Numerical analysis of rainfall infiltration in unsaturated soil slopes with interlayered structures

• Main Authors: Wei-Lun Jan, 詹偉倫
• Other Authors: T. W. Feng
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/07712844526625464516

碩士 === 中原大學 === 土木工程研究所 === 94 === In Taiwan, most of the slope failure occurred during highly concentrated rainfall season. This study uses seven rainfall records and seven types of strata in numerical analysis. Seven records include Nari-typhoon, Xangsane- typhoon, Bilis-typhoon, Herb-typhoon, Zeb-typhoon, Winnie-typhoon and Aere-typhoon; seven types of strata include sandy loam, silty caly Lungtan red soil, sandy loam/silty caly, sandy loam/Lungtan red soil, Lungtan red soil/sandy loam, and Lungtan red soil/silty clay. This study also considers Geomembrane and drain pipe in numerical analysis. The results of this study indicate that: 1) the elevation of groundwater table will have low value when the slope uses geomembrane or build drain pipe. When use geomembrane, matric suction or volume water content of slope didn't effected by infiltration. When drain pipe is used, matric suction or volume water content of the slope will have a little effect. 2) drain pipe will make water flow into the head of drain pipe. 3) At an inclined slope angle of 26.5°, the geomembrane of length of 0.8 slope height at slope top and 1.5 slope height at slope surface is a better choice. At an inclined slope angle of 45°, the geomerbrme of length of 1.25 of slope height at slope top and 0.94 slope height at slope surface is a better choice. At an inclined slope angle of 63.4°, the geomerbrme of length of 1.25 slope height at slope top and 0.75 slope height at slope surface is a better choice . 4) Intensed rainfall is more effective than long-term low intensity rainfall in infiltration. 5) If upper layer of multiple layer has high permeability, rainfall is easy to infiltrate into the slope. At a result, groundwater table, slope matric suction, and volume water content of slope change. 6)At the same height of slope, groundwater is higher in 26.5°slope than that in 45°slope,whereas it is about the same for 45°slope and 63.4°slope.