1 Introduction 1.1 Current Development Status of Long Shield Tunnels 1.1.1 The Origin of Shield Tunnels and Their Development Abroad 1.1.2 The Development of Shield Tunnels in China 1.1.3 The Development Trend of Long Shield Tunnels 1.2 Development Status of Shield Tunnel Section Air Shaft and Station Passing Construction Methods 1.2.1 Development Status of Interval Air Shaft Construction 1.2.2 Development Status of Construction Methods for Interval Air Shaft Passing Through Stations 1.3 Current Application Status of Ultra-deep Circular Foundation Pits at Home and Abroad 1.3.1 Development Status of Circular Deep Foundation Pits 1.3.2 Characteristics and Development Trends of Circular Foundation Pit Technology 1.4 Based on the Background of the Engineering Project and the Main Risks of Large-Diameter Shield Tunnel Crossing Circular Air Shafts 1.4.1 Based on the Background of the Engineering Project 1.4.2 Main Risks of Large-Diameter Shield Tunnel Crossing Circular Air Shafts References 2 Construction Technology of Retaining System for Ultra-deep Circular Air Shaft Foundation Pit in Sensitive Environment Adjacent to River 2.1 Key Technical Issues 2.1.1 High Risk of Foundation Pit Dewatering in Sensitive Environments Near the River 2.1.2 Difficulty in Reinforcement Construction of Ultra-deep Rotary Jet Grouting Piles 2.1.3 Difficulty in Controlling the Construction Quality of Connecting Walls in Ultra-deep Circular Foundation Pits 2.2 Construction Technology of "Pumping Reinjection" for Ultra-deep Circular Air Well in Sensitive Environment of Linjiang 2.2.1 Theoretical Study on "Pumping and Reinjection" of Foundation Pit 2.2.2 Construction Technology of "Pumping and Reinjection" for Foundation Pits 2.2.3 Quality Control of "Pumping and Reinjection" Construction in Foundation Pits 2.3 High-Pressure Rotary Jet Grouting Reinforcement Construction Technology for Ultra-deep Circular Air Shaft in Sensitive Environment of Linjiang 2.3.1 Theoretical Study on Grouting Reinforcement 2.3.2 On-Site Pile Testing 2.3.3 High-Pressure Rotary Jet Grouting Reinforcement Construction Technology 2.3.4 Quality Control of High-Pressure Rotary Jet Grouting Reinforcement Construction 2.3.5 Quality Inspection of High-Pressure Rotary Jet Grouting Reinforcement Construction 2.4 Construction Technology of Cutting Ground Wall for Ultra-deep Circular Air Shaft in Sensitive Environment of Linjiang 2.4.1 Feasibility Study on Machinable Ground Wall Connection 2.4.2 Slot Width Connection Technology 2.4.3 Construction Technology of Machinable Ground Wall References 3 Underwater Excavation and Underwater Mass Concrete Sealing Construction Technology for Circular Air Shaft 3.1 Key Technical Issues 3.1.1 Difficulty in Underwater Excavation of Ultra-deep Circular Air Shafts 4.2 Adaptability Improvement Technology for Shield Tunneling Machines 4.2.1 Introduction to the Shield Tunneling Machine for Weisan Road Crossing the River Channel 4.2.2 Configuration of Cutting Tools for the Front Cutterhead of Shield Tunneling Machine Passing Through Meizizhou Air Shaft 4.2.3 Optimization of Cutting Tools Before Shield Tunneling Machine Passes Through Meizizhou Air Shaft 4.3 Comparison and Selection of Construction Schemes for Shield Tunneling Machine Passing Through Meizizhou Air Shaft 4.3.1 Construction Plan I for Shield Machine Crossing Meizizhou Air Shaft 4.3.2 Construction Plan n for Shield Machine Crossing Meizizhou Air Shaft 4.3.3 Comparison and Analysis of Construction Schemes for Shield Machine Crossing Meizizhou Air Shaft 4.4 Optimization Analysis of the Strength of Plain Concrete During Shield Tunneling 4.5 Construction Technology of Shield Tunneling Machine Passing Through Meizizhou Air Shaft 4.5.1 Shield Tunneling Through Meizizhou Air Shaft Excavation Process 4.5.2 Key Control Technologies for Shield Tunneling Through Meizizhou Air Shaft 4.5.3 Backfilling Chiseling and Pipe Segment Removal 4.6 Construction Quality and Safety Assurance Measures 4.6.1 Quality Assurance Measures for Shield Tunneling 4.6.2 Safety Measures for Shield TUnneling References 5 Stability Control Technology for Meizizhou Air Shaft During Process Conversion 5.1 Key Technical Issues 5.2 Numerical Simulation of the Process Transformation of Meizizhou Air Shaft 5.2.1 Overview of Meizizhou Air Well Project 5.2.2 Calculation Using Parameters 5.2.3 Construction Analysis Process 5.2.4 Calculation Results of Force on the Air Shaft Structure 5.3 Air Shaft Stability Control Technology References 6 On-Site Monitoring and Data Analysis 6.1 Monitoring Point Distribution Settings 6.2 Monitoring Items 6.2.1 Deformation of the Enclosure Structure 6.2.2 Internal Force of the Enclosure Structure 6.3 Monitoring Requirements 6.3.1 Monitoring Frequency Requirements 6.3.2 Monitoring and Alarm Requirements 6.4 Analysis of Monitoring Results 6.4.1 Deformation Analysis of Enclosure Structure 6.4.2 Stress Analysis of Enclosure Structure 6.5 Comparative Analysis of Monitoring and Numerical Calculation Results 6.6 Monitoring Conclusion Reference 7 Summary and Outlook
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