潜水矿化度对毛细水上升高度的制约特征研究

Restriction characteristics of total dissolved solids on capillary water rising height

为了探究不同土壤类型矿化度对毛细水上升高度的制约特征,文章选取不同粒径砂性土与砂质壤土开展不同矿化度影响下的土壤毛细水室内柱试验研究,定量刻画了粒径与矿化度对毛细水上升高度的差异,建立了对数函数拟合模型。试验结果表明,矿化度通过改变土壤水的重力势、基质势来制约毛细水的上升高度。矿化度为0.8、15.0、50.0g/L时,72 h中砂最大毛细水上升高度h_(max)分别为32.5、31.3、30.2 cm,细砂h_(max)分别为50.4、48.6、48.7 cm,粉砂h_(max)分别为72.3、76.4、76.0 cm,砂质壤土h_(max)分别为59.0、60.2、58.6 cm;粉砂和砂质壤土的毛细水上升速率变化波动较大,全试验周期内毛细水上升高度h与时间t可用三参数对数函数刻画。该研究结果揭示了矿化度对毛细水上升高度的制约特征,深化了毛细水上升高度的机理研究,可为土壤盐渍化治理、确定地下水生态水位提供技术支撑。

In order to explore the restriction characteristics of mineralization degree on capillary water rising height under different soil types, three kinds of sandy soil and sandy loam were selected to carry out soil capillary water test under the influence of mineralization degree by indoor column test, the difference of capillary water rising height under the influence of particle size and mineralization degree was quantitatively characterized, and the logarithmic function fitting model was proposed. The experimental results show that total dissolved solids(TDS) restricts the rising height of capillary water by changing the gravity potential and matrix potential of soil water. When TDS was 0.8, 15.0, and 50.0 g/L, after 72 hours, the maximum capillary water rising height(h_(max)) of medium sand was 32.5, 31.3, and 30.2 cm, the h_(max)of fine sand was 50.4, 48.6, and 48.7 cm, the h_(max)of silt was 72.3, 76.4, and 76.0 cm, and the h_(max)of sandy loam was 59.0, 60.2, and 58.6 cm. In terms of capillary water rising rate, the rate change of silt and sandy loam fluctuates greatly, and the relationship between capillary water rising height(h) and time(t) in the whole test cycle can be described by a three-parameter logarithmic function. The results of this study reveal the restriction characteristics of TDS on capillary water rising height, further deepen the research on the rising height of capillary water, which can provide technical support for the treatment of soil salinization and the formulation of groundwater ecological water level.