Abstract：Mechanical experiments on large-scale rock samples(length ×height ×width：1 000 mm × 1 000 mm × 600 mm) under uniaxial cycling loading are conducted and studied. The experimental results are as follows：(1) like the acoustic emission characteristic，the rules of both stress-strain curves and crack development are closely related to the largest loading that rock experiences previously，and only when the loading reaches to the peak value can the previously formed cracks develop. The fact shows the stress gradients are steep in the rock sample；(2) the stress-strain curves of the large-scale rock specimens under cycling loading are basically the same as those of the standard rock specimen；(3) the observed strain is 100 times larger than the point strain under the same observed stress. It shows rock is a kind of material with microcosmic characteristics (microcosmic heterogeneousness). The macroscopical mechanical behaviors of rock are the comprehensive results of interaction and magnification among microcosmic characteristics；and (4) it has a nearly linear relationship between the average axial point strain and the observed stress. The slope of the relationship curve in each cycle is nearly parallel. The average transverse point strain and its dispersion coefficient increase as the cycling number increases. It shows rock cracks mainly develop paralleling loading orientation under uniaxial compression. This process is irreversible accompanied by energy dissipation.
