A Sliding Mechanism for the Landslide in Feng-Qiu, Taiwan.

• Main Authors: Yi-Dong Shen, 沈義棟
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/70206372688856814855

碩士 === 逢甲大學 === 土木工程所 === 98 === When Typhoon Sinlaku passed through Taiwan on September 14, 2008, a landslide occurred on the high steep slope of the New Middle-Transverse Highway in Feng-Qiu, Nantou. Seven persons were killed by the fallen earth and stone in such a tragic case. Therefore, the author of this thesis has firstly made use of the actual landslide conditions, in-situ topographies and geologic structures to carefully conduct analyses and found the result of that a landslide mechanism is constituted by a sliding failure of two planes. Then, slop stability analyses have implemented by the supplementary results that produced by the soil mechanics tests for in-situ soil specimens and a computer program coded by the advisor of this thesis. It is found from results of this thesis that (1) Even if there is no raining for five consecutive months, ground water still continuously flows out from the shear bands that existed in this high steep slope; (2) By the affecting of the shear resisting strength for the matrix material in the voids among structures of gravels, landslides are not easy to occur under normal conditions; however, shear bands will force the matrix material in a surface layer to be continuously decomposed and softened after being ruptured or immersed in water; (3) A safety factor for sliding resistance of this high steep slope will be reduced substantially to be around 1.0 under the attacking of an earthquake; such result indicates that some earth and stone will be fallen and surface layer will be split open up to a certain depth; (4) During a torrential rain, the unit weight of a soil stratum will be increased by the infiltrated rainwater, and the matrix material will be washed by the surface runoff; therefore, the safety factor for sliding resistance of a shallow stratum will be less than 1.0; in other words, it indicates that a sliding failure of shallow delamination is easy to occur in this high steep slope during a torrential rain. Keywords: landslide, slop stability analysis, planar sliding failure, delamination.