Analysis And Control For Damage And Dislocation Of Single-shield TBM Tunnel Segment

In the construction of TBM tunnels,because the tunnel lining segments are assembled using prefabricated blocks,the joints between the prefabricated blocks during construction are prone to damages and faults,which can lead to leakage of water and other problems.Affect the construction quality of subway tunnels and the operation safety in the later period.Based on the TBM project of Chongqing's orbital ring line,this paper studies the mechanical response of the segment during the construction of TBM tunneling,and analyzes the occurrence and damage of the segment under the action of various construction factors.Firstly,the longitudinal stress of the segmental plate under the action of non-uniform thrust force is analyzed theoretically,and then the three-dimensional discontinuous contact model is established to study the stress and deformation characteristics of the segment under different construction factors during the construction process.The main research of this paper is as follows:1.Relying on the project,analyzes the reasons for the damage and the failure of the bench during the construction of the segment,and proposes the corresponding control measures;analyzes the longitudinal offset of the segment by theoretical analysis based on the D'Alembert's principle,and concludes that the effect of the longitudinal offset of the segment is essential.Reasons,and use theoretical analysis for actual engineering calculations.2.By using the stratum structure method,a three-dimensional discontinuous contact model was established to compare and analyze the changes in the mechanical behavior of the top piece when the top piece was assembled at different assembly points.The main research was made on the assembly point at 1 o'clock,2 o'clock,and 3 o'clock.At the 4 o'clock and 5 o'clock directions,five working conditions were obtained,and the distribution rules of the corresponding pipe misalignment and stress concentration were obtained,which provided a certain reference for the selection of assembling points in the construction.3.Consider the mechanical response of the segments under different construction load conditions during construction.Using numerical simulation methods,the deformation of the segment during the TBM excavation process was determined by analyzing the jack thrust,jack thrust angle,post-grouting pressure,filling depth of the gravel grouting layer,and buried depth.The law of force variation infers the factors that affect the damage and failure of the segment during construction.Through the theoretical analysis and finite element analysis of the mechanical behavior of the segment during the construction process,the development rule of the segment and failure of the segment is obtained,and the ambience of the segment quality control during the construction process is avoided,so as to expect the shield(TBM).In the construction of the method,the quality control of the segment plays a reference role.