为研究膨胀性极软弱岩大断面斜井底鼓机理与支护方法，以窑街煤电集团某矿主斜井为研究背景，通过现场调研和室内试验，获得了围岩强度低、完整性差、黏土物质占比高、遇水软化膨胀等特性，建立Flac3D数值模型推演实际工程条件下巷道变形规律，探明了大断面软岩斜井底鼓变形机理，总结了3个防治优化策略，并结合原支护设计提出“反底拱+锚索”的优化支护方案。现场实测数据结果表明：优化后的支护方案对软岩巷道底鼓治理效果显著，提高了围岩的承载能力，降低了底鼓变形情况，实现了巷道围岩的稳定性控制，对浅部软岩大断面斜井底鼓治理提供重要参考。

To investigate the mechanisms of floor heave and support methods for large-section inclined shafts in highly expansive and weak rock, a case study was conducted on the main inclined shaft of a mine in the Yaojie Coal and Electricity Group. Through field surveys and laboratory tests, characteristics such as low rock mass strength, poor integrity, high clay content, and softening and swelling upon water exposure were identified. A Flac3D numerical model was established to simulate the deformation patterns of the tunnel under actual engineering conditions, elucidating the mechanisms of floor heave deformation in large-section soft rock inclined shafts. Three optimized prevention strategies were summarized, and an optimized support scheme of "inverse floor arch and anchor cable" was proposed based on the original support design. Field measurement data indicated that the optimized support scheme significantly improved the floor heave control in soft rock tunnels, enhanced the bearing capacity of the surrounding rock, reduced floor heave deformation, and achieved stability control of the tunnel surrounding rock. This provides an important reference for the control of floor heave in large-section shallow soft rock inclined shafts.