土石壩材料之動態性質

Dynamic Property of Earthdam soils

簡才貴(Tsai-Kuey Chien)

指導教授 ： 黃俊鴻

國立中央大學/工學院/土木工程學系/碩士(2006年)

摘要

土石壩材料之動態性質是受震反應分析最關鍵的土壤參數，然而動力三軸試驗儀不能精確求取小剪應變振幅下之動態性質，因此本研究採用共振柱試驗儀求取土石壩材料之動態性質。試驗土樣取自於湖山水庫借土區共三種土樣，即殼層土壤SM、ML與心層土壤CL，採用單位體積能量法之概念，利用特製夯模製作標準或改良夯實能量下之重模試體，以符合現地滾壓後的土石材料之乾單位重需大於95%的夯實試驗之最大乾單位重。再者，為模擬壩體長期處於水面之下土壤為完全飽和之情況，本研究也提出一改良的飽和方法使試體能在較短的時間達到要求的飽和度。
研究結果顯示，築壩材料之剪力模數隨著夯實能量與有效圍壓增加而增加，以殼層土壤SM之剪力模數最大、ML次之，心層土壤CL最小。三種土樣的 關係曲線之變化趨勢不同於前人及國內土石壩材料建議曲線，殼層土壤SM的 關係曲線之變化趨勢也不同於前人及國內土石壩材料所建議曲線，僅有殼層土壤ML及心層土壤CL的 關係曲線位於Sun and Seed (1988)對凝聚性土壤所建議範圍內，且心層土壤CL與王金山(2004)所建議曲線相似。並整理各土樣的最大剪力模數提出迴歸的經驗公式，以供工程界選擇土壤動態性質參數之依據。

關鍵字

阻尼比 ； 土石壩 ； 共振柱試驗 ； 剪力模數

並列摘要

Dynamic properties of saturated compacted soils are very important parameters in analyzing seismic responses of compacted earth dams. Few test results were found in the past literatures. That is because a number of difficulties that will be encountered in saturating the compacted soil specimens. Since the saturation process is too consuming that the complete test results for dynamic properties are difficult to obtain. This paper proposed two vacuum methods for improving the saturation of the compacted soils. One is for compacted SM and ML soils. The other is for compacted CL soils. Test results showed that both methods make the Skempton’s coefficient B of all specimens greater than 0.95. Based on the saturation techniques, complete dynamic properties of all the cohesive and non-cohesive compacted soils were measured by resonant column test (RCT). The measured properties included the maximum shear modulus and normalized modulus and damping ratio curves in the shear strain range of . The empirical equations correlating the maximum shear modulus, void ratio and effective confining pressure were proposed for different compacted soils. It was found the characteristics of normalized modulus and damping ratio curves are also much different from the typical curves of general soils.

並列關鍵字

Earth dam ； Resonant column test ； Damping ratio ； Shear modulus

參考文獻

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