不同循环加卸载速率下砂岩的力学特性研究.

Tunnel excavation, mining and other projects involve the phenomenon of periodic compression and tension of rock stress. The mechanical effect produced by construction conditions has a significant impact on rock structure. In order to study the deformation and failure characteristics of rock under different loading and unloading rates, the cyclic load test of sandstone at different loading and unloading rates under uniaxial conditions is designed. Based on tie stress-strain curve, hysteresis loop and residual strain, the evolution law of damage, instability and deterioration of sandstone rock mass under cyclic load is deeply analyzed. The results show that compared with the monotonic loading condition, the cyclic load can strengthen the peak stress of rock samples. The residual strain of banner cyclic load is related to the number of cycles in a logarithmic function. In the graded cyclic load, the change of the upper limit stress to the strain is greater than that of the lower limit stress to the strain. The fitting result of residual strain and cycle times is a linear correlation function with the same slope. The loading mode has a certain influence on the elastic modulus of rock samples, and the same loading and unloading rate has the greatest influence on it. [ABSTRACT FROM AUTHOR]