為得知鋪面材料的現有強度，作為維修標準的依據，反算的程式因而產生。由各種試驗如FWD、SASW (Spectral Analysis of Surface Waves method)所得的資料，利用反算過程得到目前材料的強度。現有的反算程式多以靜態理論為主，而反算程式所使用的現場量測數據，例如FWD試驗往往都是動態試驗的結果，顯然並不匹配，必須經過許多修正或回歸才能求得剛性鋪面的k值。為了改善這些缺點，本研究利用電腦模擬的FWD動態試驗取得不受現場材料變異與人為因素干擾之資料，利用動態解析直接求路基之k值，改善反算之後仍需找尋修正因子的缺點。
　　本研究以有限元素分析模型模擬FWD試驗取得反算所需的數據，將有限元素分析模型輸出的變位及載重資料，透過傅立葉(Fast Fourier Transform)轉換，把時間域衝擊變位歷時資料轉成具有實部和虛部頻率域資料，代入動力方程式直接積分求得路基回彈模數k值、路基阻尼係數c值。結果可直接與模型輸入之材料參數比對驗證，發現驗證誤差在0.44%。本研究適用於單層剛性鋪面，可望改善一些靜力反算程式要經過修正因子的問題，使FWD試驗結果的應用更直接，減少主觀與人為的轉換誤差。最後將結果與車速結合，分析兩者之相關性，提供工程師參照依據。

　　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.

李梓賢，「三維有限元素法於柔性鋪面之應用」，國立成功大學土木工程研究所，碩士論文，1997。

周家蓓，陳又菁，「鋪面反算程式之發展與應用」，中國土木水利工程學刊，第九卷，第二期，351~357頁，1997。

康裕明，「使用最佳化技巧進行動態撓度試體之反算分析」，中國土木水利工程學刊，第十卷，第二期，329~340頁，1998。

康裕明，「道路結構承載之非破壞性檢測技術」，檢測科技，第十四卷，第二期(3-4)， 86~93頁，1996。

許家程，「應用三維有限元素法與類神經網路於柔性鋪面彈性模數反算之研究」，國立成功大學研究所碩士論文 ，2000。

黃俊豪，「應用表面波譜法調查土層剪力波速之研究」，國立成功大學研究所碩士論文，2003。

葉麟，「FWD動態分析及探討反算修正因子」，國立成功大學研究所碩士論文，2002。

蔡雅芳，「分析鋪面動態反應並評估其績效」，國立成功大學研究所碩士論文，2001。

黎文明，「快速傅立葉變換」，復漢出版社，台南市，10~12頁，1991。

鍾美娟，「衝擊式撓度指標評估路面強度之研究」，國立台灣大學研究所碩士論文，1997。

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