Site excavation is a process in which soil, rock, and other materials are removed from a site, typically with the use of heavy earthmoving equipment such as excavators and bulldozers. There are a number of reasons to conduct an excavation of a site, ranging from a desire to explore a site to learn more about its archaeological history to an environmental remediation project. Depending on the purpose of a site excavation, it may be conducted and supervised by various professionals.
During new construction on buildings, roads, and other structures, site excavation is one of the earliest stages. The site is excavated to create a level, clean area to work, with the foundations being established in the excavated area. A site may also be excavated and backfilled to confirm that the material directly under the site is of high quality. The depth of site excavation can vary, depending on what is being built and where the building is occurring.
Archaeological excavation involves the painstaking removal of material in layers, with material being sifted and carefully examined for objects of historical interest. Excavation can be used to uncover structures which have been buried over time, to examine burial sites, to look through former settlements, and in many other types of archaeological and paleontological activities. Additionally, before building excavation can begin in some regions of the world, an archaeological investigation may be required to confirm that building will not damage or compromise material of archaeological importance, to remove material of archaeological interest, or to comply with laws surrounding native and historic burial sites.
Environmental remediation can also involve site excavation. If soil is contaminated, it may be necessary to remove it and backfill with clean soil. The excavated soil can be disposed of in a facility which handles contaminated materials. Excavation can also be used to prepare a site for sequestration of contaminated materials, with the excavation being outfitted with liners to prevent seepage.
Some construction firms specialize in site excavation. These firms have an assortment of specialized equipment and crews which can handle a wide variety of types of excavations, dealing with everything from construction supports to prevent collapse of side walls to organizing the safe removal of excavated material. Hiring such a firm usually ensures that the excavation is conducted safely and competently, reducing the risk of problems at the site in the future. For archaeological excavation of proposed building sites, specialized firms provide archaeology consulting services including excavation and site evaluation.