非均质饱和土壤盐分优先运移的随机模拟(英文)

STOCHASTIC MODELING OF CHLORIDE TRAVEL IN HETEROGENEOUS SATURATED SOILS UNDER THE CONDITION OF PREFERENTIAL FLOW

在室内使用特殊形状的土柱隔板成功地填装了在水平横截面上呈"川"字型分布、由质地相差较大的两种土壤相间构成的非均质土柱.当土柱出流达到稳态后,灌入CaC l2溶液,监测土柱出流液的浓度动态,通过计算表征氯离子迁移时间随机特征的概率密度函数,对出流盐分的优先运移采用传递函数模型进行仿真,并对构成非均质土柱的两种均质土壤分别进行了条件类似的水盐入渗实验和模拟.在此基础上获得了参与氯离子输运的土壤水运移体积和可动体积以及土壤溶液中氯离子的体积平均驻留浓度.

In this paper, the construction of a heterogeneous soil column in our laboratory is presented. The column contains two kinds of homogeneous soil of two different textures, and is successfully constructed in the Ⅲ- shaped cross - section distribution of sandy loamy and loamy clayey soil using special shape soil partition. The heterogeneous soil column （ 50cm × 50cm × 40cm） is irrigated with 0. 027 mol L^- 1 CaCl2 solution until stead water flow in soil column appears. The effluent is collected every five minutes. The data is simulated using a transfer function model （TFM）. The probability density functions of the logarithm of travel time of chloride are calculated, together with the model parameters （i. e. mean and deviation） estimated. In addition, the transport volumes of chloride, the volume - averaged resident concentrations of chloride in the soil solution and other parametric values are obtained. Finally, for a comparison between the deterministic and stochastic models, the breakthrough curves （BTC） in homogenous soils are plotted and simulated by the convection- dispersion equation （CDE）.