降雨入滲引發土體崩塌之數值分析

Numerical Analysis on Landslide of an Inclined Soil Layer Caused by Rain Infiltration

10.29417/JCSWC.201803_49(1).0005

詹錢登(Chyan-Deng Jan)；陳新霖(Shin-Lin Chen)；楊斯堯(Ssu-Yao Yang)

崩塌 ； 降雨入滲 ； 超額孔隙水壓 ； 柴比雪夫法 ； Landslide ； Rainfall infiltration ； Excess pore pressure ； Chebyshev method

中華水土保持學報

49卷1期（2018 / 03 / 01）

49 - 58

繁體中文

崩塌係指土體受重力作用沿坡面向下運動的現象。本研究以牛頓第二運動定律為基礎，考量降雨入滲對土體的影響，建構無限邊坡土體崩塌模式，然後將降雨入滲水所生超額孔隙水壓以擴散方程式來描述其傳遞方式；以柴比雪夫多項式求解法，分析超額孔隙水壓的傳遞情形，從而分析土體是否會發生崩塌。結果顯示土壤參數條件將影響土體崩塌所需的坡度與超額孔隙水壓；降雨入滲特性影響超額孔隙水壓的傳遞情形，從而影響土體崩塌時間。本研究也比較降雨入滲特性及降雨過程中地下水位增加對土體崩塌之影響。

Landslides are the downslope mass movement caused by gravity on hillsides. In this study, we developed a landslide model that describes a block sliding down an infinite slope governed by Newton’s equation of motion, considering the block weights, its internal excess pore pressure and friction. This numerical model considers pore pressure evolution within a soil layer under rain infiltration obeys diffusion equation, numerically solved by the Chebyshev polynomial method. Results show that the critical soil-layer slope, critical excess pore pressure, and the time to reaching landslide occurrence are controlled by soil properties and rainfall infiltration intensity. We also investigated the effects of rainfall infiltration characteristics and the variation of groundwater level on landslide triggering.

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