考虑吸附作用的各向异性煤体有效应力

Effective Stress of Anisotropic Coal Considering Adsorption

基于Carroll的各向异性孔隙介质有效应力公式,引入吸附气体相的影响,推导了考虑界面吸附作用的各向异性介质有效应力表达式;根据界面热力学的基本理论,在考察固相、气相、界面吸附相及系统能量方程基础上,分析了固相应力与孔隙压力及表面势的关系,推导了吸附作用影响下固相体积压缩系数的表达式;依据羊渠河矿煤样的试验数据,计算了不同气体压力条件下的固相体积压缩系数,计算结果表明:吸附作用使得固相压缩变形和煤体有效应力减小,在孔隙压力较低时吸附作用效应更加显著.

The effective stress of coal at pore pressure is one of critical problems on the governing equations coupled gas flow and coal deformation.Based on Carroll＇s effective stress law for anisotropic porous media,the effective stress of anisotropic coal considering adsorption is developed by introducing the effect of adsorbed phase.According to the fundamental theory of interface thermodynamics,the energy equations of solid phase,gas phase,adsorbed phase and system are investigated.Therefore the relation equation among pore pressure,surface potential and system internal energy and the volume compressibility of solid phase influenced by adsorption are derived.The volume compressibility of solid phase under different gas pressures is calculated by using the experimental data of the coal sample from Yangquhe Coal Mine.The numerical results show that the compression deformation of solid phase and effective stress decreases due to adsorption,and the effect of adsorption is more significant at low pore pressure.