國內外的山坡開發工程，加勁擋土牆的利用越來越普遍，但擋土結構在基腳掏空下易受到破壞，因此利用加勁擋土牆模型來探討基腳掏空情形下的變化。本試驗利用長150mm直徑1.96mm鋼針模擬2-D均勻顆粒土壤，製作500mm 高之加勁式擋土牆模型，並以10個可分離雙向荷重計量測壁面應力，採用熱熔不織布黏貼應變計量測加勁材應力。
利用加勁擋土牆模型在堅硬地盤及沉陷地盤上進行試驗，堅硬地盤上的試驗結果顯示出，當壁面與加勁材間聯結強度高時，挖掘擋土牆坡趾至傾角〖55〗^°時發生倒塌，但當壁面與加勁材間聯結強度降低時，挖掘擋土牆坡趾至傾角〖20〗^°時便倒塌，因此在堅硬地盤上，壁面聯結強度高的加勁擋土牆能夠抵抗較多的掏空。而在沉陷地盤上的試驗結果觀察到，聯結強度高對加勁力之發揮並無幫助，因此不同聯結強度的擋土牆卻在開挖坡度相近時破壞。
本研究利用試驗過程中量測到的牆背側向土壓力、剪應力計算試驗過程的安全係數發展，並且與Coulomb土壓力理論值所計算之安全係數進行比較，發現具有低聯結強度壁面之擋土牆是由內部加勁材-面牆之拉出破壞掌控，破壞時滑動安全係數約1.8，但具有高聯結強度壁面之擋土牆是外部承載力安全係數掌控，破壞時承載力安全係數低於1.0。

In using reinforced soil retaining for waterfront structures , the problem of toe scouring becomes important. A series of plane-strain model tests was performed to investigate the behavior of geosynthetic- reinforced soil retaining walls subjected to surcharging and toe cutting. Two important effects, namely the facing-reinforcement connecting strength and the settlement of foundation, on the behavior of reinforced walls were also investigated. Test results showed that toe cutting has a major impact on the wall behavior, in the sense that, only small wall displacements and reinforcement strains were obtained under surcharging, while the wall displacement and reinforcement strains increase rapidly under toe cutting. The reinforcement-facing connecting strength has a major influence on increasing the ductility of the wall against toe cutting, in the case of a firm foundation. In the case of a deformable foundation, the walls with high and low connecting strengths had a similar ultimate state against toe cutting,due partially to the small mobilized reinforcement forces in both cases. External and internal stability analyses were performed for the wall under various stages of surcharging and toe cutting. Results of stability analyses showed that for the case of low connecting strength, the ultimate state of the wall is controlled by internal reinforcement-facing pull-out with a safety factor of 1.8. In the case of high connecting strength, the ultimate state of the wall is controlled by the bearing capacity failure with a safety factor lower than 1.0.

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