Visualization of thermal fluid flow in rock sample by X-ray Computed Tomography

X射线计算机层析成像技术被成功地应用于岩土材料内部流体流动的可视化。为了设计和制作高温热流体流动实验装置，通过保持岩土材料和流体的恒温，进行了一系列的基础实验。在此基础上，发展了一套适用于高温实验的实验技术链和实验结果显示理论。将序列图像减法和局部区域平均技术成功地应用于流体孔隙结构、含水率和浓度的定量分析，并提出了改进的软件，用于多孔介质中流体运移的图像处理，土壤中的应变局部化先于渗透系数、扩散系数和热流体流动分析所需的色散系数。对于流体流动实验，提出了一种新的方法--分步加压法，并结合沿水线的基质吸力的大小，从一维水流实验得到的系列投影减去。在此基础上，提出了一种新的恒流量下定量分析多孔介质中溶质的一维方法，并以碘化钾溶液为示踪剂，给出了一个成功的应用实例，说明X射线层析成像技术是目前岩土力学模型实验和岩土流体流动现象定量分析中一种很有希望的监测工具。

X-ray Computed Tomohraphy was successfully utilized for the visualization of fluid flow within geo-materials. In order to design and produce the apparatus for a thermal fluid flow experiment at a high temperature, a series of fundamental experiment was performed by maintaining geo-materials and fluid at constant temperature. Consequently, a chain of technique available for a high temperature experiment was developed together with the theory for interpriting the experimental results.Namely the subtraction of serial images and the local region avaraging technique were successfully applied to the quantitative analysis of porosity structure, water ratio and concentration of fluid, and the improved sofyware was presented for image processing of the fluid migration in porous media, the strain localization in soil prior to the coefficient of permeability, the diffusion coefficient and the ispersivity required for the thermal fluid flow analysis.As concerns the fluid flow experiment, a new method called multi-step pressurization procedure has been presented together with the magnitude of the matrix suction along water front, from the subtraction of serial projections obtained by one-demensional water flow experiment. Moreover, a new one-demensional method available for the quantitative solute within porous media at constant flow rate was developed, and a successful case study was presented using the solution of potassium iodide as a tracer.From the present stydty, it is concluded that the X-ray Computed Tomography is a hopeful monitoring tool presently available for geomechanical model experiment and the quantitative analysis of fluid flow phenmena within rock and soil.