CN-121980659-A - Steel-concrete combined support stress deformation calculation method

CN121980659ACN 121980659 ACN121980659 ACN 121980659ACN-121980659-A

Abstract

The application discloses a method for calculating deformation of a steel-concrete combined support stress, and aims to solve the problem that the traditional separation calculation method ignores bearing capacity and deformation prediction errors caused by the synergistic effect of a steel-concrete interface. The method comprises the steps of constructing a coupling mechanism for synchronously analyzing the axial stress of steel and the bending load of concrete by a layered stress-strain model, establishing a bending moment calculation model for coupling foundation pit heave and horizontal displacement, dynamically deriving reinforcement requirements, carrying out radial micro-element division on a flange plate, carrying out integral solution on circumferential stress distribution under non-uniform load, integrating the output of multiple models to form a unified stress deformation response field, and carrying out dynamic re-analysis by combining the load change in the construction stage. According to the technical scheme, the bearing capacity prediction precision and the reinforcement design rationality are remarkably improved, the local stress concentration area is effectively identified, the dynamic safety assessment of the whole construction period is supported, and the engineering decision efficiency and the structure economy are improved.

Inventors

XU LEI
CHEN JIARU
YU GUANGYUAN
GAO MIAO
GU WEI

Assignees

上海建工一建集团有限公司

Dates

Publication Date: 20260505
Application Date: 20260205

Claims (10)

1. The steel-concrete combined support stress deformation calculation method is characterized by comprising the following steps of: step 1, constructing a whole member bearing capacity calculation model, and synchronously analyzing a synergistic mechanism of steel axial stress and concrete bending resistance bearing through a layering stress and strain relation; step 2, a foundation pit deformation and bending moment coupling calculation model is established, foundation pit heave deformation and horizontal displacement data are used as boundary conditions to be input, and the internal bending moment distribution of the supporting member and the corresponding reinforcement requirement are dynamically deduced; step 3, carrying out refined analysis on the stress of the flange, carrying out infinitesimal division on the circular flange along the radial direction, and solving the circumferential stress distribution under the action of non-uniform load based on the integral of circumferential balance conditions; And 4, integrating the output results of the models to form a unified stress deformation response field, and carrying out dynamic re-analysis according to the load change at the construction stage to output the stress state and the deformation trend of each key section.
2. The method for calculating the deformation of the steel-concrete combined support stress according to claim 1, wherein in the step 1, a continuous medium assumption is adopted at an interface of steel and concrete, mechanical behaviors of the steel and the concrete in an elastic stage and a plastic stage are respectively described by setting a material constitutive relation, a plurality of calculation layers are divided according to a section height direction, and internal force distribution proportion under the condition of strain coordination of each layer is solved in a layer-by-layer iteration mode, so that a coupling expression of the overall axial bearing capacity and the bending rigidity is obtained.
3. The method for calculating the deformation of the steel-concrete combined support stress according to claim 2, wherein in the step 2, the foundation pit heave deformation and horizontal displacement data are derived from an on-site monitoring system or a numerical simulation predicted value, the data are applied to two ends of a support member as displacement boundary conditions, a bending moment function in the whole length range of the member is deduced by a displacement method by combining geometric parameters and material properties of the support member, and the required longitudinal reinforcement configuration density and arrangement form are determined according to the position of a bending moment extreme point.
4. The method for calculating the deformation of the steel-concrete combined support stress according to claim 1, wherein in the step 3, the flange is divided into a plurality of concentric ring microelements, each microelement bears local pressure generated by the combined action of the pretightening force of the bolt and the external bending moment, and the stress distribution curve on the section of the whole flange is obtained by establishing a static equilibrium equation of the microelement body and taking the coupling effect of the shearing deformation and the bending deformation into consideration, and the area where the maximum tensile stress and the maximum compressive stress are is located is identified by integrating along the circumferential direction.
5. The method for calculating the deformation of the reinforced concrete composite support stress according to claim 4, wherein in the step 4, the dynamic re-analysis process of the construction stage is advanced by taking a time step as a unit, and the load concentration, the boundary constraint condition and the material damage state are updated when each construction working condition is completed, the calculation processes of the steps 1 to 3 are re-executed, and finally the stress evolution path and the accumulated deformation of the key node in the whole construction period are generated.
6. The method for calculating the deformation of the steel-concrete combined support stress according to claim 5, wherein in the model for calculating the bearing capacity of the integral member, the contribution of the residual strength of the concrete part after cracking is considered, the degradation effect of the bearing capacity of the steel part after buckling is considered, and the concrete part and the steel part are coupled through an interface sliding correction coefficient, wherein the coefficient is preset according to the connection construction form and the shear force transmission mechanism.
7. The method for calculating the deformation of the steel-concrete combined support stress according to claim 1, wherein in the foundation pit deformation-bending moment coupling calculation model, a mutual influence relationship exists between horizontal displacement and heave deformation, nonlinear feedback between the horizontal displacement and heave deformation is processed by adopting a bidirectional coupling iterative algorithm, and the bending moment distribution calculation result can truly reflect the space stress state of an actual support system.
8. The method for calculating the deformation of the steel-concrete combined support stress according to claim 7, wherein in the process of the fine analysis of the stress of the flange plate, a stress concentration amplification factor is arranged in the edge area of the bolt hole, and the factor is dynamically adjusted according to the ratio of the aperture to the plate thickness and the distance between adjacent bolts and is used for correcting an original stress value obtained by infinitesimal integration, so that the prediction accuracy of local peak stress is improved.
9. The method for calculating the deformation of the steel-concrete combined support stress according to claim 1, wherein the construction of the unified stress deformation response field adopts a grid mapping technology, different physical quantities are projected to the same space coordinate system, and a multidimensional data body is formed, so that the subsequent visual display and structural safety evaluation are facilitated.
10. The method for calculating the deformation of the reinforced concrete combined support stress according to claim 9, wherein the dynamic re-analysis supports multi-working-condition superposition processing, including but not limited to external disturbance factors such as earth excavation, precipitation operation, adjacent construction vibration and the like, each disturbance is converted into an equivalent load or displacement increment to participate in calculation, and the analysis result is ensured to cover the least favorable combination in a complex field environment.

