Carbon Footprints of Ground Improvement Techniques - Case Studies

Geotechnical projects generally consume large quantities of resources and energy and release considerable amounts of CO2 in the atmosphere, and therefore, have a significant impact on the environment. To minimize this effect, sustainable solutions and materials have been proposed and adopted in the literature and practice as alternatives to conventional methods wherever applicable. This study reviews and discusses sustainability in geotechnical engineering, in particular, three ground improvement techniques including deep soil mixing (DSM), dynamic compaction, and vibro replacement (VR) compared to the piling method. Three case study projects in Saudi, Egypt, and the UAE were selected for this comparison. Some eco-friendly recommendations are proposed to mitigate the environmental loads of the discussed ground improvement techniques. Moreover, carbon footprints of three case study projects, each with three alternative solutions (i.e., piling, DSM, and VR), are assessed and compared in two conditions, namely, with and without eco-friendly measures (i.e., substituting new materials with recycled or recovered construction materials or with the by-products of other industries). In the studied cases, the CO2 discharge amounts of DSM and VR were found to be around half and one-tenth of that amount in piling. The CO2 emissions of all three products showed a significant decrease when adopting the eco-measures, averagely, 34, 60, and 14% for piling, DSM, and VR, respectively. Finally, the CO2 emissions of the above cases are presented in functional units.