冲击性煤体应力结构时间效应试验研究OA北大核心CSTPCD

Coal mining engineering involves complex stress structure time effect issues,which are closely related to the occurrence and prevention of rock burst disasters.Therefore,this study conducts experimental research on the stress structure time effect of im-pact coal.Coal rock specimens were obtained from three coal mines in Shaanxi,Gansu,and Inner Mongolia.The stress-time effect of loading rate was studied through coal uniaxial compression static-dynamic load and creep tests.The stress-time effect under the con-dition of coal in situ release was investigated using a long-term segmented test method.Water immersion tests on coal and structural time-effect studies on coal-rock combinations were conducted.The experimental results indicate that there is a positive correlation between the uniaxial compressive strength of coal and the loading rate,and a negative correlation with the duration of in-situ relief and immersion time.The combined mode of coal-rock structure time effect significantly affects its energy and strength properties,while impact coal exhibits both stress and structural time effects.According to the experimental results,a plastic limit structure is proposed to explain the irreversible deformation of coal-rock mass under stress.Furthermore,by constructing a time-dependent mod-el for plastic strain in coal under impact conditions and comparing the numerical approximations of non-elastic strain and irrevers-ible strain,the plastic limit strain characteristics of shock-induced coal were verified.