煤岩高度复杂的天然结构使其力学行为同样复杂。选取同源煤样进行多加载速率力学试验,试样强度表现出随加载速率增加先升高后降低的非线性特征,依据可重复性原则确认了其存在性,试验中煤样行为细节表明,高加载速率对于裂隙发育的抑制使得细观承载结构储存更多变形能,对于强度较低的煤,其细观结构将更易出现大规模破断,即内部裂隙发育充分与否均不利于承载,因此,在最低和最高加载速率之间必然存在“临界加载速率”使强度表现出最高值,而由破断形成的局部破裂面是造成高加载速率条件下出现较低强度的关键。将高加载速率条件下较低强度对应较低冲击可能性作为该非线性特征现场应用的切入点,提出加载速率敏感度和基于监测的加载速率尺度转换方法,实现了针对具体现场的应用,表现出了较好的适用性。
The mechanical behavior of coal and rock is complex due to the highly complex natural structure. Mechanical tests for multi-loading rates of coal from the same source were carried out, a non-linear evolution law that the compressive strength first increased and then decreased with the increase of the loading rate was observed. According to the repeatability principle, the existence of the non-linear law was confirmed. Details of mechanical behavior of coal in test show that, the microscopic bearing structure would store more deformation energy while the development of crack was inhibited at high loading rate, for coal with low strength, the microscopic bearing structure would break off easily in large scale. Namely, whether the development of crack is fully or not will both reduce the strength. Therefore, the existence of "critical loading rate" between highest and lowest loading rate corresponding to highest strength is proved to be inevitable, and the local fracture plane formed by the break off of microscopic structure is the key factor causing low compressive strength at high loading rate. The characteristic that the lower strength at high loading rate corresponding to lower bursting possibility was taken as the starting point of field application of the non-linear evolution law, the "loading rate sensitivity" and scale conversionmethod of loading rate based on filed monitoring were proposed to realize the application to specific field, Which showed a good applicability.