運用有限元素程式模擬柔性加勁格網拉出行為之可行性研究

加勁土壤結構物因具有施工簡單、造價低、吸能耐震等優點使其運用面越來越廣，其中地工格網是目前使用最為廣泛的加勁材料之一。在實驗室中通常進行直接剪力試驗與拉出試驗對土壤與加勁材介面間的力學機制進行評估。大型拉出試驗通過調整土層的厚度、土壤的相對密度，控制試驗時的拉出速率與加勁材的試體寬度以及套筒長度等條件，可克服剛性前壁效應與側壁效應等邊界效應。通過改變圍壓與加勁材種類等條件下，對土壤與加勁材介面間的力學機制進行分析，可以更好的模擬現地加勁土壤結構物受力後的應力-應變特性以及加勁材的變形行為。但鑒於完成一系列的大型拉出試驗需耗費大量的時間與精力，並且需考慮拉出試驗中的客觀因素對實驗結果的影響。因此本研究將根據上述拉出試驗影響因數針對中原大學張達徳教授團隊多年大型拉出試驗數據進行篩選與統整並利用有限元素程式PLAXIS進行數值建模。通過拉出試驗結果與數值模擬結果的比對分析，探討該程式對拉出試驗的適用性。

關鍵字

加勁土壤結構物；拉出試驗；有限元素

並列摘要

The reinforced soil retaining structure has more and more advantages due to its simple construction, low cost, energy absorption and earthquake resistance. Among which the ground geogrid is one of the most widely used stiffening materials at present. Direct shear tests and pull-out tests are usually carried out in the laboratory to evaluate the mechanical mechanism between the soil and the stiffener interface. The boundary effects such as rigid front wall effect and side-wall effect can be overcome by adjusting the thickness of soil layer and relative density of soil, controlling the pull-out rate during the test and the width of the test body and sleeve length of the stiffener. By changing the confining pressure and stiffening material types, the mechanical mechanism of the interface between soil and stiffening material can be analyzed to better simulate the stress-strain characteristics of in-situ stiffening soil structure and the deformation behavior of stiffening material. However, it takes a lot of time and energy to complete a series of large pull-out tests, and the influence of objective factors in pull-out tests on experimental results should be considered. Therefore, this study will select and integrate the pull-out test data of Professor T.T Dave of Chung Yuan Chiestian University according to the above pull out test impact factors, and conduct numerical modeling by using the finite element method PLAXIS. The applicability of the program to pull-out test is discussed by comparing the results of pull-out test with those of numerical simulation.