为解决沉管结构横向设计计算中的地基刚度取值问题，基于HS本构模型，通过理论推导研究地基刚度随应力水平的变化关系，得出沉管隧道横向地基刚度分布的近似解析解。结果表明： 1)沉管横向地基刚度分布模式与地基初始刚度、结构刚度、地基应力水平和上部荷载有关； 2)在软弱地基情况下，沉管横向地基刚度为W形分布模式； 坚硬地基情况下，底板跨中可能会与地基发生局部脱开，脱开段地基刚度为水平分布； 3)通过算例分析，地基刚度分布近似解析解与数值模拟结果能够较好地吻合，可为沉管结构计算提供依据。

The foundation stiffness values in transverse design and calculation of immersed tunnel structure are very important. As a result, the variation law of foundation stiffness with stress is studied by theoretical analysis; and then the approximate analytical solution of the distribution of transverse foundation stiffness of immersed tunnel is derived based on constitutive theory of hardening soil model. The study results show that: (1) The distribution of transverse foundation stiffness is related to the initial foundation stiffness, structural stiffness, foundation stress level and upper loads. (2) In case of soft foundation, transverse foundation stiffness is distributed as Wshape; and in case of hard foundation, the structure may be locally separated from the foundation at midspan, and the foundation stiffness between separation sections is horizontally distributed. (3) The results of numerical examples show that the analytical solution of the foundation stiffness distribution is consistent with numerical results, so as to provide a basis for the calculation of immersed structure.