Environmental impacts of drilled shafts in sand

Abstract

Geotechnical constructions involve consumption of a vast amount of non-renewable natural resources and energy- and carbon dioxide-intensive materials (e.g. cement and steel) that contribute significantly to global warming and climate change. This paper uses drilled shafts as an example to illustrate the importance of environmental impact assessment in the design phase of foundations. Life-cycle assessment (LCA) is used to quantify the environmental impacts of construction of single drilled shafts and groups embedded in sandy soil profiles. Parametric studies are conducted to investigate the effects of soil properties, design parameters and hauling distances of construction materials and equipment on the environmental impacts of single drilled shafts. For pile groups, different configurations, applied load, centre-to-centre spacing and thickness of pile cap are considered in the parametric study. The global warming impact and human toxicity of a typical drilled shaft are found to be 39 and 486% of annual world impact per person, respectively. Based on the study, charts and tables are developed that may be used for quick estimation of the global warming impact of drilled shafts without the use of specialised LCA software programs.