凝聚性土壤二次壓縮指數及壓縮指數影響因子之實驗研究

An experimental study of the influence factors of secondary compression index and compression index for cohesive soils

魏碩平(Shou-Ping Wei)

指導教授 ： 馮道偉

中原大學/工學院/土木工程研究所/碩士(2016年)

https://doi.org/10.6840/cycu201600814

摘要

Mesri and Godlewski(1977)提出二次壓縮指數Cα與壓縮指數Cc之比值為常數的觀念，適用任何土壤。由於一般仍不了解不同土壤之Cα/Cc值相同或相異的原因，本研究乃探討該比值之影響因素。
本研究對石門淤泥、新塭黏土、石牌黏土、高嶺土土樣進行一般物理性質試驗、單向度壓密試驗及X光繞射試驗，並對試驗結果進行分析。
根據分析之結果，壓縮指數值與土壤內所含之黏土礦物: 伊利石、綠泥石、白雲母含量有關。土壤內之黏土礦物含量與壓縮指數呈正相關，壓縮指數值也與液性限度、孔隙比、含水量、黏土顆粒含量呈正相關。土壤的二次壓縮指數值與液性限度、孔隙比、含水量呈正相關，也與伊利石、綠泥石、白雲母含量呈正相關，由於黏土礦物屬於薄片狀礦物，使得土壤顆粒間容易產生相對運動且促進顆粒排列更為緊密，其中以綠泥石對二次壓縮指數的影響較為顯著。而Cα/Cc值與塑性限度、綠泥石含量呈正相關，與黏土顆粒含量、伊利石及白雲母總含量呈負相關。
綜合而言，本研究之成果顯示伊利石、綠泥石和白雲母三種礦物含量的多寡對Cα和Cc有不同程度的影響，進而使得不同土樣的Cα/Cc值有相似或不同的情形。

關鍵字

壓密 ； 二次壓縮指數 ； 壓縮指數 ； 礦物 ； 黏土

並列摘要

Mesri and Godlewski (1977) proposed the concept of constant Cα/Cc ratio for any soil. The reason is not known for this ratio to be the same or different for different soils. Thus, this study tries to find the influence factors for the magnitude of Cα/Cc ratio.
In this study, samples of shimen mud, shinwen clay, shipi clay, and kaolin were used to conduct general physical test, one-dimensional consolidation test, and X-Ray diffraction test.
According to the test results, compression index Cc is related to the content of clay minerals, including illite, chlorite, and muscovite. Compression index of the soils has positive correlation with the clay minerals contents, liquid limit, void ratio, water content, and clay particle content. Secondary compression index Cα has positive correlation with liquid limit, void ratio, and water content；it also has positive correlation with illite, chlorite, and muscovite contents. Because the shape of clay minerals is flaky, particles’ relative motion is promoted for a closer packing. The effect of chlorite is most obvious on secondary compression index. Then Cα/Cc ratio has positive correlation with plastic limit and the content of chlorite and has negative correlation with the clay particle content and the illite and mica contents.
In summary, this study found that different amounts of illite, chlorite, and muscovite have different effects on Cα and Cc, leading to either similar or different Cα/Cc ratios of different soils.

並列關鍵字

consolidation ； secondary compression ； compression index ； mineral ； clay

參考文獻

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