六角形金屬網結構對工程特性之影響

Structural Pattern Effects on the Engineering Properties of Hexagonal Wire Mesh

劉仁聖(Ren-Sheng Liu)

指導教授 ： 謝啟萬

國立屏東科技大學/工學院/土木工程系所/碩士(2012年)

https://doi.org/10.6346/NPUST.2012.00120

摘要

蛇籠與石籠為金屬網所組成，然實務上蛇籠與石籠用於河川護岸及擋土牆工程居多。近期因豪雨造成金屬網結構受河川沖蝕及坡面滑動，使金屬網因拉扯與內容物擠壓而破壞，故需要模擬現地進行抗拉及貫入試驗；此外，模擬金屬網受碰撞及施工時產生斷裂，將中央一條金屬線剪斷後執行其抗拉與貫入試驗。
目前工程上採用六角形金屬網（Hexagonal wire mesh）居多，且編織方式以兩金屬線交叉紐絞三個半圈編織成金屬網，稱之為六角形金屬網；然而，日據時代之工程應用上，曾採用兩金屬線交叉成四個半圈編織成金屬網，稱之為四圈六角形金屬網；故本試驗將採用三圈及四圈編織成六角形金屬網進行比較。
本研究採用之金屬網依實物上模擬縮小，再以手工編製成三圈與四圈六角形金屬網，分別針對兩種金屬網比較完整試片及中央一條金屬線剪斷試片下，依據ASTM A975規範執行抗拉與貫入特性試驗。試驗結果顯示，採用完整試片之三圈與四圈六角形金屬網，極限抗拉及貫入強度之結果大致相同，然在中央一條金屬線剪斷試片進行抗拉及貫入試驗時，其四圈六角形金屬網之抵抗特性較三圈六角形金屬網佳；故四圈六角形金屬網具有較佳之結構特性，未來可供產業界作為參考。

關鍵字

六角形金屬網 ； 石籠 ； 側向侷限 ； 護岸 ； 邊坡穩定 ； 落石防護

並列摘要

Tensile and punch test behavior of two different structural patterns hexagonal wire mesh samples subjected to lateral unconstrained and constrained conditions were investigated. The structural patterns included the three half-turn and four half-turn hexagonal wire mesh panels with and without one center cut wire mesh panel. The study results indicated that the ultimate tensile strength and punch resistance for three half-turn and four half-turn hexagonal wire mesh panels without any cut within were similar. However, the four half-turn hexagonal wire panels showed better tensile and punch resistance after one wire broke at the panel center. This implied that the presence of broken wires within the four half-turn hexagonal wire mesh showed no significant influence on the panel’s tensile strength resistance. Lateral constrained wire meshes showed better tensile resistance than that for unconstrained samples. Due to the lateral constrain, the initial slope and the first peak shown in the elongation versus tensile stress curve for the lateral constrained condition is higher than that for no lateral constrained condition. The presence of lateral constrain would assist the development of a vertical or a diagonal center hole for Type A or Type B wire mesh with or without a center cut during the tensile tests, respectively. Generally, four half-turn hexagonal wire mesh is a better structural pattern than that the three half-turn hexagonal wire mesh in the tensile tests. A uniform distribution of lateral force was observed for four half-turn (Type B) wire mesh. Bell shape non-uniform lateral force distribution was observed for three half-turn (Type A) wire mesh, center region lateral force was higher than that for other sides. The total lateral forces for all test constrained conditions were about the same.

並列關鍵字

Hexagonal wire mesh ； Gabion ； lateral constrain ； river bank protection ； slope stabilization ； rock-fall protection

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