蜂巢格網擋土結構之數值分析

Numerical Analysis on Geocell Retaining Structures

王元佐(Yuan-Tso Wang)

指導教授 ： 陳榮河

國立臺灣大學/工學院/土木工程學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.01545

摘要

地工合成材經多年之發展與推廣，已於國際工程界廣泛使用，舉凡地盤改良、邊坡加勁、加勁牆、路基、河海岸與水土保持工程等都有。其中，蜂巢格網是以提供土壤圍束作用做為加勁機制，可以改善軟弱路基土壤強度及防止邊坡沖刷，其格室更可作為植生美化之用；另外，其體積小，易收存、施工簡單、用地省，並能達到安全之要求。
本研究之主要目的是建立蜂巢格網擋土結構數值分析模式，以索元素（cable element）簡化模擬不同材料間之界面元素（interface element），；模擬對象是以蜂巢格網擋土結構之模型試驗作為依據，以探討不同牆高、牆面傾角、擋土結構型式、荷重加載區及背填土加勁等影響因素。
根據數值分析結果顯示，蜂巢格網擋土結構的牆面水平位移量與背填土沉陷量，隨著牆面傾角及背填土荷重之提高而增加。蜂巢格網設置為牆面式較重力式產生較大之水平位移，其最大水平位移發生在0.65倍牆高處。背填土加勁可有效地減少牆面的水平位移量與背填土沉陷量。上層加勁時，牆體呈凸型變化，其最大水平位移量約發生在0.8倍牆高處。下層加勁時，牆體則呈傾斜型，牆下方加勁處之位移較小，但上部則較大，牆面最大水平位移量發生在牆頂處。隨著牆面傾角增加潛在滑動面會向牆體後方延伸，且擋土結構有翻倒破壞之傾向；此外於背填土加勁之結構其破壞面會沿加勁區與非加勁區邊界發展。

關鍵字

蜂巢格網 ； 加勁牆 ； 數值分析 ； 力學行為

並列摘要

After years of development and advancement, geosynthetics has been extensively used worldwide. For example, it has been applied in ground improvement, reinforced slope, reinforced soil retaining wall, channel protection, and soil and water conservation. Among them all, geocell offers confining pressure to improve the bearing capacity of soft foundation. It also prevents soil erosion and creates better slope appearance. Besides, what makes it distinct from other material are its smaller volume, convenience for storage, simple process of construction, space-saving quality, and safety.
The purpose of this study is to establish a numerical model of geocell retaining structures by using structural cable elements to simplify the simulation of many interfaces among different interfaces. Meanwhile, geocell retaining structure model test are used to compare and discuss how structure height, structure inclination, surcharge loading type, and construction form of geocell retaining structures affect the test results.
The results of analysis show that the structural displacement and backfill settlement increase as structural inclination and surcharge loading rise. The Face-type geocell, wall, produces more horizontal displacement than gravity-type structure. The maximum displacement occurs in at height 0.65 times higher than the height of the wall. Backfill reinforcement can reduce the displacement and settlement effectively. When the upper layers of backfill are reinforced, the wall would protrude and the maximum displacement occurs in at height 0.8 times the height of the wall. When the lower layers of backfill are reinforced, the biggest displacement occurs in the part on the top. Displacements in the rest parts are relatively smaller. As the wall inclination increases, the potential slip surface expands backward and the wall tends to overturn. In addition to that, the slip surface would expand along the line between the reinforced and the un-reinforced zones.

並列關鍵字

geocell ； reinforced wall ； numerical analysis ； mechanical behavior

參考文獻

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