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

• Main Authors: Chao-Wei Shen, 沈朝偉
• Other Authors: Sung-Chi Hsu
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/74776068667231446071

碩士 === 朝陽科技大學 === 營建工程系 === 103 === 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