地下水含盐量对人工冻结效果影响分析

目前对于人工冻结法的研究主要集中在地下水渗流对冻结效果的影响，未考虑地下水含盐量的影响，对地下水含盐量对冻结效果的影响机制认识不深入。含盐量将会影响地下水的热力学性质，在近海地层和海底进行临时地层冻结加固时，高含盐量地下水将会影响地层冻结效果。基于热流耦合模型，采用COMSOL多场耦合分析软件对双管冻结条件下高含盐量地下水冻结机理展开研究，重点分析冻结温度场、冻结交圈、冻结管间距对冻结效果的影响。研究表明:当地下水含盐量高于4%时，下游的冻结范围受地下水含盐量增加的影响较大。随着地下水含盐量的增加，冻结前期用时较长，积极冻结阶段用时逐渐缩短；当冻结壁完全交圈并冻结完全时，冻结壁中心位置处温度随地下水含盐量的提高而有所升高；冻结管间距的增加将会放大地下水含盐量对冻结的影响。

Analysis of the influence of groundwater salt content on the effect of artificial freezing

Currently, the research on artificial freezing method mainly focuses on the influence of groundwater seepage on freezing effect, while neglecting the salt content. As a result, the mechanism of the effect of the groundwater salt content on freezing effect is not well understood. The salt content will change the thermodynamic properties of groundwater. If the artificial freezing method is applied to temporarily conduct ground improvement in the offshore area and the seabed, high-salt-content groundwater will affect the freezing effect. The aim of this paper is to study the freezing mechanism of high-salt-content groundwater under double pipe freezing by utilizing COMSOL multi-field coupling software based on heat flow coupling model. The influences of freezing temperature field, freezing cycle time, distance of double pipes on freezing effect are especially analyzed. The results show that the freezing range of downstream is greatly affected by the increase of groundwater salt content when the groundwater salt content exceeds 4%. The freezing time of the stage of pre-freezing increases with the increasing salt content of groundwater. While the freezing time of the stage of active freezing time gradually decreases, the salt content of groundwater increases. When the frozen walls completely intersect and freeze, the temperature at the center of the frozen wall increases with the increase of the salt content of groundwater. The freezing effect will be magnified by the increase of frozen pipe distance.