How geological variations govern local expertise this month focuses on North West England
Natural and manmade hazards combine to make North West England a challenging environ- ment for geotechnical engineers and engineering geologists.
Engineers may encounter settlement potential, inadequate load carrying capacity, unstable slopes, made ground, variable ground conditions, marginal land, groundwater recovery, collapsing shallow mine workings, abandoned mine shafts, contamination, landfill gasses, mine gases, and more.
As with many industrial areas throughout the UK, developers are adapting to the different skills associated with the redevelopment of brownfield land.
Such sites are often typified by the presence of made ground/fill deposits, often thick, very variable in composition and geotechnical properties.
Ground engineering has a significant role to play when developing such sites.
A variety of ground improvement techniques including vibroflotation, dynamic compaction, surcharging, wick/ band draining, removal and recompaction etc are used throughout the region in addition to the more traditional type of solutions including deep and/or piled foundations etc.
Large scale, integrated, land reclamation schemes are common.
Even the North West's greenfield sites are not always free of problems. Development in upland areas often has to contend with slope instability, both relict and recent.
Billiard table smooth sites in lowland areas may have to contend with soft ground problems (significant peat deposits in some areas of the region being a good example).
Add in long history of surface and underground mining (coal, flagstone etc), landfilling and a rich industrial heritage, all of which have left a legacy of additional problems.
Nevertheless, a developer's bottom line is still represented in pounds and pence and with many projects incurring significant costs rectifying or overcoming of geotechnical and 'in ground' problems, there is an increasing understanding and acceptance of ground engineering in the area.
Perhaps the key to successful development in the North West is an appreciation of the benefit of identifying and resolving problems in the ground at an early stage.
Both developers and engineers alike are becoming used to having to approach projects with an open mind.
If problems can be properly identified 'up front' then appropriate allowances can be made in project planning and/or land acquisition.
With so many potential problems, investment in the area might be unattractive but this does not seem to be the case. Development of the region continues to be a thriving industry in which ground engineering has a significant role to play.
David Lister, Associate, Wardell Armstrong