Research On The Energy Evolution Mechanism Of Coal And Rock Damage Under Different Stress And Temperature

In the underground engineering activities of mineral resources mining,mine gas,as one of the environmental factors of coal body,has always been an important factor affecting the safety of coal mine production,and along with the gradual depletion of the earth's shallow mineral resources,resource exploitation is advancing to the deep,the ground temperature is getting bigger and bigger,the stress concentration caused by engineering excavation is becoming more and more prominent,the stress is also getting bigger and bigger,the coal is in the complex environment of ground stress,gas gas and temperature coupling.In the stress state,the process of coal damage and destruction is essentially a state instability driven by energy transfer and exchange,and the continuous dissipation and release of energy will gradually reduce the carrying capacity of coal,cause damage instability,and lead to high-energy engineering disasters such as coal and gas prominent underground.Therefore,considering the influence of pressure,gas pressure and temperature on the deformation and destruction characteristics of coal,it is of great significance to study the relationship between the energy evolution mechanism of coal and the characteristics of damage deterioration and energy dissipation.The coal samples studied in this paper are all selected from No.3 coal seam of Zhaozhuang Mine,Jincheng,Shanxi.Starting from the triaxial compression test of coal and rock under different confining pressures,different gas pressures and different temperatures,using the combination of experimental research and theoretical research,The deformation and failure characteristics of coal under confining pressure,gas pressure and stress-temperature,the evolution law of energy in the process of deformation and failure,and the coupling mechanism of coal damage and deformation and energy dissipation have been studied in depth.The following research progress has been made:1)The three-axis compression test of coal under different peri-pressure,different gas pressure and different temperature was carried out,the deformation and destruction characteristics of coal under different peri-pressure,different gas pressure and stress temperature were discussed,the mechanical characteristics of the total stress strain process of coal were studied,the characteristics of strength deformation and the relationship between axial strain,radial strain and volume strain were analyzed,and the evolution of coal damage under different stresses and temperatures was revealed.2)The overall damage caused by coal is composed of force damage and thermal damage,thermal damage increases with temperature,on the basis of verifying the rationality of the original structure model of coal damage under the influence of different peri-pressure and different gas pressure,the overall damage evolution equation of coal under the dual effect of stress-temperature is put forward,the difference of elastic module at different temperatures is used to indicate the thermal damage caused by temperature change,and the model of coal damage is established by testing.3)The pressure,gas pressure and temperature have a great influence on the energy consumption characteristics of coal,corresponding to different deformation and destruction stages,and the energy conversion forms of coal under different stress and temperature are showing phased changes.Through energy analysis,the mathematical expression of coal damage-energy coupling under different stress and temperature is constructed,and based on the idea of energy dissipation,the dissipative energy coefficient is introduced,and the method of determining the damage point of coal under stress-temperature is proposed.Using energy parameters to quantitatively analyze the damage evolution characteristics in the process of coal compression destruction,it is concluded that the dissipation of energy is the main cause of damage to the internal structure of coal.