雙圓型潛盾隧道地表沉陷分析之探討-以機場捷運線臺北三重段

Ground surface settlement of Double-O-tube shield tunnel for Airport Access MRT in Taipei Basin

柯婉伊(Wan-yi Ka)

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(2011年)

https://doi.org/10.6841/NTUT.2011.00392

摘要

本研究針對雙圓型潛盾隧道施工引致地表沉陷進行評估，以桃園國際機場捷運線台北三重段CA450A標工程為案例，運用有限元素法PLAXIS 2D軟體，以實際案例之斷面地質條件進行不同覆土深度單孔隧道數值分析，依最大地表沉陷量相同，比對隧道斷面縮減率及土壤釋放應力兩種數值分析方法之參數關係。DOT潛盾隧道案例以PLAXIS數值分析七處監測斷面地表沉陷量，其數值分析地表曲線與現場監測沉陷觀測資料及經驗公式進行地表沉陷槽相互比較，可驗證PLAXIS分析雙圓型潛盾隧道之適用性，亦可了解雙圓型潛盾隧道開挖過程中可能影響情況及對鄰近建物之影響範圍，可供後續雙圓型潛盾隧道工程應用參考。
針對單孔潛盾隧道數值分析之隧道斷面縮減率及土壤釋放應力兩參數最大地表沉陷關係，於隧道中心深度20m時呈非線性關係，則於隧道中心深度24m及27m時呈線性關係。臺北三重段雙圓型潛盾隧道經由數值分析、經驗公式及現場監測沉陷三種方式比對結果，經驗公式疊加法及等面積法兩者所計算之雙圓型潛盾隧道地表沉陷槽極為相似。但經驗公式所計算結果與現場監測沉陷結果比對，其沉陷槽形狀趨勢大致吻合，但隧道中心最大地表沉陷值有差異性。數值分析模擬結果與現場監測沉陷相比對，其隧道中心最大地表沉陷值及地表沉陷槽趨勢大致吻合。經由數值分析所得之土壤釋放應力值與數值最大地表沉陷量、現地漏失率，皆為正比線性關係。可供未來雙圓型潛盾隧道數值分析土壤釋放應力值範圍，以此預測可能之地表沉陷量上下限範圍。

關鍵字

雙圓型潛盾隧道 ； 有限元素 ； 地表沉陷 ； 現場監測

並列摘要

This study evaluated the ground surface settlement caused by double-o-tube shield tunnel construction, using Taoyuan International Airport MRT Line Taipei-Sanchung Section CA450A as an example. PLAXIS 2D software of the infinite element method was used to conduct numerical analysis on the single bore tunnels at various depths of earth covering according to the geologic conditions of the sections in actual cases, in order to compare the parameter relationship between the two numerical analysis methods of percentage of area reduction of the tunnel and soil released stress based on the same maximum ground surface settlement. In the case of DOT shield tunnel, PLAXIS numerical analysis was carried out on the ground surface settlement of 7 monitored sections. Through intercomparison among the ground surface curve by the numerical analysis, settlement observation data by in-situ monitoring and empirical formula calculation in terms of the ground surface settlement trough, the applicability of PLAXIS on analyzing the Double-o-tube shield tunnel has been verified, which could help to understand possible influences in the process of Double-o-tube shield tunnel excavation and influence range to adjacent structures, and provide reference for future Double-o-tube shield tunnel project application.
The maximum ground surface settlement relationship of the percentage of area reduction of the tunnel and soil released stress by the numerical analysis of the parallel-tube shield tunnel presented a non-linear relationship at 20m of the central depth of the tunnel, and presented a linear relationship when it reached 24m and 27m of the central depth of the tunnel. In the case of Double-o-tube shield tunnel of Taipei-Sanchung Section, the ground surface settlement troughs of the Double-o-tube shield tunnel calculated by way of empirical formula superposition method and the equal-area method were similar according to the comparison of results by the three methods of numerical analysis, empirical formula and in-situ monitoring. However, in the comparison of results of empirical formula calculation and in-situ monitoring, the settlement troughs were identical in shape and trending but the maximum ground surface settlement values at the tunnel center presented certain difference. In the comparison of the results of numerical analysis simulation and in-situ monitoring, the maximum ground surface settlement values at the tunnel center and the shape and trending of ground surface settlement troughs were identical. The soil released stress value obtained by the numerical analysis presented a direct proportional linear relationship with the maximum ground surface settlement and the in-situ loss rate, which can be used in numerical analysis of the soil released stress of Double-o-tube shield tunnel in the future so as to predict the upper and lower limits of possible ground surface settlement.

並列關鍵字

Double-o-tube shield tunnel ； finite element ； ground surface settlement ； in-situ monitoring

參考文獻

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