关键词: 本构模型, 路基沉降, 结构性软土, 固结历史

Abstract: Structural marine soft soil layer is widely distributed in coastal region, which brings lots of potential disasters. Soft soil subgrade in the Jiangsu provincial section of an expressway is studied in this research. A new method, to obtain constitutive parameters of undisturbed soil of Shanghai model by consolidation test results of compressed soil is proposed. The subgrade settlement is simulated by soil-water coupled FEM software. The effect of soil structure, permeability and thickness of soft soil layer on subgrade settlement are analyzed. The results show that the stronger the initial soil structure is, the larger pore pressure and subgrade settlement are in loading stage. With the gradual destruction of soil structure after completion of construction, it is positively correlated with the amount of layer compression and soil structural parameters. The permeability affects settlement and settling time as well. The lower the permeability is, the larger total subgrade settlement and more proportion of post-construction settlement are. Thickness of the soft soil can also affect settlement and settling time. The thicker the soil layer is, the larger subgrade settlement and longer settling time are.

Key words: constitutive model, subgrade settlement, structural soft soil, consolidation history