加勁材後端連接穩定界面之窄加勁擋土牆的有限元素建模及案例分析

Abstract

本研究針對連接穩定面之窄加勁擋土牆進行現地案例分析與數值模擬，探討受限空間條件下加勁牆體之變形行為與破壞機制。研究案例位於新竹科學園區，牆高約8公尺，採用加勁材與既有RC廠房結合之支撐系統，實測資料顯示牆體於滲水事件後發生沉陷與變形。試驗階段取得回填土與加勁材物理與力學性質，並以PLAXIS 2D建構數值模型，模擬完工階段與滲水階段之牆體行為，模型結果與監測資料具良好一致性。模擬觀察指出，連接型窄牆之破壞面呈雙線性特徵，受限加勁長度與尾端固定效應造成上部應力集中，下部則顯受力遞減。研究結果與文獻理論相符，並提出加勁材配置、破壞角度修正與錨栓用量優化等具體設計建議。本研究顯示，透過合理參數校正與分階模擬，可有效預測窄加勁牆在特殊條件下之行為，對日後設計與監測策略具參考價值。

This study investigates the deformation behavior and failure mechanism of a narrow geosynthetic-reinforced soil (GRS) wall with reinforcement connected to a stable facing. The case is located in the Hsinchu Science Park, where the retaining wall, approximately 8 meters in height, adopts a composite support system with geosynthetic reinforcements chemically anchored to an adjacent RC factory wall. Field monitoring revealed post-construction settlement and deformation induced by water infiltration. Laboratory tests were conducted to determine the physical and mechanical properties of the backfill soil and reinforcement. A numerical model was established using PLAXIS 2D to simulate the wall behavior at the end of construction and under infiltration conditions. The simulation results showed good agreement with field data. The plastic failure surface exhibited a bilinear pattern, characterized by stress concentration in the upper reinforcements due to the fixed-end connection, and reduced tensile forces in the lower reinforcements. The findings align with existing literature and support design recommendations, including modified failure angle, optimized reinforcement layout, and reduced anchor usage. This study demonstrates that phase-based numerical simulation with calibrated parameters can effectively predict the behavior of narrow GRS walls under constrained conditions, offering practical reference for future design and monitoring.