Fundamental research for transport-diffusion of contaminants in the basement

这是弄清地下室中污染物运移扩散现象的基础研究。本研究的特点是将x射线CT作为一种工业应用的无损可视化技术，并对传输-扩散现象的可视化建立和评价方法进行了研究。根据以下4个主题进行了研究。本课题的研究结果如下：1)建立了世界领先的显示传输-扩散现象的示踪x射线CT方法。也就是说，这种粘度与密度无关的新型示踪剂使岩石和土壤中的输运扩散场的清晰可视化成为可能。利用示踪x射线CT法获得的图像数据，建立了分析输运扩散过程中速度结构的理论。2)建立了传输扩散场可视化的基本实验技术和示踪x射线CT法分析速度结构的方法。开发了新的图像处理技术，建立了确定扩散长度等与传输扩散相关的物理参数的实验评价方法。3)为了评价x线CT图像数据中孔隙的空间分布，明确了克里金方法的适用性。采用示踪x射线CT方法对孔隙度为10% ~ 60%的全饱和多孔砂岩和人工多孔材料进行了岩石中输移-扩散的结构依赖性分析。这些结果为今后对输运扩散现象的研究提供了有用的数据。4)建立了考虑材料非均质性和各向同性的二维输运扩散有限元程序，并通过数值分析验证了示踪x射线CT方法的有效性。这些结果为基于示踪x射线CT方法的速度结构分析误差评估提供了基础必要的数据。少

This is the fundamental studies to make clear the transport-diffusion phenomena of contaminants in the basement. The characteristic point of this study is to utilize X-ray CT for industrial use is applied as a nondestructive visualization technique, and the establishment of the visualization and the evaluation method of the transport-diffusion phenomena have been investigated.Studies have been conducted according to the following 4 subjects. The results obtained in this project are follows.1)The tracer X-ray CT method to visualize transport-diffusion phenomena was established ahead of the world. That is, the new tracer, which viscosity is independent from the density, makes possible the clear visualization of the transport-diffusion field both in rocks and soils. Utilizing the obtained image data by the tracer X-ray CT method, the theory to analyze the velocity structure during transport-diffusion was also established.2)The fundamental experimental technique for the visualization of tr … More ansport-diffusion field and the method to analyze velocity structure by tracer X-ray CT method was developed. The new image processing technique was also developed, and the experimental evaluation method to determine physical parameters related to transport-diffusion, such as diffusion length, was established.3)In order to evaluate space distribution of pores from X-ray CT image data, applicability of kriging method was clarified. The structure dependency of transport-diffusion in a rock was also analyzed by applying the tracer X-ray CT method towards fully saturated porous sandstone and artificial porous materials which has 10 to 60% porosity. These results provided useful data to future studies of transportation-diffusion phenomena.4)2-D transport-diffusion FEM code which can consider the heterogeneity and the isotropy of materials was developed, and validity of the tracer X-ray CT method was confirmed by numerical analyses. These results provided fundamental necessary data to the error evaluation in the analysis of velocity structure based on the tracer X-ray CT method. Less