單剪試驗下細粒料對砂土臨界狀態參數之影響

Effects of fines content on critical state soil parameters under simple shear conditions

李彥霆(Yan-Ting Lee)

指導教授 ： 張文忠

國立暨南國際大學/科技學院/土木工程學系/碩士(2009年)

https://doi.org/10.6837/NCNU.2009.00209

摘要

細粒料含量為影響顆粒性土壤之臨界狀態參數之重要因子，但其相關研究仍無一致之理論，本研究利用反覆單剪試驗系統，將渥太華砂與麥寮砂之細粒料混合配比，並以濕搗法製作試驗試體，進行K0狀態下不等向壓密不排水之單向剪動試驗，並根據試驗結果，探討與分析土壤之臨界狀態行為。研究結果顯示，在p'-τ平面上之臨界有效應力比與狀態轉換線之臨界有效應力比在細粒料含量0%至10%其斜率會隨著細粒料含量的增加而減少，而細粒料含量10%至100%範圍其臨界有效應力比隨著細粒料含量的增加僅些微增加；不排水剪力強度在細粒料含量20%至35%間有最低點存在，當細粒料含量小於該範圍時，不排水剪力強度隨著細粒料含量的增加而降低，而細粒料含量大於該範圍時，則有相反的趨勢；臨界狀態線會隨著細粒料含量的增加而降低，且傾斜趨勢漸緩，而類穩定狀態線亦有相同的趨勢，且在不同的細粒料含量下類穩定狀態線皆會比臨界狀態線低，且與臨界狀態線平行。

關鍵字

單剪試驗 ； 細粒料含量 ； 顆粒性土壤 ； 臨界狀態參數

並列摘要

Fines content has been recognized as an important factor that affects the critical state soil parameters of granular soils, but no consistent correlation has been established. Undrained simple shear tests were performed on sand-fine mixtures prepared by moisture tamping method to study the critical state behavior under k0 conditions. The results show that the effective stress ratios on p'-τ plane at critical state and quasi-steady state decrease as fines content increases from 0 to 10% but only slightly increases from 10 to 100%. Undrained shear strength decreases as fines content increases from 0 to 20% and the minimum undrained shear strength observes around 20 to 35% fines content, which is in the proximity of transitional fines content. The trend reverses as fines content exceeds 35%. Additionally, fines content will lower the position of critical state line on p’-e plane and reduce the slope. Quasi-steady lines are parallel to the corresponding critical steady lines with smaller void ratios.

並列關鍵字

Simple shear tests ； Fines content ； Granular soil ； Critical state parameters

參考文獻

洪明琳(2005)，「以反覆單剪試驗探討含細粒料砂土其不同孔隙參數與液化強度之關係」，國立暨南國際大學土木工程學系，碩士論文。

曾章凱(2008)，「 狀態下礫石-砂土混合物之液化行為探討」，國立暨南國際大學土木工程學系，碩士論文。

黃耀道 (2008)，「台灣中西部粉土質砂土液化行為分析」，國立交通大學土木工程學系，博士論文。

ASTM D 6528-00, “Standard Test Method for Consolidated Undrained Direct Simple Shear Testing of Cohesive Soils,” American Society of Testing and Materials, West Conshohocken, PA, USA.

Bouckovalas, G. D., Andrianopoulos, K. I., and Papadimitriou, A. G. (2003), “A critical state interpretation for the cyclic liquefaction resistance of silty sands,” Soil Dynamics and Earthquake Engineering, Vol. 23, No. 2, pp. 115-125.