核能發電所產生之核廢料處置技術近年在各工業先進國家是極受矚目的課題。地質深層處置法利用穩定地質的天然障壁及人為的工程障壁似，防止核種遷移已成為世界各國處理高放射性核廢的共同趨勢。工程障壁中的緩衝材料直接包裹核廢料桶，因此，對於各項工程性質的要求極為嚴格，也是工程障壁極為重要的一環。經壓實之緊密砂-皂土混合物由於具有良好的阻絕性能、適當的自癒性及優良的力學、熱學性質，已普遍被各國學者選為緩衝材料之主要的候選材料。適切配比的砂-皂土混合物構成的緩衝材料雖然性能上較純皂土為佳，但其性質與配比有密切的關連。過去包括晚近的國外學者在研究此一主題時常依賴大量的試驗，由於配比繁多，結論多為定性的描述，不易獲致定量化的預測模式，使得對其整體性質難有精確的掌握。回脹及熱傳導係數為緩衝材料重要的工程性質之一，過去學者在對此類問題的探討較少從理論與實驗並重的方式進行。本計畫擬從實驗研究與理論分析並行的方式針對砂-皂土混合物探討其回脹特性，期望經由實驗成果發展出適切的數學模式。本計畫將密砂-皂土混合物視為複合材料，擬引入複合材料力學微觀力學模式，以求取不同配比之砂-皂土遲延回脹模式的相關參數，以作為緩衝材料之篩選參考及處置場緩衝材料回脹問題之數值模擬的基礎。 The development of technique for disposing of radioactive wastes from nuclear power stations has recently become a significant subject in industrial world. The disposal facility is planned to be constructed under the ground. The emplacement of bentonite-base buffer surrounding canisters and overpack has long been a feature of disposal concepts adopted for high-level waste and spent fuel disposal programmes within a number of countries. Such barriers are constructed from well-defined and quality-controlled bentonite or sand-bentonite mixture. Sand-bentonite mixture is seen as an effective component of artificial barriers for repositories of high-level nuclear waste. In order to provide reasonable assurance that buffer materials will ensure long-term waste isolation, it is essential to understand the swelling characteristic under a variety condition. Since there are few studies about the swelling behaviors of compacted sand-bentonite mixture from both experimental and theoretical point views, it is first necessary to Clarify the fundamental swelling characteristics in detail. For this purpose various laboratory tests on the swelling pressure and swelling strain of sand-bentonite mixture will be performed. It is expected based on the experimental results, the approprite swelling model and micromechanics will be proposed. 研究期間：9001 ~ 9012
