2019-01-012024-05-16https://scholars.lib.ntu.edu.tw/handle/123456789/669839摘要：加勁擋土結構物與一般擋土結構物相比，具有美觀、與自然環境相容、經濟、耐震 、建造簡易快速、與可承受較大變形等多項優點。加勁擋土結構物的穩定性取決於 加勁材與回填土的強度，然而在實際應用上、為了施工方便與節省成本，往往就近 利用現地細粒料含量較多的土壤為回填土。這些土壤因滲透性不佳，往往當颱風暴 雨來襲時，雨水滲流至回填土內不易排除，造成孔隙水壓累積，最終導致擋土結構 物破壞。 有鑒於此，本研究申請書規劃一三年期研究計劃，將利用一系列物理模型試驗與數 值分析探討不同回填土與加勁排水系統之加勁擋土結構物在降雨作用下之穩定性 ，改善措施與對抗極端降雨之設計方法。在第一年計劃裡，將進行一系列縮小模型 試驗，探討不同加勁擋土結構物系統受降雨作用的力學行為，如牆面牆頂變形、穩 定性、土內孔隙水壓分布、加勁材受力發展以及破壞機制。在第二年計劃裡，考慮 不同的改善措施如增加加勁材強度，提昇系統排水能力，以及考慮薄砂層等，將以 物理模型試驗的方式評估這些改善措施的效益與可行性。在第三年計劃裡，將以不 飽和土壤力學為架構，進行一系列數值模擬與參數分析，模擬降雨入滲，土壤基質 吸力與有效應力改變，導致影響加勁擋土結構物的穩定性。將利用數值分析成果針 對加勁擋土結構物發展出降雨強度與延時曲線圖 (I-D curve)，以提供後續加勁擋 土結構物抗強降雨實務設計上參考使用。<br> Abstract: Compared with conventional gravity-type retaining walls, the acceptance of geosynthetic-reinforced soil (GRS) structures has been driven by a number of factors, including aesthetics, compatibility with natural environment, cost-effective, seismic performance, easy and fast construction, and the ability to tolerate large deformations without structural distress. Often, to reduce the construction cost and minimize the transportation cost and environmental impact associated with the disposal of the excavated soil, locally available soils with relatively low hydraulic conductivity (usually referred to as marginal fills) have been used as alternative backfills.; however, such soils often have low permeability, which can cause drainage problem and pore water pressure accumulation, and finally lead to the instability of GRS structures during typhoon and heavy rainfall season. Accordingly, this proposal plans a three-year research project to investigate the behavior, stability, remedial measures, and design methods of GRS structures with various backfill-reinforcement-drainage systems subjected to rainfall infiltration. In the first year, a series of model wall tests will be conducted to study the behavior of GRS structures subjected to rainfall. The wall settlement and face deformation, stability, porewater pressure distribution, development of reinforcement tensile load, and failure mode will be evaluated and discussed. In the second year, model wall tests will be performed to evaluate the effectiveness and feasibility of remedial measures including increase of reinforcement tensile strength, enhancement of system drainage capacity, and installation of sand cushions. In the third year, a series of finite element analyses based on the framework of unsaturated soil will be performed. As the rainfall progresses, the change of soil matric suction and soil effective stress will be simulated and it impacts on the stability of GRS structures will be evaluated. Based on the numerical results, the rainfall intensity and duration (I-D) curves will be developed for GRS structures. Design implications and recommendations will be proposed based on the results and findings from this research to benefit the practical design of GRS structures against heavy rainfall.加勁擋土結構物力學行為防災極端降雨物理模型試驗數值分析Geosynthetic-reinforced soil structuresMechanical behaviorDisa