Site characterisation is the process of understanding the conditions that influence the installation of structures and their operation. Ground modelling is the principal activity that enables geoscientists to carry out site characterisation efficiently. It is an effective way to integrate various site characterisation datasets, like terrain maps, geological and geotechnical samples, seismic profiles and soil parameters.
Our approach to ground modelling uses the best available data to design new data collection programmes and site investigations carefully, and to gain maximum value for money from expensive field programmes.
The ground model is a live, up-to-date state of knowledge of site conditions relevant to the development. It contains all available site characterisation data and analysis products. It is usually hosted in a geographical information system (GIS) to help with integration, analysis and providing outputs to client specifications – it also automatically enables efficient and secure retrieval and archiving.
Our site characterisation services include:
- Desk studies using all available data for early-stage investigations and initial site selection
- Geomorphological mapping
- 2D and 3D seismic interpretation
- Design of data collection and testing programmes
- Integration of multi-discipline datasets and interpretation reports
- Client representation
- Site visits
We help our clients gain a good understanding of site conditions. This knowledge is essential in order to design and install any building or structure successfully on land or on the seafloor.
In our experience, on large and complex developments like bridges, tunnels and deepwater offshore oil and gas fields, a relatively modest investment in site characterisation can pay for itself many times over, because it ensures trouble-free foundation design and installation.
Typical site characterisation applications
The ground model to design the foundations for large bridges may need to extend over land and the nearshore. It may also need to involve geophysical and geotechnical data collected from both environments. We recommend assigning a single integrated team, with a common approach to sampling, laboratory testing, data interpretation and analysis.
Installation of offshore structures
Marine developments often consist of many individual sites, sometimes spread across a large area of seafloor and linked by cables or pipelines. So we often recommend constructing a regional ground model, perhaps involving reconnaissance data collection, to give early warning of the different ground conditions. We follow this up with site-specific investigations that provide vital information for foundation design.
Offshore power cables
Cable routes must be chosen carefully, to avoid existing infrastructure (like oil and gas fields), shipwrecks, prohibited areas such as dumping grounds, and unfavourable seafloor conditions like sand banks, steep slopes and rocky outcrops.
We can provide a reconnaissance survey to help select a suitable route. We follow this up with a detailed geophysical and geotechnical survey, to refine the ground model and provide the information needed for cable burial.
Ground investigations for construction developments and to investigate failures need to be supervised and monitored carefully by specialists. We can provide experienced geotechnical engineers for this important task.
Our approach to site characterisation is based on the concept of an evolutionary ground model that encompasses the following principles:
- We make full use of all available and existing data, including research papers and other public sector information. This is especially useful and relevant in a desk study that will establish the ground model and often provide valuable information about initial site selection
- We include geomorphological mapping when studying land and marine development areas. Much can be learned about structural history from the shape of the land or the seabed, and the characteristics of its natural features
- Our geophysicists apply their comprehensive understanding of data collection and processing to interpret 2D and 3D seismic data according to sound stratigraphic principles. The limitations of a seismic dataset can then be understood and the maximum value extracted
- We use the ground model to design geological, geophysical and geotechnical data collection and testing programmes
- We combine the different datasets in an integrated interpretation using a GIS platform. This provides access to data analysis tools and facilitates efficient data management and exchange
- We make sure that the appropriate quality control is applied to the collection of new data and that preliminary findings are incorporated into the ground model as soon as possible. This can provide valuable guidance to the data collection programme and ensure that it meets the project’s needs
Our scientists and engineers are guided by the above principles, which they apply to help solve our clients’ problems and reduce costs on a wide range of projects – large or small, land or marine.