力热耦合作用下煤岩损伤的能量特征

Energy characteristics of coal or rock damage under thermo-mechanical coupling effect

为有效预防煤岩动力灾害发生,利用含瓦斯煤热-流-固耦合三轴伺服渗流试验装置,开展不同温度下三轴压缩试验。基于统计损伤力学理论,得到温度荷载下煤岩的整体损伤演化方程,推导煤岩变形破坏过程中的能量数学表达式,并通过引入耗散能系数,提出力热耦合下煤岩破坏点的确定方法。研究结果表明:不同温度下煤岩变形破坏过程的阶段特征基本相似,对应煤岩不同的变形破坏阶段,能量演化特征呈现阶段性变化;总能量的分配在变形破坏过程中基本不受温度的影响,不同温度下弹性能占比和耗散能占比的演化规律具有较大的相似性;能量的耗散是造成煤岩内部结构产生损伤的主要原因,伴随着能量不断耗散煤岩的整体损伤变量总体上呈幂函数增长。

In order to prevent coal dynamic disasters effectively,the triaxial compression test at different temperatures was carried out by using the triaxial servo-controlled seepage equipment for thermal-hydromechanical coupling of coal containing methane.Based on the theory of statistical damage mechanics,the overall damage evolution equation of coal under temperature load was put forward,and the mathematical expression of energy in the process of deformation and failure of coal was deducd.The method to determine the failure point of coal under stress and temperature coupling condition was put forward by introducing the dissipation energy coefficientω.The experimental results show that the stage characteristics of deformation and failure process of coal are basically similar at different temperatures,that corresponding to different deformation and failure stages,the energy evolution characteristics of coal show periodic changes,that the distribution of total energy is basically not affected by temperature in the process of deformation and failure,and evolution laws of elastic energy ratio and dissipated energy ratio at different temperatures have a great similarity,and that the energy dissipation is the main cause of the internal structure damage of coal,and the overall damage variable of coal increases in a power function with the constant dissipation of energy.