Implementation of the Dynamic-Based Backcalculation Method on Single-Layer Rigid Pavements

• Main Authors: Wan-Chuen Su, 蘇婉淳
• Other Authors: Chen-Ming Kuo
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/zk9k59

碩士 === 國立成功大學 === 土木工程學系碩博士班 === 92 === 　　To evaluate the pavement condition, the backcalculation program is used to determine the present stiffness of pavements. The structural properties of existing pavement needed in the backcalculation procedures are normally obtained from non-destructive test, such as FWD and SASW (Spectral Analysis of Surface Waves method). However, most backcalculation programs are based on static theory, the field data are tested dynamically. Arbitrary adjustments are needed to obtain the practical k value of the rigid pavement. 　　To eliminate the controversial adjustment of backcalculated results, this study obtained the FWD data with the FEM analysis to avoid material variation and human errors associated with field tests. The FEM output time history of loading and deflection is transferred into real and imaginary parts in frequency domain through the fast Fourier transform, and then the dynamic equations are used to solve the coefficient of subgrade reaction (k) and the radiation damping coefficient (c) directly. 　　Comparing the backcalculated results with the original parameters in FEM analysis, the error is about 3%. For single-layer rigid pavement, this study can reduce the transformation error and increase the application of FWD test. Finally, it was found that the pavement loaded by various vehicle speed is associated with various k-values.