Enhancement of Permanent Deformation Model for Unbound Materials Used by DARwin-ME
Enhancement of Permanent Deformation Model for Unbound Materials Used by DARwin-ME
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发表时间：
2013
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通讯作者：
Elham Bani Hashem;C. Zapata
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文献类型：
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作者：
Elham Bani Hashem;C. Zapata
This study deals with the assessment and enhancement of the Mechanistic-Empirical Pavement Design Guide (MEPDG) permanent deformation model for unbound materials. A preliminary sensitivity study of the current model was conducted which yielded some limitations when typical soil properties were used for a variety of AASHTO Classification groups. Based on the results from the sensitivity analysis, an enhanced mechanistic model was developed and is the main goal of this paper. The proposed model was developed based on a database consisting of a total of nearly 4,000 laboratory data points obtained from experiments previously conducted at Arizona State University. The database contains results of static triaxial shear strength and repeated load triaxial tests conducted on four subgrade materials from the State of Arizona. The materials included gravelly and sandy materials with a wide range of fines content (1% to 32%). The proposed model predicts the permanent to resilient strain ratio (ap/ar) and was found to be a function of the degree of saturation, shear stress/strength ratio, number of stress repetitions, plasticity index of the soil and percentage passing US Standard No. 200 sieve. The model was found to be rational, unbiased, and statistically sound. Interestingly, the shear stress/strength ratio proved to be a better predictor than the resilient modulus, provided degree of saturation and properties of the fine material were considered.