Description

Steel-concrete combined support stress deformation calculation method Technical Field The application belongs to the field of civil engineering structure analysis and calculation, and particularly relates to a steel-concrete combined support stress deformation calculation method. Background With the development of urban underground space and the wide development of ultra-large foundation pit engineering, the steel-concrete combined support structure has become a key bearing member in a deep foundation pit support system and a large building structure by virtue of high strength, high rigidity and excellent construction durability. The stress deformation calculation of the steel-concrete combined support is a core basis for evaluating the safety and economy of the support system, and relates to the accurate quantification of multisection connection deflection, section load distribution and construction process dynamic stress. Especially when the requirements of complex working conditions and high-precision deflection control are met, the calculation model needs to reflect the cooperative evolution state of steel and concrete under multidimensional stress in real time, and the modeling precision of the mechanical model, the cooperative processing efficiency of multi-source data and the analysis capability of local key nodes are more required. However, the traditional stress calculation model is dependent on a separation calculation method or an equivalent stiffness method, the combined structure is simplified into homogeneous materials or simply overlapped, and the nonlinear synergistic effect of steel and concrete in the load sharing process is ignored, so that the calculation accuracy of macroscopic bearing capacity is difficult to meet the design standard of a deep foundation pit. Meanwhile, the prior art has insufficient refined resolution on connection nodes such as flange plates, nonuniform stress distribution of a circular section under complex constraint and bending resistance stress characteristics of bolts are difficult to capture, so that local stress concentration phenomenon is covered, and the risk of structural instability is increased. In addition, the traditional calculation flow lacks dynamic coupling analysis on foundation pit heave deformation, horizontal deformation and component stress state, and cannot capture nonlinear state change caused by load redistribution in the construction stage, so that deviation exists between a calculation result and an engineering actual stress state. Disclosure of Invention The invention aims to provide a steel-concrete combined support stress deformation calculation method which can effectively solve the problems in the background technology. In order to achieve the purpose, the technical scheme adopted by the invention is that the steel-concrete combined support stress deformation calculation method comprises the following specific steps: The method comprises the steps of 1, constructing a calculation model of the bearing capacity of an integral component, synchronously analyzing a synergistic action mechanism of steel axial stress and concrete bending load through a layered stress-strain relation, 2, establishing a foundation pit deformation-bending moment coupling calculation model, taking foundation pit heave deformation and horizontal displacement data as boundary conditions for input, dynamically deducing the bending moment distribution inside a supporting component and corresponding reinforcement requirements, 3, carrying out flange stress fine analysis, carrying out micro-element division on a circular flange along the radial direction, solving circumferential stress distribution under the action of uneven load based on circumferential balance condition integral, and 4, integrating the output results of the model to form a unified stress deformation response field, carrying out dynamic re-analysis according to load change in a construction stage, and outputting the stress state and deformation trend of each key section. Preferably, in the step 1, the interface between the steel and the concrete adopts a continuous medium assumption, the mechanical behaviors of the steel and the concrete in an elastic stage and a plastic stage are respectively described by setting a material constitutive relation, a plurality of calculation layers are divided according to the height direction of the section, and the internal force distribution proportion of each layer under the condition of strain coordination is iteratively solved layer by layer, so that the coupling expression of the whole axial bearing capacity and the bending rigidity is obtained. Preferably, in the step 2, the foundation pit heave deformation and horizontal displacement data are derived from an on-site monitoring system or a numerical simulation predicted value, the data are applied to two ends of the supporting member as displacement boundary conditions, a bending moment function in the whole l