用過核燃料產生之長期衰變熱會對生物圈造成極大衝擊，目前國際上多傾向以深層地質處置作為最終處置之方式。在長期的處置時間內，衰變熱會使處置場溫度急劇升高，造成高度熱應變；更會因為地下水入侵，在處置場再飽和的過程中，引發熱-水力-變形的耦合效應（簡稱T-H-M效應）；此外，在處置過程中，亦極可能因為工程開挖、地層變動、或地震等因素，在近場形成裂隙，由此伴隨的效應將會加速障壁之劣化。在T-H-M的耦合效應及裂隙的交互影響下，其所相應的力學與水力行為有待審慎的研究與評估。本研究擬採用三維有限元素暫態分析模式，分析深層地質處置設施多孔配置之近場熱-水力-變形耦合效應，觀察其溫度、飽和度、及變形之分布。研究中擬建立處置設施多孔配置有限元素分析數值模型，並採行一耦合迭代運算方案，以預估近場之T-H-M耦合依時行為，同時將考慮不同的裂隙之幾何及材料特性，針對其在系統再飽和過程中可能引致之熱應力與地下水分布之影響進行評估。評量結果期可提供作為我國處置場設計概念參考，以確保處置環境之穩定及安全。 ;Based on the concept of deep geologic repositories, spent nuclear fuel is stored in deposition holes located deep below the ground surface. The heat generated by the waste will induce both significant strain changes and ground water transportation in the multiple geologic barrier system. During water re-saturation process, the ability of the barrier system is inevitably reduced by coupling between the T-H-M responses. In addition, the stability of a system may also depend particularly upon the presence of cracked region resulting from excavation, ground movement, and earthquake. Due to the interaction between the cracked region and the coupling T-H-M behavior, distribution of deformation and water saturation in the near field becomes difficult to solve and more investigations on such an issure are therefore in need. The aim of this proposed research is dedicated to analysis of the near-field T-H-M coupling behavior of multiple deposition holes in a deep geological repository. The involved study will be conducted by using three-dimensional transient analysis. The T-H-M analysis during the water re-saturation process will be carried out by first constructing a series of finite element models that properly simulate the near-field of the multiple deposition holes. Also, an effective iterative computational scheme will be presented for solution of the nonlinear problem. The finite element analyses will be carried out to predict the effects of the influencing factors resulting from the presence of cracked region. Results of the presented analyses are anticipated to be applicable for future reference in practical engineering design.
