中文摘要：

为了研究冻融环境对黄土工程特性的影响,对山西阳曲1号黄土隧道施工过程进行了监测,可知冻融循环会通过对土中水的作用改变黄土特性,从而导致黄土工程特性的改变.以山西阳曲1号黄土隧道掌子面黄土为研究对象,运用损伤力学的研究方法,对土样进行了冻融循环后的CT扫描试验并分析,结果表明：冻融循环会造成土样原孔隙扩展、伸长、分叉、贯通;冻融循环对试件的破坏作用与初始孔隙分布密切相关;冻结过程发生水分向低温端（由内向外）迁移,土样发生明显的冻胀密减现象;随着冻融循环次数的增加,黄土CT数均值减少,方差增大,当15次冻融循环后,CT数均值趋于平缓.总体上来看,土样ME随冻融循环次数的增加而降低,SD随冻融循环次数的增加而增加.

英文摘要：

In order to study the influence of freeze-thaw environment on the engineering properties of lo- ess, mointoring the Shanxi Yanqu No. 1 loess tunnel construction process, know the freeze-thaw cycle will change the loess characteristics through effects on soil water, thus leading to changes in the engineering properties. Taking the Loess of Shanxi Yangqu No. 1 tunnel face as the research object, using damage mechanics research methods, the soil was tested and analyzed under the freeze-thaw cycle after CT scan- ning. The results show that：the freeze-thaw cycle can cause the soil pore expansion, the original elonga- tion, bifurcation, through ; freeze-thaw damage to the specimen is closely related to the distribution of ini- tial pore;during the freezing process of water to lower temperature side （from the inside to the outside） migration, soil frost density decrease obviously;with the increase of freeze-thaw cycles, the mean CT val- ue decreased,the variance increases, after 15 cycles of freezing and thawing, mean CT value tends to be smooth. On the whole, soil ME decrease with the freeze-thaw cycle increase, SD increase with the in- crease number of freeze-thaw cycling.