箱型金屬石籠破壞模式與解決對策之探討

本研究之目的在探討箱型金屬石籠破壞模式與強度，並蒐集箱型金屬石籠損壞之工程案例，進而提出解決之對策，以供工程界設計及施工參考。依試驗文獻資料顯示，箱型金屬石籠之編織採用四圈斜向編織比三圈直向編織的優點為：(1)完整網片之橫向抗拉強度，四圈金屬網比三圈金屬網大18.1％。(2)金屬網身經中央剪斷後，三圈直向編織金屬網之抗拉強度保留率為完整時之40～50％左右；四圈斜向編織金屬網有80～90％的強度保留率。(3)在邊框線接合抗拉試驗結果，四圈金屬網比三圈金屬網之強度大50％。(4)在貫入試驗方面，金屬網片有斷裂時，四圈金屬網比三圈金屬網之強度大97.9％。經本研究蒐集調查與彙整臺東縣轄內之山區道路中石籠護坡及石籠護岸，探討箱形金屬石籠現地結構體破壞模式主要為：(1)基礎因沖刷淘空，造成箱籠下陷損壞。(2)側壓力太大，造成側向位移損壞。(3) 箱籠金屬網本身強度不足造成損壞，金屬線斷裂或金屬線銹蝕損壞。建議解決對策為：(1)加強基礎深度避免基礎底部因沖刷淘空。(2)提高箱型金屬石籠結構體與基礎間抗滑力、箱籠間之接合強度。(3)箱籠金屬網之編織採用四圈斜向編織，以提高金屬網之抗拉強度。

關鍵字

六角形金屬網；箱籠；蛇籠；生態工法

並列摘要

This study aimed to investigate the failure mechanism and strength of metallic gabion box, to collect engineering cases of metallic box gabions failure, and then to propose a solution, which could serve as a reference for engineering design and construction. Experimental literature indicated that the advantages of 4-ring diagonal weaving adopted for metallic gabion box compared to the 3-ring straight weaving e were: (1) Transverse tensile strength of a complete 4-ring metal mesh was larger than that of a 3-ring mesh by 18.1%; (2) When the metal mesh is cut off in the middle, its retention rate on tensile strength retention of the 3-ring straight weaving metal mesh was about 40-50% of the complete mesh, while the tensile retention of the 4-ring weaving metal mesh was about 80-90%; (3) The border line joint tensile test result showed that the tensile strength of a 4-ring metal mesh was larger than its 3-ring counterpart by 50%; and (4) In light of penetration tests, the tensile strength of a 4-ring metal mesh was larger than its 3 ring counterpart by 97.9% when metal mesh was broken. The main failure patterns of the in-situ structure of metallic gabion box collected, investigated and collected by this study were: (1) The foundation bottom was scoured and eroded away, causing damage or sinking of Gabion box; (2) The over-high lateral pressure caused lateral displacement damage; and (3) Insufficient strength of the gabion box metal mesh caused damage, e.g. metal wire broken or corrosive metal wire damage. The suggested solutions were: (1) Increasing the foundation depth to prevent the foundation base from being scoured and eroded away; 2. Enhancing the slip resistance between metallic gabion box structure and foundation, and increasing the joint strength between gabion boxes; and (3) Using the 4-ring diagonal weaving adopted for metal mesh of gabion box to improve the tensile strength of metal mesh.