力行產業道路五處崩塌地崩積層的試驗與研究

Testing and Study on Colluvium from Five Sliding Locations Along Lixing Industrial Road

沈朝偉(Chao-Wei Shen)

指導教授 ： 徐松圻

朝陽科技大學/理工學院/營建工程系/碩士(2014年)

摘要

極端氣候下各種天災豪大雨，常造成山區山壁崩塌、路基淘空流失，頻頻傳出坡地災害造成道路封閉，為了解（投89線道）力行產業道路地質、水文、環境及配合現地狀況，本研究針對道路之崩積層進行採樣及大型直剪試驗，以求得相關剪力參數，供後續分析用。
本研究位於南投縣仁愛鄉之力行產業道路沿線12.3K、15.85K、22.53K、32.5K及49K崩塌地，現地進行崩積土層篩分析及現地密度試驗，由統一土壤分類法歸類為越級配礫石土壤。進行室內基本物理、夯實試驗，求得現地土壤溼單位重及最佳含水量約在4.4~8.2%。並改良之大型直剪試驗，推估飽和及不飽和土壤剪力強度參數。為求此類崩積土層之滲透係數，設計一土柱量測滲透係數，其量測結果為0.04cm/sec，及用壓力鍋量土壤之水分特性曲線。大型直剪試驗結果飽和土壤摩擦角約為31.9到42.2度。而22.53K處及49K處之摩擦角較高於其他處，推估原因為夯實試體單位重明顯高於其他處單位重，且夯實試驗所得最大乾密度也大於其他的土樣。除22.53K及49K之摩擦角外，其他摩擦角平均為33度，凝聚力平均為0.83kg/cm2。後續使用Geo-Studio進行數值模擬，以莫拉克颱風時的雨量，分析降雨時邊坡崩塌的情形，以得到目前現地之安全係數及可能崩滑範圍。
關鍵詞：崩積土、大型直剪試驗、土柱試驗、Geo-Studio

關鍵字

大型直剪試驗 ； 崩積土 ； 力行產業道路 ； 土柱試驗 ； Geo-Studio

並列摘要

The world has faced extreme weather conditions with heavy rainfall and natural disasters very often during past 10 years. The outcome of the results often causes slides and rock falls, debris flow, erosion of road bases, and slope failures in the mountain areas of Taiwan. In order to understand the geology, hydrology, environment, and in situ condition of Lixing industrial road, the colluvium samples are taken in situ to study the material properties. Large direct shear tests are performed to obtain the shear strength of the soil.
The study site is along the Lixing industrial road located in Renai Township of Nantou County. Five major sliding locations, 12.3, 15.85, 22.53, 32.5, and 49 K, are chosen for this study. Sieve analyses are run in situ and in the laboratory. The colluvium soil can be classified as gap-graded gravel. Index property and compaction tests are carried out and the optimum moisture content is around 4.4 to 8.2%. A modified large direct shear test device, 25x25x42 cm, is designed to run unsaturated and saturated shear strengths of the colluvium. The permeability of the soil, 0.04 cm/sec, is measured by using a 15 cm diameter soil column. Pressure plate is used to obtain the soil water characteristic curve (SWCC).
The friction angles of saturated colluvium from large direct shear tests are 31.9~42.2 degrees. The compacted unit weight of the soils from 22.53 K and 49 K are higher than the other places, and may cause the corresponding friction angle is also higher. The average friction angle and cohesion of the other three locations are 33 degrees and 0.83 kg/cm2, respectively. Numerical simulation using the software by Geo-Studio is performed to simulate the rainfall during Typhoon Moraka. The slope stability and range of potential landslide are revealed.
Keywords: colluvial soil, large-scale direct shear tests, soil column experiments, Geo-Studio

並列關鍵字

large-scale direct shear tests ； colluvial soil ； Lixing Industrial Road ； soil column experiments ； Geo-Studio

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