| Rockburst refers to the phenomenon of sudden and violent destruction of surrounding rock caused by engineering excavation and unloading under high ground stress conditions,accompanied by rapid energy release.The ejection characteristics of rockburst are remarkable,and the energy is huge,and it has high suddenness,which has brought serious threats to people’s life safety in production and engineering,and also caused huge economic losses.In deep engineering,most rock masses are in a certain state of water content.In this study,sandstones with different water content are selected to conduct experiments on rockburst acoustic emission characteristics.The failure process and shape further verified the influence of water content on the acoustic emission characteristics,and some regular conclusions were obtained,in order to provide a theoretical basis for monitoring and early warning of rockburst disasters in engineering.The main conclusions are as follows:(1)The whole process of sandstone rockburst failure is divided into three stages according to the time series,loading to the initial stress stage,load maintenance stage and rapid unloading of the free surface to the rockburst damage stage;the time series energy and cumulative The released energy can correspond to counting and cumulative counting;the sandstone rockburst failure process after unloading can be divided into four stages,calm period,particle ejection stage,mixed ejection stage and collapse and exfoliation stage.(2)Water content has a significant impact on the acoustic emission characteristics of sandstone.Acoustic emission counts,cumulative counts,energy,and cumulative energy decrease with the increase of water content;the average value of acoustic emission counts in the dry group is about 2.2 times that of the saturated group,the average value of the total count is about 2.4 times that of the saturated group;the average value of the peak acoustic emission energy of the dry group is about 2.1 times that of the saturated group,and the average value of the total count of energy is about 2.8 times that of the saturated group.(3)The fractal dimension can quantitatively represent the fragmentation degree of rock debris caused by rockburst,thus reflecting the energy release characteristics of rockburst activities.With the increase of water content,the mean value of the debris fractal dimension of sandstone strain-type rockburst failure gradually decreases,indicating that when rockburst failure occurs,the dry sandstone rockburst consumes the most energy,followed by the natural state sandstone,and the saturated state sandstone is the smallest.The degree of debris fragmentation decreases successively,which is consistent with the effect of water content on acoustic emission energy.(4)The degree of rockburst damage in the dry state is more severe than that in the natural state and saturated state.In actual engineering,reasonable moisture content treatment of the surrounding rock of the cave wall under certain conditions can reduce the possibility of rock eruption. |
