Many geotechnical engineers aspire to innovation and excellence in their work. Achieving this requires good engineering skills tempered with a wide variety of experience and a commercial attitude which sees a project as an opportunity for innovation.
In the 1960s the foundation options available were the basic pile types (bored and driven), retaining walls, grouting, anchoring and ground treatment. Over the past 30 years all these have been developed to provide a much wider range of solutions.
For example, the underpass built at Hyde Park Corner in the early 1960s was one of the first diaphragm walling projects in Britain and was considered a temporary works solution. We now use temporary works techniques such as sheet piles as permanent works for underground structures, for instance at the Millennium Basement car park in Bristol.
There have also been advances in materials. Use of reinforced earth in embankment design and foundation construction has been a growth business over the past 20 years.
Major UK civil engineering projects have required technological innovation. These include the Channel Tunnel; the use of compensation grouting on the Jubilee Line Extension; ground stabilisation by soil mixing on the Channel Tunnel Rail Link; and the use of jet grouting on the British Museum Library. The rapid growth of the geoenvironmental market has also led to ground engineering solutions for containment and treatment.
Some techniques have been reinvented.
CFA piles, for example, were introduced to Britain in the 1980s. In the US they are called mortar screw piles and have been used for more than 50 years.
Curtain grouting with H-piles and bentonite slurry was used to form cut-offs in reservoir walls in the late 1950s. Hundreds of years ago the Chinese were innovators in the use of plants (willows) for ground stabilisation. Even the much lauded tube-àmanchette is not a recent innovation.
Ground engineering technical development and innovation in the UK has also been assisted by the influx of European specialist contractors since the early 1980s.These firms brought with them techniques used in the differing ground conditions across Europe: NATM tunnel construction is a good example.
Alan Harris, a structural engineer of repute, made an enlightening statement when he said: 'The foundation of engineering is knowledge of material, not, as engineers are so often apt to preach, a knowledge of mathematics.' For geotechnical engineers the material is the ground, which unfortunately does not have the guaranteed parameters for strength and stiffness of concrete and steel.
Advances in mathematical modelling and computing are not the be-all and end-all of design, but coupled with sound judgement and engineering, they can provide powerful additions to the geotechnical engineer's toolkit.
Innovation and creativity require a fundamental understanding of the behaviour of the ground in response to a structure or building foundation requirements and performance.
Understanding ground behaviour relies on obtaining as representative and accurate a ground model as possible. However, the quality of information provided from the fragmented subcontract site investigation and laboratory testing specialists can be suspect. The number of reputable specialist companies has diminished over the past 20 years because of the way the market has been allowed to develop. Proper full-time supervision of site investigation projects continues to be an anathema to some clients and, unfortunately, some engineers.
There is a worrying shortage of suitably qualified young engineers choosing civil and, in particular, geotechnical engineering. Low salary levels and lack of appreciation of the engineer in society are major concerns. The possible demise of postgraduate courses in geotechnical subjects is not in the best interests of innovation.
The variety of practical experience and problem solving that helps in the proliferation of new ideas is not generally available to young graduate engineers. The ability to provide in-depth training on a variety of foundation projects is beyond the capability of many specialist geotechnical companies.
Commercial attitudes can foster innovation, particularly where enlightened clients are involved. But the idea of partnering is not new. This sort of collaboration between client, contractor and engineer was the way I was brought up as a young geotechnical engineer long before the confrontational techniques of the 1980s and 1990s became the norm.
Although there are still more projects and enlightened clients, the creativity required to develop innovation in ground engineering is being threatened by reduced academic capability and a lack of training and experience. These issues need to be addressed to enable innovation to continue.
Jim Cook is director of Buro Happold's Ground Engineering Group.