荖濃溪河道土砂現地拌合配比對固結抗壓強度影響之研究

Effect of Mixing Ratio on the Strength of In-Situ Mixture of Cement and Sediment in the Lao-Nong River

謝立軒(Li-Shiuan Hsieh)

指導教授 ： 許中立

國立屏東科技大學/工學院/水土保持系所/碩士(2015年)

https://doi.org/10.6346/NPUST.2015.00248

摘要

臺灣地區每年平均總砂石需求量約5,000萬立方至6,000萬立方，由水利署各河川區轄管之流域中下游段清疏土方量，便已滿足臺灣每年平均砂石需求量。一般山坡地野溪為流域中上游段，淤積土砂品質不佳，致使清疏砂石價格較低且不易標售。目前國內針對山坡地野溪淤積土砂相關處裡之方法，除清疏外運及堆置外，另可應用於現地拌合工法、回填農地、土石籠等。本研究針對荖濃溪不同河道段之淤積土砂施作現地拌合工法進行試驗，比對分析不同水泥與骨材比例、不同河道段骨材性質對現地拌合材強度之影響，綜合分析結果歸納如下：
1.控制坍度條件下，現地拌合材抗壓強度主要受水泥比例及水灰比影響，而水灰比受淤積土砂中細骨材飽和吸水率及細度模數所影響。
2.比對粗骨材比重與抗壓強度分析，分析顯示較高粗骨材比重對抗壓強度較有明顯之影響。
3.試驗結果將不同養護天數7天與28天之抗壓強度，與水泥比例(X1)、細骨材吸水率(X2)及粗骨材比重(X3)等作為推估現地拌合材強度之重要因子，進行複迴歸分析得7天與28天養護天數現地拌合材抗壓強度預測公式：
Y7=896.366 X1-17.017 X2+10.907 X3
Y28=1014.952 X1-17.128 X2+15.646 X3
其R2皆接近於1，應可作為本研究河段之應用。

關鍵字

荖濃溪 ； 淤積土砂 ； 現地拌合 ； 骨材配比

並列摘要

In Taiwan, a mean total volume of approximately 50 to 60 millions cubic metres sandstone is required annually. The volume of dredged earthwork at the mid and downstream of the watershed in river regions controlled by the Water Resources Agency, Ministry of Economic Affairs is sufficient to satisfy such demand. Typical hillside streams are located at the mid and downstream of watersheds where low-quality river sediments are present. Therefore, dredged sandstones are generally cheap and difficult to sell. Currently, the government in Taiwan processes river sediments obtained from hillside streams by dredging, transporting, and piling them. In addition, these river sediments are also applied in in-situ mixing and used to backfill farmlands or to produce earth cage. This study performed in-situ mixing of cements with sediments from various segments of the Lao-Nong River to analyze the effects of varying mixing ratios and properties of aggregates from various river segments on the strength of the in-situ mixtures. The following analysis results were obtained:
1. When slump was controlled, the compressive strength of the in-situ mixture was primarily influenced by the mixing ratios and water–cement ratios, whereas the water–cement ratios were primarily influenced by the saturated water absorption rate and fineness modulus of the fine aggregates in the sediment.
2. The analysis of coarse aggregate proportion and compressive strength revealed that a high proportion of coarse aggregates evidently influenced compressive strength.
3. In a multiple regression analysis, the compressive strength, as well as water–cement ration (X1), absorption rate of fine aggregates (X2), and proportion of coarse aggregate (X3) obtained after a curing period of 7 days and 28 days were used as the key factors for estimating the strength of in-situ mixtures. Subsequently, the formulae for estimating the compressive strength of the in-situ mixtures cured for 7 days and 28 days were respectively obtained as follows:
Y7=896.366 X1-17.017 X2+10.907 X3
Y28=1014.952 X1-17.128 X2+15.646 X3
The R2 of both formulae approximated one, indicating that the formulae can be applied to examine the river segment selected in this study .

並列關鍵字

Lao-Nong River ； Sediment deposition ； In-situ Mixing ； Mixing Ratio

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