土石流數值模擬之體積量估計與參數檢定方法之初步研究

台灣地區因位於歐亞大陸板塊和菲律賓海盆板塊衝撞之接合區，造山運動不斷進行，地震發生頻繁，地層中礫石間的膠結料又以泥或砂為主，膠結不固，再加上山地地形陡峭，溪短流急，土層淺薄而鬆軟，每遇颱風豪雨，山洪暴發，脆弱而不當開發之山坡地常會造成土壤沖蝕、崩塌、土石流等土砂災害。1999 年921 大地震發生前，根據政府於1992 至1996 年間之調查，全國土石流潛勢溪流數目為485 條，921 地震後，台灣地區原本脆弱的地質再次遭受到重創，中部災區震災前土石流危險溪流僅133 條，震災後暴增為370 條，共計增加237 條。由此看來，受到地震之影響，土石流發生之頻率及規模，勢必將有愈來愈嚴重之趨勢。然而，近年來由於全球暖化的影響，極端降雨事件發生的機率增高，其中尤以2009年8 月8 日之莫拉克颱風為最。根據雨量記錄，2009 年8 月6 日零時至8 月11 日零時，台灣南部地區之累積雨量竟然達到將近3000 公釐，造成全台多處嚴重之土石流及坡地災害，高雄縣甲仙鄉小林村更有超過400 人慘遭土石活埋，雖然致災原因複雜，但如此重大之傷亡，卻也暴露出台灣地區在相關的疏散避難規劃和作業程序上，確有值得討論及調整之處。土石流的模擬，可以幫助防災的決策，在災害發生前可以於第一時間疏散可能災區之居民與遊客，減少傷亡損失，本論文將對土石流體積量的估算與參數檢定之方法進行研究，並分析數值模擬後之成果。

關鍵字

土石流體積量；數值模擬；土石流平衡濃度；設計雨量；參數檢定

並列摘要

Because Taiwan located between the Continental plate and the Philippine tectonic plate,the orogenesis is frequent and the earthquake occurs frequently. Cemented material between stratum cobble-stone material by mud or granulated substance primarily. It is unstable. The mountainous region terrain is steep. brook length short, fast and quick. The soil layer is superficial and is soft. When the typhoon or torrential rain approaching, the mountainous area is flooded. Frail but un appropriate hilly land development regular creates soil the eroding,collapse and debris flows. before 1999’s 921 earthquakes occur, according to the government from 1992 to 1996 investigations, entire national territory have 485 debris flows potential brooks. After 921 earthquakes occur, Taiwan area frail geology is exposed once more originally the heavy losses. Middle disaster area have only 133 debris flows potential brooks before, but after earthquakes occur increases 237 to 370 debris flows potential brooks. Comes under influence of the earthquake, the debris flows has the frequency and the scale more serious. However, a result of the global warming's influence recently, the extreme rain event has increases the probability of its occur. The most serious is Typhoon Morakot on August 8, 2009. According to the rain records, between August 6 to August 11, 2009, accumulating the rainfall to be more than 3000 mm in south Taiwan, creates entire Taiwan place serious debris flows and slope land disaster. The Xiaolin Village in Jiasian Township,Kaohsiung County, it has surpasses 400 people to suffer the stone to bury alive. Although causes disaster's reason to be complex, the heavy casualties let the related dispersal seeks asylum in the plan and the operational procedure, really has is worth asking for discuss and adjustment. The earth flow simulation, may help the disaster prevention the decision-making, before the disaster occurs may resident and the tourist in the first time dispersal possible disaster area,reduces the casualties loss. The paper will conduct the research method to the earth flow volume quantity's estimate and the parameter examination, after and will analyze the numerical simulation, the achievement.