Numerical simulation method for hydraulic structure under dry-wet cycle

Abstract

The invention provides a numerical simulation method for a hydraulic structure under a dry-wet cycle, and relates to the technical field of numerical simulation of hydraulic constructions.The method comprises the steps that the initial porosity phi 0 corresponding to a to-be-tested concrete structure is obtained; obtaining corresponding porosity and degradation depth after different dry-wet cycle times are carried out on the concrete test piece, so as to obtain a porosity and degradation depth group list A; establishing an initial concrete structure model corresponding to the to-be-tested concrete structure; adding a load G to the initial concrete structure model according to the actual stress state corresponding to the to-be-tested concrete structure to obtain a target concrete structure model X0; performing finite element simulation on X0 according to A to obtain the maximum number of dry-wet cycles corresponding to the to-be-tested concrete structure; according to the invention, accurate simulation of the maximum dry-wet cycle index of the hydraulic structure in a real stress state can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of numerical simulation of hydraulic structures, in particular to a numerical simulation method for hydraulic structures under dry-wet cycles. Background Art

[0002] The main structure of hydraulic structures is concrete. Due to the unique nature of their working environment, concrete structures are often subject to a cycle of wetting and drying, which has a variety of impacts on concrete structures. In terms of physical properties, the alternating wetting and drying cycles cause concrete to expand and contract, inducing internal microcracks, reducing structural density, and increasing the porosity φ within the concrete structure. This leads to a decrease in concrete strength, a change in the elastic modulus, and increased structural deformation. Furthermore, the depth of these deteriorations (d) accumulates with the number of wetting and drying cycles, gradually reducing the durability and safety of the concrete structure and threatening its long-term stability. Therefore, accurately simulating the maximum number of wetting and drying cycles a concrete structure can undergo to assess its durability has become a pressing technical challenge. Summary of the Invention

[0003] In view of the above technical problems, the technical solution adopted by the present invention is: According to a numerical simulation method for dry-wet cycle hydraulic structures provided in the present application, the method comprises the following steps: S100, obtaining the initial porosity φ0 corresponding to the concrete structure to be tested; S200, obtaining the porosity and degradation depth corresponding to different dry-wet cycles of the concrete specimen to obtain a porosity and degradation depth group list A = (A1, A2, ..., A i ,…,A n ), i=1, 2,...,n; among them, A i is the porosity and degradation depth group corresponding to the concrete specimen after i dry-wet cycles, n is the maximum number of dry-wet cycles for the concrete specimen; A i =(φ i , d i );φ i and d i The porosity and deterioration depth of the concrete specimen after i dry-wet cycles are obtained. The concrete material of the concrete specimen is the same as that of the concrete structure to be tested. S300, establishing an initial concrete structure model corresponding to the concrete structure to be tested; wherein the initial concrete structure model includes a degraded area and a non-degraded area, and the porosity of the concrete corresponding to the initial concrete structure model is φ0; S400, adding a load G to the initial concrete structure model according to the actual stress state corresponding to the concrete structure to be tested, to obtain a target concrete structure model X0; S500: Based on A, perform finite element simulation on X0 to obtain the maximum number of dry-wet cycles corresponding to the concrete structure to be tested.

[0004] Furthermore, step S500 includes the following steps: S510, obtaining a preset value N=1 and an intermediate model QR=X0; S520, import QR into the preset finite element calculation software, and convert the QR surface to d N The deep area is divided into the degraded area, and the remaining area of QR is divided into the non-degraded area; enter S530; S530, set the porosity of the concrete in the QR deterioration area to φ N , the porosity of the concrete in the non-deteriorated area is set to φ0, and the load G is added for simulation; enter S540; S540: If QR is not destroyed after the simulation, the concrete structure model after the simulation is finished is derived to obtain the Nth concrete structure model X. N , enter S550; otherwise, determine the number of dry-wet cycles of the concrete structure to be tested is N; S550, obtain N=N+1 and QR=X N , enter S520.

[0005] Furthermore, step S100 includes the following steps: S110, collecting a concrete sample DW from the concrete structure to be tested; S120, obtain the volume V and dry weight m of DW d and wet weight m s ; S130, according to V, m d and m s , determine φ0=(m s -m d ) / (V×ρ); where ρ is the density of water.

