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冻土是寒区工程建筑赖以支撑的基础,同时,又是引起建筑物破坏的主要因素。究其原因在于随温度变化及荷载作用在其中产生的水分的相变、迁移和结构变化,以及由之引起的地基土的冻融变形和蠕变变形。以往对冻土的物理、力学性质宏观变化规律做了大量的研究,但对土在冻融过程中及已冻土在荷载作用下物理、力学性质变化及破坏机理从细观或微观上研究甚少。为了开展这方面的研究,我们首次利用医用计算机断层扫描仪(CT)进行功能开发和改造,对冻融过程中的土及在载荷作用下的冻结土、岩及冰进行CT扫描,对其内部结构的变化及裂纹、空洞的发展过程进行了无损定量观测。通过细致的图像分析,获得试样内部水分、密度和结构变化的数据,取得了一系列创新性的研究成果。
Permafrost is the basis for the construction of cold areas, and at the same time it is also the main factor that causes the destruction of buildings. The reason lies in the phase change, migration and structure change of water produced by temperature change and load, as well as the freeze-thaw deformation and creep deformation of soil caused by it. In the past, a great deal of research has been done on the macroscopic changes of the physical and mechanical properties of frozen soils. However, the study on the changes of the physical and mechanical properties and the failure mechanism of soils during the freeze-thaw process, less. In order to carry out this research, we use the medical computed tomography scanner (CT) for the first time to develop and improve the function of CT scan of the soil during freezing and thawing and frozen soil, rock and ice under load, Structural changes and cracks, hollow development process of non-destructive quantitative observation. Through careful image analysis, the data of moisture, density and structure change in the sample were obtained, and a series of innovative research results were obtained.