为探究TBM掘进斜井巷道时破碎软弱围岩损伤失稳机制及合理支护方案设计，以陕西榆林可可盖副斜井TBM掘进工程为研究对象，采用UDEC离散元模拟方法进行围岩稳定性分析，并针对无支护、锚网喷支护、锚网喷索支护、锚网喷索+钢带支护４种条件进行支护效果分析；基于数值结果提出支护优化方案并进行工程应用。结果表明： 1）TBM开挖巷道围岩失稳类型为由剪切塑性主导变形、由拉伸塑性控制破坏的“鹅蛋形”塑性破坏，需要及时采取支护手段； 2）锚杆、锚索、喷混凝土及钢带支护均可有效缓解围岩变形及破坏情况，“锚网喷索+钢带”支护效果最佳，相较于无支护方案，顶板位移降低50.9%，拉伸塑性面积减少99.85%。通过分析最终采用“锚网喷索”作为巷道支护方案，顶板冒落危险区域增设W形钢带加强支护。该支护方案可有效控制浅部围岩变形与深部围岩塑性拓展，实现对突发冒落的预控，最终成功应用于可可盖煤矿斜井施工。

The authors present a case study to investigate the damage and destabilization mechanisms of broken and soft surrounding rocks and provide a reasonable support scheme design for an inclined shaft bored using a tunnel boring machine(TBM). This study is conducted on the Kekegai subinclined shaft bored by a TBM in Yulin, China. A discreteelementsimulation software, UDEC, is employed to analyze the stability of the surrounding rocks as well as the support effects under four conditions: no support, anchornetwork shotcrete support, anchornetwork shotcrete cable support, and anchornetwork shotcrete cable + steel belt support. Based on the numerical results, a supportoptimization scheme is proposed and applied in practice. Accordingly, the following results are verified: (1) The rock destabilization in the TBM tunnel demonstrates ovalshaped plastic damage, which is dominated by shear plasticity and controlled by tensile plasticity, requiring the timely adoption of support means. (2) The anchor rod, anchor cable, shotcrete, and steel belt support can effectively limit the deformation and damage to the surrounding rocks. Therefore, the anchornetwork shotcrete cable + steel belt support exhibits the best support effect compared with all the other support types, with a reduction of 50.9% and 99.85% of the roof displacement and the tensile plastic area of the surrounding rocks, respectively, compared with those of the system without any support. The anchornetwork shotcrete cable scheme is finally used as the support solution, and a Wtype steel belt is added to strengthen the support in the roof area, which displays a falling risk. The adopted support scheme can effectively control the deformation of shallow surrounding rocks and plastic expansion of deep surrounding rocks, thereby achieving precontrol of sudden falls.