As a young civil engineer in the (now) British Geological Survey in 1972, I had a paper published in New Scientist ambitiously titled “End of the landslide menace?” By way of introduction it harked back to the Aberfan tragedy of 21 October 1966 (New Civil Engineer last month). That disaster was brought about by the National Coal Board’s tipping relatively impermeable colliery spoil onto water seepage from the hillside which caused the groundwater pressure to increase beneath the spoil. I have investigated countless landslides throughout the world since then and found that many of them, in both man-made and natural strata, are caused by essentially the same mechanism.
The 1976 and 2013 Isle of Wight geology maps, on which I am credited as a member of the team which inserted landslip zones, provide an example of a natural instability in the island’s undercliff which is host to the biggest semi-urban landslide complex in Europe. Various parts of it are reactivated at frequent intervals because a naturally subsiding clay stratum has sealed off underlying seepage.
The fact that none of the components in the undercliff (or elsewhere) are man-made should not absolve authorities or engineers of their responsibility to stabilise such landslides by implementing drainage measures to relieve the underlying groundwater pressure and remove the threat of further road closures, extensive loss of property and, potentially, life. Until that happens the lessons of Aberfan will not have been learned.
- Bruce Denness (M) Cinxia Cottage, Ashknowle Lane, Whitwell, Isle of Wight PO38 2PP
Fifty years ago I was a student of civil engineering. One morning in October 1966 we students shuffled into our morning lecture on the topic of “soil mechanics”. Our lecturer told us to set aside our course notes for the day. Instead, we were going to talk about Aberfan, the village in South Wales that had, just days before, suffered a catastrophic disaster from the collapse of the mining waste tips that had long been an accepted part of the landscape above the settlement. In the disaster, 144 people lost their lives, 116 of whom were children from the local primary school. The collapsing tip had engulfed the school as well as neighbouring homes just as school had started on the morning of 21 October 1966.
Our lecture that day turned to the subject of pore water pressures and the use of piezometers to measure and monitor the build up of water pressures in made up ground. It was about how these risks could be assessed, quantified and analysed. By today’s standards it was very basic geotechnics, but in 1966 it was still a relatively new science. New, and beginning to be clearly established within the civil engineering profession but far less so within the mining industry.
I doubt I was the only student that day who hung on every word and every principle espoused by our lecturer that morning. It inspired me to follow a career in roads engineering and in geotechnical design and risk monitoring that resulted in one of the most dramatic and impressive motorway cuttings in the UK, the 150m deep M40 cutting through the chalk escarpment of the Chilterns on the borders of Oxfordshire and Bucks.
Civil engineers in the UK continue to build remarkable, innovative and inspiring structures that push the boundaries of design and materials. Our safety record is second to none. Nevertheless we are all properly humbled by engineering failures and it behoves us all to learn from such tragedies and to improve our understandings of the science of engineering for the benefit of mankind.
- Colin Carritt (Retired Member) Posted online on article headed Special Report | Aberfan 50 years on
How to Make Smart motorways safer
The safety of all lane running continues to attract attention, and rightly so.
It could be considerably improved by providing enough width to park a stationary vehicle partly on the verge and clear of the inside running lane. This is currently precluded along most lengths by the safety barrier being set unnecessarily close to the carriageway. If it could be moved back a metre or so, the risks would be significantly reduced.
- Steve Riley (M) email@example.com
Old Hands make light work
I was very interested in the letter from Ian Cosgrove (New Civil Engineer, October 2016) as it closely echoes a letter of mine (New Civil Engineer 9 October 2014).
As he rightly says, there is a pool of people who remain unemployed, but would rather be working in the industry to which they can offer so much skill and experience. Regrettably the industry seems to be all too willing to ignore a keen, willing and able group of people purely on the basis of age!
- Richard Middleton (F) firstname.lastname@example.org
Vanity projects versus essential spending
Richard Ashley asks if engineers are in thrall to vanity projects (New Civil Engineer October). I live in the Lake District, and so have an interest.
It seems very odd to me that the country can spend £185M
on the Garden Bridge over the Thames, while authorities up here have to struggle to find the £200M to repair the damage caused to roads and bridges in Cumbria by Storm Desmond.
These are absolutely essential, and yet almost a year on, many are not repaired.
In the village closest to me many businesses have been badly damaged by the loss of the bridge, which means that the village is now completely split in two. This may be replaced in 2017. The government’s initial offer of help was £40M. Something is wrong with our priorities.
Of course up here we do not have Joanna Lumley on our side.
- Peter Bettess, Brow Head, Kentmere, Cumbria, LA8 9JL
Plea for more accessible language
Today I received ICE Proceedings Civil Engineering, Volume 169, Issue CE4, November 2016 and it includes a briefing by Tom Dolan and Ellie Cosgrave from University College London on aligning systemic infrastructure decisions with social outcomes as part of the ICE’s “thought leadership programme”.
I admit to being old, I admit to being retired and I also admit to being, until I bowed out earlier this year, chairman of BSI’s Infrastructure Advisory Committee.
After much thought, could it be that the briefing’s title translates as “Designing with common sense”?
- Haydn White email@example.com
Our emissions reduction targets clarified
Carbon emissions cropped
Derek Godfrey (Your View, last month) seems to have been confused by the deliberate obfuscation of the government. The government does not just aim to produce 15% of our electricity from renewable sources by 2020, which it will probably achieve. Under the European Union Renewable Energy Directive 2009 it has committed to produce 15% of our total energy from such sources by 2020. This includes not just electricity, but also all energy used for transport and heating. While a third of EU member states have already achieved their targets, we will fail to meet ours and may be liable to financial penalties (although Brexit may get us out of this).
- Jonathan Martin firstname.lastname@example.org
Hyperloop is the answer to inter-urban transport
Railways are old technology from which we are attempting to squeeze a last gasp soupçon of improvement. Air friction and shock waves pose a finite limit to how fast we can travel by train in close proximity to people and the environment.
We already have a road and railway network connecting all the major population centres and we have the infrastructure to handle containers. So, pack goods and people into containers, put the containers into a hyperloop tube and run the hyperloop on piers along the central reservation or in the margins of our existing motorways and railways. The system can be readily extended to connect with Ireland, Holland and France at less cost than conventional bridge and tunnel techniques. The Hyperloop offers the advantages of speed, reduced capital and maintenance costs, low environmental impact and negligible land requirement.
We should delay High Speed 2 and plough a few millions into Hyperloop investigation and development with the aim of connecting and developing all of the country.
- Eoin Gorman (F) email@example.com