冻结作用下黏土中水、盐迁移试验研究

为了探究冻结作用下黏土中水盐迁移特性，采用室内单向冻结试验装置，基于TDR技术对添加不同溶质（NaCl）浓度的土样进行了土中温度、含水率及电导率（EC）的同时连续测量。结果表明：溶质的添加引起土中孔隙水冰点下降，造成土中成冰量减少，从而导致含溶质土样的冻结深度大于不含溶质土样；在封闭系统中随着溶质浓度的增大，土中水分迁移量和溶质迁移率均有增大趋势，距离冻结锋面越远，水分、溶质迁移量就越少；冻结锋面附近液态水凝结成冰，引起冻结锋面附近溶质浓度变化剧烈，溶质浓度急剧增大。

Experiment study on water and salt migrations in clay under freezing effect

In order to explore the characteristics of water and salt migrations in clay under freezing effect, indoor soil unidirectional freezing test equipment was used to measure the soil temperature, water content and electrical conductivity (EC) continuously with TDR (time domain reflectometry) technology for soil samples containing different solute concentrations (NaCl). The results show that the addition of solute causes the freezing point to drop, resulting in decrease of ice mass in the soil, resulting in the freezing depth of the solute-containing soil being larger than that of the solute-free soil. With the increase of solute concentration in the closed system, the migration of water and solute in soil increases with the increase of solute concentration. The farther from the freezing front, the smaller the migration amount of water and solute; the liquid water near the freezing front condenses into ice, causing the solute concentration changing strongly near the freezing front and the solute concentration increasing rapidly.