All construction takes place in or on the ground. Buildings, retaining walls, fill slopes, excavations, pavements, pools, etc. must all be supported by the underlying subsurface. And, conversely, these very same project elements affect the subsurface and must be engineered appropriately.
A geotechnical exploration is performed by a licensed geotechnical engineer and results in a signed and sealed written report. The report will document the general subsurface conditions on your site and will include geotechnical recommendations for your project. The report contains information that is pertinent to you, your design team, and your contractors. The report itself is often included in the project bidding and contract documents.
There are many different ways to explore the subsurface soils, rock and groundwater. In Western North Carolina, the methods of exploration typically include soil test borings, hand auger borings, or test pits. Each of these methods includes physically penetrating the ground, sampling, and testing. The method of exploration used is chosen in conjunction with the geotechnical engineer as the geotechnical engineer has to be comfortable with the quality and quantity of subsurface information gathered in order to develop recommendations for your project. Site access, terrain, proposed grading and project plans affect the choice of exploration method. As you can imagine, a geotechnical exploration for a 20-story building would be different than one for a house.
The recommendations in your report will be site specific and will speak directly to your proposed project. Geotechnical recommendations for foundation design are always included for projects involving proposed buildings. You might also find information regarding improving soft soils at your site, de-watering, limiting difficult excavations, retaining wall design parameters, and structural fill placement.
Your report will inevitably include recommendations for some followup consulting and testing to be performed during construction. These followup items typically include foundation excavation evaluations, testing of earthwork fill placement, among other things. Some owners decide to do no followup testing. Others do it all. We can assist you in making this choice but you’ll also want to consult with your design team and your contractors.
Many projects are completed without the involvement of a geotechnical engineer. Our geotechnical expertise is sometimes replaced with assumptions as allowed by the residential building code. But, we urge you to weigh your options. Nine times out of ten our services save projects more money than the total cost of services alone! We believe that reducing your risk and saving you money in the process is a good choice. Many of our clients agree!