Theoretical And Experimental Study On Effects Of Disturbance To Rock Creep And Damage Characteristics

Different depth of roadways under various stresses, and so its stability is different. When depth of roadways is larger, it is closer to critical state, small disturbance can cause rock crack to extend dynamically at instantaneous time, and finally roadways will collapse. Hence, it is of great importance for supporting of soft rock and deep mining to study on creep characteristics and damages of rock under disturbance load and to establish a theory of creep disturbance effects. This dissertation is centered on the study of rock creep and its disturbed effects .In this paper, the disturbance effects of rock creep when the load is approaching its ultimate strength is studied. Tests of creep under triaxial compression and its disturbance effects, rock beam bending,MTS and CT scanning were carried out in indoor laboratory. Achievements of the dissertation are following as,Compared with axial creep,lateral creep is sensitive to confining pressure. Confining pressure have different influence on strength, elastic modulus and damage form obviously.On the basis of static loading triaxial creep test, tests of triaxial disturbed creep effects were taken. It can be found that rock creep damages have a relationship with disturbance impact energy under same confining pressure.According to rock creep characteristics under continuous disturbance impact, further study on creep damages characteristics of rock was made. Damages of continuous disturbed impact have a relationship with load impulse and impact times under same confining pressure; Damages of continuous disturbed impact have a relationship with impact times and confining pressure under same load impulse. Confining pressure increase rock strength, decrease damages rate of rock creep.Study on micr-mechanism of disturbed damages was made by CT scanning under step-wise loading conditions. Results show that creep damages is a process of turning plastic into brittle under low confining pressure conditions.Analysis of median surface creep of grey sand stone, red sand stone and oil shale were made that cut-open departure from median surface of rock beam by bending test.