非線性反算分析於LTPP 試驗道路之研究

The Nonlinear Backcalculation for LTPP Test Sections

反算分析是使用落體測位儀試驗結果之資料進行反算，並將所得之材料參數做為鋪面強度評估及鋪面維護與管理之依據。由室內之試驗及現場FWD試驗結果皆證實鋪面材料具有非線性之應力與應變關係。故本研究之目的即在發展非線性反算及結構分析程式，並探討非線性與線性參數對反算與結構分析之影響。首先將由美國聯邦公路總署之長期鋪面績效(Long-Term Pavement Performance, LTPP)資料庫選擇六個試驗路段，取其落體測位儀(Falling Weight Deflectometer, FWD) 之試驗資料進行線性與非線性反算分析。並將反算結果與試驗值作比較。此外，反算所得參數亦用於預測FWD其它落錘荷重所造成之位移，並與FWD之試驗結果作比較。最後亦將所得之反算參數進行結構分析，結果說明使用線性與非線性反算參數所得之位移與應力有所差異。

Backcalculation analyses are used to analyze the Falling Weight Deflectometer test results, and the backcalculated material properties can be used for the evaluation of pavement structural capacity and management. From laboratory and FWD test results, it can be shown that pavement materials have a nonlinear stress-strain relationship. The purpose of this study is to develop a nonlinear backcalculation and structural analysis program, and the effect of nonlinear and linear backcalculated properties to the backcalculation and structural analysis are studied. At first, the six test pavement sections from the Long-Term Pavement Performance (LTPP) database of the Federal Highway Administration in the United States are selected, and the FWD test results from these sections are used for the linear and nonlinear backcalculation analysis. The FWD results will be compared with the results obtained from the linear and nonlinear backcalculation analysis. The backcalculated material properties are also used to predict the deflections of FWD tests which are not used for the backcalculation analysis. Finally, structural analyses based on nonlinear and linear backcalculated properties are studied, and the structural responses are different from these two properties.