[0006] Furthermore, step S200 includes the following steps: S210, set n groups of identical concrete specimens, and number each concrete specimen to obtain a concrete specimen number list B = (B1, B2, ..., B i ,…,B n ); Among them, B i is the number of the i-th concrete specimen; B i =i; S220, for Bi The corresponding concrete specimen is subjected to i dry-wet cycles to obtain the corresponding concrete porosity φ i and degradation depth d i .

[0007] Furthermore, the concrete specimen is in the shape of a cube.

[0008] Furthermore, the preset finite element calculation software includes: ABAQUS and ANSYS CivilFEM.

[0009] Furthermore, after step S500, the method further includes the following steps: S600, according to the maximum number of dry-wet cycles NUM corresponding to the concrete structure to be tested max and the average duration of a single dry-wet cycle t p , determine the durability service time limit T=NUM of the concrete structure to be tested max ×t p .

[0010] The present invention has at least the following beneficial effects: The numerical simulation method for hydraulic structures subjected to dry-wet cycles of the present invention obtains the initial porosity of the concrete structure to be tested and establishes an initial concrete structure model including degraded areas and non-degraded areas based on the dry-wet cycle test data of concrete specimens of the same material. Finite element simulation is performed after applying load in combination with the actual stress state. The method can accurately quantify the cumulative effect of concrete porosity and degradation depth during the dry-wet cycle, thereby effectively solving the physical property degradation problem of concrete volume expansion and contraction, microcrack development, porosity increase and strength degradation caused by dry-wet cycles in the background technology. Through the coupling analysis of test data and structural models, the material degradation law at the specimen scale is extended to the actual structural scale, thereby achieving accurate simulation of the maximum number of dry-wet cycles of hydraulic structures under real stress states.

[0011] In addition, the present invention fully considers the consistency of concrete materials, the cumulative characteristics of the deterioration process and the actual stress conditions of the structure, avoiding the defects of traditional methods that ignore load coupling effects or material parameter mismatches, and provides a scientific quantitative basis for evaluating the durability of concrete structures. It effectively solves the problem of structural durability and safety assessment that has long plagued the engineering community, and has important engineering significance for ensuring the long-term stable operation of hydraulic structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0013] Figure 1 A flow chart of a numerical simulation method for dry-wet cycle hydraulic structures provided by an embodiment of the present invention; Figure 2 A schematic diagram of a concrete structure model provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0014] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0015] It should be noted that, based on this disclosure, those skilled in the art will appreciate that an aspect described herein can be implemented independently of any other aspect, and that two or more of these aspects can be combined in various ways. For example, any number of the aspects described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement such an apparatus and / or practice such a method.

[0016] The following will refer to Figure 1 The flowchart of the numerical simulation method for dry-wet cycle hydraulic structures shown in FIG. 1 introduces a numerical simulation method for dry-wet cycle hydraulic structures.

[0017] The numerical simulation method for a dry-wet cycle hydraulic structure may include the following steps: S100: Obtain the initial porosity φ0 corresponding to the concrete structure to be tested.

[0018] In this embodiment, the concrete structure to be tested can be any concrete structure that is exposed to a dry-wet cycle, such as an aqueduct. Initial porosity is a fundamental parameter of concrete materials, directly affecting their impermeability, strength, and other properties. By measuring the volume, dry weight, and wet weight of the concrete sample, the initial porosity is calculated, providing initial material properties for subsequent modeling.

[0019] Furthermore, step S100 may include the following steps: S110 , collecting a concrete sample DW from the concrete structure to be tested.

[0020] S120, obtain the volume V and dry weight m of DW d and wet weight m s .

[0021] The dry weight can be obtained by measuring the weight of the concrete sample after drying it, and the wet weight can be obtained by measuring the weight of the concrete sample after soaking it in water.

[0022] S130, according to V, m d and m s , determine φ0=(m s -m d ) / (V×ρ); where ρ is the density of water.

[0023] In this embodiment, it can be understood that concrete pores can absorb water, and the difference between the wet weight and the dry weight is the mass of the water in the pores, which is divided by the density of water to obtain the pore volume; the porosity is the ratio of the pore volume to the total volume of the concrete; this method can obtain key parameters through simple physical measurements (weight, volume), is easy to operate, and has low cost; based on the principle of conservation of mass, the calculation results are reliable and provide accurate initial material properties for subsequent models.

