臺灣位處於環太平洋地震帶上，地質條件上屬於相對年輕，地質條 件處於破碎、不穩定的狀態。在氣候條件上屬於亞熱帶季風氣候，主要 有東北季風及西南季風所造成的降水，以及夏季容易受颱風所影響，因 此，每當有降雨過後山區邊坡等常有土石滑落鬆動等現象，不僅人員及 財產容易受到威脅;為此上述原因，本研究主要分為兩大主軸，前半部 分主要以無限邊坡計算各種地質與材料的因素來探討邊坡穩定。研究 中考慮的變因有坡度、土層厚度、凝聚力、摩擦角、土壤單位重等因素， 並改良非飽和土壤無限邊坡公式與加入地震力影響公式，進一步分析 地質的不確定性、材料的不確定性、或人為的不確定性因子對於邊坡穩 定性有顯著的影響。此研究中使用蒙地卡羅法計算，可發現邊坡夾角比 起其它因子(土層厚度、地下水位、凝聚力、摩擦角)等有相對較大的標 準差，因此邊坡夾角的變化對於坡地安全係數有著顯著的影響。第二部 分使用數值模擬，本研究所使用的軟體為STEDwin、Geostudio 及Visual Slope 等軟體進行一般邊坡的分析，且使用Goestudio 進行非飽和土壤 的分析，並參考既有範例進行建模，比較何種參數對安全系數影響甚巨， 及何種軟體對安全係數計算較為保守。並發現在相同參數下，軟體間差 距並不明顯。但仍發現邊邊坡夾角的變化具有較大之標準差。;Taiwan is located in the Pacific Rim seismic zone, and the geological conditions are relatively young and fragmented. In terms of climate, it is a subtropical monsoon climate and easily affected by typhoons in summer. Thus, slopes of mountainous areas are often subject to sliding after rainfall. The first half of the study focuses on the stability of the slope by calculating various geological and material factors. The variables considered in the study are slope, soil thickness, cohesion, friction angle, soil unit weight, etc. The formula of infinite slope for unsaturated soil and external earthquake force are improved and modified. Regarding the uncertainties of geology and material parameters using the Monte Carlo method, it is found that the slope angle has a relatively larger standard deviation than other factors (soil thickness, groundwater level, cohesion, friction angle), so the change of slope angle has a significant effect on the slope safety coefficient. In the second part, numerical simulation with STEDwin, Geostudio and Visual Slope for general slope analysis are implemented, and Goestudio is used for unsaturated soil analysis. The modeling is carried out with reference to existing case to compare which parameters have a great influence on the factor of safety and which software is more conservative. It was found that the difference between the software was not significant for the same parameters. However, it was found that the variation of the side slope angle has a large standard deviation.
