考虑变形影响的黄土土-水特征及其滞后效应

Soil-water characteristics and hysteresis effects of loess considering deformation

为了研究变形对非饱和黄土土-水特征和滞后效应的影响,通过先构建恒定吸力条件下土体含水率与孔隙比的关系,再引入吸力的影响,建立了一个能够考虑变形的三维土-水特征曲面模型,模型能够很好地描述不同初始孔隙比黄土吸脱湿过程中含水率随孔隙比和吸力的变化规律。为了证实所提出模型的可靠性,对压实黄土进行一系列吸脱湿过程的土-水特征试验。试验结果表明,恒定吸力条件下土体含水率与孔隙比成线性关系,验证了模型的理论假设。另外由模型可以确定恒定孔隙比状态的土-水特征,将其与试验结果对比发现,脱湿路径由吸力引起的变形对土-水特征影响较大,会使特征参数减小,并抑制滞后效应。

A three-dimensional soil-water characteristic surface model considering deformation is established to study the effect of deformation on the soil-water characteristics and the hysteresis effect of unsaturated loess.It is established by first constructing a relationship between water content and pore ratio under constant suction conditions,and then introducing the effect of suction.The model can describe the change of water content with pore ratio and suction during wetting or drying of loess with different initial pore ratios.Wetting and drying tests on loess show that the water content under constant suction conditions is linearly related to the pore ratio,which verified the theoretical assumptions of the model.Additionally,soil-water characteristics of equal pore ratio state can be determined from the model,and by comparing them with the experimental results,it is found that the deformation caused by suction in the drying path has a greater influence on soil-water characteristics,which will reduce the characteristic parameters and suppress the hysteresis effect.