Study On Natural Ice Microstructure Based On Analyses Of CT Imagery

Natural ice widely exists in nature and is closely related to human production and life.The presence of natural ice will not only affect the design and construction of water conservancy engineering facilities(reservoirs,dams,buildings along rivers,etc.),but may even cause disasters when the ice situation is serious.The study of the internal microstructure of natural ice is of great significance to the definition of its basic physical properties(mechanics,heat,optics,etc.).Natural ice is a kind of multi-phase mixed material with complex pore morphology and distribution,which may contain sediment,bubbles,brine,crystal salt and other impurities.In the traditional methods,the research on the internal microstructure of natural ice is mostly based on the two-dimensional plane(such as slicing method,microscopic observation,etc.),and the description of impurity distribution and pore complexity in the three-dimensional space is relatively rough.In this study,CT scanning technology and image processing technology were used to provide a feasible method for the description of the internal microstructure of natural ice.The specific research content includes the following three aspects:1.CT scanning tests were conducted on natural ice samples.The CT images obtained can reflect the geometric morphology and CT value characteristics of various impurities in natural ice.CT image cutting,filtering,threshold segmentation and other processing,for the construction of three-dimensional(3D)model to provide the image foundation.2.In combination with the theoretical basis of CT value inversion density and the application of CT scanning in other material fields,the mass volume method was used to measure the density of natural ice samples,and the results were fitted with the measured CT values to obtain the relationship between the natural ice density and CT values.3.The CT images of natural ice were used to select the appropriate 3D modeling method for the 3D modeling of various impurities and microstructure inside natural ice,and the 3d pore model of natural ice was obtained.The advantages and disadvantages of traditional formula and 3D model for calculating porosity are compared.The CT images of various impurities in natural ice were summarized and summarized by combining CT images with three-dimensional model analysis.Among them,the micro-bubble aggregation structure in the ice of Wuliangsuhai Lake,the ribbonlike pores of the ice in the Yellow River during the thawing period,and the sediment in the ice of the Yellow River in different freezing-thawing states were all found for the first time in the CT scanning natural ice experiment.The internal microstructure of natural ice can be quickly scanned and identified with the rapid,nondestructive and standardized features of CT scanning technology.