Plus: • Geotechnique Lecture report • Jet grouting at May 2010 £10 $18 Sydney airport northern exposure Drillers brave winter conditions to improve Shetlands ferry routes Ground improvement site investigation wet ’n wild A drilling team braved everything the weather could throw at them last winter in an important project to improve Shetland’s ferry and fishery infrastructure.Neil Jaques reports. ust off the shore of Whalsay, er, a fleece, a waterproof jacket and sphere,” says Howard Marine structure dates to the 1970s and in Shetland’s sixth largest island, a trousers, and selection of mad hats,” founder John Howard. “You really recent years has started to incur seri- drilling crew is jostling for space he shivers. On occasions tempera- know you’re up against the elements ous maintenance burdens from ever- J o atop a bright orange jack-up barge. tures plummeted as low as -8 C and here – the wind and the rain is in increasing ferry sizes. It is early December, and a vicious the winds reached gale force 9. your face the minute you get out To remedy the situation, and to wind is roaring through the air, cru- Howard Marine, the company of the car and you know if you fall improve the lives and businesses on elly accentuating the sub-zero tem- that supplied the jack-up barge and in the water your life expectancy is Whalsay and the wider Shetland perature and slamming bullets of its associated facilities and person- only a matter of minutes. community, Shetland Island Coun- rain against the fluorescent-suited nel (a barge master plus assistant) “I’ve been up there working in the cil aims to complete a £25M project bodies. The notoriously truculent is experienced in over-water drill- summer and we’ve still encountered to build two new ferry terminals on North Sea swells and laps leadenly ing expeditions worldwide, but was extreme conditions,” he adds. Shetland (one for back-up in case of and ominously at the edges of the under no illusions as to the chal- Extensive over-water drilling bad weather) and another on Whal- 12m by 10m barge, but the drillers lenge presented by the north of projects are a tricky proposition at say itself. The entire project is set to imperviously push on. Scotland in winter. the best of times, let alone in the be completed within the next four Between last October and this “In the Shetlands, you’ve got midst of last winter’s cold snap, but to five years, with the first terminal January, under some of the worst some of the most severe weather the project’s pressing urgency forced finished in 2012. winter weather conditions for dec- conditions in this part of the hemi- the issue. The Whalsay ferry’s infra- “It is unusual that we’re working ades, drilling contractor Structural at this time of year, and we have Soils worked on a vast over-water considered at various points wheth- drilling programme to help Shet- “The wind and the rain is in your face the er it was wise to continue or better to land Islands Council enhance the delay works,” says Shetland Islands ferry route between Whalsay and minute you get out of the car and you know Council contract manager Trevor the mainland. Sodden and wind- if you fall in the water your life expectancy Smith. “But there is an urgency to pummelled after one 12-hour shift, obtain the geological data we need project engineer Grant Davis runs is only a matter of minutes.” to progress the design phase.” through the prerequisites for basic John Howard, Howard Marine Structural Soils, which is part of comfort: “I’m wearing a thermal the RSK group, drilled more than T-shirt, an ordinary T-shirt, a jump- 30 boreholes up to 20m deep, using 14 ground engineering May 2010 Swining Lunning Skaw “The secret to safety Vidlin at sea is that you The Shetland don’t chance your Islands Marrister luck beyond a certain Laxo Flugarth WHALSAY point, and we all Levaneap North Voe know exactly what is required of us.” B9075 Symbister Huxter Jon Bassett, Structural Soils Dury cable percussion to drill through Marine) to Aberdeen, ferried over- for the drilling team to trouble- ent risks enabled Structural Soils to overburden and rotary coring for night to Lerwick, Shetland, and shoot with the rest of Structural offer Shetland Islands Council an the underlying schist. All core driven across the island to another Soils’ project team in Glasgow, and investigation option that involved samples were sent to the company’s ferry, which could only accommo- if equipment broke down replace- using a smaller barge than usual, in-house laboratory in Castleford, date one lorry at a time. ments could take up to three days to bringing considerable mobility and Yorkshire, where the data is being Following assembly by mobile arrive, so the work had to be meticu- cost benefits. collated into a report that will crane, the equipment was put to lously planned and carried out with “A lot of people are afraid of jobs inform the design of the ferry termi- sea to drill at proposed ferry ter- a near-obsessive eye for detail. like this or think that the answer is nals’ foundations. minal locations at Laxo and Vidlin “It really puts the onus on the ‘let’s have the biggest thing [barge] Once the work was complete at on Shetland’s mainland, and Sym- engineer to get things absolutely we can get’, because the theory is the prospective terminal locations, bister and North Voe on Whalsay. right,” says Structural Soils’ project that it should be the safest. But that’s the equipment was packed up and Moving between site locations was manger Jon Bassett, who has an inti- not always the case,” says Howard, a taken to Wails on the west coast slow, as it involved a tugboat pulling mate understanding of the terrain man who is well versed in the notion of Shetland to ascertain ground the barge around the unpredictable having worked for Fugro on pre- of calculated risk, having worked as conditions for a fishery-related pier headland waters. liminary site investigations at Laxo, a lion tamer in a former life. extension that falls under the same “You need a good window of Vidlin and North Voe in 2001. He equates the company’s cho- contract. opportunity and good weather to Although fraught with unpredict- sen method to the Battle of Trafal- Howard Marine and Structural make a move,” Davis explains. able risk and unknown variables, gar: nimble English fighting ships Soils have worked together on this “Otherwise you’ve got to break the particularly those of the meteorolog- outmanoeuvring Napoleon’s lum- type of project for almost 20 years, barge up and transport it on flat- ical variety, Bassett emphasises that bering fleet. and on paper it should have been bed lorries across land, which is a Structural Soils and Howard Marine “We looked at the situation and routine. But Shetland’s remote and different proposition altogether. have the collective experience to get said, ‘yes, it’s challenging, but it’s climatically unforgiving environs It’s a part of the job that is hard to the job done safely and economically. going to be challenging whatever you made it more of a challenge. Simply predict in terms of cost and safety “The secret to safety at sea is that you use’, and our method has proven very getting to site was tricky: equipment implications and needs to be judged don’t chance your luck beyond a cer- successful,” he says. “Ultimately, this was driven on eight low-load flat- very carefully.” tain point, and we all know exactly kind of work is all about working bed lorries from Castleford (Struc- Mobile phone reception was a what is required of us,” he says. together to make every operational tural Soils) and Plymouth (Howard luxurious rarity, making it difficult Awareness of the project’s inher- moment count positively.” The jack up barge with drilling gear in Symbister harbour Conditions on board the barge were tough at times ground engineering May 2010 15 Structural Soils offices: Bristol (Tel: +44 (0)117 947 1000), Castleford (Tel: +44 (0)1977 552255), Glasgow (Tel: +44 (0)141 332 8440), Hemel Hempstead (Tel +44 (0)1442 437500) For further information, visit us at www.soils.co.uk or contact: John Lawrence: [email protected] (Tel: +44 (0)1977 552255), Adrian Barby-Moule: [email protected] or Jon Bassett: [email protected] (Tel: +44 (0)141 332 8440) STRUCTURAL SOILS LTD .