英文篇名
Design and Construction of Beads Ringer Net Technique on Flexible Rockfall Prevention
作者
田島与典、岩崎征夫、陳立憲、徐紳翔
關鍵字
落石、BRN、柔性工法、剛性工法、明隧道
摘要
針對較難以監測防治之落石課題,台灣目前主要以明隧道等相對剛性之工法因應設計,以承接岩石崩落之高衝擊能量,然因緩衝消能技術未臻成熟而需設計出量體較大之場鑄鋼筋混凝土結構系統;及付出較長工期與較大工料成本,顯示台灣之剛性工法應用尚有改良空間。審度日本之地質條件與台灣相似,且柔性落石防治及維護行之有年,依其文獻,柔性工法除可與剛性工法配搭施行源頭治理,亦可獨立行之,故本文介紹柔性工法之應用例:兜式攔石防護網(Beads Ringer Net, BRN)工法。該法因可架設於鄰近落石發生源位置,以承接較小落距之衝擊能量;而其金屬網、繩攔截特性與緩衝機構之設置,可增加其消能效果;此外BRN工法亦具有耐久經濟性、施工維護易(工期短)、環境友善、自然地景融入等技術優勢,即以全生命週期之工程思維審度落石防治之目的。
BRN工法在日本廣泛應用,主因有系列完備之理論與規範、數值模擬與足尺試驗等實例,得因地制宜設計所需抵抗能量。本文由設計與施工兩向度說明BRN工法,及於台灣落石防治應用之可行性探討,冀能對實務之新工法與新材料的研發推展,有參佐之效。
英文摘要
For uncontrollable rockfall monitoring and prevention issues, rigid techniques such as rock shed acts as the main design solution in Taiwan nowadays, to absorb the high rockfall energy from the great falling distance. However, the reinforced concrete structure results in bulk designed volume, huge labor, and material costs due to the immaturity absorption technique, which reveals that rockfall techniques in Taiwan still got room for improvement. Japan has similar geological conditions with Taiwan, and flexible rockfall techniques have developed for years. By Japanese reference review, flexible techniques could be co-operated with rigid techniques, or have them independently set. Thus, the application of flexible technique: Beads ringer net (BRN), is mentioned in this paper. Setting at the position nearby the source of falling rocks, which receives relatively less energy owing to the short falling distance. Besides, feature of wire net, wire rope, and energy absorber makes better energy absorbing capacity. Furthermore, BRN considers rockfall prevention with the concept of whole life cycle, and it possesses advantages such as short construction period, economy, long duration, simply maintenance, environmental friendly, and natural landscape integration.
BRN technique has been widely used in Japan, it could be suitably apply to most conditions due to the support of series of complete theory, standard established, numerical simulation, and full scale tests. Introducing the BRN technique by design and construction aspects, and the adaptation in Taiwan, this article is expected to be helpful in developing the new engineering techniques and new construction materials in the future.