| Among numerous factors which affect the safety and stability of mining engineering,underground water is the most active one.If the rock mass is in the state of water saturation for a long time,the stability of rock mass will be reduced continuously.For rocks that contain clay minerals,the weakening effect of water-rock coupling on the mechanical properties and stability of rock mass is more significant.Hence,it is meaningful for the stability monitoring of surrounding rock and disaster warning to carry out the experimental study of acoustic emission characteristics in the process of fracture and instability of rocks that contain clay minerals under long-term immersion in practical engineering.Based on the research object of Huangshan related to Multi water mine,the uniaxial anti pressure test and acoustic emission test are carried out on the saturated rock samples with different soaking time to analyze the influence of water on the mechanical properties of rock,and the influence law of soaking time on the time-frequency characteristics of acoustic emission of saturated rock is mainly analyzed;finally,according to the weakening law of the strength of the immersed rock,combined with the information of the structural plane of the rock mass in the mine,the rock constitution is affected The BQ value of the quantity index shall be corrected.The results show that the long-term immersion has a significant effect on the strength weakening of rock.Combined with the change of water content,it can be found that the coupling weakening of water and rock has a certain effect time;the main effect of long-term immersion on the acoustic emission time domain of rock is that the total amount of counting rate and energy rate is continuously reduced,and the stress variable is gradually reduced in the exponential growth period,that is,the plastic deformation stage,so that the failure of the test piece has a certain effect time The main change in the frequency domain of acoustic emission is that the low dominant frequency band disappears gradually,and only the dominant frequency band of about 100 k Hz is left at last,and the precursory characteristics of specimen rupture also disappear gradually.This paper summarizes the weakening law of rock by long-term water immersion,and calculates that the BQ value of the rock mass in bailitan coal mine decreases significantly after the modification of the rock mass quality classification method.After the modification of the rock mass quality classification method,it is more in line with the actual situation of the site and has better theoretical basis and guidance value for the actual project.Figure 36;Table 9;Reference 91... |
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