Chul-Soo Park/In-Beom Park/Eun-Jung Kim/Young-Jin Mok
International Journal of Railway, vol. 1, no. 2, pp.64-71, 2008

Abstract : The quality of track-bed fills of railways has been controlled by field measurements of density (γd) and the results of plate-load tests. The control measures are compatible with the design procedures whose design parameter is k30 for both ordinary-speed railways and high-speed railways. However, one of fatal flaws of the design procedures is that there are no simple laboratory measurement procedures for the design parameters (k30 or, Ev2 and Ev2/Ev1) in design stage. A new quality control procedure, in parallel with the advent of the new design procedure, is being proposed. This procedure is based upon P-wave velocity involving consistently the evaluation of design parameters in design stage and the field measurements during construction. The key concept of the procedure is that the target value for field compaction control is the P-wave velocity determined at OMC using modified compaction test, and direct-arrival method is used for the field measurements during construction. The procedure was verified at a test site and the p-wave velocity turned out to be an excellent control measure. The specifications for the control also include field compaction water content of OMC±2% as well as the p-wave velocity.

Keyword : Railway track-bed, Quality control, P-wave velocity, Compaction test, Direct-arrival method