Acoustic Emission Response and Fracture Evolution Analysis of Thermally Damaged Sandstone under Uniaxial Compression
The stability of surrounding rock under the influence of temperature is an urgent problem in the engineering practice of nuclear waste storage,geothermal development and restoration of surrounding rock after fire,etc.It is important to clarify the acoustic emission(AE)response and deformation and failure characteristics of rock bearing process under the influ-ence of different temperatures for the stability analysis of heat-damaged surrounding rock.In view of this,this paper adopts the methods of laboratory experiment,statistical analysis and microscopic morphology observation to study the sandstone after heat treatment at different temperatures of 25~600℃.Firstly,the uniaxial compression AE experiment is carried out,and then the AE parameters are analyzed.Finally,the fracture morphology and fracture morphology after damage are comprehensively ana-lyzed.The results show that the AE ringing count and amplitude show the same time sequence evolution trend after different temperature heated,and the activity of AE signal is closely related to temperature.By analyzing the dynamic evolution law of the high-density concentration area of acoustic emission AF-RA data points based on the nuclear density estimation method,it can be seen that the dominant rock fracture position of the shear fracture mode is particularly obvious after the temperature reaches 600℃,which is basically consistent with the results of the macro fracture mode and the microscopic morphology of failure sam-ples.The study results can provide reference for the mechanical properties analysis and stability discrimination of heat-damaged rocks in engineering practice.
rock mechanicshigh temperatureacoustic emissionfracture mode
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