Research On The Calculation Methods And Major Parameters On CO₂Emission During The Construction Of Urban Mass Transit Open-Cut Station

Urban mass transit engineering is one of the most important facilities in urban transit service system, a large amount of resources and energy are demanded during its construction and operating processes, with massive solid waste and greenhouse gas produced. Greenhouse gas contributes greatly to global warming though it’s free from the category of pollutants.Energy-saving and emission-reduction has now become a major goal of China, thus a comprehensive development of urban mass transit is in urgent need. Efforts have been made on reducing the greenhouse gas emission within the operating period of urban mass transit, while specific researches on the construction period is somewhat lagging.Some research has shown that energy consumption and waste amount in the construction period might make up25%or more of the entire life cycle, so due attention should be paid to emission of urban mass transit’s construction period. Based on the analysis mentioned above, this thesis has done research in following ares:1.Comparison of CO2emission’s computing models in civil construction projects in China and abroad such as bridge engineering and building engineering. This includes identifying characteristics of different methods and feasibility, then choosing the most suitable computing model that is in line with the urban mass transit’s features.2. Based on the life-circle-assessment theory and construction features of the open-cut metro station, this thesis has systemized construction methodologies of each sub-project in the construction process. In line with quote, a top-down framework analysis including unit-project/sub-project/sub-branch project/subdivision project/element items were completed. Furthermore, a CO2emission computing model, inventory database of construction-related labor, material and machines’consumption has been established. Applying quote’s computing model in CO2emission, a CO2emission quote for the open-cut metro station has been established to calculate CO2emissions of each sub-project.3. Using computing model mentioned above to calculate overall CO2emissions of a standard open-cut metro station. Comparison of emission amounts of discrimination in particular stages. Identifying major sources of emissions and analyzing the reasons for this distribution.4. Several controlling factors in the planning period were selected to quantify their impact on CO2emissions of each major step (major structure, envelopment, groundwork). Fundamental factors being station depth and width were finally chosen to conduct the parameter sensibility analysis. Particular designs and calculations were carried out on major structure and groundwork to identify their impact on CO2emission. Several rules were deduced and flexible advice of optimal construction was given.A couple of controlling indicator in planning period was selected to quantify their impact on CO2emission of major step (major structure, envelopment, groundwork)when they vary within a certain range. Embed depth and station’s width are finally chosen to conduct the parameter sensibility analysis to identify those two factors’impact on CO2emission of major structure、envelopment and groundwork. Several rule was deduced and flexible advice of optimal construction was given.