Physical And Mechanical Properties Of Thermal-liquid-stress Coupled Granite

Based on the science and technology research project of universities and colleges in Hebei Province(Study on Surrounding Rock Stability of Deep Dry Hot Rock Drilling Considering Thermal-liquid-stress Coupling),this paper carries out thermal-liquid coupling experiments and physical property experimental tests,and uses uniaxial compression experiments of rocks to perform mechanical experiments on thermo-liquid coupled granite,and analyis the the relationship between the physical and mechanical properties of thermo-liquid-stress coupled granites.The ultrasonic wave tester is used to test the wave velocity of rocks,and the influence of the influencing factors on the wave velocity of rocks is analyzed.A uniaxial compression experiment was performed on the thermo-liquid coupled granite using a universal testing machine system to obtain the mechanical parameters such as the stress,strain and deformation modulus of rock failure,and the influence of each influencing factor on the mechanical properties of rock was analyzed.At the same time,rock uniaxial compressive strength and wave velocity were used to study rock drillability and energy loss.The significance and importance of each influencing factor were analyzed using mathematical statistical methods.The conclusions of the study are as follows:1.The thermal-liquid coupling cycle experiments were performed on granite.The temperature range was 250 ?-450 ?,and the number of thermal-liquid coupling cycles was 1-5.The relationship between the stress and deformation of the rock and the physical factors is analyzed,and the influence of the number of thermal-liquid coupling cycles on the granite is greater than that of the temperature.2.The influence law of temperature and the number of thermal-liquid coupling cycles on the physical properties of granite is as follows: the color of granite becomes dark with the increase of temperature,and there are brown and yellow spots.The impact sound of granite becomes turbid as the temperature increases and the number of thermo-liquid coupling cycles increases.Granite wave velocity decreases with increasing temperature and increasing number of thermo-liquid coupling cycles.The mass loss rate of granite during heating and the rate of mass increase during immersion increase with increasing temperature and the number of thermo-liquid coupling cycles.3.The stress of thermal-liquid-stress coupled granite varies with physical factors: the peak stress decreases with the increase of temperature and the number of heat-liquid coupling,and increases with the increase of loading rate.4.The deformation of the thermal-liquid-stress coupled granite varies with physical factors: the elastic modulus and secant modulus decrease with the increase of temperature and the number of heat-liquid coupling,and increase with the increase of loading rate.5.Significance analysis results of influencing factors of granite physical and mechanical parameters: among the influencing factors of density,the number of thermal-liquid coupling is the significant factor,while the temperature is the non-significant factor.Among the influencing factors of wave velocity,the order of primary and secondary factors is: number of times of heat-liquid coupling cycle > density > temperature.Among the influencing factors of mechanical properties,factor importance order(low ? high): density,wave velocity,experimental loading rate,temperature and number of thermal-liquid coupling cycles.The influence of external conditions is greater than that of physical factors.6.Research on drillability and energy damage of thermal-liquid-force coupled granite: the hardness of thermal-liquid-force coupled granite is between relatively strong and solid,but the drillability is poor.The energy damage of granite increases with the increase of temperature and the number of thermal-liquid coupling cycles.