Study On The Large-diameter Slurry Shield Tunnelling-induced Settlement In Water-rich Sandy Cobble Ground

The subject of this paper has important engineering significance, because lessrelevant theories at present can be guided in the research of ground deformation causedby large diameter slurry shield machine in center of big cities. The subject of this paperis based on the Beijing railway terminal project of Beijing Railway Station to BeijingWest Railway Station Zhijingxian Project. The reasons of ground deformation causedby large diameter slurry shield machine in the area of water sandy pebble stratum arediscussed in the following aspects:The first chapter, giving an introduction on the development history of slurryshield machine, working principle and construction characteristics, stratum deformationresearch in shield construction method at home and abroad, the engineering backgroundand engineering significance of this paper, research aim and main contents, researchmethods and technical route, etc.The second chapter, giving an introduction on the engineering characteristics andspatial distribution of sand pebble stratum in Beijing railway Zhijingxian project, andmaking a detailed analysis on the reasons and principles of ground surface deformationand surrounding rock deformation caused by slurry shield construction. At last, carry ona detailed discussion and analysis on surface transverse, longitudinal settlement andsettlement duration rule caused by slurry shield construction.The third chapter, making a research on the mud pressure setting and tunnelingparameters selection constructed by large diameter slurry shield machine. The factorswhich make impacts on the stability of machine excavation face is introduced in thispaper, and support pressure of computing and setting methods in slurry shield tunnelexcavation face are discussed in details. Making a research in detail on shield thrust,cutter head torque, driving speed and other parameters which should pay attentionduring shield construction process in this paper. At the same time, making a simpleintroduction on engineering division and actual excavation parameters in Beijingunderground railway project Zhijingxian Railway Project.The fourth chapter, making an experiment research on the parameters for largediameter slurry shield tunneling engineering. Making an introduction on engineeringsite design methods and development of test section in Beijing railway Zhijingxian Project. Making an exploration and analysis on the construction parameter settingproblems and influence on surface subsidence in sandy pebble stratum during shieldconstruction. Practical suggestions are given from the view of practice argumentationand correct theoretical attention on aspects of slurry parameters synchronous groutingparameters, thrust, torque and driving speed.The fifth chapter, making a research on slurry shield tunneling surface subsidencenumerical simulation for large diameter slurry shield. The three-dimensional finitedifference software FLAC3D is adopted to make sensitivity analyses on the threeparameters: slurry supporting pressure, synchronous grouting and excavating speed byslurry shield in sandy pebble stratum. In this paper, making discusses on the surfacedeformation law in different construction parameters configuration cases, meaningfulSuggestions and predictions are put forward for the subsequent railway construction.Finally, the sixth chapter, making a complete and simple summary on the aboveresearch results, introducing the engineering significance of research achievements forslurry shield construction in sandy pebble stratum, and giving a clear direction andSuggestion for further research.