陳榮河2006-07-252018-07-092006-07-252018-07-092005http://ntur.lib.ntu.edu.tw//handle/246246/2916本研究針對土石流之地文及水文因子作探討，其中，地文因子部份 探討土石流材料之空間分佈特性，特別針對現地無法進行採樣部份，以 碎形理論探討粒徑分佈曲線，並加入「影像篩分析」的概念，研究如何 模擬現地真實之粒徑分佈情形。 水文因子部份則探討土石流發生時孔隙水壓所產生之影響，將特別 著重在土壤孔隙管道分佈之情形。其中，土壤內孔隙毛細管道之粗細與 長短受土粒粒徑分佈之影響，因此毛細吸水能力亦將不同，進而影響土 壤之抗剪強度等。本研究將碎形理論之觀念，應用於土壤顆粒篩分析 上；利用篩分析資料獲致土粒大小分佈之碎形維度，並借保水試驗結 果，結合碎形理論模式驗證之，以瞭解土壤孔隙之大小分佈特性。 此外，利用已建立之保水曲線之碎形理論模式，模擬毛細現象。並 應用於物理模型試驗中，用以瞭解土體內部水壓力及含水量變化情形。 本研究藉由結合材料性質、水文特性之關聯性，期望對土石流發生機制 有更深入之認識，預期對未來土石流之潛勢之判定有所助益。A general model which can identify potential debris flow ravines, including both geophysical and hydrological parameters, is developed. For the geophysical parameters, the fractal theory is employed to rebuild the in situ particle size distribution curve. For the larger sizes that are hard to be sampled in the field, the concept of image sieve analysis, employed to obtain the actual grain size distribution in the field. On the other hand, for the hydrological parameters, this study focuses on the pore sizes and its distribution, concerning the pore pressures depend highly on the grain gradation of materials. The box-counting method of fractal theory is used on the analysis of soil sieve data. Then, the fractal dimension to respond the soil gradation will be obtained from the double-logarithm plot of grain size distribution curve. This fractal dimension is used to the fractal model for predicting the moisture retention curve. In addition, a new device of water transporting test is developed in this project to measure the water content and the capillary pressure distributions due to simulated rainfall infiltration. Based on the experiment results, a water transportation model in the debris flow material can be constructed. Thus, the assessment of potential debris flow can also be made accordingly.application/pdf8288994 bytesapplication/pdfzh-TW國立臺灣大學土木工程學系暨研究所土石流發生機制碎形維度影像篩分析debris flowinitiation mechanismfractal dimensionimage sieve analysisreporthttp://ntur.lib.ntu.edu.tw/bitstream/246246/2916/1/932625Z002024.pdf