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  • 學位論文

非飽和紅土剪力強度之研究-以林口台地為例

A Study on the Shear Strength of Linkou Terrace Unsaturated Lateritic Soil

指導教授 : 魏敏樺

摘要


近年來臺灣由於經濟蓬勃發展、居住品質提昇及休閒旅遊盛行,致使許多坡地開發案孕育而生,但在開發設計的同時卻無考慮坡地非飽和殘積土壤之工程性質,因此隱藏了水土保持不當與坡地滑動之潛在危險。紅土為殘積土的一種,而臺灣地區紅土分布於西部一帶,其中林口台地為最大紅土台地之一,該台地之地下水位通常很深,以致地下水位上之紅土層通常呈現非飽和狀態,在大氣壓力下,這些非飽和土層中之初始孔隙水壓力通常為負值,而這負孔隙水壓力(基質吸力)在平時能增加土壤剪力強度,提高土坡之穩定性,但在發生連續降雨期後,地表雨水入滲至土層中,使土層原有之基質吸力減少,連帶降低土壤剪力強度,導致土坡發生滑動破壞,因此建構紅土之非飽和與飽和狀態之剪力強度為一項相當重要且急迫之課題。由於其主要紅土於USCS分類上屬CH,故本文針對CH的林口紅土為主要研究對象。將針對林口紅土台地所取得之現地不擾動土樣,透過改良式傳統三軸試驗儀,來探討在不同基質吸力下紅土之剪力強度變化情形,並搭配兩種控制不同含水量之擾動紅土做剪力強度之比較。接著以試驗所得之土壤水份特性曲線來預測紅土之非飽和剪力強度,並與三軸試驗結果作比較。最後建議將此量化之非飽和紅土剪力強度參數應用於工程實務上,使坡地設計開發能更精確地使用適當之土壤強度參數。

並列摘要


Due to rapid economics development, the enhancement of living quality and the demand on leisure traveling have resulted in massive hillside developments. Therefore, potential hazards such as improper water conservation and sliding of slopes are therefore followed. So, the engineering behavior of the soil slopes has become the most important discussion topic. Lateritic soil is a kind of residual soils that is widely distributed in the western part of Taiwan, in which Linkou terrace is the largest of them. The water table of Linkou terrace is very deep and hence the upper part of the soil layer is found in an unsaturated state. The negative pore water pressure (matric suction) contribute to the shear strength in general, but during rainy seasons, water infiltrate into the soil and reduce the matric suction and hence the shear strength. For this reason, the understanding of the shear strength behavior of the saturated and unsaturated lateritic soils is necessary. In this study, high plasticity lateritic soil (CH) was obtained from Linkou terrace and tested with a modified triaxial system at various matric suction levels. The shear strength was also estimated from the SWCC using various empirical equations and compared with the laboratory results. Good comparison has been obtained. Finally, an extended Mohr-Coulomb envelope for the study lateritic soil was also proposed.

參考文獻


[30] Gui, M. W., Chen, S. L. and Chang, W. T. (2003). “Preliminary Study of a Collapsed Lateritic Slope in Taiwan.” Proc. of Int. Conf. on Slope Engineering, Hong Kong, p.654-659.
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[2] Arya, L. M., and Paris, J. F. (1981). “A Physico-Empirical Model to Predict the Soil Moisture Characteristic from Particle-Size Distribution and Bulk Density Data.” Soil Science Society of America Journal, Vol. 45, p.1023-1030.
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[4] ASTM. C114-03 (2003). “Standard Test Method of Chemical Analysis of Hydraulic Cement.” West Conshohocken. Pa.

被引用紀錄


謝昇翰(2012)。非飽和山崩堆積岩屑剪力強度之探討〔碩士論文,國立臺北科技大學〕。華藝線上圖書館。https://doi.org/10.6841%2fNTUT.2012.00469
吳永銘(2011)。濕吸力平衡路徑與水入滲對非飽和紅土之影響〔碩士論文,國立臺北科技大學〕。華藝線上圖書館。https://doi.org/10.6841%2fNTUT.2011.00253
陳家豪(2009)。非飽和紅土K0 壓密行為之研究〔碩士論文,國立臺北科技大學〕。華藝線上圖書館。https://doi.org/10.6841%2fNTUT.2009.00478
鄭雅仁(2009)。台灣部分地區土壤水份特性曲線之預測〔碩士論文,國立臺北科技大學〕。華藝線上圖書館。https://doi.org/10.6841%2fNTUT.2009.00452
Li, C. Y. (2007). 邊坡崩塌因子與豪雨影響之研究 [master's thesis, National Taipei University of Technology]. Airiti Library. https://doi.org/10.6841%2fNTUT.2007.00032

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