Geotechnical drilling is drilling which is often related to the construction of a structure such as a building or an oil rig. It can be part of the construction process as well as part of the investigation process conducted on site before the structure is built. This process is usually performed by a firm which specializes in providing geotechnical drilling services, under the supervision of a geotechnical engineer who remains present to make sure that the drilling meets the needs of the project. Such firms may also offer other drilling services, depending on their size and where they are located.
One common reason for geotechnical drilling is site investigation. Site investigation is conducted to determine whether or not a site will be suitable for construction. It includes drilling to remove rock and soil samples, along with drilling to evaluate soil stability and other topics of interest. In the case of an oil rig, the drilling can also include investigation to find out more about the quality of the oil and where it is located.
Site investigation is critical for large structures. Unsafe soil or rock conditions may lead to structural collapse, or could create a dangerous situation in an earthquake or flood. The law often requires that a site be investigated for safety before permits to build will be issued, and that ongoing safety monitoring occur to detect any changes or signs of developing problems which could pose a threat to the development.
As part of the construction process, geotechnical drilling includes drilling to prepare for foundations, caissons, and various supports. Drilling of this kind is overseen by an engineer who confirms the placement of the drill and makes sure that the drilling is conducted properly. Sinking a hole in the wrong place or drilling improperly can create problems which may lead to delays.
Geotechnical exploration in searches for deposits of oil, gas, minerals, and other things of value inside the Earth may also utilize geotechnical drilling. Drilling is used to take core samples and to gather data about the site. It is also used by scientists who want to learn more about the Earth, and to take samples such as ice cores in regions like the poles. Ice cores can be a fascinating record of the Earth's climate history, preserved neatly on ice for the convenience of scientists who are interested in climate topics. In this case, geotechnical drilling may be performed by a company which specializes in scientific drilling applications, rather than drilling for construction.