Ground response data capture for railway vibration prediction

For new rail schemes, an environmental impact assessment is required to estimate the impact of vibration and propose mitigation measures. A method widely used for evaluating railway vibration mitigation is the detailed design procedures produced by the US Federal Transit Administration. Although used globally it is not widely used in the UK but has been specified within some UK light rail schemes. The Federal Transit Administration procedure characterises the ground through line source transfer mobility, which requires impact tests on the ground at multiple points along the proposed route. However, characterising ground dynamic behaviour through line source transfer mobility is challenging, particularly in urban areas where access to a site to undertake measurements can be limited. Based on the Federal Transit Administration framework, this paper proposes a simplified methodology based on the results of sensitivity analysis of ground dynamic behaviour at ten urban sites within the same UK city. It also identifies some of the issues with the use of line source transfer mobility method in urban sites; one of the findings is that where there are difficulties in obtaining access, data analysis can be used to circumvent issues where a full line of impacts (required by the technique) cannot be obtained.