基于孔隙分布的变形土土水特征曲线模型

A water retention curve model for deformable soils based on pore size distribution

土体孔隙分布对土水特征曲线具有决定性影响。虽然土体孔隙分布随变形的演化规律较为复杂,但实验研究表明,土体在变形过程中,孔隙分布的基本形态未发生显著变化、统计分布特征基本不变。基于这一结论,假定变形后的孔隙分布函数可以从参考状态孔隙分布函数经过平移、缩放得到。在此基础上,建立了考虑土体变形并反映滞回效应的土水特征曲线模型。由于变形对土水特征曲线的影响是通过孔隙分布随变形的改变来表征的,因此模型参数的物理意义明确,仅有7个参数,均可通过常规室内试验确定。最后,通过一系列试验数据验证了该模型的正确性与可靠性。

It has been recognized that the pore size distribution plays a decisive role in the water retention curve of soils.Although the pore size distribution evolves in a rather complicate way during deformation,experimental observations have shown that the overall shape and the distribution characteristics of the pore size distribution are not significantly altered.Based on these findings,it is assumed that the pore size distribution in a deformed state can be obtained from the pore size distribution in a reference state by horizontal shifting and vertical scaling of the pore size distribution function.On this basis,a water retention curve model is formulated to account for the effects of soil deformation and hydraulic hysteresis.Benefited from the characterization of the effects of soil deformation on the water retention curve by the change of pore size distribution,the proposed model contains a compact set of seven parameters with clear physical meanings,which can be easily calibrated by regular laboratory tests.The proposed model is finally validated against a number of laboratory tests,showing good agreements between the model predictions and the experimental measurements.