LOCORPS: Lowering the Costs of Railways using Preformed Systems

Lead Research Organisation: University of Dundee
Department Name: Civil Engineering

Abstract

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Description Through small scale physical model testing, we successfully simulated settlement response of the novel embankment systems, finding from that a very ductile and stable response is obtained in these structures under repeated loading from many train movements. Measured settlements were consistently lower than comparably loaded conventional ballast embankments. This applied across a range of soil substrates, and although analysis of data is still ongoing it appears most pronounced above the softest subsoil conditions.

A new system has been developed in order to apply rail loading to model embankments on a geotechnical centrifuge. i.e. in order to make the weight of all small-scale components appropriate we artificially increase gravity using a large (3 m radius) centrifuge and spin the models at 120 rpm (50g). During spinning, a train has been developed that moves back and for along a track at the top of the embankment simulating many repeated train passes. Further, a system has been developed to enable deformations of the embankment to be measured, by means of a Perspex wall at the end of the model through which digital images may be recorded and correlated. A further exprerimental development was the calibration of small flat pressure plates that were able to measure the pressure between the embankment and the soil below, showing how the embankment structure transferred the train's weight into the foundation soil.
Exploitation Route * The experimental method has application in other long linear infrastructure work, both at Dundee and on other centrifuge facilities, and shall be presented in the International Journal of Physical Modelling.
* The lead grant on this award (EP/N009207/1) has uncovered similar findings related to the rail-embankment interface, so work is ongoing to combine the results for a more impactful publication in due course.
* Data is to be made open access in line with EPSRC regulations: this ongoing and should be available mid-2021
Sectors Environment,Transport
 
Description For the main impact generated by the project, especially related to within the rail industry, please see the impact description provided for the lead partner, EP/N009207/2. The equipment developed at Dundee during the project - a centrifuge-mounted rail track simulator to enable small-scale models to be tested under full-scale stress conditions - is unique, and is on the cusp of generating further impact for us at Dundee, both in terms of knowledge transfer to other experimental facilities and also in growth of this research area. Whilst still in early stages and not yet leading to specific new projects (thus not mentioned elsewhere) it has enabled us to join the Scottish Engineering Rail Cluster Builder in which industrial stakeholders are able to work with academic partners to solve problems arising on the Scottish rail networks. Thus, the centrifuge mounted rail simulator developed in this project is now available to a variety of other partners who would benefit from such a facility. As an unexpected but (in my view) no less important outcome, the technologies developed in creating the centrifuge-mounted rail track simulator have facilitated a new research strand into subsea drag anchors. The mechanism of moving a train proved identical to that required to tow a drag anchor, and since the end of LOCORPS we have been able to utilise the equipment/method expertise into growing our capability in anchoring renewable energy resources. This is generating impact of its own through our association with anchoring specialists Bruce Anchors, who have adapted data from Dundee testing into their design know-how. The project work had particular influence on researcher Scott Robinson who came to the project to complete testing after the departure of the original RA. Now Scott has recently been appointed to an academic position at Dundee he has begun to develop his own research strands based around the technologies developed during the project - to date, improving the embankment designs via UG project work - and I look forward to seeing his own development as an independent researcher.
First Year Of Impact 2023
Sector Transport
 
Title Centrifuge mounted linear rail actuator 
Description Whilst the geotechnical centrifuge is spinning at ~120 rpm/50g, the challenge was to devise a means of applying a rail load repeatedly to a small scale model embankment. Equipment previously developed for subsea ploughing (grant EP/M000362/1) was able to provide a controlled translation but not return movement or feedback control. The solution proved more tricky than originally anticipated but by means of a simple and relatively low-cost feedback controller we can now translate full-weight trains along realistic rails on slabtrack (or, possibly, ballast, if required) in order to measure embankment deformation. Further, the application of a Perspex end wall enables the 2D strain field of the supporting soil/embankment to be measured digitally. This is very recent and to be presented in a method paper explaining the system to fellow modellers at the European Conference on Physical Modelling in Geotechnics, as well as in more detailed form to the International Journal of Physical Modelling in Geotechnics. After the end of the project, this technology was able to be leveraged further as the methodology proved similar to that required for the testing of subsea drag anchors, at just the time when anchoring contractors have found that the mooring of floating offshore renewable energy devices requires engineering knowledge that they didn't have. So using the technology developed in EP/N009215/1 we have been able to answer a number of additional (and previously unforeseen) questions for other sectors of the civil engineering profession. 
Type Of Material Improvements to research infrastructure 
Year Produced 2020 
Provided To Others? Yes  
Impact New method - impact to follow after use! 
 
Title LOCORPS: Centrifuge model data for settlement of rail embankments over various substrates 
Description This is a collection of model test data for settlement of rail support embankments from both traditional and prefabricated reinforced soil construction. Each structure is placed over sand or clay substrate and subjected to 1000 train movements. Data records settlement of the track, the structure and the soil surface away from the embankment, as well as earth pressure recorded between the structure and soil surface throughout. This data was completed in March 2020, then final processing was delayed as the research team were scattered due to covid. However, work has resumed to publish the data set in a final form usable for others during early 2022. doi: 10.15132/10000177 https://doi.org/10.15132/10000177 (reserved but awaiting formal publication) 
Type Of Material Database/Collection of data 
Year Produced 2022 
Provided To Others? Yes  
Impact Preliminary interpretation suggests that prefabricated rail structures produce smaller settlements than the traditional gravel embankments, due to their ductility and loadsharing capabilities. Work is underway to publish this formally, together with the dataset itself, as well as to combine results with the lead project. Further, the experimental set up created and refined to both implement the train load and also to take measurements especially of the earth pressure beneath the structure represent experimental advances that are to be published separately in their own right - as originally intended, though a little delayed due to personnel changes in-project and then lockdown.