Abstract:

Representative slab-rupture original rocks (i.e.,slab ruptures have occurred in the rock blocks) were taken as examples.To obtain the anisotropic properties for related strength parameters,we perform the uniaxial compression tests with the loading directions vertical and parallel to slab rupture.At the same time,the microscopic identification and analysis of slices from the original slab-rupture rock are conducted by using polarizing microscope.We try to explore the potential relations among mechanical properties of the rock,compositions and slab rupture of rock mass.The study shows that:the original slab-rupture rock has anisotropic characteristics,closely relevant to the direction of slab rupture;under the same magnitude of load,the load parallel to slab rupture is more likely to cause deformation and failure of potential slab-rupture rock mass than that vertical to slab rupture.As for cataclastic granite,it had suffered a strong tectonic stress during geological period,and the stress is significant in the direction parallel to the slab rupture surface,forming the tiny (small) cracks parallel to the slab rupture surface which is partially filled with tiny dykes.Furthermore,for chlorite-sericite phyllite and quartz muscovite schist,the mechanical properties of such rock structures show obvious tendency of anisotropy,under given stress at the later stage,tiny(small) cracks will occur,which are oblique to the schistosity at a small angle.Finally,we conclude that the rock texture and structure feature of slab-rupture original rock are the intrinsic factors of generating slab ruptures.

Key words: slab-rupture original rock, slab-rupture direction, compression test, polarizing microscope, extinction characteristics