土壤吸力對緩衝材料飽和行為之影響及模擬研究

The Influence of Soil Suction on the Saturation Behavior of Buffer Material

李宛諭(Wan-Yu Li)

指導教授 ： 黃偉慶

國立中央大學/工學院/土木工程學系/碩士(2007年)

摘要

隨著科技工業發展，核能為多數先進國家主要供電來源，對於核廢料之處置，國際間多以深地層處置進行最終處置。其中，緩衝材對於處置場的成敗扮演關鍵性角色，當緩衝材受到地下水與廢料衰變熱之影響，其行為所產生耦合效應，將對近場環境帶來重大影響，故本研究模擬緩衝材料受水份滲透及溫度升高的影響，進行實驗與數值模擬。文中分別進行日興土及BH膨潤土在25℃、40℃及60℃下進行濾紙法試驗與攝取水試驗，探討溫度變化下緩衝材之水分特性曲線與飽和度之變化。並利用實驗所得之參數，應用ABAQUS進行程式模擬。
結果顯示BH膨潤土持水能力較日興土佳，且土壤吸力隨環境溫度升高而降低。試體受到水份入侵時，其飽和度隨時間增長而趨近飽和，飽和時間與緩衝材厚度平方成正比，且溫度越高其飽和速率愈快，而BH膨潤土飽和速率較慢。不論吸力或飽和速率，BH膨潤土受溫度影響均較日興土小。程式模擬結果多與實驗值趨勢相近，考慮材料參數之影響的研究發現，當膠體含量與膠體回脹倍率增加時，會使滲透係數降低，導致飽和速率降低及孔隙比減小，而滲透係數與土壤－水分特性曲線越大，其試體飽和速率愈快。

關鍵字

飽和程序 ； 土壤－水分特性曲線 ； 緩衝材料

並列摘要

With scientific and technological industrial development, nuclear energy supply the power source mainly for most advanced country. For final disposal of nuclear wastes, most countries adopted the deep geological disposal. Among the engineering barriers, buffer material is considered the key role to the success of deep geological disposal. As the buffer material will be influenced by groundwater intrusion and decay heat generated by the waste material, the coupling effects will bring great impacts on near-field environments. This study simulates the buffer material as affected by the permeation of moisture and temperature increases, using experimental and numerical techniques. Soil suction of Zhisin clay and Black Hill (BH) bentonite were determined using filter paper method and water uptake tests were conducted on the 2 bentonites at 25℃, 40℃ and 60℃.
The results show that soil suction of BH bentonite is higher than that of Zhisin clay. And soil suction was found to increase as the temperature decreases. In the saturation processes, the degree of saturation of bentonite increases with increasing time, and the higher the temperature is, the faster the specimen reaches saturation. Both soil suction and the rate of saturation speed for BH bentonite are less affected by temperature than Zhisin clay. Results of numerical simulation on water uptake test were found to close to the experimental observations. Increase in the gel content and gel swelling rate will cause reduction in hydraulic conductivity. And thus cause the rate of saturation to reduce.

並列關鍵字

Buffer material ； Soil Water Characteristic Curve ； Saturation processes

參考文獻

陳炳坤，(2006)，「高放射性廢棄物最終處置場緩衝材之回脹穩定性與微觀結構研究」，碩士論文，國立中央大學土木工程研究所，中壢。

蕭宗璿，(2006)，「不飽和土壤濕化水分特性曲線影響因子之研究」，碩士論文，國立中央大學土木工程系，中壢。

許俊賢，(2003)，「深層岩體熱力-水力-力學偶合行為之研究」，碩士論文，國立成功大學資源工程學系，台南。

戴豪君，(2002)，「深層岩體熱力-水力-力學偶合行為之初步研究」，碩士論文，國立成功大學資源工程學系，台南。

林士哲，(2003)，「金崙地區溫泉資源調查分析之研究」，碩士論文，國立成功大學資源工程研究所，台南。