結合廣域統計、坡地力學模擬與可靠度分析之坡地安全評估架構可行性—以濁水溪流域及萬大崩塌地為例

Abstract

本研究針對現行崩塌災害分析多侷限於單一方法、難以掌握災害特性全貌的問題，提出一套整合廣域統計、物理模擬與可靠度分析三種方法的坡地安全評估架構，並實際以濁水溪流域及萬大崩塌地為例進行此架構之效果探討。本結果顯示，若僅依廣域統計（頻率比法）建立的崩塌敏感度地圖，雖可辨識出萬大崩塌地屬於高敏感區，但無法捕捉此坡地在滑動機制上，實際具有的滑動調適能力，可能導致防災資源投入過度；反之，若僅依物質點法模擬與AK-PSO-HHs可靠度分析，雖能指出其在極端條件下失效機率偏低、滑動具回穩特性，但也容易忽略其所處萬大區域整體敏感性及持續潛移對周圍設施的影響。唯有透過三者整合後更新出的標準常態CDF LSI平均值（μ_LSI0'' ），才得以最適當地量化推估萬大崩塌地的滑動預期損失，具體而言建議須達到10.22公尺滑動量的防護能力，才可有效防範萬大崩塌地之潛移行為對道路與建設的損害。 由此數值也反映出，本研究建議之保護標準並非在於阻止較不可能於萬大崩塌地發生的大規模崩塌，而是更貼近該坡地對於潛移行為的控制需求，並實際提出量化後的防護建議。本研究以濁水溪流域及萬大崩塌地為例，說明了所提出的「整合性坡地安全評估架構」在分析結果上初具可行性與有效性，因此建議後續可進一步精進，以使此評估架構在未來可受到更廣泛的應用與驗證。

This study addresses the limitations of conventional landslide hazard analyses, which often rely on a single method and fail to capture the complex mechanisms of slope behavior. To resolve this, an Integrated Slope Safety Assessment Framework is proposed, combining statistical mapping, slope mechanics simulation, and reliability analysis. The framework is applied to the Jhuoshuei River Basin and the Wanda Slope to evaluate its feasibility and effectiveness. The results show that while statistical mapping based on the Frequency Ratio Method effectively identifies the Wanda Slope as a high-susceptibility area using terrain, geological, and land-use factors, it does not account for the slope’s actual response mechanisms under stress, potentially leading to excessive or misallocated mitigation. In contrast, the Material Point Method (MPM) and AK-PSO-HHs reliability analysis indicate a low probability of large-scale failure under extreme conditions and reveal the slope’s tendency to recover after deformation. However, relying solely on these physically-based analyses may overlook the broader susceptibility of the Wanda area and the long-term impact of creep on surrounding infrastructure. By integrating all three approaches, this study introduces a standardized posterior mean of the normal CDF-based Landslide Susceptibility Index （μ_LSI0'' ） for balanced quantification of expected slope displacement. For the Wanda Slope, the integrated results recommend that mitigation measures be designed to accommodate a displacement of 10.22 meters, targeting the control of progressive creep rather than preventing improbable large-scale collapse. These findings demonstrate the feasibility and initial effectiveness of the proposed Integrated Slope Safety Assessment Framework, suggesting its potential for further development and broader application to other complex landslide-prone regions.