GEOTECHNICAL INTERPRETATIVE REPORTING
A geotechnical interpretative report (GIR) provides a vital link between the factual laboratory and site investigation data and the analyses performed during geotechnical engineering design. A good GIR brings together all available data sets to form a coherent ground model that provides geotechnical values for the intended design purpose or purposes. Consequently, the GIR must be prepared by a qualified and experienced team of geotechnical engineers, engineering geologists, and geophysicists.
Unlike other engineering material such as steel and concrete, the strength of a soil is highly dependent on the direction of shearing, the rate of loading, and the drainage conditions during loading; to make things even more complicated, the stiffness of soil is also highly nonlinear. Unfortunately, this complex variability makes it commercially impractical to develop a generic GIR that covers all potential design scenarios—instead, GIRs tend to be produced for a defined range of purposes or even a single purpose.
The complexity of GIRs depends significantly on the design purpose—for example, the design of a noncritical lightly loaded structure in uniform soils would require a much simpler GIR than the design of a heavily loaded critical structure in complex soils
GROUND MOVEMENT ANALYSIS
Ground movements can arise for a wide range of reasons, including excavation of basements, tunnelling, foundation loadings, and clay shrinkage and swelling.
The analysis of movements due to basement excavation often forms part of a basement impact assessment and needs to consider the heave movements resulting from the excavation, along with movements behind the retaining walls. We use a range of industry-standard software to model the resulting movements, including consideration of timing of prop installation and excavation stages.
On many sites that have been developed previously, or where a building is being remodelled or refurbished, additional load may be applied to existing foundations that have been loaded for many years. In such situations detailed consideration needs to be given to the movements that will arise from the additional load and the often complex interaction between new and existing foundations. We adopt a pragmatic and sensible approach and in many cases clients have been able to save the cost of new foundations as a result of our detailed movement predictions.
We are often consulted to resolve issues arising from party wall matters, and can provide a forensic service to investigate situations where movements have arisen. With our extensive experience of ground investigation methods we are able to ensure that the required data is obtained from any intrusive investigations that may be necessary, to allow proper ground movement predictions to be made.
BASEMENT IMPACT ASSESSMENT
With an increased demand for space in ever expanding towns and cities, many Clients are looking to extend below the ground by constructing basements beneath existing homes and gardens.
As part of a Basement Impact Assessment (BIA) a soil/structure interaction analysis needs to be carried out prior to construction. Central Piling use state of the art numerical analysis software Plaxis3D for finite element analysis.
Soil Consultants also have an extensive history of using this methodology to attain agreements with water and rail authorities where structures are to be constructed adjacent to their assets
PHASE 1 DESK STUDIES