泥岩及紅土之內部沖蝕防止

Prevention of Internal Erosion for Mudrock and Laterite

蘇苗彬(Miau-Bin Su) ； 張雲竹(Yun-Chu Chang) ； 陳旺志(Wang-Jyh Chen)

《中華水土保持學報》 27卷4期 (1996/12) Pp. 325-334

https://doi.org/10.29417/JCSWC.199612_27(4).0007

摘要

水從土石結構物排放出或從較細粒徑土壤中流至較粗粒徑土壤時，滲流的水可能導致土壤中細粒土料流失而產生土壤沖蝕和管湧現象，因此需要使用過濾材料來防止其發生，在泥岩與紅土地區常發現有嚴重之沖蝕問題，因此本文以泥岩與紅土為基礎土壤，建立一套過濾材料選定過程作為沖蝕防止的方法，並加以分析及討論其結果。研究中進行（1）土壤之基本性質試驗，作為分析土壤所需之過濾材料之用。（2）過濾材料之理論探討與試驗，參考Sherard（1984）之細溝試驗，求取土壤之適當過濾料。（3）試臨結果分析探討，討論細溝試驗中通過過濾料之水量、排出水之污濁程度、排出土壤顆粒重量及試體裂縫大小等判定過濾材料之適用性。試驗所得泥岩的過濾料適當之D_(15) = 0.71mm，紅土的過濾料適當之D_(15) =0.77 mm，和其土壤本身之D_(85)比較為D_(15)（過）／D_(85)（泥岩）=10.6 及D_(15)（過）／D_(85)（紅土）=15.4 與sherard（1984）提出之D_(15)（過）／D_(85)（土壤）大於9皆相符。另外與Bertram（1940）等人之規範D_(15)（過）／D_(85)（土壤）；≤5相較，顯然研究結果中泥岩及紅土之適當過濾材料有較大的粒徑範圍選擇空間。本試驗方法亦適用於其他土壤之保護，且使用之細溝試驗具有可信賴且可重現的結果，相當可靠。

關鍵字

泥岩 ； 紅土 ； 過濾 ； 內部沖蝕

並列摘要

The objective of this study is to select the appropriate filter material for protecting mudrock and laterite. Methods suggested herein are based on basic soil property together with Pinhole test suggested by uses (1976) and Slot Test suggested by Sherard (1984). The work done in this study can be divided into three parts: (1) Field investigation of in-situ soil erosion condition. (2) Lab and field studies of soil properties. (3) Slot tests to decide on an appropriate filter material, on the basis of erosion quantity and drainage. Results of Pinhole test show that the weathered mudrock belongs to medium dispersive soil, and that laterite is not belong to dispersive soil. 'The results of Slot Test reveal that the best filter material for mudrock should have its D_(15)=0.71mm, whereas D_(15)=0.77mm for laterite. In this study, new methods to choose proper filter material are developed. The test results of which are shown to be reliable and reproducible. The method suggested herein should be applicable to other soil materials in filtering design.

並列關鍵字

Mudrock ； Laterite ； Filtering ； Internal Erosion