邊坡滑動面之研究-以174縣道地滑區為例

Study of Failure Plane-A Case of County Road Number 174

高翊唐(Yi-Tang Kao)

指導教授 ： 陳水龍

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2014年)

https://doi.org/10.6841/NTUT.2014.00647

摘要

一般而言，當邊坡崩塌災害發生時不論緊急搶修或長期整治，均須調查滑動面深度，若在未確切掌握滑動面深度之情形下，即使施作邊坡整治工法，往往由於施作之工法未達到滑動面之深度，造成整治結果不佳，而再度造成災害，故掌握滑動面深度對崩塌地整治成功與否有著決定性的影響。
本研究承接前人進行之研究、監測，對於滑動面判釋方法(1)由滑動規模之推估方法(2)岩心檢視之經驗方法(3)監測之定量分析方法三種作綜合整理，並以有限元素法軟體PLAXIS對地滑區進行穩定分析，加以判斷滑動面深度，並採用Van Genuchten的SWCC曲線來分析崩積層中吸力與飽和度之關係。邊坡穩定分析後研判邊坡常時下之安全係數為1.385。並將邊坡常時安全係數、南瑪都颱風期間之安全係數、土壤含水特徵曲線等成果與相關文獻所提出之成果做比較，皆有相近之趨勢。根據鑽探報告之結果於岩層中增設一弱面，模擬觀測期間，邊坡之地下水高程抬升，弱面浸水後隨著時間的增長，使弱面之剪力強度逐漸降低，分析後顯示滑動面深度與監測數據相近，以此更加提升研究成果之可靠度，藉以瞭解邊坡穩定分析方法在監測數據不足時，如何設法研判邊坡滑動面之可行性。

關鍵字

滑動面 ； 邊坡滑動 ； 監測 ； 非飽和土壤

並列摘要

Generally speaking, it is necessary to investigate the depth of sliding surface for either emergency repair or long-term remediation after a landslide occurs. Without the solid knowledge of sliding surface depth, the slope remediation work may not yield satisfactory results and more disasters are likely as the remediation work fails to reach the depth where the sliding surface is located. Therefore, the knowledge of sliding surface depth holds the key to a successful remediation of landslide area.
This study is a continuation of previous study and monitoring process. Three methods of slide plane interpretation, (1) estimation using scale of slides; (2) empirical method by examining rock core samples; and (3) quantitative analysis on monitoring, were introduced for this study. PLAXIS, a finite element analysis program, was employed for the stability analysis of landslide areas and the identification of slide plane depth. The SWCC curve proposed by Van Genuchten was used for the investigation of the relationship between the matric suction and saturation in colluviums. The slope stability analysis produced a factor of safety of 1.385 form normal time. This factor of safety was compared with the factor of safety during Typhoon Nanmadol, results from water storage function and those presented in previous literatures, and a similar trend was found. A weak plane was added in the rock formation based on the boring report to simulate the increased groundwater elevation in the slopes during the monitoring. As the weak plane was soaked in groundwater, the shear strength in this plane decreased as the time went by. This simulation suggested similar results between the slide depth obtained and monitoring data, indicating improved reliability of the study results. It helps to identify the feasibility of the slide plane in slopes for slope stability analysis when monitoring data is insufficient.

並列關鍵字

Sliding Surface ； Slope Sliding ； Monitoring ； Unsaturated soil

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