With growing concerns about global warming and greenhouse gas (GHG) emissions, there is an urgent need to evaluate and reduce the carbon footprint (CF) of surface excavation (SE). CF are GHG emissions caused by an activity or event. It is expressed in terms of the amount of carbon dioxide (COR2 R), or its equivalent of other emitted GHGs. Choosing an appropriate low-carbon emission method for SE is a vital task and involves environmental concerns due to several energy-consuming activities. Since essentially, every SE impacts the environment, it becomes very important to evaluate this impact and take necessary actions to minimize any negative consequence. The objective of this paper is to present a comprehensive overview on progress acquired over the years in understanding GHG emissions from SE and to discuss the steps in CF estimation. Publications were identified that reported GHG emissions and CF of SE over past 30 years. This literature review suggests that for most of the SE, the material production phase consumes a large amount of energy and is a major contributor of GHG emissions. Early phases of project planning should include appropriate ecological decisions consistent with the life-cycle assessment (LCA) and CF considerations. Pipe material and outside diameter should be considered during the SE to allow a detailed evaluation and reduction of their environmental impacts (EI). Incorporation of additional factors, such as cost and duration of the project into the environmental analysis is also recommended.
Tunnel Deformation Behavior due to Ground Surface Excavation above the Tunnel