To investigate decay law of acoustic emission and microseismic activities caused by disturbances associated with multilevel loading and mining blast,a new exponential decay(ED)law was proposed.The results show that th...To investigate decay law of acoustic emission and microseismic activities caused by disturbances associated with multilevel loading and mining blast,a new exponential decay(ED)law was proposed.The results show that the micro-fracture activity decay law after multistage stress loading and blasting disturbance conforms to the ED model,in which the sum of A and n represents the number of initial micro-fracture events,and n represents the level of background micro-fracture events.The ED model can describe the number of initial micro-fracture events with a deviation less than 10%.The ED model outperforms the traditional aftershock models in describing the micro-fracture event decay law in the three cases considered.The ED model can provide a reference for selecting the blasting interval in mines,which is of great significance to maintain the stability of the surrounding rock and ensure safe production in metal mines.展开更多
在"自感"知识教学中,演示断路自感现象通常都采用图1所示装置。断开开关K,小灯泡 S 发出明亮的一闪后才熄灭,以此说明自感现象。可是在教学实践中发现,不少的人对断路自感实验存在着一些似是而非的错误认识,而且这些错识具有...在"自感"知识教学中,演示断路自感现象通常都采用图1所示装置。断开开关K,小灯泡 S 发出明亮的一闪后才熄灭,以此说明自感现象。可是在教学实践中发现,不少的人对断路自感实验存在着一些似是而非的错误认识,而且这些错识具有一定的普遍性、代表性和迷惑性,以下对其一一进行剖析。典型佯缪之一:断开电源开关、灯泡明亮的一闪后才熄灭是因为断电瞬间线圈中的电流突然增大了。剖析:断开电源开关 K,线圈中产生的自感电动势大小为ε<sub>L</sub>=（r+B）/rε·e<sup>-（R+r）/L·t</sup>（R 为灯泡的电阻,L 为自感系数,r 为线圈的内阻,ε为电源电动势,其内阻忽略不计）。可见,断开展开更多
基金financial supports from the National Natural Science Foundation of China(Nos.51704056,51974059)the China Postdoctoral Science Foundation(No.2017M621152)the Fundamental Research Funds for the Central University of China(Nos.N160103006,N180115010,N2001001)。
文摘To investigate decay law of acoustic emission and microseismic activities caused by disturbances associated with multilevel loading and mining blast,a new exponential decay(ED)law was proposed.The results show that the micro-fracture activity decay law after multistage stress loading and blasting disturbance conforms to the ED model,in which the sum of A and n represents the number of initial micro-fracture events,and n represents the level of background micro-fracture events.The ED model can describe the number of initial micro-fracture events with a deviation less than 10%.The ED model outperforms the traditional aftershock models in describing the micro-fracture event decay law in the three cases considered.The ED model can provide a reference for selecting the blasting interval in mines,which is of great significance to maintain the stability of the surrounding rock and ensure safe production in metal mines.
