为研究全风化花岗岩地层隧道浅埋偏压段初支结构受力特性，依托相思山隧道采用室内试验获取全风化花岗岩黏聚力、内摩擦角等参数，并通过FLAC3D数值软件对洞口浅埋偏压段施工过程模拟，研究不同地层因素对初支结构受力特征。结果表明：各地层因素下初支轴力和弯矩均呈“上大下小”分布特征，而初支安全系数则相反，横坡坡度的增大使初支内力呈非对称性分布，正弯矩向深埋侧偏移并逐渐增大，负弯矩和轴力在浅埋侧拱腰处不断增加，横坡坡度达到40°时初支安全系数小于允许值，但采用多段变坡面可提高初支结构安全性；随着隧道埋深的增大可减弱初支内力的非对称性分布，但内力不断增大；土石界面与隧道相交于不同位置时，初支内力大小受较大影响，而分布特征变化较小。通过现场监测隧道各位置钢拱架与混凝土应力变化以验证各地层因素作用下初支结构受力特性的合理性。

To investigate the stress characteristics of the primary support in the shallow buried biased section of the tunnel in fully weathered granite strata. Based on the Xiangsishan Tunnel, laboratory tests were conducted to determine the mechanical parameters including cohesion and internal friction angle of fully weathered granite. The construction process was simulated by FLAC 3D numerical software for the shallow buried bias section of the tunnel entrance. To study the effects of varying ground slopes, tunnel depths, and soil-rock interface locations on the stress characteristics of the primary support structure. The results indicate that, under various impact factors, the axial force and bending moment of the primary support exhibit the distribution characteristics of "upper large and lower small", while the safety factor displays the opposite trend. The internal stresses of the primary support are distributed asymmetrically as the ground slope increases. The positive bending moment shifts toward the deeper-buried side and gradually increases, while the negative bending moment and axial force increase at the arch waist on the shallow-buried side. When the ground slope reaches 40°, the safety factor of the primary support falls below the standard allowable value. However, the stability of the primary support can be enhanced by implementing multi-stage variable slopes. As the depth of the tunnel increases, the asymmetric distribution of internal stresses in the primary support decreases, while the overall magnitude of internal stresses continuously increases. When the soil-rock interface crosses the tunnel at various locations, the magnitude of the internal stresses in the primary support is significantly affected, whereas the distribution pattern remains relatively stable. The reliability of the stress characteristics of the primary support under various impact factors was verified through on-site monitoring of the stress variations in the steel arch and concrete at various locations of the tunnel.