Sustainable Practices in Mitigating Liquefaction-Induced Foundation Settlements: A Focus on Carbon Footprint Reduction During Sheet Pile Design

The phenomenon of liquefaction-induced ground settlements has been frequently observed in several significant earthquakes, such as the 2010–2011 Canterbury Earthquake Sequence (CES) in New Zealand, the 2011 Tohoku earthquake in Japan, and the more recent 2023 Kahramanmaras Earthquake in Turkey. Various ground improvement methods have been used in engineering practice to lessen the effects of soil liquefaction at shallow depths. Those ground improvement methods signify the outflow of ozone-depleting substances and the release of greenhouse gases, resulting in global warming and consequential environmental changes. Amongst all greenhouse gases, carbon dioxide (CO2) stands as the predominant compound. In our study, we adopted the installation of sheet piles as a measure to mitigate the liquefaction-induced foundation movements. However, the carbon footprint and cost associated with the installation of full-length sheet piles can be reduced by adopting partial floating sheet piles (PFS). Nevertheless, the behavior and characteristics of PFS have not been thoroughly investigated in the existing literature, indicating a research gap in this area. To accomplish these objectives, a 1/5 scaled model, representative of a large-scale shake table test conducted by the University of Nevada, Reno (UNR), is utilized. The scaled model comprises three distinct soil layers with different relative densities: a 50% relative density top crust layer, a 30% relative density middle liquefiable layer, and an 85% relative density bottom dense layer. A shallow foundation is placed atop the crust layer, followed by the insertion of sheet piles (both full-length and PFS) at 0.625 times the foundation width (B) from the center, utilizing the press-in technique. Finally, the scaled models are subjected to harmonic input motions with amplitude and dominant frequency properly scaled based on the large-scale shake table test. The effectiveness of PFS is assessed by comparing reductions in carbon footprint, foundation movements (settlement and tilt), and generated excess pore water pressures with those achieved by full-length sheet piles. In addition, this research also contributes to raising awareness regarding the environmental impact of carbon emissions when selecting mitigation measures.