Analysis of ground motion due to moving surface loads induced by high-speed trains

A three-dimensional time domain boundary element (BE) approach for the analysis of soil vibrations induced by high-speed moving loads is presented in this paper. An attenuation law is included in the formulation. By doing so, internal material damping can be taken into account. The characteristics of the BE model required for the study of travelling load problems are analysed. Thus, mesh size, type of elements, internal damping representation and the complete numerical approach are validated. Existing analytical solutions for some simple problems are used as a reference. Experimental results measured in a simple soil dynamic load problem are also accurately reproduced by the proposed model. The analysis of the type of BE mesh required for a good representation of high-speed train effects is carried out using different discretizations under the sleepers and the free field near the track. All these analyses allow to define a model very well suited for the study of soil vibration effects due to high-speed train passage. Vibrations produced by an Alstom (Thalys-AVE) train travelling at 256 and 300 km/h speed are evaluated at different locations near the track. Results show that the proposed numerical procedure and attenuation law allow for a realistic representation of the effects of the different passing loads. The BE approach presented in this paper can be used for actual analyses of high-speed train-induced vibrations. Layered soils, ballast or coupled vibrations of nearby structure can be included in the model in a straightforward manner.