在桩的线弹性地基反力法基础上，求出考虑承台以及埋深影响的沉井水平位移的通解，即在沉井计算中，经常遇到的地面处水平抗力不为0时新的计算方法。并对沉井的边界条件作出了数学上的归纳总结，它们涵盖了在实际中可能遇到的大多数情况。推导出了对应于每种工况的显式表达式，并利用安徽马鞍山长江大桥的实际数据验证了所求得的显式解的数学上的正确性和力学上的合理性。所得出的公式对长桩、短桩、细桩、粗桩以及沉井桩都适用。承台对沉井（桩）的约束体现在桩顶的边界条件中。

A general elastic solution for single pile constrained by buried platform was derived to calculate the horizontal displacement, the shear stress and the bending moment of the pile. The specially explicit solutions for several boundary condition groups which are merged into three group scenarios are presented. Three examples are presented to highlight the mathematical correctness and the mechanical rationality of the obtained solutions. The solutions are applicable to both short and long piles and even caissons.