深部暗斜井大变形破坏机理及其控制技术研究

Large deformation and failure mechanism of deep sub-inclined shaft and its control technology

深部软岩巷道常处于“三高一扰动”复杂环境中,其大变形一直是支护难题。针对新元煤矿轨道暗斜井掘进期间大变形问题,实测分析巷道变形破坏特征,建立UDEC数值模型,利用实验室测试结果和GSI法校正模型参数,基于“应力弱化系数”指标,反演巷道围岩变形及裂隙分布特征,揭示巷道变形破坏机理。研究结果表明:剪切裂隙首先出现在巷道围岩表面,而后向深部发育,拉伸裂隙滞后剪切裂隙出现,且分布围岩浅部区域,底板裂隙发育程度高,变形严重。提出“全锚索+反底拱+网喷混凝土”联合支护方案,工程应用结果表明,优化后的支护方案使围岩整体承载能力显著提高,顶底板及两帮最大移近量分别为126 mm、116 mm,有效地控制围岩变形,为类似深部软岩巷道支护设计提供有益参考。

Deep soft rock roadway is often in the complex environment of“three-high and one-disturbance”,and its large deformation is always a problem for support.Aiming at the large deformation of track inclined shaft in Xinyuan Coal mine during the excavation,the deformation and failure characteristics of roadway were analyzed by field measurement,the UDEC numerical model was established,the model parameters were corrected by laboratory test results and GSI method,and based on the index of stress weakening coefficient,the deformation and fracture distribution characteristics of roadway surrounding rock was inverted,and the roadway deformation and failure mechanism was revealed.The results show that shear fractures first appear at the corner and bottom of the roadway,then develop to the deep;tensile fractures appear after the shear fractures,which are distributed in the shallow surrounding rock.The floor fractures are highly developed and seriously deformed.The combined support scheme of“full anchor cable+reverse bottom arch+mesh shotcrete”is proposed.The engineering application results show that the optimized supporting scheme can greatly improve the overall bearing capacity of surrounding rock and the maximum roof-to-floor and side-to-side convergence is 126 mm and 116 mm,respectively,indicating that,the deformation is under control.