| The surrounding rock often collapse suddenly in the construction of vertical shaft through fractured rock, causing casualties accidents. Classification standard of rock strength and supporting level, which is operationally and can be quantitated, should be proposed necessarily by analyzing the problems of existing technology. Taking into account basic quality indicators of rock mass, RQD value and softening coefficient of rock, the strength grade of surrounding rock was classified. The stability of broken surrounding rock was numerically simulated through different strength of surrounding rock, different excavation diameter and different depth shaft, and the critical values of displacement were picked up and analyzed. Using rock failure displacement criterion, the standard of supporting grade was classified for broken surrounding rock in vertical shaft. Combined with current support technology in shaft construction, the technology of stability control for corresponding fractured rock was formed on the basis of different supporting level in vertical shaft. The technology is actually used for vice shaft through fractured rock in Jingfu coal mine, and proved scientifically, reasonably and effectively. |
