邊坡崩塌因子與豪雨影響之研究

An Investigation of some Factors that Triggered Landslides

李芷妍(Chih-Yen Li)

指導教授 ： 魏敏樺

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2007年)

https://doi.org/10.6841/NTUT.2007.00032

摘要

台灣地處亞熱帶，屬於海島型氣候，全年雨量豐而不均，具有雨量豐沛且集中的豪雨特性。颱風帶來的豪雨常造成山坡地沖刷及侵蝕等現象，引發土層滑動等不同形式的坡地災害。台灣山地面積約佔總面積之百分之六十四，隨著工商業的發展、人口急劇的增加，開發山坡地已成必然之趨勢。然而，山區道路的開發卻對生態造成傷害，也成為近年來豪雨過後大規模邊坡破壞的發生處。當豪雨發生時，地下水位的位置皆處於地表面下，介於地下水位及地表面間的土壤為非飽和狀態，稱為非飽和土壤。此時雨水入滲使得土體本身的基質吸力變化造成土壤內強度的降低，進而產生坍滑現象。
本文探討94年四個主要侵台颱風（海棠、馬莎、泰利、龍王）所造成1718件的道路邊坡崩塌案例為研究對象，進行致災原因的統計分析。並以台北藝術大學之破壞案例為例，針對『非飽和紅土邊坡』進行邊坡穩定性之影響分析與探討。研究內容為雨水入滲對土壤基質吸力的影響以及降雨對邊坡崩塌之安全性研究。
然而現地本身就擁有過多的不確定性，例如地層資料、地下水文、雨量變化情形及坡面植被情況等，為了有效考量現地情況以及探討實驗室試驗所可能造成土壤參數的誤差值，使用非飽和邊坡穩定分析理論，探討各項參數對邊坡的貢獻及影響。

關鍵字

颱風 ； 降雨 ； 邊坡破壞 ； 入滲 ； 非飽和土壤

並列摘要

The geology of Taiwan is complicated, and the precipitation is rich and concentrated. Three quarter of Taiwan is made up of hillsides and the increase of the island population has directed many new developments towards the hillsides. As a result, the number of slopes failure has also increased; this is particularly so after a heavy rainfall for residual soil slopes. In mostly cases, due to the unique location of ground water table in the slope, soils between the slope surface and ground water table are in unsaturated state. It’s called unsaturated soil. During long raining season, heavy rainfall intensity will inevitably force the shear strength of these soils to depreciate and subsequently cause the slope to fail. Consider the engineering characteristics such as matric suction of unsaturated soil in the stability problem.
In this study, four typhoons: Haitang, Matsa, Talim and Longwang have been found to cause 1718 slope failures in 2005. Based on the forensic diagnosis of the observed failures, we can generalize the important factors for slope failures. Numerical analysis using SoilVision program is adopted to model the NTUA slope failure. Uncertainties such as soil layer distribution, ground water table, rainfall distribution and laboratory testing may affect the result of the stability analysis of slope. Finally, this study assessed the effect and contribution of soil parameters to an unsaturated slope.

並列關鍵字

Typhoon ； Rainfall ； Slope Failure ； Infiltration ； Unsaturated Soil

參考文獻

[51] 徐鐵良 (2002)，台灣工程基本資料叢書之四 地質與工程，中國工程師學會。

[55] 陳榮河、林美聆、廖洪鈞、林三賢、廖瑞堂、周南山、李維峰 (2004)，台灣坡地與土石災害防治之回顧與展望，地工技術，第100期，第107-126頁。

[56] 游淳名 (2005)，非飽和紅土剪力強度之研究-以林口台地為例，碩士論文，國立臺北科技大學土木與防災研究所，臺北。[論文引用為Yu (2005)]

[2] Ambraseys, N., Srbulov, M. (1995). “Earhtquake induced displacements of slopes.” Soil Dynamics and Earthquake Engineering 14, pp59-71.

[3] Aleotti, P., Chowdhury, R. (1999). ”Landslide hazard assessment: summary review and new perspectives.” Bull Eng Geol Env 58, pp21-44.