對於放射性廢燃料的最終處置，國際間一致採行「深層地質處置」(deep geological disposal)的方式，使其與人類的生活圈完全地隔離。在此概念中又以緩衝材料的選擇影響最為重要，本研究即在針對緩衝材料試驗之步驟及結果進行數值上的驗證及分析，以期進一步了解緩衝材料的性質。 本研究採用有限元素法，進行熱–水力耦合之效應分析，針對緩衝材料試驗試體進行實驗結果之驗證以及討論。 熱傳導分析方面採用傅立葉熱傳導定律(Fourier’s law of heat conduction)，以求得其溫度場。根據其分析結果可知飽和度對於熱傳導的結果影響極大，亦即飽和度愈高，熱傳導係數愈高，溫度擴散的速度也相對較快。在水–力學分析方面採用有效應力理論(effective stress theory) 、廣義虎克定律(generalized Hooke’s law)、達西定律(Darcy’s law)。其結果顯示水力傳導係數與孔隙壓力間存在互制關係，較高之水力傳導係數將致使孔隙壓力的消散迅速，加快飽和度的增加速率，進而影響溫度場的分佈。 Deep geological disposal is the kind of method used worldwide for radioactive spent fuel, which needs to be completely isolated form human life cycle. Selection of buffer material is the most important factor in this concept. Our study uses finite element method and conducts analysis of the coupled thermo-hydro calculations. The effect due to water saturation is discussed and compared with experiment results of buffer material. The heat conduction analysis uses the Fourier’s law of heat conduction to obtain the temperature field. The degree of saturation plays an important role in heat conduction analysis. High saturation results in high thermal conductivity. The temperature diffusion rate is consequently increased. Hydraulic calculation uses effective stress theory, generalized Hooke’s law and Darcy’s law. The relation between hydraulic conductivity and pore pressure is shown. Higher hydraulic conductivity resulis in higher diffuse rate of pore pressure. This increases the rate of saturation and influences distribution of temperature field.
