Experiment and analysis of coal sample destruction precursor based on load-unload response ratio
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摘要: 基于加卸载响应比理论，实验研究了煤样在加卸载过程中声发射与电磁辐射的响应比特征，得出如下结论：① 在单轴加卸载过程中，声发射与电磁辐射的加卸载响应比能比较好地反映煤样的稳定状态，煤样状态稳定时加卸载响应比较低，反之升高。② 加卸载响应比增加到峰值之后，煤样开始遵循自身的演化规律，在发生宏观破坏之前加卸载响应比有明显的“急剧增长-迅速回落”过程，可以通过这一特征来预测煤样的宏观破坏。③ 由于煤样的不均匀性，加卸载响应比峰值时间与发生宏观破坏时间不一致，在应用加卸载响应比方法进行灾变预测时，应充分考虑煤岩不均匀程度，根据具体情况确定特征时间的尺度。实验结果表明，通过声发射和电磁辐射加卸载响应比预测煤岩动力灾害具有一定的可行性。Abstract: The paper researched and analyzed response ratio characteristics of acoustic emission and electromagnetic radiation of coal sample in load-unload by experiment based on load-unload response ratio theory , and got conclusions: ① Load-unload response ratio of acoustic emission and electromagnetic radiation can well reflect stable state of coal samples in process of homotaxial load-unload, and load-unload response ratio is lower when coal sample status is stable , otherwise is higher. ② The coal samples will begin to follow itself evolution rule after the load-unload response ratio increased to peak, and the load-unload response ratio has process 'sharp growth-quickly dow' before the coal samples break, which can be used to predict macroscopic damage of the coal sample. ③ Peak time and macroscopic damage time of the load-unload response ratio is inconsistent because of inhomogeneity of the coal sample, so when method of load-unload response ratio is used to predict disaster, uneven degree of coal and rock should be considered to determine characteristic time. The experiment results show that predicting coal or rock dynamic disasters has certain feasibility by load-unload response ratio of acoustic emission and electromagnetic radiation.
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