南投縣母安山深層滑動

Abstract

深層崩塌自小林村事件後便開始受到重視，深層崩塌帶來的大量土方不僅可能直接掩埋下方村落，更可能堵住河流形成堰塞湖，而一旦不穩定的堰塞湖土牆承受不住水壓潰決，將造成更大規模且嚴重的災害。 母安山，是繼小林村後國內學者認為最可能發生深層崩塌的地區，其滑動原因主要是由板、頁岩互層之順向坡地質、過高的地下水位、崩塌面基腳被塔羅灣溪長期掏刷降低穩定度等三項主因構成，且該滑動面下方就緊鄰著知名的廬山溫泉觀光區，一旦發生深層崩塌將對保全對象造成嚴重的生命財產損傷。 母安山的深層滑動目前並無任何根治的辦法，唯一辦法就只剩下遷村，但由於遷村涉及事項龐大，所需考量層面繁雜，以母安山的案例而言，到目前為止，原居住在南投縣仁愛鄉廬山溫泉地區的民眾或業者都尚未完全同意遷村建議，因此目前只能做好監測母安山滑動的工作，訂定250mm時雨量的嚴苛撤離標準，並做好事前撤離防範工作之演練，以期降低災害造成的傷亡。但在未來降雨漸趨嚴苛情況下，當地民眾遷村進度仍如此緩慢，此類案例該如何找到正確且快速執行方式，母安山的案例值得供為未來執行上的參考。

More and more people concern about deep-seated landslide after it occurred in Shaolin Village, Kaohsiung County. Deep-seated landslide resulted in the landslide dam and the following flooding disasters after the landslide dam failed. The floods might not only directly destroy the downstream village but block the stream then cause landslide dam. Once the unstable wall of landslide dam could not endure the hydraulic pressure and results in collapse, it will cause large-scale and severe damage. Muan Mountain, domestic researchers think this region is the most likely to occur deep-seated landslide. There are three main reasons to cause deep-seated landslide. The first reason for the possible serious landslide disaster in Lushan area is the dip-slope geological formation with alternations of slate and shale. And the second one is over high ground water elevation. The last one is the low stability of footing which is scoured by Taluowan River for long-term. Besides, below the surface of slide is the famous Lushan hot spring attraction. Thus, if it occurs to deep-seated landslide, there will be great life and property damage to secured objects. So far, there is not exact solution to solve the problem of deep-seated landslide which occurred in Muan Mountain. The only way is let local residents who live there relocate to a safer place. However, moving to another place is a huge project. It needs a lot of considerations from many different sides. Take the case of Muan Mountain as an example, most of the villagers and industries who live there do not agree to move. As a result, the only thing we can do currently is monitor the condition of Muan Mountain, set 250 mm rainfall per hour as a strict standard to move away, and practice the relocation drill previously. With these ways, it can reduce casualties from disaster in the future. Nevertheless, due to global climate change, the rain falls extremely in recent decades. And the process of relocation is so slow. It is still a problem to figure out a correct and effective solution.