Experimental study on pressure stimulated current response characteristics during damage evolution of water?bearing coal samples

摘要

The damage and rupture behavior of water-bearing coal induced by coal mining disturbance can lead to large-scale rock engineeringinstability and engineering geological disasters. In order to study the influence of water on the pressure stimulatedcurrent (PSC) characteristics, four groups of coal samples with different water contents were set for uniaxial compressiontest. The response characteristics of PSC signals for water-bearing coal are analyzed, and the evolution characteristics ofPSC energy are discussed. The results show that water can significantly reduce the mechanical strength of coal samples.The variation of PSC signals is complex and weak in the early loading stage, and the change in the late stage is severe. Withthe water contents enhanced, the PSC peak value of coal samples increases. Meanwhile, the increase amplitude of PSC andthe percentage between the increase in PSC and the change in stress from elastic stage to plastic stage show linear and exponentialincreasing relationships respectively. The accumulated charge released gradually increases with the water contentsand is affected by the increase of stress. The peak value of time function F based on acoustic emission (AE) hits graduallyincreases with the water contents. The PSC energy can well reflect the coal damage as well as damage variable. The PSCsignals can provide forecast information for upcoming fracture as well as AE activity. The electrokinetic effect generated bywater–rock interaction can significantly promote the strength of PSC signals.