以數值模型探討大地工程不確定性對大規模順向坡滑動機率與影響範圍

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Title:	以數值模型探討大地工程不確定性對大規模順向坡滑動機率與影響範圍
Authors:	謝昀亨;Hsieh, Yun-Heng
Contributors:	土木工程學系
Keywords:	地質;地盤及地工模型不確定性;大規模邊坡穩定分析;離散裂隙網絡;蒙地卡羅模擬;Geological, ground and geotechnical model uncertainty;large-scale dip slope stability and reliability analysis;discrete fracture network;Monte Carlo simulation
Date:	2025-07-21
Issue Date:	2025-10-17 11:02:33 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究選定國立陽明交通大學陽明校區作為研究區域，該校區為順向坡敏感區，此區域過去曾發生數次淺層崩塌，但較少探討深層滑動之可能性，因此本研究著重於探討大規模順向坡滑動情境，在本研究共考慮四種邊坡滑動情境作為分析對象，包括：【情境1】沿厚層砂岩底部滑動，滑動面距地表下40m；【情境2】沿厚層砂岩內裂隙、節理及貫通岩橋滑動，滑動面距地表下20m至30 m；【情境3】沿砂頁互層底部滑動，滑動面距地表下20m；【情境4】綜合考量情境1、2與3之滑動面，並不預設滑動面。本研究使用RS2有限元素二維分析，於邊坡模型內建立離散裂隙網絡(DFN)，利用剪力強度折減法(SSR)計算各滑動情境之臨界強度折減因子(Critical SRF)，作為評估邊坡穩定性之依據，接著透過蒙地卡羅法將弱面凝聚力與摩擦角作為隨機變數，決定其對應之SRF反應曲面方程式，最後計算各情境下之滑動機率。模擬結果顯示，以情境2來說，受到平行層面裂隙影響，呈現階梯型破壞面，其影響範圍落在8,800~8,900 m2，而情境1及情境3之關鍵滑動面皆沿著地層間介面滑動，破壞機制受到岩橋貫通與高角度走向節理剪入及剪出，影響範圍分別落在12,000~13,000 m2及2,000~3,000 m2，最後，情境4為平面型破壞，滑動面距地表下10m，影響範圍則落在3,000~4,000 m2。可靠度分析結果顯示，陽明邊坡在情境2且弱面強度為殘餘強度狀況下有最高的滑動機率(1.57×10-4)。未來可透過此種分析方式，模擬裂隙岩坡之滑動面，並透過可靠度分析快速得到邊坡滑動機率及可靠度指標。;The Yangming Campus of National Yang Ming Chiao Tung University was selected as the research area in this study. This study focuses on exploring the sliding mechanisms of large-scale sliding events under various scenarios. Four slope sliding scenarios are analyzed in this study, including: Scenario 1 involves sliding along the bottom of the thick sandstone layer, and the sliding surface is located 40m below the surface. Scenario 2 focuses on sliding along the fractures, joints, and rock bridges within the thick sandstone layer, and the sliding surface is located 20m to 30m below the surface. Scenario 3 examines sliding along the bottom of the sandstone-shale interbedding, and the sliding surface is located 40m below the surface. Finally, in Scenario 4, the potential sliding surfaces were not predefined. In this study, RS2 finite element 2D analysis was used, and a discrete fracture network (DFN) was established within the slope model. The simulation results show that for Scenario 2, a step-wised failure plane occurred due to the influence of parallel-to-bedding fractures. The sliding area is between 8,800 and 8,900 m². In both Scenarios 1 and 3, the key sliding surfaces mainly occur along the interfaces between layer strata, with failure mechanisms influenced by rock bridge formation, high-angle joints, and shearing. The sliding areas are between 12,000 and 13,000 m² for Scenario 1 and between 2,000 and 3,000 m² for Scenario 3. Finally, Scenario 4 shows a planar failure, with the sliding surface located 10m below the surface, and its sliding area is between 3,000 and 4,000 m². Reliability analysis results show that the highest sliding probability (1.57×10⁻⁴) occurs in Scenario 2, under a residual shear strength condition. In the future, this type of analysis can be used to simulate the sliding surfaces of fractured rock slopes and quickly obtain the slope sliding probability and reliability indices through reliability analysis.
Appears in Collections:	[Graduate Institute of Civil Engineering] Electronic Thesis & Dissertation

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