[0024] S200, obtaining the porosity and degradation depth corresponding to different dry-wet cycles of the concrete specimen to obtain a porosity and degradation depth group list A = (A1, A2, ..., A i ,…,A n ), i=1, 2,...,n; among them, A i is the porosity and degradation depth group corresponding to the concrete specimen after i dry-wet cycles, n is the maximum number of dry-wet cycles for the concrete specimen; A i =(φ i , d i );φ i and d i These are the porosity and deterioration depth corresponding to i dry-wet cycles of the concrete specimen; the concrete material of the concrete specimen is the same as that of the concrete structure to be tested.

[0025] In this embodiment, concrete specimens made of the same material as the structure to be tested are subjected to different numbers of dry-wet cycles, such as 1, 2, ...n dry-wet cycles, and the porosity and degradation depth after each cycle are recorded. Table A reflects the quantitative relationship between the number of dry-wet cycles and the degree of concrete degradation, and serves as key input data for subsequent simulations.

[0026] Furthermore, step S200 may include the following steps: S210, set n groups of identical concrete specimens, and number each concrete specimen to obtain a concrete specimen number list B = (B1, B2, ..., B i ,…,B n ); Among them, B i is the number of the i-th concrete specimen; B i =i.

[0027] S220, for B i The corresponding concrete specimen is subjected to i dry-wet cycles to obtain the corresponding concrete porosity φ i and degradation depth d i .

[0028] In this embodiment, the test specimens are made of the same material as the structure to be tested to ensure the engineering relevance of the experimental data; each group of test specimens is only cycled i times, such as B1 only once and B2 only twice, to avoid cumulative errors caused by repeated cycles of the same test specimen (e.g., after multiple cycles, the test specimen is partially damaged, resulting in distortion of subsequent data); by controlling variables through grouped experiments, the porosity and degradation depth data corresponding to each number of cycles are ensured to be independent and accurate; parallel experiments on multiple groups of test specimens can reduce accidental errors and improve data reliability.

[0029] Furthermore, the concrete specimen is in the shape of a cube.

[0030] During the dry-wet cycle test, the cubic specimens are subjected to uniform stress on all surfaces and experience consistent degradation (e.g., the depth of water penetration expands uniformly along the direction perpendicular to the surface), making it easier to measure the degradation depth. Furthermore, the cubic shape facilitates processing and fixation, making experimental operations simpler.

[0031] The standardized shape of the cubic specimens reduces experimental errors, ensures the comparability of porosity and degradation depth data, and provides more reliable input for subsequent simulations.

[0032] S300 , establishing an initial concrete structure model corresponding to the concrete structure to be tested; wherein the initial concrete structure model includes a degraded area and a non-degraded area, and the porosity of the concrete corresponding to the initial concrete structure model is φ0.

[0033] In this example, the initial concrete structure model must distinguish between degraded regions (which may not actually degrade initially, but reserve space for subsequent iterations) and non-degraded regions. The initial porosity is uniformly set to φ0. This model serves as the starting point for the simulation and must be consistent with the geometry and boundary conditions of the actual structure.

[0034] The deterioration depth of concrete structure will change with the increase of the number of dry-wet cycles, so the concrete structure model can be simplified into deteriorated area and non-deteriorated area. The difference between the deteriorated area and the non-deteriorated area is reflected in the difference in porosity, such as Figure 2 shown.

[0035] S400 , adding a load G to the initial concrete structure model according to the actual stress state corresponding to the concrete structure to be measured, to obtain a target concrete structure model X0 .

[0036] In this embodiment, the concrete structure to be tested will be subjected to loads such as deadweight, water pressure, and temperature stress in actual applications. Load analysis can be performed on the concrete structure to obtain the load G. By applying these loads to the initial model, the model is made closer to the actual stress state, ensuring the engineering relevance of subsequent simulation results.

[0037] S500: Based on A, perform finite element simulation on X0 to obtain the maximum number of dry-wet cycles corresponding to the concrete structure to be tested.

[0038] Based on the experimental data in List A, the deteriorated area and porosity of the model were iteratively updated using finite element software to simulate the damage process of the structure under different numbers of dry-wet cycles. Ultimately, the maximum number of cycles the structure could withstand before failure was determined.

[0039] Furthermore, step S500 may include the following steps: S510, obtaining a preset value N=1 and an intermediate model QR=X0.

