Geotechnical investigation is a process in which the physical properties of a site are assessed for the purpose of determining which uses of the site will be safe. Before land can be developed or redeveloped, geotechnical investigation is often required. This process is also required or recommended in the wake of incidents like earthquakes, the emergence of foundation cracks on land which was thought to be solid, and so forth. The goal of such investigation is to confirm that the land is safe to build on.
The nature of a geotechnical investigation can vary. Sometimes, a geologist simply visits the site and makes a visual assessment, taking note of any signs of problems or deviations from the surrounding area. In other cases, a geologist will take samples for the purpose of study so that he or she can learn more about the rock and soil composition at the site. Geotechnical investigation can also involve tests on the site which are designed to create a profile of subsurface conditions.
A number of things can be a concern for geologists when evaluating a site which has been proposed for development. They may be concerned that the soil cannot safely support a structure, or that structures above a certain size could be dangerous. Geotechnical investigation can also reveal issues which could be problematic in an earthquake, such as soils which are subject to liquefaction. The investigation could also be used to find a formation which would be capable of supporting development, such as bedrock which can be used as an anchor to reduce the risk of damage in an earthquake.
The cost of a geotechnical investigation can be high, especially if a site is in an area which is prone to geologic activity, because the level of investigation will usually need to be higher to satisfy the law. For this reason, sites which already have documentation of geotechnical investigation can be appealing to developers, as they know that the sites are safe to build on. Geotechnical investigation may also be recommended to people who are considering the purchase of real estate during the phase of the transaction in which the property is inspected, so that if there is a serious problem with the site, people can cancel the deal.
A number of companies offer geotechnical services, and in large communities, there may be several options. People with complex or unique projects may want to work with geotechnical consultants who have experience with that type of project and the local terrain, so that they can get an assessment tailored to their intended use.