Abstract: To calculate the settlement, the Kelvin creep model and the Duncan no-linear model in series were installed as a new model to describe the settlement and creep. The model was combined with governing equations of pore water and pore air and a new consolidation theory of unsaturated soil was obtained, including the creep of subgrade. The equations used can be used to get values of pore water and pore air at any place and time. The consolidation-creep theory was applied to engineering to verify that the correctness and the test results were consistent with the conclusion. Using the proposed unsaturated soft soil theory, the influence of the soft soil roadbeds boundary conditions on the consolidation speed was explored. It was found that boundaries with better permeability are advantageous to complete the dissipation of pore pressure as soon as possible and accelerate the process of consolidation. Pore pressure is not necessarily monotonically decreasing in the process of consolidation of unsaturated soft soil and negative pore water pressure could occur in the process of consolidation.

Key words: geotechnical engineering, subgrade of soft soil, unsaturated soils, creep, consolidation theory

摘要： 为解决非饱和软土路基在长期荷载作用下的沉降问题，将Kelvin蠕变模型与Duncan非线性弹性模型串联为一个新的非线性黏弹性蠕变模型，来描述非饱和土路基的应力应变关系。结合孔隙水和孔隙气体的控制方程，推导出非饱和软土路基一维条件下的固结-蠕变耦合方程，可以求解非饱和土路基任意时间任意位置的孔隙水压力、孔隙气压力和沉降量，并考虑了长期荷载作用下路基的蠕变变形。结合工程实例对方程进行了验证，计算结果与实际工程有良好的吻合性。利用推导出的一维固结-蠕变耦合方程，对非饱和土固结的边界条件和初始孔隙水压力分布对其固结的影响进行讨论，发现其边界的排水条件对孔隙压力的消散速度有明显的影响，并且非饱和软土在固结过程中的孔隙压力并不一定是单调递减的，固结过程中可能出现负孔隙水压力。

关键词: 岩土工程, 软土路基, 非饱和土, 蠕变, 固结理论