Title

RESILIENT MODULUS OF SOFT SOIL BENEATH HIGH-SPEED RAIL LINES

Document Type

Journal Article

Publication Date

1999

Subject Area

infrastructure - track, mode - rail

Keywords

Tracks, Subgrade (Railroads), Stiffness, Soft soils, Soft ground, Rigidity, Railroad tracks, Modulus of resilience, Measuring, Measurement, Mathematical prediction, Mathematical models, Land water marginal areas, High speed trains, Design, Alluvium, Alluvial deposits

Abstract

Modern high-speed rail lines are being built increasingly on marginal land, to reach city centers while avoiding housing areas. Often this land is composed of soft alluvial soils, which exhibit a low resilient modulus. The measurement, prediction, modeling, and implications of resilient modulus values for such subgrades are discussed. Measurement considers the use of repeated-load triaxial testing, resonant column, and in situ methods, illustrating these with sample data. Prediction draws on both analytical and finite-element techniques to illustrate the critical speed (the bow-wave effect) and how it is influenced by resilient modulus. Modeling reveals the available relationships--and their limitations--for deriving subgrade stiffness in this dynamic situation. Implication then uses these to define the relevant effects of resilient modulus values on design problems.