为解决深部软岩巷道围岩大变形、返修次数多难题，以泉店煤矿21皮带下山为工程背景，采用理论分析、数值模拟及工程实践等方法，提出了巷道变径分区卸压技术，建立了卸压参数理论模型，得出了卸压关键参数选取区间与弹性应变能密度分布规律，揭示了钻孔卸压能量耗散原理，确定了卸压关键参数的最佳取值。研究表明：①通过变径分区卸压技术改善了浅部围岩能量环境，减少了顶底板能量升高区面积，并将肩角和底角区域聚集能量向深部转移，实现了巷道精准卸压控制。②随着浅部小直径钻孔长度(L₁)、深部大直径钻孔长度(L₂)、深部大直径钻孔半径(r)增加，其弹性应变能密度曲线相应的前峰值、后峰值以及后峰值升高，整体呈正相关。③随着深部大直径钻孔间距(D)增加，孔间弹性应变能密度峰值变化呈现先升高后降低再稳定的特点，而钻孔间联合卸压效果与其呈现负相关，依据弹性应变能量峰值增幅大小得出了影响卸压效果的关键参数权重顺序依次为：L₁、L₂、r、D。④依据理论分析和数值模拟确定了21采区皮带下山巷道卸压技术关键参数合理值，巷道实施变径分区卸压技术后，两帮及顶底板变形量分别降低了58.7%、23.7%以及27.4%，巷道稳定得到有效控制，证实了变径分区卸压技术的有效性。

Addressing significant deformation in the surrounding rock of deep soft rock road-ways subjected to repetitive repairs, this study focuses on the 21st transportation downhill of Quandian coal mine as the engineering context. We propose the variable-diameter partition roadway pressure relief technology. This approach utilizes theoretical analysis, numerical simulation, and practical engineering methods. We established a theoretical model for pressure relief parameters, derived essential parameters for pressure relief, and outlined the distribution pattern of elastic strain energy density. Additionally, we uncovered the principles governing energy dissipation in borehole unloading, ultimately determining the optimal value for key pressure relief parameters. The study findings indicate the following: ① The variable-diameter zoned pressure relief technology enlarges the energy reduction zone near the roadway while diminishing the energy elevation zone in the roof and floor. It redirects concentrated energy from the shoulder and floor corners deeper into the area, achieving precise pressure relief control within the roadway. ② Increasing the length of shallow small-diameter boreholes (L₁), the length of deep large-diameter boreholes (L₂), and the radius of deep large-diameter boreholes (r) corresponds to increasing pre-peak, post-peak, and post-peak values in the elastic strain energy density curves, demonstrating an overall positive correlation. ③ As the spacing (D) of deep large-diameter boreholes increases, the peak value of elastic strain energy density between holes shows the characteristics of firstly increasing, then decreasing and then stabilizing, and the effect of unloading joint pressure between boreholes is negatively correlated with it, and based on the magnitude of the increase in the peak value of elastic strain energy, the key parameters affecting the effect of unloading are weighted as follows in the order of: L₁, L₂, r and D. ④ Based on the theoretical analysis and numerical simulation to determine the key parameters of the 21st transportation downhill roadway pressure relief technology reasonable value, roadway implementation of variable-diameter zoned pressure relief technology, the two ribs and the roof and floor deformation were reduced by 58.7%, 23.7%, and 27.4%, respectively, the stability of the roadway has been effectively controlled, confirming the effectiveness of the variable-diameter zoned pressure relief technology.