This book introduces the research background and significance of carbon emissions in the tunnel industry and systematically reviewed the research progresses of carbon emission researches for tunnels， LCA （life cycle assessment） research framework， and uncertainty research progress. The authors propose a novel modular carbon emission calculation method for highway tunnel construction and expounds on the modular LCA system boundary theory of tunnel construction. This method does not require abundant knowledge of LCA modeling， which is convenient for general engineering and technical personnel to calculate the carbon emission level of tunnel construction.
　　The calculation formulas for input and carbon emissions of each module arc provided. It also analyzes the parameter uncertainty， model uncertainty， and scenario u uncertainty of the carbon emissions from tunnel construction by the Monte Carlo method. Further， this book proposes the fitting model of carbon emissions of unit engineering quantity in tunnel construction， which benefits to simplify the calculation of carbon emissions.
　　This book is mainly aimed at engineering and technical personnel in the construction industry， especially tunnel and underground engineering， including tunnel design engineers; tunnel construction engineers， experts， and scholars; tunnel owners; management departments.

　　A tunnel is a transportation facility buried in the ground. Surrounding rock conditions are the critical basis for tunnel design and essential variables that affect carbon emissions from tunnel construction. The complex and changeable surrounding rock conditions require different design schemes， resulting in different tunnel construction emission levels. With surrounding rock conditions taken into consideration， this book is striving to establish accurate calculation models to analyze the carbon emission hotspots for tunnel construction and clarify differences in tunnel construction carbon emissions under different design parameters. Also， the tunnel's emission reduction potentials under changes in design parameters and emission factors are explored， which can provide scientific theoretical support for low-carbon design and scientific emission reduction in China's tunnel industry.
　　This book is mainly available to the engineering and technical personnel in the construction industry， especially tunnel and underground engineering， involving design engineers， construction engineers， scholars， tunnel owners， management departments.

1 Introduction
1．1 Research Background and Significance
1．1．1 China's Emission Reduction Targets and Actions
1．1．2 The Development Status of Highway Tunnel Industry in China
1．1．3 Research Backgrounds of the Tunnel Emission Reduction
1．2 Research Status and Review
1．2．1 Research Progress on Carbon Emissions from Tunnels
1．2．2 LCA Framework for the Carbon Emissions of Tunnels
1．2．3 Research Progress on LCA Uncertainty
1．3 Existing Problems
1．4 Main Research Content
References

2 Carbon Emission Quantification Theory and Modular LCA Method
2．1 Introduction
2．2 Basic Knowledge of Carbon Emissions
2．2．1 Greenhouse Gases
2．2．2 Carbon Exchange Pathway
2．3 Basic Methods for Quantifying Carbon Emissions
2．3．1 Direct Measurement Method
2．3．2 The Process Analysis Method
2．3．3 The Input-Output Method
2．3．4 The Hybrid Method
2．4 Overview of LCA
2．4．1 Objectives and Steps
2．4．2 Functional Unit and Reference Flow
2．4．3 Product System and Unit Process
2．4．4 System Boundary
2．4．5 Data Collection and Calculation
2．4．6 Environmental Effects and Assessment Methods
2．4．7 Main Features of LCA
2．5 Overview of Product Modularization
2．5．1 Concept of Modularization
2．5．2 Modular LCA Method
2．6 Conclusions
References

3 Carbon Emission Prediction Method for Tunnel Construction
3．1 Introduction
3．2 Method
3．2．1 Potential Factors Affecting Tunnel Construction Emissions
3．2．2 Overview of the Tunnels
3．2．3 Calculation Method for Tunnel Construction Emissions
3．2．4 Common Prediction Models
3．2．5 Data Analysis Method
3．3 Results
3．3．1 Carbon Emissions of Tunnel Construction
3．3．2 Factors Influencing Carbon Emissions from Tunnel Construction
3．3．3 Models Predicting Carbon Emissions from Tunnel Construction
3．4 Discussion
3．5 Conclusions
References
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4 A Modular Calculation Method for the Carbon Emissions of Highway Tunnel Construction Based on the Chinese Standard Quota
5 Uncertainty Analysis of Carbon Emissions from Highway Tunnel Construction
6 Carbon Emission Transition of Highway Tunnel Construction
7 Influence of Tunnel Lining Design Parameters on Construction Carbon Emissions
8 Carbon Emission Characteristics of Inclined Shaft Construction in Highway Tunnel