非饱和土与饱和冻融土导湿系数的变化特征

Hydraulic Conductivity of Unsaturated Soil and Its Changing Regularity in Saturated Soil After Freezing-thawing Cycles

通过室内试验,得出非饱和土壤的导湿系数是其含水量与土水势的指数函数,且随含水量的降低而快速降低。并对影响导湿系数的干容重、土类、含水量等因素进行了分析与讨论。饱和土冻结融化后,其导湿系数均大于冻前,经历数次冻融后,导湿系数每次都略有变化,但基本趋于一常数。

The hydraulic conductivity both in unsaturated and saturated soil after freezing-thawing cycles has been determined in laboratory. Results show that the hydraulic conductivity of unsaturated soils is in relation to saturation degree (or water content) and soil-water potential in the power form. It decreases quickly with decreasing water content and increases with increasing dry density. The hydraulic conductivity decreases with increasing fineness content while the water content and the dry density are the same. The hydraulic conductivity of saturated soil after thawing is greater than that before freezing and its increment is greater in fine-grained soil than in coarse-grained soils after one freezing and thawing cycle and is also greater in the soil with greater dry density. After several freezing and thawing cycles, the hydraulic conductivity is slightly increased, compared with that experienced one freezing and thawing cycle.