降雨型態對猴山岳邊坡穩定之影響

Housanyan Landslide induced by Different Rainfall Types

賴毅銘(I-Ming Lai)

指導教授 ： 陳水龍

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2012年)

摘要

在邊坡預警系統中，觀測降雨量之方式最為省錢與便利，且更容易讓一般的民眾瞭解，故此方法常被利用在山坡預警的發布，但由於每個邊坡都有不同的地質與水文特性，因此就算在相同的降雨強度與延時下，對地下水位的影響也都會有所不同。本研究採用Van Genuchten的SWCC曲線、儲水方程式與非飽和水力傳導方程來模擬降雨對非飽和土壤之入滲行為。利用PLAXIS 模擬猴山岳邊坡在辛樂克颱風期間之破壞案例。透過軟體中的Flow mode計算降雨與地下水位之關係，再將分析之地下水資料代入Advance mode中計算不同地下水位下之安全係數的變化。另外再設計四種不同雨型、三種降雨強度與是否考慮前期降雨之條件，探討24種不同降雨條件下，猴山岳邊坡(崩塌整治後)之各時段地下水位變化與安全係數之變化，得到在何種降雨條件下猴山岳邊坡可能會產生滑動，並代入台北市南區機率式崩塌警戒基準中做比較，再利用相同方法建立一套猴山岳邊坡之預警值，供猴山岳邊坡附近居民做為參考。

關鍵字

有限元素法 ； 降雨 ； 安全係數 ； 警戒值

並列摘要

Rainfall observation is the most economic and convenient way for slope early warning system and much easier for the public to understand.It is very often used in the announcement of slope warnings.However, the geologic and hydraulic features are different from slope to slope.The rainfalls have difference influence on groundwater table given the same intensity and hysteresis.The SWCC curves, water storage function and hydraulic conductivity function developed by Van Genuchten were introduced to simulate the infiltration behaviors of rainfall in unsaturated soil. PLAXIS was used to simulate a failure case that happened on the slopes of Housanyan during typhoon Sinlaku.The Flow mode of the program was used to calculate the rainfall vs. groundwater table.The groundwater data from analysis was substituted in the Advance mode for the calculation of changes in factors of safety at different groundwater tables.4 different rainfall patterns and 3 intensities were designed to investigate the changes in groundwater tables and factors of safety in various periods of the Housanyan slopes (after remediation of slopes) under 24 rainfall conditions with or without the consideration of antecedent precipitation.It was intended to find out what rainfall condition(s) may trigger the sliding of Housanyan slopes.The probability-based landslide rainfall warning model of southern Taipei City was substituted for comparison.With the same procedure, a set of early warning values were established for the Housanyan slopes for the reference of people living in this area.

並列關鍵字

finite element method ； rainfall ； factor of safety ； warning value

參考文獻

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