ISSN 1330-3651 (Print), ISSN1848-6339 (Online)

Original scientific paper Failure tests were conducted on marble under different unloading confining pressure rates to obtain the energy change curve of whole-process deformation and failure. With increasing unloading rate, the peak stress differences in marble failure were reduced, confining pressure differences in failure increased, the increment ratios of each stress confining pressure were smaller, and the volume deformation was more sensitive to changes in unloading confining pressure. Unloading failure was caused by volume expansion, and the greater the unloading rate was, the easier the rock failure was. With the increasing unloading rate, total absorbed energy increment, elastic energy increment and dissipated energy increment were reduced in the unloading stage of marble. The dissipated energy increment in the unloading process was more than five times that in the loading process, while the elastic energy increment only accounted for 10 % of total stored energy. The unloading process showed increasing dissipated energy, and the geo-stress state of the engineering rock mass determined the level of energy released in failure.