Estimating Static and Dynamic Stresses in Geosynthetic-Reinforced Pile-Supported Track-Bed under Train Moving Loads

This study presents an estimating method to calculate the static and the dynamic stresses in the geosynthetic-reinforced pile-supported track-bed (embankment), based on a series of full-scale model tests under train moving loads. The testing results indicate the distinct soil arching effect for both the static and the dynamic stresses, with the same height of soil arching and similar values of pile efficacy. The pile efficacy for the dynamic stress in the proposed method is thus estimated by the existing analytical model for the static stress. The distributions of the static and the dynamic stresses estimated by this method are evaluated by comparisons with the testing data in the present model test. The results show that above the height of soil arching, the static and the dynamic stresses follow the variations of the self-weight of the track-bed (including static surcharge) and the Boussinesq solution (strip load; 3 m width as that of the concrete base; applied dynamic stress at the specific train speed), respectively. In the soil arching area, the predictions by this method are consistent with the testing data above the pile cap, whereas this method provides slightly higher values above the surrounding subsoil than the experimental results. Generally, this method appears reasonable, showing the difference of the dynamic stress no more than 5 kPa between the tests and the estimations.