冻融作用对土壤水分迁移和地下水位波动影响的实验研究

Freeze-thaw effect on soil water migration and groundwater level fluctuation

相比于非冻土分布区,季节性冻土区冬春季节的冻融作用显著影响着土壤水分运动和地下水位动态,进而改变地下水土环境中的水力条件和污染物分布特征.针对冻融作用下地下水位的波动过程尚缺乏定量化的具体研究,本文首次建立包气带、含水层水分迁移过程的冻融循环模拟实验装置,定量模拟分析了不同介质粒径和不同温度条件下冻融过程造成的水位波动差异,揭示冻融作用下土壤水分迁移和地下水位的波动规律.结果表明:冻融过程地下水位变化阶段与土壤冻融阶段相对应,且存在滞后现象;土壤的介质条件和温度条件均对冻融过程中地下水的波动具有重要影响,粒径越细,温度梯度越大,水分迁移量越大,水位波动越显著.

Different from areas of non-frozen soil,seasonal freezing and thawing of soil significantly affects soil water movement and groundwater level dynamics,resulting in altered hydraulic conditions and pollutant distribution characteristics in groundwater and soil environment.Specific quantifications in the fluctuation process of groundwater levels under freeze-thaw conditions have not been performed before.Therefore in the present work we established a device to simulate freeze-thaw cycle for moisture migration in aerated zones and aquifers,to quantitatively analyze different particle sizes and different temperature conditions.Differences in water level fluctuation due to freezing and thawing process indicated that freezing and thawing had direct effects on soil water migration and groundwater levels.Changes in groundwater levels in the freeze-thaw process corresponded to freeze-thaw stage of soil,and hysteresis was observed.Soil media conditions and temperature conditions were found to have marked effect on fluctuations in groundwater during freeze-thaw process.With larger amount of water migration,the water level fluctuations become more significant.