Influence Of Large Diameter Pipe Jacking Construction On The Surrounding Environment Under Complex Conditions

This thesis relies on the one Pipe jacking Project.Through the combination of theoretical analysis,experimental research,numerical analysis and field measurement,the influence of large diameter pipe jacking construction in complex environments on surrounding soil and adjacent structures is analyzed,and the influence of key parameters on surrounding soil is summarized during pipe jacking construction.The related research can provide technical support for the pipe jacking control in this area in the future.The main work and achievements of this thesis are as follows:(1)The principle and mechanism of the mud of the pipe jacking are explained systematically.Through experimental studies,the specific gravity,funnel viscosity,absolute viscosity,water release rate and filtrate loss of bentonite slurry were determined.The mud parameters determined by this project can be used for reference in future similar geological conditions and a certain range of requirements for the performance requirements of slurry is also put forward.(2)Using the finite element analysis software ABAQUS to simulate different working conditions in the construction process of the pipe jacking,analysis of the impact of different parameters under the law of the surrounding environment.The analysis shows that: Under the condition of buried depth of 8m,soil bulges occurred at about 1.5D in front of the machine head;the settlement gradually stabilized at about 2.5D behind the machine tail;subsidence is larger in the 3D cross section;friction resistance has a great influence on the settlement after the machine and the support pressure has a great influence on the front of the machine head.(3)During large diameter pipe jacking construction,field measurement of surrounding soil mass,nearby wall and power pipelines was carried out,and construction state can be timely feedbacked.Measured results can be used to modify the control parameters of pipe jacking,optimize the construction technology,and achieve information construction of project safety.Through the field measurement,it is found that the maximum of the ground surface heave in the machine head on the axis of the pipe jacking is 5mm while the maximum of the ground surface settlement in the machine rear is 34 mm,and it tends to be stable about 15 m around the rear.The wall settlement is about 6-7mm and its maximum inclination is 0.48%.The maximum heave and settlement of the power pipelines are between-4-2mm.It can be concluded that large-diameter pipe jacking construction has less impact on the surrounding environment.By comparing the measured data with the results of numerical simulation,we can verify the reliability of the data.On the basis of theoretical analysis and numerical simulation,combined with experimental study on engineering bentonite slurry and actual measured data analysis,influence of large diameter pipe jacking construction on the surrounding environment under complex conditions is studied.However,Later settlement of the pipe jacking and the model test are not involved in this study which are considered necessary to be further investigated.