AN EXPERIMENTAL STUDY ON THE DEFORMATION AND FAILURE FEATURES OF A BASALT UNDER UNLOADING CONDITION
卸荷应力状态下玄武岩变形破坏特征的试验研究

The deformation and failure features of a basalt on unloading condition were studied in laboratory using unloading triaxial test. The test results show that the rock can be failed not only under loading condition, but also under unloading condition, With the increase in confining pressure of sample failure, the unloading fracture types gradually change from tensile failure to tensile-shear failure. The deformation characteristies of the rock on unloading condition are different from that on loading condition, showing strong dilatancy. In addition, the unloading fracture caused by the release of strain energy is stronger than loading fracture.