A Calculation Method for Segment Heterogeneous Equivalent Beam Element Model Structure of Shield Tunnel

Abstract

The invention discloses a shield tunnel segment non-homogeneous equivalent beam element model structural calculation method. The method includes the steps that firstly, basic data are collected, a routine method model is established, calculation is carried out, and the values of internal force of the section of each joint is extracted; secondly, equivalent section mechanical parameters are calculated; thirdly, a non-homogeneous equivalent beam element model is established, and structural calculation is carried out; fourthly, equivalent section parameters are calculated again; fifthly, the equivalent section mechanical parameters input in the third step are compared with the section mechanical parameters output in the fourth step, whether the comparison result meets error precision requirements or not is judged, and if not, the third step is executed, iterative calculation is carried out again, and the third step, the fourth step and the fifth step are repeated. The calculation model adopted in the method is more approximate to the truth, and calculation results are more accurate.

Description

Technical field: [0001] The invention relates to a calculation method for a shield tunnel segment structure, in particular to a calculation method for a shield tunnel segment heterogeneous equivalent beam unit model structure. Background technique: [0002] During the design, construction and operation of shield tunnels, how to calculate the internal force of shield tunnel segment structures is a current research hotspot and difficulty. In recent decades, with the large-scale development of urban rail transit, the calculation model research for shield tunnel segment structure has made great progress and progress, including homogeneous ring model, equivalent stiffness ring model, A variety of computational structural models including free-hinged ring model, beam-spring model and beam-joint model. However, due to the complexity of the structure itself and the environment in which it exists, there are still some deficiencies and defects in several models currently used in the ...

AI Technical Summary

Problems solved by technology

However, due to the complexity of the structure itself and the environment in which it exists, there are still some deficiencies and defects in several models currently used in the structural mechanical calculation of shield tunnel segments. For example, the homogeneous ring model completely ignores the The impact of the piece joint is obviously inconsistent with the actual situation, resulting in the calculation of the internal force of the hard formation is too large, resulting in waste; the deformation of the soft formation is too small, resulting in increased safety risks

However, the modified customary model itself is still reflected by artificially reducing the stiffness of the entire segment ring joint and the increase coefficient of the bending moment, which has greater randomness and uncertainty; the free hinge ring model regards the joint as a single hinge structure , not only does not reflect the cross-sectional force transmission properties of the joint, but also it is a statically indeterminate system, which can only be solved statically with the help of the support of the tunnel surrounding rock, and there is still no exact and reliable calculation parameter for the support force of the tunnel surrounding rock, so This model also has great limitations and uncertainties; the beam-spring and beam-joint models can better reflect the influence of segment joints on the stiffness of the entire ring structure, but there is still no mature theoretical basis for obtaining the spring coefficient , most of them need to be set through specific experiments or engineering experience, and the calculation results inevitably have certain arbitrariness

[0003] The Chinese Invention Patent Publication No. CN101364241A discloses the calculation method of the continuous-non-uniform stiffness model structure of the shield tunnel lining. When dealing with the equivalent stiffness of the segment joints, only one comprehensive equivalent stiffness coefficient obtained through the back calculation of the joint rotation angle is used, and The equivalent of the height and width of the compression zone of the equivalent beam unit, the equivalence of the elastic modulus of the material and its actual stress state are not considered separately. In fact, these three and the equivalent stiffness are closely related to the actual stress state of the segment structure. And the relationship between the three is not a linear change, so the comprehensive equivalent stiffness coefficient is still not enough to characterize the actual stress state of the joint and reflect the stiffness of the joint.

[0004] It can be seen that although the vast number of scientific and technological workers have done a lot of research work on the calculation of the internal force of the shield tunnel segment structure and achieved rich results, there are still many difficult problems that need further extensive research

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