A Study on the Compassion with FEM and DDA to The Airport Rigid Pavement Strength Analysis

• Main Authors: Yen-Chih Wang, 王彥智
• Other Authors: 詹添全
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/71143091860089635933

碩士 === 中國文化大學 === 建築及都市計劃研究所 === 99 === Damage to pavements at airports, including those of the runway, taxi way, parking apron, and warm-up apron, is inevitable under the impacts of and wear by different weather conditions and aircraft weights. The type of pavement, thickness of pavement, subgrade strength, subbase strength and thickness, among other factors, will all affect the degree of damage aircrafts do to the pavement and the relative relationship in the degree of damage. Once it is damaged, the airport will have to shut down, causing delays and inconvenience for both the airport and affected. passengers. The airline companies will also suffer huge losses. In the case of a military airport, it will directly compromise national defense readiness. This study applied computer programs written with the “finite element method” (FEM) and “discontinuous deformation analysis” (DDA) as their underlying framework and calculated values obtained through the two analytical methods by entering different subgrade thicknesses and different moduli of elasticity of rigid pavements to explore the influence of the thickness of subgrade aggregate and modulus of elasticity on the strength of airport rigid pavements. The measure site shifts obtained through the two different types of programs showed a linear relationship with the SAP program and non-linear relationship with the WIN-DDA program, which met the design theories for the two programs. Analysis with the SAP program showed that the modulus of elasticity was in a negative correlation with the measure site shift under the same subgrade aggregate thickness, indicating that the pavement strength weakened as a result of a smaller modulus of elasticity for the rigid pavement, and that the measure site shift enlarged when the subgrade aggregate thickness was larger under the same modulus of elasticity, indicating that when the rigid pavement was bearing a carrying capacity, its subgrade aggregate thickness was in a positive correlation with the variance. Analysis with the WIN-DDA program showed that the greater the subgrade aggregate thickness the greater the vertical variance at the measure site would become at a friction angle of 15° and 30° under the same modulus of elasticity. The report on this study comprises five chapters and 17 sections. The following are brief highlights of each chapter. Chapter 1：Introduction defines the study motives and purpose, including the scope and content of the study, and drafts study steps, methods, and procedures. Chapter 2：Literature Review compiles related publications on airport design specifications, types of pavements, pavement damage and cause discussions, rationales for the finite element method and discontinuous deformation analysis, etc. Chapter 3：Establishment of Rigid Pavement Analysis Model encompasses establishment of the rigid pavement model for analysis and simulation. Different subgrade aggregate thicknesses, different moduli of elasticity, and different friction angle settings with the WIN-DDA program were the variants in the basic model to analyze and assess the influence on the strength of rigid pavements. Chapter 4：Analysis Results of Rigid Pavement Model deals with results obtained through analyses with the two programs and establishment of analytical graphics. Chapter 5：Conclusions and Suggestions include conclusions obtained through the analyses and related suggestions that are produced. Keyword：FEM, DDA, rigid pavement, modulus of elasticity, aggregate thickness, friction angle