注浆是提高冻融环境下的地下建筑结构抗冻胀破坏能力的常用技术手段，传统注浆材料难以满足严寒气候条件对其高抗冻性的要求。碳纳米管（CNTs）/氧化石墨烯（GO）等纳米增强水泥为研制高强抗冻水泥基注浆材料提供了新的科学依据，但目前尚不明确冻融对其基本物性的影响规律和机理。有鉴于此，本项目拟对CNTs/GO增强水泥基注浆材料在冻融环境下的宏观物理力学性质进行系统研究；然后结合原子力显微镜、背散射电子成像、聚焦离子束-扫描电镜等纳米表征技术，探究冻融对材料微观断裂、纳观杨氏模量和孔隙结构等特征的影响，建立可以评价和预测冻融导致材料强度变化的微观损伤模型；建立模拟含CNTs/GO的水泥基注浆材料分子动力学模型，揭示冻融环境下CNTs/GO影响材料变形破坏及强度特性的微观力学机理。研究旨在阐明冻融环境导致纳米增强水泥基注浆材料物性变化的微观机理，为高海拔、高纬度寒区内注浆加固工程的设计提供理论依据。

Grouting is a commonly adopted method to enhance the resistance to frost damage of the underground structures sustaining the freeze-thaw geological environment. It is difficult, however, for the traditional grouting materials to meet the requirement of cold weather conditions for high frost resistance. The carbon nanotubes (CNTs)/graphene oxide (GO) enhanced cement provide a new idea for developing cement-based grouts with the enhanced performance in strength and frost resistance, whereas more research is needed to know the influencing laws of freeze-thaw conditions on its material parameters. Therefore, in this project, the macroscopic physical and mechanical properties of the CNTs/GO enhanced cement-based grouts under the freeze-thaw conditions will be studied firstly. Then the effects of temperature variations on the characteristics of micro-fracture, nanoscale Young’s modulus and pore structures of the grouts will be furtherly investigated by utilization of Nano-characterization techniques of atomic force microscope (AFM), backscattered electron imaging (BSE), focused ion beam - scanning electron microscopy (FIB-SEM), et al., comprehensively. The micro damage model that can evaluate and forecast the changes of strength performance of grouts caused by freeze-thaw conditions will be established. After that, the molecular dynamics simulation model simulating the cement-based grouts containing CNTs/GO will be established, according to which the micromechanical mechanism of CNTs/GO influencing the fracture and strength performance of grouts will be revealed. This research aims to clarify the micro mechanism of the material parameters changing of the nanoscale reinforced cement-based grouts caused by freeze-thaw environment. The results can work as the theoretical basis for the designing of grouting projects conducted in cold regions with high altitude or high latitude.