Abstract
This paper presents an improvement framework on accuracy for the evaluation of stiffness of unbound aggregates using portable FWD(PFWD) by Shakedown theory. According to the theory, the unbound aggregates is liable to show almost no progressive accumulation of permanent strains under repeated loading if the magnitude of the applied loads does not exceed a limiting value, called the Shakedown load. The growth of permanent was shown to level off by the 10 cycle load applications at the same strain level using PFWD and a conventional triaxial compression test. Therefore, this PFWD loading test is said to have attained a state of Shakedown. By visualization method, the photos taken at the cross section of small earth tank before and after loading by PFWD were revealed the upward displacements of soil particle on the surface.
