不同类型铁路桥梁建造碳排放及环境影响OA

[Objective]Few studies have conducted quantitative analyses of carbon emissions and environmental impacts in railway bridge construction.[Methods]Based on the carbon emission factor method and the environmental impact factor method,a quantitative calculation method for carbon emissions and environmental impacts of railway bridges was developed,and commonly used railway beam bridges and suspension bridges were analyzed as case studies.The study aims to provide support for reducing pollution and carbon emissions in railway bridge construction.[Results]The results showed that although the suspension bridge was shorter than the beam bridge,its height was 20 times that of the beam bridge.The consumption of construction materials and energy exceeded that of the beam bridge,and the total carbon emissions from constructing the suspension bridge were about 5 times those of the beam bridge.The proportion of indirect carbon emissions generated from the production and processing of construction materials was relatively high for both suspension and beam bridges,with steel and cement being the largest contributors.Carbon emissions from suspension bridge construction accounted for 21.64%of the total carbon emissions,of which the direct carbon emissions from fuel consumption were 2.13×107 kgCO2 eq,about 10 times those of the beam bridge.The superstructure and substructure of the suspension bridge contributed 90%to the seven selected environmental impact indicators,while the main structure of the beam bridge contributed significantly to all environmental impact indicators except for ozone depletion potential(ODP).The indirect environmental impacts from the production and processing of steel,cement,and aggregates were substantial,particularly regarding abiotic depletion potential of fossil fuels(ADP Fossil),global warming potential(GWP),and acidification potential(AP).Direct environmental impacts from fuel consumption during bridge construction mainly included GWP,AP,and photochemical ozone creation potential(POCP).Due to the low contents of N,P,halogens,and metal elements in the energy consumed during construction,Eutrophication potential(EP),ODP,and abiotic depletion potential of elements(ADP Elements)were low.[Conclusion]Therefore,the use of green and low-carbon construction materials,especially recycled steel,industrial waste cement,and the reuse of tunnel slag,can reduce the indirect carbon emissions and environmental impacts of railway bridges.Adopting electrically powered construction equipment and utilizing renewable energy,particularly for suspension bridges,not only reduces carbon emissions but also lowers direct environmental impacts and improves the environmental quality of high-altitude and semi-enclosed construction sites,which is an important measure for reducing pollution and carbon emissions in bridge construction.