中文摘要：

拖尾分布是溶质运移规律研究的热点和难点。死端孔隙、透镜体等空间结构形成的非均质性以及密度变化产生的指状流会导致溶质运移拖尾分布。论文选择保守性溶质氯化钠作为示踪剂,采用砂柱实验系统地研究了以死端孔隙导致的非均质性以及由不同浓度和温度形成的变密度条件对溶质运移拖尾分布的影响。实验结果表明：死端孔隙的存在会延迟溶质运移穿透曲线出峰时间,降低峰值及出现拖尾分布,随着死端孔隙介质体积或数量的增加这一现象越明显;随着溶液浓度的增加拖尾现象越明显,且温度的升高会加剧这一现象。对比死端孔隙、温度和浓度三者对溶质运移拖尾分布的影响,其中影响最大的是死端孔隙,其次是浓度和温度。

英文摘要：

Heavy tail is an important topic of solute transport. Spatial structures like the immobile domain and lenticle lense will lead to the heterogeneity of porous media which results in the distribution of heavy tail. Finger flow caused by variation of density will also lead to heavy tail. Based on the above theory, this paper chooses NaC1 as the tracer since it is a kind of conservative solute. The sand column experiment is used to study the influences of the immobile domain, concentration and temperature on solute transport. The results show that the immobile domain will lead to the delay of the breakthrough curves, the reduction of peak and the distribution of heavy tail. The larger the amount of the immobile domain is, the more obvious the heavy tail is. The higher the concentration is, the more obvious the heavy tail is. The heavy tail will be intensified with a higher temperature. Among all the influence factors, the immobile domain mostly influences the distribution of solute transport more, and concentration and temperature follow.