滲流現象對坡地穩定之影響

The Influence of Rainfall Infiltration on the Slope Stability

鄭正隆(Zheng-Long Zheng)

指導教授 ： 張德鑫

中原大學/工學院/土木工程研究所/碩士(2004年)

https://doi.org/10.6840/cycu200400027

摘要

目前對於邊坡穩定之探討，大都忽略降雨滲流造成土壤含水量之時變過程，而僅著重於在某特定土壤狀態與環境條件下之分析，因此只能得知該邊坡於某條件下是否安全。若得知此邊坡在某種條件下可能破壞時，此種分析並未能顯示於何時會發生崩坍，故邊坡穩定之時變性分析實為必要，因此種分析方法可預測在某種特定土壤與環境條件下，邊坡可能於何時發生破壞。
本研究主要就平面坡頂場址與裂縫坡頂場址兩種類型邊坡，結合降雨、滲流及邊坡穩定分析等知識與方法，應用3D-FEMWATER地下水水流數值模擬模式，模擬降雨後邊坡土壤內含水量隨時間之變化，以及地下水水位升降情形。其次將含水量轉換其所對應之各點土壤物理參數，再應用STABL邊坡穩定分析模式，針對不同狀況下採逐時計算各階段之坡地安全係數值。
本研究在邊坡安全時變分析之模擬結果顯示，邊坡之安全係數值會因降雨入滲過程而有所改變，且同樣降雨12小時累積雨量100mm情況下，有裂縫坡頂場址安全係數值較平面坡頂場址變化大。由此可知，在有裂縫之邊坡，其所受降雨入滲影響較大。其次於分析結果中，可顯示安全係數值變化與時間之關係，當以安全係數值小於1.0為設定之破壞情況時，即可推估邊坡在經降雨入滲後之可能破壞時間，依此可建立邊坡安全之預警制度。

關鍵字

none

並列摘要

At present, most analyses of slope stability don’t include influence of rainfall infiltration. They only emphasize the analysis under a specific soil and environment conditions, so we just learn whether it’s safety under a condition of that slope. If it was destroyed under a condition of that slope, the analysis won’t show when the collapse will happen. It’s essential to analyze the slope stability depending on time’s changing because the analysis method can predict when the destruction might happen under a specific soil and environment conditions.
The research use two sorts of slopes－flat and crack slope to combine the knowledge and methods of rainfall, infiltration, and slope stability, applies 3D-FEMWATER in simulating the soil moisture content after a rainfall depending on time’s changing, and the increase and decrease of groundwater. Next, there are different soil parameters in different moisture content. Then, it applies the mode of STABL to count each stage the relations between safety factors of slope and time.
According to simulated result of slope depending on time’s changing, we learn that the slope factor of safety will change which depends on rainfall infiltration. Factor of safety (F.S.) of crack slop has much changing than F.S. of flat slop by raining 12 hours to accumulate the rainfall of 100mm. Thus, the slope with crack is influenced much by rainfall infiltration. From the result of analysis, it shows the relations between F.S and time. It will destroy when F.S is under 1.0, and we can estimate when will destroy after slope rainfall infiltration. Then, we can establish the warning system of slope safety.

並列關鍵字

none

參考文獻

9.郭麗娥(2003)，「未飽和紅土水力傳導係數之研究」，中原大學土木工程研究所碩士論文。

13.盧惠生、胡蘇澄、林壯沛(1996)，「蓮華池坡地檳榔園土壤入滲模式之研究」，台灣林業科學第十一卷第四期，第409~420頁。

12.盧惠生、胡蘇澄(1993)，「應用Philip入滲模式推估台灣中部山區土壤入滲」，林業試驗所研究報告季刊第八卷第四期，第259~270頁。

14.鄧子榆(2001)，「以有限元素法進行邊坡穩定安分析之研究」，中原大學土木工程研究所碩士論文。

17.Biot, M. (1940), ‘General Theory of Three-dimensional Consolidation’, J. Appl. Phys. Vol.12, pp.155-164.