Geotechnical engineering is a branch of civil engineering that covers earthworks, soil stability, and building foundations. During geotechnical design, engineers evaluate the condition of the earth above and below the soil within a specific project site. Using this information, they develop blueprints that help contractors determine how best to develop the project site. Without geotechnical design, buildings would be subject to instability, which could result in failure or collapse over time. This engineering process helps to maximize the life of a structure while protecting the occupants inside from danger.
The geotechnical design process begins with a site survey. During the survey, engineers measure changes in elevation across the site to develop a topographic, or contour, map. They may also take soil samples and subsurface bores to determine the composition of the earth within that area. Finally, engineers evaluate weather conditions and seismic activity of the region. By combining all of this information with information about the potential building project, geotechnical design consultants can determine what changes need to take place before work can begin.
Site contractors often begin by adding or removing soil to achieve the desired slopes or elevations on the site. They may also add subsurface supports ranging from piles to foundation systems based on recommendations from geotechnical design professionals. These supports are designed to stabilize the soil and prevent the building from sinking or collapsing. This type of design process may also apply to non-building projects, including dams, tunnels, and marine structures.
Geotechnical design also involves site drainage and environmental issues. Based on soil conditions and site slope, engineers can properly direct rainwater off a site while minimizing erosion and runoff issues. This not only helps to keep the site dry and minimize pollution, but also protects the building foundation from moisture damage over time. This process may also include site remediation techniques aimed at reducing the level of pollutants found in the soil or on the ground above the soil.
Geotechnical services may be performed by civil engineers, or by geotechnical consulting firms. Many of the individuals who perform this work obtain graduate-level degrees in some branch of engineering. Many areas also require geotechnical engineers to pursue professional licensing from the local state or government agency. This includes completion of an accredited design program and some form of test or exam. Those who complete the licensing process can then use the title "professional engineer."