Dynamic ground interaction; a critical issue for high speed train lines on soft soil

摘要

Results from instrumented test runs with a high speed train on a soft soil site in Sweden are presented. It is shown that large dynamic amplifications appear in the dynamic response of the rail/embankment/ground system as the train speed approaches an apparent critical value. The measured dynamic response is analysed in detail, and it is shown that the critical speed is controlled by the minimum phase velocity of the first Rayleigh mode of the soil and embankment profile at the site. The displacement response is found to consist of a speed-independent portion in quasi-static equilibrium with the train loads and a dynamic portion representing freely propagating Rayleigh waves. An efficient computer code for the prediction of ground response to high speed trains has been developed and its ability to reproduce the observed behaviour is demonstrated.