经典土压力理论的应用是基于半无限土体，但当墙后土体范围有限时经典土压力理论可能就不再适用，出现有限土体土压力问题。针对较复杂条件下无黏性土的有限土体土压力问题，建立了计算模型，并采用薄层单元法推导出解析公式，证明经典的郎肯土压力和库仑土压力皆为所提出的新公式的特解。在综合考虑不同计算条件后，制定土压力计算流程，涵盖了各个条件下土压力计算方法。通过计算分析表明：极限破裂角不为定值，随计算参数的变化而变化；不存在有限土体时，所提新公式解与库仑解较接近；出现有限土体时，新公式解趋近于模拟解，从而证明了新公式解的合理性。此时与库仑解相比，则存在明显差异。

The classical earth pressure theory is based on the assumption of semi-infinite space. However, the dimension of soil behind the retaining wall is limited, so that this theory is no longer suitable for calculating the earth pressure. The aim of this study is to develop the earth pressures for the limited cohesionless soil under complex conditions. The new solution for the active earth pressure is developed using the thin-layer element method. It is shown that the Ranking and Coulomb’s earth pressure theories are the particular cases of the proposed model. It is also shown that the limit rupture angle is not constant and it varies with the calculation parameters. The new solution approaches to Coulomb’s active earth pressure when the soil is infinite. When there are limited soils, the new solution tends to be consistent with the simulation solution, proving the reasonability of the new solution. In this case, it is significantly different from Coulomb’s solution.