Mass transport in frozen ground is typically regarded slow. However, a highly permeable path can exist in frozen saline sand if the unfrozen water is interconnected at the pore scale. We therefore should consider when the unfrozen water is connected and how permeable can frozen saline sand be, yet there are few studies. This research utilizes in-situ X-ray CT to evaluate unfrozen water connectivity and permeability in frozen saline sand considering effects of initial salt content, temperature, freezing rate, and temperature gradient. Results show that higher initial salt content and/or temperature, both of which results in a higher unfrozen water content, easily maintains unfrozen water connectivity. Rapid freezing minimizes the brine expulsion and permits a higher unfrozen water content hence better connectivity. Permeability in frozen saline sand can be several orders higher than the typically reported value, highlighting the potential presence of rapid mass transport through the connected unfrozen water.

中文翻译：

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冻盐沙具有高度渗透性


冻土中的质量传递通常被认为是缓慢的。然而，如果未冻结的水在孔隙尺度上相互连接，则冻结的盐沙中可以存在高渗透性路径。因此，我们应该考虑未结冰的水何时连接以及冻存盐沙的渗透性如何，但研究很少。本研究利用原位 X 射线 CT 评估冻盐砂中未冻结的水连通性和渗透性，考虑初始盐含量、温度、冻结速率和温度梯度的影响。结果表明，较高的初始盐含量和/或温度（两者都会导致较高的未冻结水含量）很容易保持未冻结的水连通性。快速冷冻最大限度地减少了盐水的排出，并允许更高的未冻结水含量，从而获得更好的连通性。冻盐沙的渗透率可能比通常报告的值高几个数量级，这凸显了通过连接的未冻结水存在快速质量传输的可能性。