Research On Circumferential Reliability Of Shield Lining Based On Modified Routine Method Theory

In recent years,with the continuous development of urban underground space,the construction of underground tunnels has been increasing.As a safe,reliable,and efficient construction method,the shield construction method has played an important role in the construction of urban subways.As an important component of the lining ring of a shield tunnel,the segment is subjected to the pressure of surrounding rocks for a long time.The study of the reliability of its bearing performance is a key scientific and technical issue related to engineering safety.Segment joints,as the weak link of segment joints,have a decisive effect on the bearing performance of the entire shield lining ring.So whether to consider the discontinuities of segment stiffness is the theoretical standard for segment design.In this thesis,the shield tunnel in the subway section between Changqingqiao Station and Hunnan Avenue Station of Line 10 of Shenyang Metro is used as the research background.The influence of the stiffness of the high-strength bolt rotating spring at the segment joint position on the inward force of the entire lining is analyzed.Based on the reliability theory,it further analyzes its influence on the reliability of segment ring load carrying capacity.Based on this,a shield segment ring stability reliability evaluation system is established to provide theoretical guidance for similar practical projects.The research content is as follows:1.Calculate the surrounding rock pressure based on the statistical characteristic values of the survey indicators of the Shenyang Metro Line 10 actual engineering geological rock,and use the homogeneous ring method to calculate the ring inward force value of the shield segment,and obtain the peak moment of the segment.On the basis of this,the reinforcement calculation of the existing segment is carried out to verify the credibility of the theoretical analysis by comparing with the actual engineering.2.By using the method of rotating spring,the step property of the bending moment at the joint of the pipe piece was analyzed,and the bending moment of the pipe piece joint was transferred to the circumferential adjacent pipe piece.According to this method,the toroidal distribution of bending moment is obtained,which was further compared with the calculation result of the mean ring method,and the influence of the stiffness of the pipe piece joint on the internal force of the lining ring was discussed.In order to verify the scientificity of the theoretical calculations based on the homogeneous circle method and the k-? method,a non-linear finite element comparative analysis was carried out using ABAQUS software.3.Based on the reference statistics of subway engineering geological survey data in Shenyang area,geometric parameters of shield segments,concrete strength grades,steel bar spacing,steel bar strength,and stiffness of segment rotating springs,the reference statistics of soil layer parameters,surrounding rock pressure,steel bar strength,and rotary spring stiffness were obtained.On this basis,the bending moments of the shield lining buried in silty clay,cobbles and considering homogeneous strata to were analyzed to explore the surrounding rock parameters sensitive to the influence of segment internal forces.4.Reliability theory was used to check the circumferential reliability index of shield segments,which include the amount of reinforcement required for the maximum circumferential bending moment of the shield segment and the actual amount of reinforential under the homogeneous ring method and the rotaing spring metod,and establish a reliability evaluation system.It realizes the probability of diseases such as staggered seams and water leakage in actual engineering from the perpective of reliability theory,thereby providing theoretical guidance for similar projects.