Subway tunnel structure safety assessment method based on external project additional stress

Abstract

The invention discloses a subway tunnel structure safety assessment method based on external project additional stress, and the method comprises the following steps: calculating the additional stress of a tunnel structure by adopting a corner point method according to the load action position of an external operation project and the spatial position relation of the external operation project and the subway tunnel structure; calculating an initial load of a tunnel structure according to tunnel investigation and design data; and establishing a tunnel load-structure model under the additional stress action of the external operation project. According to the method, additional stress generated on a tunnel structure under the load action of an external operation project is applied to a tunnel load-structure model, and the influence of the external operation project on the safety of the tunnel structure is evaluated through structural mechanics calculation.

Description

technical field [0001] The invention belongs to the technical field of subway tunnel safety evaluation, in particular to a subway tunnel structure safety evaluation method based on the additional stress of external projects. Background technique [0002] In recent years, with the improvement of the land development intensity along the subway lines, the security situation of the subway safety protection areas has become more and more severe. Since 2005, my country has implemented the "Urban Rail Transit Operation Management Measures", which stipulates the scope, external operation types and Corresponding legal responsibilities, and the "Technical Specifications for Safety Protection of Urban Rail Transit Structures" has been implemented since 2014, which further clarified the impact level and control protection requirements of various operations, and stipulated the safety control indicators and various monitoring regulations of urban rail transit structures. etc.; local governm...

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Problems solved by technology

[0004] The finite element method refers to the establishment of a three-dimensional finite element model of the stratum-external operation project-subway tunnel structure by analyzing the drawings and materials of the project survey, foundation pit support, building structure and existing subway structure, and simulates the impact of the project construction process on the deformation of the tunnel structure, Under the influence of force, further evaluate the safety of the subway tunnel structure. This method can realize the quantitative evaluation of the impact of the project on the safety of the subway tunnel structure. However, due to the uniqueness of the project, one model can only analyze one project, and other similar projects need to be remodeled For calculation, the modeling of the 3D stratum-structure finite element model is complicated, the model volume is large, the convergence is not good, and the calculation efficiency is low; in addition, due to the different professional levels of the modelers, the selection of stratum physical and mechanical parameters varies, and the calculation results have certain differences. randomness, the reliability of the assessment conclusions is also open to question

[0005] The fuzzy comprehensive evaluation method refers to evaluating the safety of the subway structure by establishing a hierarchical-fuzzy comprehensive evaluation model. The structural safety evaluation index system uses the product scale method to analyze and determine the weight of the evaluation index, divides the classification evaluation standard, combines the calculation of the degree of membership, and adopts multi-level fuzzy comprehensive evaluation to obtain the impact level of the construction of the external operation project on the safety status of the subway structure, which is relatively limited This method is not affected by the uniqueness of the project. It can not only realize the impact of this project on the structural safety of subway tunnels, but also can be extended to other similar operation projects. However, the establishment of the evaluation system and the weight analysis of indicators for this method are subjective. Judgment, and many evaluation indicators such as construction schemes, hydrogeological conditions, etc. cannot be quantified and can only be set through experience. Lack of rationality, scientificity, or even contrary to reality, and poor verifiability of evaluation results

[0006] The analytical method considers the tunnel-stratum as a one-dimensional elastic foundation beam model, and obtains the additional vertical displacement of the tunnel beam structure by applying additional stress of the external operation project. This method can realize the quantitative evaluation of the impact of the project on the safety of the subway tunnel structure , and is not affected by the uniqueness of the project, it can also be extended to other similar projects, but this method is complex to solve the deflection differential equation, the calculation volume is large, and it requires high mechanical and mathematical skills for engineers. In addition, this method is based on one-dimensional The beam-spring model can only obtain the longitudinal displacement and curvature of the tunnel, but the tunnel deformation is three-dimensional. This method cannot directly obtain the tunnel’s lateral convergence deformation, tunnel structure internal force and other indicators, and the evaluation indicators are not comprehensive and systematic.

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