[0040] The initial number of simulations N = 1, and the intermediate model QR is set as the target model X0, that is, the initial model after the actual load is applied.

[0041] S520, import QR into the preset finite element calculation software, and convert the QR surface to d N The deep area is divided into the degraded area, and the remaining area of QR is divided into the non-degraded area; enter S530.

[0042] Transform the surface of the intermediate model QR to d N The depth area is divided into degradation areas, for example: the degradation depth after one dry-wet cycle is d1, and the rest are non-degraded areas.

[0043] Furthermore, the preset finite element calculation software includes: ABAQUS and ANSYS CivilFEM.

[0044] It should be noted that those skilled in the art can use ABAQUS or ANSYS CivilFEM to perform finite element simulation according to actual needs, which will not be described in detail here.

[0045] S530, set the porosity of the concrete in the QR deterioration area to φ N , the porosity of the concrete in the non-deteriorated area is set to φ0, and the load G is added for simulation; enter S540.

[0046] The porosity of the degraded region is set to φ N (Experimental value after N dry-wet cycles), the non-degraded area maintains the initial porosity φ0, and the finite element calculation is performed after applying the actual load G.

[0047] S540: If QR is not destroyed after the simulation, the concrete structure model after the simulation is finished is derived to obtain the Nth concrete structure model X. N , enter S550; otherwise, determine the number of dry-wet cycles of the concrete structure to be tested is N.

[0048] If the structure of the model is not damaged after simulation, such as no cracks or stress exceeding the limit, the current model is saved as the Nth concrete structure model X after the Nth cycle. N , continue to iterate; if it is damaged, then N is the maximum number of dry-wet cycles.

[0049] S550, obtain N=N+1 and QR=X N , enter S520.

[0050] N increases by 1, and the intermediate model QR is updated to X N , that is, the model after the last simulation, repeat S520-S540 until the structure is damaged.

[0051] In this embodiment, an iterative simulation driven by experimental data truly reflects the cumulative effects of concrete degradation under dry-wet cycles, such as increased porosity and extended degradation depth. The successive approximation approach avoids the error of assuming all degradation at once, thereby improving simulation accuracy.

[0052] Furthermore, after step S500, the method may further include the following steps: S600, according to the maximum number of dry-wet cycles NUM corresponding to the concrete structure to be tested max and the average duration of a single dry-wet cycle t p , determine the durability service time limit T=NUM of the concrete structure to be tested max ×t p .

[0053] In this embodiment, the average duration of a single dry-wet cycle is t p It can be obtained through experiments or analysis of a large amount of historical data; the number of dry-wet cycles needs to be converted into actual time to provide a direct basis for project maintenance, such as formulating maintenance cycles and reinforcement plans; if it can withstand 500 cycles, each cycle lasting 24 hours, then the service life is 500×24 hours=5.5 years.

[0054] Converting the number of cycles obtained from the simulation into actual time improves the engineering application value of the method; T can be used to intuitively evaluate the service life of the structure and assist in decision-making.

[0055] The method in this example achieves a quantitative assessment of the durability of hydraulic structures subjected to dry-wet cycles through a complete process of experimental data collection → model construction → iterative simulation → time conversion. Its core advantages lie in the integration of experimentation and simulation, the true reflection of cumulative degradation through iterative simulation, and the engineering practicality of the results, namely the time limit T, which provides a scientific basis for design optimization and maintenance decisions for hydraulic structures.

[0056] By obtaining the initial porosity of the concrete structure to be tested and based on the dry-wet cycle test data of concrete specimens of the same material, an initial concrete structure model including deteriorated areas and non-deteriorated areas is established. After applying loads in combination with the actual stress state, finite element simulation is performed. The cumulative effect of concrete porosity and deterioration depth during the dry-wet cycle process can be accurately quantified, thereby effectively solving the physical performance degradation problems of concrete volume expansion and contraction, microcrack development, porosity increase and strength degradation caused by dry-wet cycles in the background technology. Through the coupling analysis of test data and structural models, the material degradation law at the specimen scale is extended to the actual structural scale, realizing the accurate simulation of the maximum number of dry-wet cycles of hydraulic structures under real stress conditions.

