Experimental study of nonlinear evolution mechanism of coal strength under multi-loading rates and its application
LI Haitao1，2，SONG Li3，ZHOU Hongwei1，SONG Feng4
(1. School of Mechanics and Civil Engineering，China University of Mining and Technology，Beijing 100083，China；2. Beijing Anke Technology Co.，Ltd.，Beijing 100083，China；3. Material Structure Laboratory，Jiangsu Hydraulic Research Institute，Yangzhou，Jiangsu 225002，China；4. State Grid Yantai Power Supply Company，Yantai，Shandong 264000，China)
Abstract：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 conversion method of loading rate based on filed monitoring were proposed to realize the application to specific field，which showed a good applicability.
李海涛1，2，宋 力3，周宏伟1，宋 峰4. 多加载速率影响下煤强度的非线性演化机制试验研究及应用[J]. 岩石力学与工程学报, 2016, 35(S1): 2978-2989.
LI Haitao1，2，SONG Li3，ZHOU Hongwei1，SONG Feng4. Experimental study of nonlinear evolution mechanism of coal strength under multi-loading rates and its application. , 2016, 35(S1): 2978-2989.
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2016, Vol. 35 
