飽和疏鬆砂土盤轉改良效果之研究

A Study of the Effectiveness of Disc Rotation on Improvement of Saturated Loose Sand

林子傑(Zi-Jie Lin)

指導教授 ： 馮道偉

中原大學/工學院/土木工程研究所/碩士(2017年)

https://doi.org/10.6840/cycu201700620

摘要

摘要
　　本研究目的為探討飽和砂土盤轉之行為及效果，因過往實驗中並未對於飽和之砂土施作盤轉改良，且在工程中亦有機會遇到飽和之土層，故進行一系列試驗觀察飽和砂土盤轉之效果。
　　盤轉係以圓盤施加一垂直正向應力和水平向之剪應力於疏鬆砂土之水平表面上，使砂土顆粒發生位移後排列更為緊密。本實驗藉由改變砂土種類、靜壓載重大小及圓盤底部砂輪等變因進行盤轉試驗，試驗土槽內徑為200 mm，土樣初始厚度82 mm且初始相對密度為30 %。試驗中施加靜壓載重43 kPa及78 kPa，盤轉單位轉角為5°、10°或15°，藉由圓盤轉動使試體壓縮，進而測得圓盤沉陷量，之後另進行靜壓載重驗證試驗來評估改良成果。並對砂樣施以電子顯微鏡照相及X光粉末繞射試驗，以更細微的觀察砂樣特性。
試驗結果顯示，飽和試體在靜壓加載部分產生了較乾試體大的沉陷量，再經過盤轉後未含有細顆粒飽和試體盤轉後相對密度較乾試體高12%~15%，含有細顆粒之飽和試體相對密度較乾試體高較2%~8%。並發現當試體顆粒愈接近圓狀，飽和試體盤轉後相對密度與乾試體差值愈大。盤轉後試體之相對密度隨著正向應力的增加而增加，圓盤愈粗糙則盤轉後相對密度愈高。

關鍵字

飽和砂土 ； 盤轉 ； 相對密度

並列摘要

Abstract
This study investigated the effect of disc rotation on saturated loose sands. Past studies did not utilize saturated sand, but in engineering practice there will be opportunity to work on saturated loose sands.
In this study, five sand samples with different particle characteristics were utilized. X-Ray diffraction test and SEM were made on these sands to know their particle characteristics. The diameter of sand specimen is 200 mm and the thickness is 82 mm, with an initial relative density of 30%. A static loading of either 43 kPa or 78 kPa was applied on the sand specimens before disc rotation. The angles of disc rotation was either 5°、10°、or 15°. Compression of sand specimen was measured to determine its relative density and unit weight after the disc rotation. At the end of the test, sand specimen was unloaded and then reloaded to determine its compressibility for verification of improvement.
Test results show that the change in relative density increases with increasing the static load. With the same disc rotation operation, saturated sand specimen was improved slightly more than dry sand specimen.

並列關鍵字

saturated sands ； disc rotation ； Relative Density

參考文獻

2. 任芬頤 (2006)，「盤剪方式影響疏鬆砂土相對密度之研究」，中原大學土木工程學系碩士論文。

3. 李尚杰 (2011)，「盤轉影響砂土相對密度之研究」，中原大學土木工程學系碩士論文。

4. 林國偉 (2012)，「白雲母-砂土之剪力強度特性研究」，中原大學土木工程學系碩士論文。

9. 楊佳勳 (2002)，「以盤剪方式改良砂土相對密度之研究」，中原大學土木工程學系碩士論文。

10. 黃中源 (2013)，「往復盤轉改良砂土密度之室內實驗研究」，中原大學土木工程學系碩士論文。