Abstract:The influence of stress amplitudes of cyclic dynamic disturbance on the fracturing behavior and other dynamic response of rock is investigated. Red sandstone specimens used in the testing are subjected to a preloaded biaxial compression load which reaches rock yield strength and then coupled with a cyclic fatigue loading. Sine wave cyclic loads with of frequency 2 Hz and five different stress amplitudes of 6,10,14,18 and 22 MPa are adopted as dynamic disturbance. The obtained results show that fatigue life of specimen is usually no more than several decadal cycles under present loading conditions;the fatigue life of rock,when the preloaded biaxial compression load is beyond its yield strength,is much shorter than that when the preloaded biaxial compression load is within the elastic limit. Large disperse of fatigue life can be found in the tests,even for the cyclic loads with the same stress amplitudes. However,the total axial deformation at failure point for the fatigue loads with the same stress amplitude is almost the same. It is worthy noting that the axial deformation will decrease with the increasing of stress amplitude. For the specimen with a relatively longer fatigue life,their characteristic curves of axial deformation versus fatigue cyclic times can be divided into three stages and they are quite similar to that of rock creep curves. The accumulative deformation of three stages will lead to the final failure of the rock specimen,and the proportion of each stage in total deformation,failure mode and size distribution of rock fragments are all greatly affected by the stress amplitudes.
马春德,李夕兵,陈枫,徐纪成. 双向受压岩石在扰动荷载作用下致裂特征研究[J]. 岩石力学与工程学报, 2010, 29(06): 1238-1244.
MA Chunde,LI Xibing,CHEN Feng,XU Jicheng. FRACTURING BEHAVIOR STUDY OF BIAXIAL COMPRESSION OF ROCK SUBJECTED TO DYNAMIC DISTURBANCE LOAD. , 2010, 29(06): 1238-1244.