[0057] In addition, it fully considers the consistency of concrete materials, the cumulative characteristics of the deterioration process and the actual stress conditions of the structure, avoiding the defects of traditional methods that ignore load coupling effects or material parameter mismatches, providing a scientific quantitative basis for evaluating the durability of concrete structures, and effectively solving the problem of structural durability and safety assessment that has long plagued the engineering community. It has important engineering significance for ensuring the long-term stable operation of hydraulic structures.

[0058] Furthermore, although the steps of the method of the present disclosure are described in a particular order in the accompanying drawings, this does not require or imply that the steps must be performed in this particular order, or that all steps shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps.

[0059] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should also be understood by those skilled in the art that various modifications may be made to the embodiments without departing from the scope and spirit of the present invention.

Claims

1. A numerical simulation method for dry-wet cycle hydraulic structures, characterized in that: The method comprises the following steps: S100, obtaining the initial porosity φ0 corresponding to the concrete structure to be tested; S200, obtaining the porosity and degradation depth corresponding to different dry-wet cycles of the concrete specimen to obtain a porosity and degradation depth group list A = (A1, A2, ..., A i ,…,A n ), i=1, 2,...,n; among them, A i is the porosity and degradation depth group corresponding to the concrete specimen after i dry-wet cycles, n is the maximum number of dry-wet cycles for the concrete specimen; A i =(φ i , d i );φ i and d i The porosity and deterioration depth of the concrete specimen after i dry-wet cycles are obtained. The concrete material of the concrete specimen is the same as that of the concrete structure to be tested. S300, establishing an initial concrete structure model corresponding to the concrete structure to be tested; wherein the initial concrete structure model includes a degraded area and a non-degraded area, and the porosity of the concrete corresponding to the initial concrete structure model is φ0; S400, adding a load G to the initial concrete structure model according to the actual stress state corresponding to the concrete structure to be tested, to obtain a target concrete structure model X0; S500: Based on A, perform finite element simulation on X0 to obtain the maximum number of dry-wet cycles corresponding to the concrete structure to be tested.

2. The numerical simulation method for dry-wet cycle hydraulic structures according to claim 1, characterized in that: Step S500 includes the following steps: S510, obtaining a preset value N=1 and an intermediate model QR=X0; S520, import QR into the preset finite element calculation software, and convert the QR surface to d N The deep area is divided into the degraded area, and the remaining area of QR is divided into the non-degraded area; enter S530; S530, set the porosity of the concrete in the QR deterioration area to φ N , the porosity of the concrete in the non-deteriorated area is set to φ0, and the load G is added for simulation; enter S540; S540: If QR is not destroyed after the simulation, the concrete structure model after the simulation is finished is derived to obtain the Nth concrete structure model X. N , enter S550; otherwise, determine the number of dry-wet cycles of the concrete structure to be tested is N; S550, obtain N=N+1 and QR=X N , enter S520.

3. The numerical simulation method for dry-wet cycle hydraulic structures according to claim 1, characterized in that: Step S100 includes the following steps: S110, collecting a concrete sample DW from the concrete structure to be tested; S120, obtain the volume V and dry weight m of DW d and wet weight m s ; S130, according to V, m d and m s , determine φ0=(m s -m d ) / (V×ρ); where ρ is the density of water.

4. The numerical simulation method for dry-wet cycle hydraulic structures according to claim 1, characterized in that: Step S200 includes the following steps: S210, set n groups of identical concrete specimens, and number each concrete specimen to obtain a concrete specimen number list B = (B1, B2, ..., B i ,…,B n ); Among them, B i is the number of the i-th concrete specimen; B i =i; S220, for B i The corresponding concrete specimen is subjected to i dry-wet cycles to obtain the corresponding concrete porosity φ i and degradation depth d i .

5. The numerical simulation method for dry-wet cycle hydraulic structures according to claim 1, characterized in that: The shape of the concrete specimen is a cube.

6. The numerical simulation method for dry-wet cycle hydraulic structures according to claim 2, characterized in that: The preset finite element calculation software includes: ABAQUS and ANSYS CivilFEM.

7. The numerical simulation method for dry-wet cycle hydraulic structures according to claim 1, characterized in that: After step S500, the method further includes the following steps: S600, according to the maximum number of dry-wet cycles NUM corresponding to the concrete structure to be tested max and the average duration of a single dry-wet cycle t p , determine the durability service time limit T=NUM of the concrete structure to be tested max ×t p .

Images