Study of stability in surrounding rock masses and in-situ stress measurement for deeply buried metal mine

The following results are obtained based on the study of in-situ stress measurements using stress relief by overcoring technique and stability of surrounding rock masses in the some deeply buried metal mine: (1) the dominative stress at depth of 820m is tectonic stress and the maximum principal stress is 28.1MPa The principal stress dispersion is 21.4MPa very big and which is apt to cause the rib spoiling damage phenomenon of the surrounding rock masses. Which explain well the phenomenon of rib spoiling, floor heave and roof falling of the mine rock tunnels at present. (2) The elastic modulus and Poisson´s ratio of sandstone were obtained through laboratory experiment, in which the tested rock core were get from the field test. The surrounding rock of tunnel is a typical brittle rock with high strength. It is a burst-prone mine in high level tectonic stress under the action, which was revealed the internal factors of the mine tunnels local occurred in rockburst. (3) According to the in-situ stress orientation and size, some measures were puts forward to maintain the stability of surrounding rock masses. The above results can provide references for similar projects, in which deformation mechanics of surrounding rock masses, defects of prophase support system and prevention rockburst.