動態彈黏塑性模式於鋪面分析之研究

Dynamic Analysis of Pavement by Using Elasto-Viscoplastic Model

使用合理的力學模式預測鋪面材料在荷重下之反應是為鋪面研究者努力之焦點。因鋪面材料具有彈黏塑性之特性，過去已有不少學者使用此模式進行鋪面材料之模擬，但大都仍以實驗室材料行為之模擬為主。本研究擬將彈黏塑性動態有限元素程式與最佳化理論結合發展鋪面動態之反算與正算分析程式，並用於實際鋪面之結構分析。為驗證所發展程式之正確性，本研究將使用美國聯邦公路總署所建立之LTPP （Long-Term Pavement Performance） 資料庫中之資料作為發展模式驗證之基礎。首先選擇六個試驗路段得其相關之資料，及進行反算分析求得發展模式之參數，並利用此參數進行鋪面結構分析，探討鋪面在不同車速反覆作用下之位移與應力反應相互間之差異。

It is a major concern of highway research to use rational mechanicalmodels to predict the responses of pavement under loading. It has beenshown that pavement material has viscoplastic behavior. The viscoplasticitymodel has been used to predict the behavior of asphalt concrete material inthe laboratory. However only a few studies combined viscoplastic meas- urement with a finite element program for the pavement structural analysis.In this study, the elasto-viscoplastic dynamic finite element isincorporated with an optimization approach for the backcalculation analysis,and the layer moduli and viscoplastic parameters are backcalculatedand the results used for structural analysis. The comparison of thedisplacement and stresses are also studied for different traffic loadings. Inorder to verify the backcalculation program, the LTPP database developedby FHWA in the United State is used for verification. At first, six testpavement sections were selected from the LTPP database. The informationin the database includes pavement structure information andtime-history response data to FWD tests. The field model parameters areobtained from backcalculation and the results used for structural analysis ofpavement under repeated traffic loading.