| 摘要: | 由於過去著重於經濟發展的前提下，公路的闢建從都市到農村，從沿海到山林，蓬勃的經濟發展帶動國民生生活水準提高，生活品質之提升及世界潮流趨勢發展觀光事業，台灣地區崇山峻嶺好山好水，政府對於山區道路之拓建不遺餘力，卻忽略了大自然的力量，台灣山區地質脆弱、地形崎嶇、坡度陡峭，921地震後地質更加破碎鬆動，當遭遇颱風豪雨、強震侵襲後，極易發生重大坡地災害，導致山區道路受損而交通中斷。 桃113號道路為桃園縣復興鄉通新竹縣尖石鄉之山區道路，艾莉颱風所挾帶之豪大雨，造成道路邊坡崩塌、交通中斷，經研究調查其受先天不良因素－地質作用強烈、地層結構較為破碎、風化土壤層較厚、膠結弱及岩層為順向坡，復由於後天人為因素－早期道路之拓建對於水土保持未予重視，排水系統及設施未臻完善，釀成重大災害。 山區道路災修復建工程，必須視災害成因及類型而有所不同之因應對策，本研究案例依據行政院「公共設施災後復建工程經費審議作業要點」，並考量道路功能性、安全性、經濟性、永久性及生態環境景觀交通之和諧性，因地制宜採用生態工程及傳統結構工程進行復建，本案災害主因為豪雨導致重大災害，因此歸納各災害點破壞模式與災害成因之相關性，並經水文水理分析、大地問題分析，提出邊坡穩定、排水、植生等整治工法，對於仍屬不穩定可能會再重覆發生邊坡滑動崩塌之路段，採取柔性施工之方式，平時維持道路服務之功能，豪雨時允許其非立即性之破壞，甚或位在斷層帶大規模崩塌區採取避險改線方式，同時在不同崩塌滑動破壞點設置監測設備，以了解地下水位、水壓、地滑等變化情形，作為後續追蹤分析整治及達到防災預警功效，減少生命財產之損失。 Transportation is the foundation of the development. With the strong emphasis of the economic development, highway construction becomes the major engineering construction in this island. Over the past years, the Taiwan Government has spent major effort to build highways between the cities and rural farming areas and from coastline to the inland mountain region to stimulate the growth of nation’s economy and to increase the higher living standard and quality of living across the Island. Seeing the trend of the rest of the world and the gorgeous landscaping of the inland mountain region, the Government has put the major effort to build roadway system into the inland mountain region to promote the tourist industry. However, the government overlooked the power of the nature and the poor geological condition in the mountain, the rolling terrain, and the steep hills. With the torrential rain brought by the seasonal tyfengs and the earthquakes, especially the 921 Earthquake, the soil layer of the land became very loose and unstable, the disaster happens easily, especially, in the sloping hills, and causing the road damages and traffic closure. Tao Yuan Rd #113 is the major road that connects Tao Yuan, Fu-Hsing Shiang and Shin Tzu, JianShih Shiang. The heavy rainfall brought by the Tyfeng Alice flooded the area, collapsed the roadway, and consequently the landslide, road caved in and the closure of the traffic. Our preliminary study has found that the vigorous geographic movement, the fragility of the soil structure, the heavy deposit of the weathered soil, the weakened coherence between soil and roadside rock layer have caused the damages. The excessive damages in this area also resulted from the lack of the soil conservation and drainage system when the highway was first built. In order to rebuild the damaged highway in the above mountain region, it is necessary to understand the causes, and the types of disaster. The goal of this research is to study and develop a specific method to rebuild the local damaged roadway by using the combination of the technologies of Environmental and Conventional Structural Engineering. The study is thus designed based on the careful examination of concurrence of the functional, safety, economical factor, long-term, ecological and landscaping concerns, and according to the guideline published by the Legislature Yuan “Operation point of the After - Calamity Reconstruction Engineering Budget of the Public Facilities Deliberates”. Our study has shown the high correlation between the mode of the destructions and the cause of the damages, and between the analysis of hydrology and geodetics. Therefore we recommend the following methods to restore the total damaged areas: stabilizing the embankment, enhancement of the drainage system, and plant vegetation along the roadside. In terms of other unstable and possible recurrent landslide embankment sites, we also recommend to take more flexible methods, such as, routine road maintenance service to tardy and lessen the flood damage; providing detour service to avoid major collapses. Finally, we recommend to install a system monitoring the changes of the ground water level, water pressure, and land sliding characteristics in various embankment sites, to provide information for future study, analysis, rebuilding and prevention, thus to minimize the human life and property losses. |
