以分離元素法探討顆粒材料之極限承載力研究 = Distinct Elem...
國立高雄大學土木與環境工程學系碩士班

 

  • 以分離元素法探討顆粒材料之極限承載力研究 = Distinct Element Approach to the Bearing Capacity of Granular Material
  • 紀錄類型: 書目-語言資料,印刷品 : 單行本
    並列題名: Distinct Element Approach to the Bearing Capacity of Granular Material
    作者: 鄭承昌,
    其他團體作者: 國立高雄大學
    出版地: [高雄市]
    出版者: 撰者;
    出版年: 2009[民98]
    面頁冊數: 136面圖、表 : 30公分;
    標題: PFC2D
    標題: PFC2D
    電子資源: http://handle.ncl.edu.tw/11296/ndltd/80495536055269672983
    附註: 指導教授:翁孟嘉
    附註: 參考書目:面
    摘要註: 傳統上,在大地工程領域中,淺基礎及擋土牆之主、被動土壓力之分析皆根據極限平衡法之理論,然其架構於連體力學之上,對於許多日常可見之大地材料而言,其破壞時產生顆粒流動之行為,連體力學之計算方式及假設是否適用,值得進一步探究。為了解大地材料破壞時之顆粒材料分離之特性,本研究採用架構於分離元素法(DEM)上之軟體(PFC2D)進行分析,藉由鋁棒直接剪力試驗驗證基本參數,在以基本參數出發,改變土壤中不同之粒徑大小、排列、摩擦角及勁度參數,探討淺基礎於破壞時顆粒材料之承載力變化及滑動破壞之型態,然根據分析之結果可知:(1)針對線性與非線性勁度之比較,採用非線性勁度模擬較符合鋁棒集合之行為。(2)在基礎分析時,可知不論何種勁度、摩擦角及粒徑,其簡單排列與隨機排列之承載力皆低於緊密排列,而各因子間以勁度對於承載力之提升較為明顯,勁度提高三個量級,承載力提高約可達二個量級。(3)在土壓力分析時,其主動土壓力中,隨機排列之情況下,勁度與摩擦角對於主動土壓力係數之影響較為明顯,在勁度提高二個量級或摩擦角提高15°之情形下,主動土壓力係數約降一個量級,而粒徑對於主動土壓力係數之影響,為粒徑提高八倍則主動土壓力係數約提高一個量級。(4)在土壓力分析時,其被動土壓力中,緊密排列及簡單排列之被動土壓力係數,在勁度提高三個量級之影響下,被動土壓力係數提高近二個量級,在粒徑提高八倍之影響下,被動土壓力係數則些微的下降。綜合以上可知,勁度、摩擦角、粒徑及排列皆為影響強度之因子。(5)在三軸試驗中,可知模擬之強度破壞準則為一非線性準則,且其塑性變形呈現非諧和流現象。 Traditionally, the bearing capacity of shallow foundation and the active or the passive earth pressure of retaining wall are obtained from limit equilibrium method based on the mechanics of continuum. However, the geo-material is mainly composed of discrete particles, and it often exhibits flow behavior, which is different from the continuous solid. Therefore, this research aims to realize the mechanical behavior of granular material using the software PFC2D based on the distinct method (DEM). Firstly, the micro parameters of granular material were verified by the direct shear test. Then, the influences of the particle size, the packing, the friction coefficient of particle and the stiffness on the bearing capacity and the earth pressure were explored. The simulation results show that: (1) For particles with simple packing and random packing, the bearing capacity of foundation is lower than that with dense packing; (2) an increasing friction coefficient increase the bearing capacity; (3) the larger size and the higher stiffness will lead to the higher strength. Among the factors, the influence of stiffness is more apparent than that of other factors. For the results of earth pressure, aforementioned tendencies are also observed. Furthermore, triaxial tests of granular material are simulated. The results shows that the failure envelope is nonlinear and the plastic deformation reveals non-associated flow.
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310001863102 博碩士論文區(二樓) 不外借資料 學位論文 TH 008M/0019 541606 8716 2009 一般使用(Normal) 在架 0
310001863094 博碩士論文區(二樓) 不外借資料 學位論文 TH 008M/0019 541606 8716 2009 c.2 一般使用(Normal) 在架 0
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