Yin Zhenhua, Zhang Hu, Zhang Jianming, Chai Mingtang
Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, State Key Laboratory of Frozen Soil Engineering, Lanzhou, 730000, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Sci Rep. 2020 Oct 1;10(1):16297. doi: 10.1038/s41598-020-73148-3.
The foundation of constructions built in the permafrost areas undergo considerable creeping or thawing deformation because of the underlying ice-rich permafrost. Soil improvement may be of advantage in treating ice-rich permafrost at shallow depth. Sulphoaluminate cement was a potential material to improve frozen soil. Simultaneously, two other cements, ordinary Portland cement and Magnesium phosphate cement were selected as the comparison. The mechanical behavior of modified frozen soil was studied with thaw compression tests and unconfined compression strength tests. Meanwhile, the microscopic mechanism was explored by field emission scanning electron microscopy, particle size analysis and X-ray diffractometry. The results showed Sulphoaluminate cement was useful in reducing the thaw compression deformation and in enhancing the strength of the frozen soil. The improvement of the mechanical behavior depended mainly on two aspects: the formation of structural mineral crystals and the agglomeration of soil particles. The two main factors contributed to the improvement of mechanical properties simultaneously. The thicker AFt crystals result in a higher strength and AFt plays an important role in improving the mechanical properties of frozen soils.The study verified that Sulphoaluminate cement was an excellent stabilizer to improve ice-rich frozen soils.
由于下层富含冰的永久冻土，在永久冻土地区建造的建筑物基础会经历相当大的蠕变或融化变形。在处理浅层富含冰的永久冻土时，土壤改良可能会有帮助。硫铝酸盐水泥是改良冻土的一种潜在材料。同时，选择另外两种水泥，即普通硅酸盐水泥和磷酸镁水泥作为对照。通过融化压缩试验和无侧限抗压强度试验研究了改良冻土的力学行为。同时，通过场发射扫描电子显微镜、粒度分析和X射线衍射法探索微观机制。结果表明，硫铝酸盐水泥有助于减少融化压缩变形并提高冻土强度。力学性能的改善主要取决于两个方面：结构矿物晶体的形成和土壤颗粒的团聚。这两个主要因素同时有助于力学性能的改善。AFt晶体越厚，强度越高，AFt在改善冻土力学性能方面起着重要作用。该研究证实，硫铝酸盐水泥是改良富含冰的冻土的优良稳定剂。
