Research on carbon emission quantification and evaluation for prefabricated inverted arch construction in drill and blast tunnels

Drill and blast methods cannot meet the requirements of modern tunnel construction in terms of efficiency and carbon emissions. This study proposes a prefabricated inverted arch construction technology and carbon emission calculation method applicable to drill and blast tunnels. The carbon emissions during prefabricated inverted arch construction were calculated, and the carbon emission model for on-site transportation was optimized. The indirect impact of improved construction efficiency on carbon emissions was discussed, further refining the carbon emission evaluation system for drill and blast tunnels. The results show that (1) The new technology of prefabricated inverted arch significantly improves construction efficiency and has promising application prospects; (2) Carbon emissions during prefabricated inverted arch construction are 9051.67 tCO2eq less than those during cast-in-place construction, with a reduction of over 15%, mainly due to reduced cement and steel usage resulting from optimized arch structure; (3) Considering the limitations of material transportation due to tunnel excavation distance, the carbon emission model for on-site transportation is optimized, resulting in a reduction of 35%-56% in on-site transportation emissions; (4) Incorporating the indirect impact of improved construction efficiency on carbon emissions into the calculation model, this indirect effect accounts for approximately 70% of the total emission reduction achieved by the prefabricated inverted arch technology.