Not all sites are created equal – neither should your investigations.
Every site is different and appreciating local ground conditions is a crucial step to ensure your project’s success. Inaccurate information or poor interpretation of ground conditions will affect the economics of a project in the design, construction and even through to operation.
Without a high quality and well scoped site investigation your project has a one in three to one in two chance of running over time or budget. Whether due to inadequate site investigations at project initiation or a lack of ground condition review during construction – unexpected conditions will impact a development.
Understanding the uncertainty in ground conditions is fundamental to managing your risk.
Improved knowledge of the site reduces uncertainty and will enhance your ability to identify and manage project risk.
Simply spending more money on site investigation isn’t the silver bullet. Developing an appropriate scope of work aimed at reducing uncertainty in ground conditions and executing that scope with appropriately focussed and qualified people on site is the key to successful and economic delivery of a project.
If a scope of work is based on the configuration of the proposed development and doesn’t consider the likely ground conditions you’ll often end up with an over scoped investigation - unnecessarily increasing costs. Alternatively under scoping will increase uncertainty and risk.
A prognostic geotechnical investigation can result in significant savings during construction
For large scale linear projects such as greenfield road or rail a detailed understanding of the geology along the route is critical in understanding the geotechnical investigation requirements. Appreciating the end user requirements is also of critical importance. Various things like rail speed, traffic volumes, axel weight and projected maintenance expenditure will all affect the required outcomes.
Even over a 2km stretch of rail track a train can traverse a number of geological profiles and the performance of a small section of rail can significantly limit the speed that a train can travel – having a knock on effect on the overall efficiency of the rail line.
Understanding the dynamic properties of soils can result in more effective analyses, which will allow for more economical design and construction, including reducing the reliance on imported fill for capping or road base.
Dynamic soil properties can be obtained in the field using in-situ geophysical methods such as Seismic Cone Penetration Testing and Electrical Resistivity Tomography and in the laboratory by undertaking Cyclic Triaxial Compression testing.
A targeted geotechnical investigation using these advanced techniques can achieve significant cost savings in cut/fill volumes as well as a reduction in ballast and capping requirements for road or rail projects.
Using the right people to deliver the best outcome
On site, the focus of the investigation team must be to obtain the best information available. This isn’t possible unless you use experienced engineers, engineering geologists or geotechnicians on site during the investigation. Their primary role is to collect and interpret the information from the investigation and develop engineering logs which are fed directly into the site’s geological model. The advantage of using experienced staff is that they’re able to interpret conditions accurately and continually evaluate this information against the geological model, allowing scope refinements to be considered before leaving site.
How Coffey can help
Selecting companies to provide geotechnical investigation and ground model interpretation services based on price alone will often cost the project many times over in design, construction and operation. However, engaging experienced and qualified geotechnical specialists will ensure an appropriate scope of work is identified and developed, one that will deliver your required outcome. At Coffey we will design and implement a geotechnical investigation to identify site conditions and properly manage risk and uncertainty around your project and help to manage on time and on budget delivery.
When considering site investigation and geotechnical advice for your next project ask yourself – are you getting value from your site investigation?