大規模地滑區地下排水穩定工法之效益評估

Evaluating the Efficiency of Subsurface Drainage Systems during Large Landslides

林德貴(Der-Guey Lin) ； 張國欽(Kuo-Ching Chang) ； 朱家勁(Eugene Choo) ； 蘇苗彬(Miau-Bin Su)

《中華水土保持學報》 49卷4期 (2018/12) Pp. 199-213

https://doi.org/10.29417/JCSWC.201809_49(4).0001

摘要

為評估梨山大規模地滑區地下排水系統在穩定邊坡之工作效益，本研究採用地下排水（集水井及排水廊道）施作前（安珀颱風，1997）、後（桃芝颱風，2001）之降雨事件，進行邊坡之降雨入滲－地下水滲流－穩定數值分析。數值模型中，將集水井及排水廊道之橫向集水管集排水效應，分別設定為：線型自由排水邊界，以及點型排水邊界，來進行深層地下排水模擬。研究顯示設置於梨山地滑區之地下排水系統能有效且迅速集排高強度及長延時降雨之入滲雨水，並減緩邊坡穩定性迅速惡化之不利影響。

關鍵字

大規模地滑區 ； 地下排水 ； 集水井 ； 排水廊道 ； 潛在滑動面

並列摘要

This study investigated the efficiency of subsurface drainage systems-which comprise drainage wells and galleries-to analyze the slope stability of landslides in Lishan in central Taiwan during Typhoon Toraji in 2001 (with subsurface drainage remediation) and Typhoon Amber in 1997 (without remediation) by using the numerical analysis method. The drainage effects of drainage wells and galleries were simulated by assigning a series of line-type and point-type drainage boundary conditions along drainage boreholes in the numerical model. The numerical results and monitoring data indicated that the subsurface drainage systems for handling landslides in Lishan are functional and capable of accelerating drainage of infiltrated rainwater caused by prolonged heavy rainfall and reinforcing slope stability against rapid deterioration during landslides.

並列關鍵字

large landslide ； subsurface drainage ； drainage well ； drainage gallery ； potential sliding surface