Study on Correction Method of Subgrade Modulus Based on FWD

Abstract:

In order to calibrate subgrade back calculation modulus, the correction method of subgrade back calculation modulus was put forward based on theoretical analysis and indoor/outdoor experiments, and the detailed implementation process was analyzed combined the latest results of subgrade dynamic modulus and subgrade moisture forecast. The results show that the equivalent resilient modulus of subgrade simultaneously consider subgrade material moisture condition and stress dependency and the forecast equation has higher correlation. The ratio of the loading plate test results to the predicted results ranges from 0.25 to 0.4 and the mean is 0.32, which conforms to the requirements of AASHTO normal value. Utilizing the scale factor 0.65 to calibrate subgrade back calculation modulus is viable and validated. The results provides a new perspective and approach for deformation analysis of subgrade structure. As well, the established method makes up the defect that can't reflect the effect of moisture and stress on equivalent resilient modulus of subgrade.

• Periodical: Key Engineering Materials (Volumes 579-580)
• Pages: 862-865
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.579-580.862
• Online since: September 2013
• Authors: Xiao Hua Luo, Qing Yang, Xin Qiu
• Keywords: Back Calculation, Falling Weight Deflectometer, Modulus, Subgrade

References

[1] AASHTO: Mechanistic-Empirical Pavement Design Guide (American Association of State Highway and Transportation Officials, USA 2004).

[2] H.B. Seed, C. K. Chan and C.E. Lee: Proc. International Conference on Structural Design of Asphalt Pavement (Michigan 1962), Vol. 1, pp.611-636.

[3] A. Dragos, W. W. Matthew and W. S. Charles, et al: Proc. 82th Annual Meeting of Transportation Research Board (Washington D.C. 2003), Vol. 1, pp.231-236.