侧压力系数对隧道围岩变形和支护结构力学响应具有重要的影响，准确得到隧址区侧压力系数 λ可有效指导隧道的设计与施工。首先从理论角度分析了侧压力系数对隧道拱顶沉降位移和边墙水平位移的影响；其次，通过监控量测得到隧道边墙水平位移与拱顶沉降位移的比值，并结合数值模拟手段，建立了水平-竖向位移系数K与侧压力系数λ之间的数学关系，从而实现了侧压力系数的反演；最后，将反演得到的侧压力系数应用于隧道断面的优化设计。研究结果表明：在相同的地质条件下，K与λ近似呈线性关系；无论隧道的埋深或围岩条件如何变化，水平位移与沉降位移之间始终存在比例关系，可用于隧址区侧压力系数的反演；根据监控量测数据反演得到隧道侧压力系数为1.1，施工中通过不断调整隧道轴比m，使其逐渐趋近于λ^-1，有效控制了隧道变形，降低了衬砌变形破坏比例。

During tunnel construction, the deformation of surrounding rock and the mechanical response of the supporting structures are significantly influenced by the lateral pressure coefficient λ. Accurate determination of the on-site lateral pressure coefficient is essential for guiding tunnel design and construction. Firstly, the impact of the lateral pressure coefficient on settlement displacement of the tunnel vault and horizontal displacement of the side walls was analyzed theoretically. Secondly, the ratio between horizontal displacement of the side walls and settlement displacement of the vault was monitored, and a numerical simulation was employed to establish a mathematical relationship between the horizontal-vertical displacement coefficient K and the lateral pressure coefficient λ, enabling the inversion of the lateral pressure coefficient. Finally, the inverted lateral pressure coefficient was applied to optimize tunnel cross-section design. The results indicate that, under the same geological conditions, an approximately linear relationship exists between K and λ. Regardless of changes in tunnel depth or surrounding rock conditions, a proportional relationship between horizontal and settlement displacements is maintained, which can be used to invert the lateral pressure coefficient at the tunnel site. By adjusting the tunnel axis ratio m to gradually approach λ^-1, deformation is effectively controlled and the proportion of lining damage is reduced.