Seabed ploughing: modelling for infrastructure installation

Lead Research Organisation: Durham University
Department Name: Engineering

Abstract

Soil ploughing, an activity carried out by man for thousands of years for agriculture, is now used at a much larger scale on the seabed to connect offshore energy production and generation devices to the supply network. In the next 50 years many more of these offshore devices (wind, wave, current and oil & gas) will be installed, meaning that considerably more seabed ploughing will be undertaken. However, we do not possess the same level of understanding of the mechanical and hydraulic processes associated with soil ploughing as we have developed for other soil-structure interaction problems. This means that ploughing schemes and equipment have to be designed on the basis of semi-empirical and conservative approaches, leading to financial uncertainty. In this project, new computational methods will be applied to the simulation of seabed ploughing to provide better estimates of key parameters such as the towing force and speed of ploughing in a given seabed deposit along with insights into plough stability. Given the likely ploughing activity in the next 20-50 years in UK waters and elsewhere, we expect that this new predictive approach will result in major savings for industry.

Planned Impact

Beyond academia this research project will lead to economic and environmental impacts.
Cheaper installation costs:
(a) the key advance in this project will be provision of a numerical method to allow economic design of cable and pipeline ploughing projects where there is none of sufficient accuracy at present. This will lead to reductions in the costs of these operations and since this is a highly competitive industry, these cost reductions will be passed on to clients, who are major energy companies and government bodies.
(b) The cost of delivering offshore wind energy projects and in the future, marine energy projects will be reduced, as cabling of these installations will be cheaper.
(c) The new tool will also allow cabling contractors to choose routing with more confidence, allow cabling in areas of the seabed where perhaps they would be less willing to work in due to a lack of previous cabling projects.
(d) There are many cases where offshore pipeline laying projects incur huge additional costs because of an inability of the ploughing operation to achieve the correct depth, and the only solution is costly rock-dumping, e.g. the Breagh development in Canada which cost £566m compared to an expected £485m, www.sterling-resources.com/news/2012/nr0068.html

The project work indirectly supports environmental goals for renewable energy sources, making offshore projects more feasible, but there are many other environmental benefits, e.g.

Hazard Avoidance:
(a) The tool can be used not just for ploughing predictions but also to predict the scouring behaviour of icebergs (which are a hazard for shallow cabling in seabeds).
(b) Shallow burial of pipelines is also cited as a potential factor in various oil pipeline leaks which have occurred, e.g.
www.telegraph.co.uk/finance/newsbysector/energy/oilandgas/8698916/Shell-battles-to-stem-North-Sea-oil-leak.html
www.bbc.co.uk/news/uk-scotland-north-east-orkney-shetland-18540318

The project will also develop the skil of two Post-Doctoral Research Assistants in experimental geotechnics and computational geotechnics respectively.

We will also disseminate our findings to the general public by employing local communications expertise to design and disseminate press releases targeting publications deemed most likely to reach the broad general public. These will communicate our excitement about our research and why our work is necessary to achieve the above-stated beneficial goals.

Publications

10 25 50
 
Description Visiting Industrial Researcher from the Taisei Corporation, Japan 
Organisation Taisei Corporation
PI Contribution Provision of research equipment and advanced physical modelling techniques to simulate offshore cable plough performance in a laboratory environment. Training of visiting researcher in advanced modelling techniques
Collaborator Contribution Financial support of visiting researcher
Impact Creating of a data set looking at cable plough perfroamcne modelling suring centrifuge testing as well as a study (data) on how plough share geometry affects plough performance.
Start Year 2017
 
Description Cathie Associates, Newcastle: Invited presentation, with link to French and Belgium offices on "the advantages and disadvantages of physical modelling 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Presentation on the benefits of physical modelling for supporting research and indsutrial projects. 15 practicing engineers attended or viewed online which sparked questions and discussion. This has also lled to further research collaboration and the recomendation of University of Dundee facilities to simulate real industrial problems.
Year(s) Of Engagement Activity 2015
 
Description ETH Zurich, Institut für Geotechnik, Invited colloquium speaker, Offshore plough modelling 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact 10 Postgraduate students attended research talk on the physical modelling of offshore ploughs and methods of predictiong tow forces and advance rates and research that has been doen to improve these predictions. This sparked questions and discussion afterwards and some existting publications were requested after the event.
Year(s) Of Engagement Activity 2016
 
Description IET's First Lego Dundee University leg 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact University of Dundee hosted a regional heat of the IET Lego Mindstorms international competition. The competition aims to encourage school pupils into science and engineering, by completing a range of competition tasks using programmable Lego robots built by the pupils.
As a part of this event, a Civil Engineering stall was setup to provide activities for the pupils when they were not competing and over lunchtime. The aim of the stall was to:
• Provide pupils with an understanding of what civil engineering is
• Raise pupils interest in Civil Engineering in a fun and engaging way
• Highlight the importance of Civil Engineering in fields such as renewable energy, infrastructure and earthquake resilience
The display included Lego models of offshore wind turbines and seabed cable ploughs, posters of Civil Engineering topics and leaflets with further information on how to pursue engineering as a career path for those pupils interested.
Practical activities were available for the students focussed on EPSRC funded projects at the University of Dundee:
• Screw piles: Pupils were able to test Lego models of both straight shafted and screw piles embedded in sand and compare the differences in pullout force
• Seabed ploughing: Pupils were able to watch interactive videos of the seabed ploughing process and interact with model Lego cable ploughs
• Earthquake liquefaction: Students were able to design and make their own foundations for a Lego model house and compare how it coped with earthquakes using a miniature shaking table.
100 school pupils visited the stall during the day, with the majority of pupils undertaking all of the activities listed above.
Year(s) Of Engagement Activity 2016
URL https://www.dundee.ac.uk/scienceengineering/news/2016/article/first-lego-league-takes-place-at-unive...
 
Description University of Sheffield Colloqium series on Mechanics and Infrastructure research 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Postgraduate students
Results and Impact 60 post graduate ad undergraduate students attended an invited presentation at the University of Sheffield Engineering School on Physical Modelling for Offshore Energy Infrastructure Deployment which sparked questions and discussion afterwards and raised awareness of the use of physcial modelling and interesting research areas for renewable energy research.
Year(s) Of Engagement Activity 2016