Wilson Energy (United Kingdom)

The process of managing contaminated land projects is complex and the necessary skill set required to communicate contaminated land risk has become extensive. The communication of contaminated land risk has become more important as a result of greater pressure placed on the redevelopment of brownfield sites, easier access to basic environmental information, increased public concern about human health risk and possible harm to controlled waters, and less trust that risk is communicated fully and honestly to stakeholders. These drivers have culminated in the task of effective communication associated with contaminated land becoming more onerous but a detailed consideration of their impact on stakeholders is critical to the successful delivery of remediation projects. The necessary skills required for the effective communication of contaminated land risk are considered. These skills are appropriate for contaminated land consultants, planners, civil engineers, specialist contractors and land owners who have to communicate risk issues to a lay audience. The part IIA Manywells landfill site is provided as an appropriate case study, in which effective communication and stakeholder management has been successfully implemented.

The offshore caisson breakwater at Costa Azul installed in 25m water depth is designed to withstand Pacific swell waves up to a PLS test case Hs 9.2m Tp 18.6s. Overall stability design is in accordance with the recommendations of PIANC WG 28. The critical failure mechanism is sliding, and the caisson base is cast with a deliberately roughened (serrated) profile to increase sliding resistance and optimize the caisson cross section. Site based testing at prototype scale was conducted to validate the coefficient of friction used for design between the caisson base and nominal 100mm single size granular bedding material. This testing confirms that the use of a suitably dimensioned serrated base profile allows the full internal angle of friction (with allowance for dilation) of the bedding material to develop at the base of the caisson, allowing the cross section design to be optimized.

This paper investigates the relationship between mode of asphalt mixture compaction and resulting mechanical performance in terms of stiffness modulus, permanent deformation and fatigue resistance. Four modes, comprising three laboratory methods of gyratory, vibratory, and roller compaction together with site compaction were included in the study. An interlaboratory program was undertaken using these compaction methods and three asphalt mixture designs. The results showed that mold based compaction methods, such as gyratory and vibratory, generally produce stiffer specimens with higher resistance to permanent deformation when compared to roller compacted or field specimens of comparable air voids. However, the results also showed significant variability within a particular compaction method between different laboratories. The statistical two-sample t-confidence test was used to compare the sample means of air voids content and stiffness modulus between the different compaction methods. The statistical analysis showed that producing volumetrically identical asphalt mixture specimens using different compaction methods does not produce materials with identical mechanical properties. Statistical analysis was also undertaken on stiffness and permanent deformation results to provide engineers with the number of tests required to obtain a mean value within a certain accuracy of the true value, for a given confidence level. Stiffness modulus was found to have a far higher repeatability than permanent strain with the mode of compaction not affecting the variability of the results.

The Teifi Pools are notable for their freshwater plant communities of the Natura 2000 ‘oligotrophic to mesotrophic standing waters with vegetation of the Littorelletea uniflorae and/or Isoeto-Nanojuncetea standing water’ habitat type (EU Habitat Code: 3130) and for an internationally important population of the aquatic plant floating water-plantain (Luronium natans (L.) Raf.) (EU Species Code: 1831).

There is an ever-increasing demand for land to cope with the rapid economic development worldwide. As a result, new land is always reclaimed from the sea to meet the demand. The soft marine deposit in the seabed is often too weak to support the reclamation and the infrastructure to be built upon it. However, dredging of marine deposit has to be minimized to prevent ecological damage to the marine environment. In-situ improvement of the marine deposit is thus often required. Vacuum preloading is a proven technique to improve the engineering properties of soft clay onshore. However, the viability of applying the technique underwater is yet to be established. Practicality and constructability are important issues. The results of a field-scale constructability evaluation of underwater vacuum preloading are presented in the paper. Different techniques to install a membrane underwater to provide the required air-proof barrier were evaluated by monitoring the vacuum pressure underneath the membrane, pore pressure in the clay in the seabed, and ground settlement as a function of treatment duration.

Abstract Vertical stereographic aerial photographs obtained as photographic plates or, more recently, as digital images represent a primary source of data for desk studies on all engineering projects. New methods of data acquisition from both airborne and spacecraft-based scanners provide unparalleled opportunities to obtain high-resolution data. However, interpretation of the images remains as much an art as a science and is critically dependent on the skill and experience of the interpreter. Relevant experience can be obtained only by the practice of ground-truthing an interpretation that the interpreter has carried out. Although it has rarely been quantified there are important lessons for all engineering projects on the divergence between the interpreted image and the actual ground situation. Some of these are exemplified in a case study undertaken by the authors using large-scale aerial photographs for a landslide hazard investigation in Spain. Based on this investigation it can be assumed that up to 50% of landslide features of engineering geological significance might not have been identified by the aerial photograph interpretation. The alternative is to use the images to divide the landscape into terrain units that allow the landslide potential to be evaluated. It can be demonstrated that this approach is more effective than trying to create a landslide inventory based on aerial photographs alone. Given the potential expansion in the use of large-scale image analysis associated with the recent improvement in data acquisition systems this has implications for the use of images and the training of interpreters.

Worldwide, public works/construction is considered to be one of the most corrupt of all sectors. The problem is most acute in developing countries, where corruption often accounts for leakages of 20% or more. As a result, project planning is distorted, construction quality undermined, maintenance neglected and professional standards compromised. In the past, some donors and many governments have turned a blind eye to, or even encouraged, such corruption. In recent years, however, a consensus has emerged that corruption not only harms the poor, but is also bad for business and for security. Yet corruption persists in the sector, spurred on by the ease with which it can be hidden and by the pressures of globalisation. There is no single, or simple, solution to this problem, but much could be achieved by creating more incentives for good practice, and by making better use of existing tools to improve transparency and accountability.

The need to recycle thin surfacing systems is more critical than for many other generic surfacing materials because they contain a high quantity of relatively scarce aggregates with high skid-resistance properties. Laboratory investigations and site trials have been successfully undertaken to assess the feasibility of incorporating reclaimed surfacing materials in these systems. The trials were on an access road to an asphalt plant and on two heavily trafficked sites on the UK road network and included the use of polymer-modified binders and up to 30% reclaimed asphalt in the mixed asphalt. The trials demonstrate that 10% reclaimed asphalt can be easily added to new materials without processing the reclaimed asphalt. As the proportion of reclaimed asphalt increases up to 30%, greater care needs to be taken on assessing grading compatibility and how to treat the residual binder present in the reclaimed asphalt as a proportion of the ‘active’ binder content in the recycled surface course layer. The use of reclaimed asphalt in the surfacing has also been monitored on a major motorway contract.

Abstract The Crawford Field was discovered in 1975 in UK Block 9/28 and the first oil was produced in April 1989. The field has a complex structural history. The reservoir is located on a down-faulted, westward tilting faultblock along the western margin of the Viking Graben. The eastern margin of the faultblock is severely truncated at Base Cretaceous level. The main producing zones comprise Middle Jurassic (Brent Group equivalent) and Triassic (Skagerrak Formation) sandstones. The seal is formed by Cretaceous marls and limestones. Reservoir quality and thickness are extremely variable, and drainage areas are limited. The reservoir fluid is a medium gravity oil having a thin gas cap. Oil in-place is in the order of 130 MMBBL but recovery factors are expected to be low.