臺灣大學: 土木工程學研究所陳榮河陳志信Chen, Chih-ShinChih-ShinChen2013-04-012018-07-092013-04-012018-07-092012http://ntur.lib.ntu.edu.tw//handle/246246/255477降雨為影響邊坡破壞的重要因素；近年來，有一些利用邊坡模型試驗對降雨引發邊坡破壞進行研究，並於坡體內埋設監測儀器觀測破壞之機制。研究探討之主要水文條件有給水情形(降雨或滲流)、降雨強度等；幾何條件有坡型、模型邊坡之尺寸等；地質條件有土壤中細料含量、土壤之相對密度等；然而甚少針對現地土壤特性進行研究。本研究則以臺灣北部石門水庫集水區鐵立庫地區某崩塌地為研究地點，並於現地取樣後調整現地之級配，使符合模型相似性以進行室內模型邊坡試驗。 模型材料性質主要考量為材料之粒徑與分佈、剪力強度、滲透性等。模型則考慮現地之邊坡坡型、崩積層厚度、不均質岩層面與不同保護工法配置：如坡面鋪設抗沖蝕之地工織物，坡體內埋設水平排水管，及坡趾埋置濾層等，嘗試由室內試驗尋求對現地破壞機制之瞭解與尋求有效之保護工法。實驗過程中以攝影機觀察邊坡破壞現象及型態，並記錄土壤孔隙水壓與體積含水量，以及收集沖蝕土壤之重量與粒徑分佈等。 由試驗觀察得知，岩盤不深且未設保護措施之邊坡容易於坡體內快速累積水壓，且發生滑動的時間甚早於覆土較厚者。而地工織物鋪設於坡面上可有效穩定邊坡；另一方面，坡體內埋設橫向排水管之效果極佳，能有效降低坡體內水壓，使整體邊坡之穩定性提高，但需注意將排水引導排放，以免其對坡面造成沖蝕之影響。而於坡趾前方堆積區設置濾層則會使坡面產生淺層破壞，故需配合坡面保護工法防治，或將濾層由坡趾延伸入坡體內以防止坡面淺層破壞和避免產生大規模之弧型破壞。Rainfall is one of major factors that cause slope failures. In recent years, there have been researches employing model tests on slopes subjected to rainfalls. Instrumentations embedded in the slopes were monitored to investigate the failure mechanism of the slopes. Main variables considered in the researches were as follows: hydrological factors such as water supply conditions (e.g., rainfall or seepage) and rainfall intensity, geometric factors such as slope profile and model dimensions, and geological factors such as the fines content and relative density of soil. However, few have been reported using in-situ soil for research. In this study, the test soil was taken from a site in Tieliku area, located within the catchment area of the Shimen Reservoir in northern Taiwan. The site had experienced slope failures and was under restoration. Before test, the grain size distribution of the in-situ soil was modified in the laboratory to be in accordance with the similarity laws for model test. The major characteristics considered for simulating the in-situ soil were the grain sizes and their distribution, the shear strength and permeability of the soil, etc. With regard to in-situ conditions, the factors considered were slope profile, the thickness of soil, impervious stratum in slope, and slope protection works such as an anti-erosion geotextile blanket placed on slope face, horizontal drainage pipes embedded in the slope, and a filter blanket under the deposition area near the toe of slope. The aim was to investigate the failure mechanism of the slope and to evaluate the effectiveness of the protection works through model tests. During the tests, the process of slope failure was recorded by three video cameras, and piezometers and moisture sensors measured the variations in pore-pressure and volumetric water content of soil. The eroded soil was collected for weigh measurement and for conducting grain size analysis. Based on the test results, the unprotected slope with an impervious stratum at shallow depth tended to induce a quicker accumulation of pore water pressure in the slope and to fail earlier than the slope having a thicker layer of soil. However, the geotextile blanket displayed a good effect on stabilizing the slope. The horizontal drainage pipes also showed excellent results not only reducing pore water pressure, but also improving the overall slope stability. Nevertheless, the filter blanket that placed in the area adjacent to the toe of the slope caused shallow slope failures. In this regard, the filter blanket should be used in combination with other protection works or extended into slope so that shallow slope failures as well as deep circular failures would not be induced.140 bytestext/htmlen-US邊坡模型試驗降雨破壞護坡工法slopemodel testrainfallfailureslope protection worksthesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/255477/1/index.html