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LOCORPS: Lowering the Costs of Railways using Preformed Systems

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

Abstract

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.
 
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 (Narrative largely added in previous years, and communicated through lead partner, PI: Woodward). Benefits to Engineers operating in the rail sector: Through the lead partner, data communicated efficacy of prefabricated low land-take embankments for rail application to key UK stakeholders, esp. HS2, to aid their decision making. Novel testing methods at all partner institutions were communicated to industry (largely through publication), increasing awareness of advanced testing as a verification and ratification tool. University of Dundee now participate in the Rail Cluster Builder (https://rail.scoteng.org/) led by Transport Scotland/Scottish Engineering/Scottish Enterprise/Skills Development Scotland; though have found that our particular skills are more needed on the landslide side than new rail infrastructure.
First Year Of Impact 2020
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. Work is ongoing to publish the data set in a final form usable for others during early 2024. doi: 10.15132/10000177 https://doi.org/10.15132/10000177 (reserved but awaiting formal publication) 
Type Of Material Database/Collection of data 
Year Produced 2024 
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. 
 
Description Central South University, China 
Organisation Central South University
Country China 
Sector Academic/University 
PI Contribution In 2023 we began discussions with staff at China's Central South University (CSU). This is one of China's foremost institutions for railway engineering, and they have full size track bed facilities but nothing that facilitates testing at smaller scale. In 2024, Yuqing Zhou, a PhD student of Professor Xiaobin Chen, visited University of Dundee to use the centrifuge moutned rail simulator developed during the LOCORPS project. This project was to look at ground improvement to support rail systems in certain difficult ground conditions. We were able to apply the method to the centrifuge models and demonstrate some improvement of behaviour. A joint paper [Chen, X., Zhou, Y., Yu, Z., Zhang, J., Brennan, A.J., Tai, Q. & Lu, X. Hydrophobic and strength characteristics of weathered red-layer mudstone modified by octadecylamine.] has been submitted to Materials Today Communications and is currently under consideration
Collaborator Contribution The hydrophobic treatment was proposed and some preliminary testing was carried out at CSU. Centrifuge testing of wider application of the method under train loading was carried out at University of Dundee.
Impact First paper is still under consideration at this stage. Chienese contributors are Railway Engineers and UK contributor is a Geotechnical Engineer. [Chen, X., Zhou, Y., Yu, Z., Zhang, J., Brennan, A.J., Tai, Q. & Lu, X. Hydrophobic and strength characteristics of weathered red-layer mudstone modified by octadecylamine. Submitted to Materials Today Communications]
Start Year 2024