三峽庫區黃土坡非飽和滑帶土之水－力相互作用之研究

Hydro-Mechanical Properties of Sliding Zone Soil in Huangtupo Landslide, Three Gorges Reservoir Area

王菁莪(Jin-Ge Wang) ； 葉信富(Hsin-Fu Yeh) ； 劉清秉(Qing-Bing Liu)

《中華水土保持學報》 46卷2期 (2015/06) Pp. 106-113

https://doi.org/10.29417/JCSWC.201506_46(2).0005

摘要

黃土坡滑坡是中國三峽庫區範圍最大且社會危害性最嚴重的地質災害之一。隨著三峽水庫水位週期性漲落，黃土坡滑坡部分區域，特別是滑坡體內最軟弱的滑帶區域，將長期處於乾濕迴圈狀態。本研究採用暫態排水和吸水試驗方法（TWRI）測試滑帶土乾濕路徑的土壤水分特徵曲線（SWCC）和水力傳導函數（HCF），並結合吸應力理論和飽和-非飽和剪切試驗定量化研究滑帶土不同含水狀態下的土－水相互作用性質與強度變化規律。試驗和分析結果顯示，滑帶土的基質吸力、滲透係數以及吸應力與含水量變化有緊密之關係。土壤水分特徵曲線、水力傳導函數和吸應力特徵曲線（SSCC）均存在明顯的遲滯效應。利用基於吸應力理論的擴展莫爾-庫倫破壞準則評估滑帶土非飽和狀態抗剪強度，可以較方便且準確地在滑坡穩定性分析中充分考慮滑動土體非飽和狀態時的強度性質。

關鍵字

黃土坡滑坡 ； 非飽和土壤 ； 土壤水分特徵曲線 ； 吸應力

並列摘要

The Huangtupo landslide was one of the largest and most harmful geo-hazards in the Three Gorges Area, China. With the periodical water level fluctuation of the Three Gorges Reservoir, partial regions, especially the sliding zones that are the weakest parts in sliding mass, are under circulating drying and wetting conditions. This study employs the transient water release and imbibition method (TRIM) to test the soil water characteristic curve (SWCC) and hydraulic conductivity function (HFC) of sliding zone soils during drying and wetting paths. Combining suction stress theory and saturated-unsaturated direct shear tests, the soil-water interaction and strength variation properties of sliding zone soils with variable saturation are studied quantitatively. The tests and analysis results indicate that the suction, permeability and suction stress of sliding zone soils are related closely to the water content. The soil water characteristic curve, hydraulic conductivity function and suction stress characteristic curve (SSCC) exhibit significant hysteresis. By calculating the strength of unsaturated sliding zone soils by generalized the Mohr-Coulomb failure criterion based on suction stress theory, researchers can conveniently and accurately assess the unsaturated strength properties of sliding soils in slope stability analysis.

並列關鍵字

Huangtupo landslide ； unsaturated soil ； soil water characteristic curve ； suction stress