滲流水之離子濃度及電導度與土體崩塌發生關係之研究

Abstract

摘要 本研究主要目的在探討滲流水之離子濃度及電導度與土體崩塌發生之關係。土壤樣本採自南投縣信義鄉豐丘村、神木村及台北縣新店市雙城里之土石流潛勢溪流集水區，經過篩後，模擬現地土壤之物理性質，以等重量替代法製作試體，並進行滲流槽試驗，藉以探討當土體破壞時，滲流水離子濃度及電導度之變化。結果顯示，當滲流水水位逐漸上升導致土體發生崩塌之前，豐丘村、神木村及雙城里三地土樣滲流水之上游硫酸根離子濃度與坡頂電導度無明顯變化，但下游硫酸根離子濃度與坡腳電導度則有明顯上升之趨勢，並在崩塌時達到最高值。 關鍵字：滲流水、離子濃度、電導度、土體崩塌

Abstract The main purpose of this study is to investigate the relationships among ion concentration、electrical conductivity (EC) of seepage water and soil mass movement occurrence. The sites of this study were selected at Feng-Chiu and Shen-Mu in Nantou and Sindian in Taipei. Soil samples for the tests were collected from the watersheds of the debris flow potential streams of the sites. After the soil samples were sieved and prepared in the flumes in a manner of simulating the soil physical conditions in the field and Equal-Weight Replacement Method, the seepage flow and slope stability tests were then conducted to investigate the variation of the ion concentration and EC of seepage water while the soil slopes failed. Meanwhile, the ion concentration and EC of seepage water in the field was also observed and evaluated. The results showed that while the seepage water table gradually increased and a curtain time period before the soil slope failed, for the samples collected from Feng-Chiu and Shen-Mu in Nantou and Sindian in Taipei, the concentration of SO42- and EC of the seepage water at upstream of the mass movement did not change significantly. However, the concentration of SO42- and EC of the seepage water at downstream of the mass movement started to increase and reached to a maximum value while mass movement occurred. Keywords: seepage water, ion concentration, electrical conductivity, soil mass movement