基于近场动力学的煤体单轴压缩全过程损伤演化规律研究*

为了研究煤体受压变形破坏情况，采用近场动力学理论、室内单轴压缩实验及数值模拟相结合的方式，演绎推导PD损伤本构力函数，分别在宏、微观2个方面对煤体损伤规律进行研究。研究结果表明:以近场动力学所推导的本构力函数对于复杂裂隙演化过程的研究具有独特优势，煤体受到外荷载作用后内部微结构会产生不同程度的损伤，损伤过程可分为:压密阶段、微裂纹的萌生扩展阶段、断裂破坏阶段；压密阶段后均伴随键的断裂，至破坏阶段时，键几乎完全断裂，导致煤样宏观失稳破坏；模拟模型在受到外载荷作用下，内部能量开始聚集，随着压力的增大，内部能量散开，最终呈“X”型分布，这与实验加载后煤样的损伤效果基本一致，以此来反演煤体内部微结构变化从而得到煤体损伤规律切实可行。

Research on damage evolution law of coal and rock in whole process of uniaxial compression based on peridynamics

In order to study the deformation and failure of coal mass under compression,a combination method of peridynamics (PD) theory,indoor uniaxial compression experiment and numerical simulation was used to deduce the PD damage constitutive force function,and the coal damage law was studied from the macroscopic and microscopic aspects.The results showed that the constitutive force function derived from PD had unique advantages for the study on the evolution process of complex fracture.The internal microstructure of coal mass would be damaged to varying degrees after the effect of external loads,and the damage process could be divided into the compaction stage,the initiation and propagation stage of microcracks,and the fracture failure stage.After the compaction stage,all the bonds were broken.At the failure stage,the bond was almost completely broken,resulting in the macroscopic instability and failure of the coal sample.For the simulation model subjected to external load,the internal energy began to accumulate,and as the pressure increased,the internal energy dissipated and finally presented an “X”-shaped distribution,which was basically the same as the damage effect of coal sample after the experimental loading,so it is practical and feasible to invert the internal microstructure change of coal mass and obtain the damage law of coal mass.