型推广,得到煤壳中应力强度σi与应变强度εi之间的物理关系式;求得煤壳弹、塑性区径向位移u的表达式,并发现其可分解为相应偏应变的位移ud与平均应变的位移um。综合运用几何方程、力平衡方程、几何方程和应力强度与平均应力的关系,对突出前煤壳进行的能量分析表明:煤壳位移、形变时的外力功变化可分解为相应偏应力、平均应力和渗流力的外力功δWd,δWv,δWs,它们分别与煤壳偏应力应变能、体积应变能和孔隙体积能的变化的δU d,δU v,δU s相对应,得到三个功、能增量关系的研究结果。为建立单个煤壳失稳的突变模型,对地应力、瓦斯压力与煤介质三因素在煤壳解体、瓦斯膨胀内能释放及高压瓦斯流对碎煤喷射的突出过程进行研究提供了基础。
On the condition that the kinetic energy of coal shell in premonitory phase of its outburst is ignored;the equilibrium equation of spherical symmetric force of pore medium is established,which is under the coupling action of ground stages,gas pressure and effluent seepage.The character of spherical symmetry makes the strain Lode parameter at elastic and plastic stages is the same,and meet the condition of the physical relation of single curve.Popularized the uniaxial constitutive model,it can be educed that the relational expression between stress intensityσ i and strain intensity εi of coal shell.It is discovered that,the educed expression of radial displacement u in elastic and plastic zones of coal shell,can be broken down into the displacement ud corresponding to deviatoric strain and the displacement um corresponding to average strain.The energy analysis,which is carried through by using geometry equation,force equilibrium equation,physical equation and the relation of stress intensity and average stress synthetically,shows that the external force work change can be broken down into the external force workδ Wd,δ Wv and δWs corresponding to deviatoric stress,mean stress and seepage stress;they are respectively corresponding to changes of strain energy of deviatoric stress,volumetric strain energy and pore volume energy;i.e.δU v,δ Ud.and δU s The findings of two work-energy increment equilibrium relationship can be educed.It builds up the foundation for engaging catastrophe theory analysis of disintegration and outburst of a single coal shell in the outburst process.
On the condition that the kinetic energy of coal shell in premonitory phase of its outburst is ignored;the equilibrium equation of spherical symmetric force of pore medium is established,which is under the coupling action of ground stages,gas pressure and effluent seepage.The character of spherical symmetry makes the strain Lode parameter at elastic and plastic stages is the same,and meet the condition of the physical relation of single curve.Popularized the uniaxial constitutive model,it can be educed that the relational expression between stress intensityσ i and strain intensity εi of coal shell.It is discovered that,the educed expression of radial displacement u in elastic and plastic zones of coal shell,can be broken down into the displacement ud corresponding to deviatoric strain and the displacement um corresponding to average strain.The energy analysis,which is carried through by using geometry equation,force equilibrium equation,physical equation and the relation of stress intensity and average stress synthetically,shows that the external force work change can be broken down into the external force workδ Wd,δ Wv and δWs corresponding to deviatoric stress,mean stress and seepage stress;they are respectively corresponding to changes of strain energy of deviatoric stress,volumetric strain energy and pore volume energy;i.e.δU v,δ Ud.and δU s The findings of two work-energy increment equilibrium relationship can be educed.It builds up the foundation for engaging catastrophe theory analysis of disintegration and outburst of a single coal shell in the outburst process.
引文
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[2]潘岳.地压动力现象研究的突变理论方法[J].有色金属,1991,43(2):1-8.PAN Yue.Catastrophe theory method for research dynamic phenomena of rock[J].Nonferrous Metals,1991,43(2):1-8.
[3]蒋承林.煤与瓦斯突出阵面的推进过程及力学条件分析[J].中国矿业大学学报,1994,23(4):1-9.JIANG Cheng-lin.Analyses on the developing and mechanical conditions of coal gas outburst front[J].Journal of China University of Mining&Technology,1994,23(4):1-9.
[4]蒋承林.煤壁突出孔洞的形成机理研究[J].岩石力学与工程学报,2000,19(2):225-228.JIANG Cheng-lin,Study of forming mechanism of outburst hole[J].Chinese Journal of Rock Mechanics and Engineering,2000,19(2):225-228.
[5]蒋承林.煤与瓦斯突出过程能量耗散规律的研究[J].煤炭学报,1996,21(2):173-178.JIANG Cheng-lin.Rules of energy dissipation in coal and gas outburst[J].Journal of Coal Society,1996,21(2):173-178.
[6]梁冰,煤与瓦斯突出固流藕合失稳理论[M].北京:地质出版社,2000.
[7]贾乃文.黏塑性力学及工程应用[M].北京:地震出版社,2000:51-52.
[8]JEGER J C,COOK G W.Fundamentals of Rock Mechanics[M].London:Chapman and Hall Press,1979.
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