砂土顆粒特性影響密度之實驗研究

An Experimental Study of Effects of Sand Grain Characteristics on Density

張育愷(Yu-Kai Chang)

指導教授 ： 馮道偉

中原大學/工學院/土木工程學系/碩士(2008年)

https://doi.org/10.6840/cycu200900246

摘要

近年來，雲林填海造地所用砂土為近海地區砂土，該區砂土顆粒形狀為扁平狀且含有5%~45%的細顆粒土壤，其顆粒特性與力學行為可能與一般砂土有所不同。本研究以現地麥寮砂、越南砂、標準砂進行物理性質試驗，再利用不同比例麥寮砂混合越南砂、麥寮砂混合標準砂、越南砂混合標準砂及實驗室麥寮砂，分別進行最大和最小孔隙比試驗及室內夯實試驗，以探討顆粒特性對砂土緊密狀態之影響。
試驗結果顯示：(1)砂土經過混合後，原砂土的最大孔隙比往另一混合砂土的孔隙比趨近。最小孔隙比方面，麥寮砂混合越南砂則隨著越南砂比例增加而略有上升；麥寮砂混合標準砂則在標準砂含量60%之後趨於定值；(2)實驗室麥寮砂在細料含量15%時，最大孔隙比和最小孔隙比有最小值；(3)三種混合砂土均勻係數與最大孔隙比和最小孔隙比分別成正比和反比；(4)麥寮砂含量較高時，最大孔隙比差異百分比較大，越南砂混合標準砂則最大孔隙比差異百分比保持在1%以下；(5)實驗室麥寮砂最大孔隙比各次試驗下差異百分比不大，最小孔隙比則差異明顯；(6)夯實次數的增加造成顆粒破碎也使乾單位重增加；(7)含水量對夯實後乾單位重有明顯的影響，呈現先降後升的趨勢，細料含量愈多要達到含水量0%時的乾單位重所需含水量愈少，顯示砂土細料含量對夯實後砂土緊密度之影響。(8)標準砂最小孔隙比與夯實後孔隙比相差無幾，越南砂是夯實後孔隙比較大，麥寮砂則是最小孔隙比較大，可見顆粒形狀對砂土緊密度之達成度有影響。

關鍵字

最小孔隙比 ； 最大孔隙比

並列摘要

In recent years, Yun-Lin sea sand has been meed to build the ground in coastal region sand. The sand's grain shape is flat and has 5%~45% fine grains. Its grain characteristics and mechanical behavior may be different from normal sand. This experimental research used the Mai-liao sand, Vietnamese sand, and standard sand. Laboratory compaction tests,minimnm void ratio test, and maximum void ratio test one conducted to study the influence of the characteristic upon the sand close appearance.
The results of this study show (1) Sand, after being mixed, its void ratio will decrease toward that of another type of sand. On the aspect of the minimum void ratio, Mai-liao sand mixed with Vietnam sand's minimum void ratio slightly increases as Vietnam sands proportion increases. That of Mai-liao sand mixed with standard sand tends to be a constant after standard sands proportion is more than sixty percent ; (2) Mai-liao sand's maximum and minimum void ratios have a minimum when the quantity of fine particles is 15% ; (3) Three kinds of mixed sand's coefficient of uniformity is directly proportional to maximum void ratio and is inversely proportional to minimum void ratio , respectively ; (4) When the proportion of Mai-liao sand was higher, the difference percentage in maximum void ratio was higher, For Vietnamese sand mixed with standard sand, the maximum void ratios were with in 1% difference; (5) Mai-liao sands maximum void ratio changes slightly with measurements, but, minimum void ratio changes obviously with measurements ; (6) The increase of the number of compaction breaks the sand and causes the grain dry unit weight to increase ; (7) Water content of has obvious influence on dry unit weight affer compaction. Sand with more fine reaches dry sand unit weight with less water content. This shows the influence of fine content on density ; (8) The standard sand’s minimum void ratio is about the same as the void ratio affer compaction. Vietnam sand has a higher void ratio affer compaction. Mai-liao sand has a higher minimum void ratio. It is thus clear that grain shape of sand has an influence on its particle arrangcment.

並列關鍵字

minimum void ratio ； maximum void ratio

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