Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/33825
標題: 地滑地區滲流及地下排水工法對邊坡穩定影響之數值模擬﹘以梨山地滑區為例
Numerical Simulation of the Effects of Seepage and Underground Drainage on Slope Stability- A Case Study of Li-San Landslide-
作者: 鄧鳳儀
關鍵字: Seepage;滲流;Underground Drainage;Slope Stability;Landslide;rainfall;Li-San;catch wells;Horizontal Drains;地下排水工法;邊坡穩定;地滑;降雨;梨山;集水井;橫向排水管
出版社: 水土保持學系
摘要: 
地滑區產生邊坡災害之主要原因為暴雨及地下水位上升,因此排水為整治工程之首要工作。地表排水設施之設置可縮短雨水停滯於坡面的時間並減少入滲。地下排水工法則在排除地層內之滲流水及降低地下水位,以減少土壤孔隙水壓並增加邊坡之穩定性。
一般地下排水工法降低地下水位之效應並無法採傳統方法進行分析,同時降雨對於邊坡穩定之影響分析亦侷限在靜態地下水位或固定孔隙水壓之條件下來進行,而未考量地下水滲流及降雨延時之孔隙水壓對邊坡之影響。
本研究使用Seep/W二維有限元素滲流分析程式及Slope/W極限平衡法邊坡穩定程式針對地下排水工程降低地下水位及其對邊坡穩定性之影響進行數值模擬分析。第一部分研究成果顯示降雨入滲時滲流狀態下之邊坡穩定潛在滑動面與監測滑動面相吻合。另外,第二部份研究結果顯示地下排水工法降低地下水位之效應可經由本研究之數值模擬程序適當呈現,其中集水井及橫向排水管可採用滲流出口邊界加以模擬,此類邊界由總流量節點組成其功能尤如一潛勢滲流面。

Landslides event are frequently resulted from torrential rainfall and upwelling of groundwater. Therefore, it is crucial in the slope stabilization how to implement dewatering techniques effectively. The installation of drainage system on ground surface is capable of shortening the infiltration of rainwater while the underground dewatering system is advantageous to the dissipation of pore water pressure and increases the stability of slope.
In general, it seems that the effect of underground dewatering on the groundwater drawdown was commonly neglected in the conventional slope stability analyses. At the meantime, the analyses were normally performed under hydrostatic condition and exclude the variation of pore water pressure during rainfall.
Incorporating two dimensional finite element seepage analyses with limit equilibrium analysis, this study investigates the effect of underground dewatering on the slope stability of Li-San landslide. It was found that the predicted potential sliding surfaces under the rainfall condition during Typhoon seasons are excellently in agreement with those from the field observations. In addition, the effect of vertical well shaft for groundwater collection and horizontal drains on the slope stability can be successfully simulated by imposing an outflow seepage boundary on the drainage path. The boundary is alternately consisted of an aligned flux nodal points and which makes the outflow seepage boundary function as a potential seepage surface.
URI: http://hdl.handle.net/11455/33825
Appears in Collections:水土保持學系

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