Improving railway subgrade stiffness - assessment of traditional in-situ ground improvement techniques

With increasing pressure for higher line speeds, heavier axle loads, lower possession times and the need to reduce maintenance costs there is a necessity to develop in-situ ground improvement techniques that can be applied between sleeper cribs or through the ballast shoulder. This paper summarises traditional ground improvement technologies and assesses their suitability for application on existing rail track. This assessment is based upon discussions with geotechnical and permanent way engineers. The physical, cost and time implications in the possession times available under the working restrictions of an operational railway are also considered. The paper concludes with suggested ground improvement techniques for implementation in UK railways. This investigation, funded by the government approved EPSRC LINK programme, forms part of a project that will undertake field trials of the most appropriate techniques. For the covering abstract see ITRD E125214.