A numerical simulation method for hydraulic structures under wet-dry cycles

Abstract

This invention provides a numerical simulation method for hydraulic structures under wet-dry cycles, relating to the field of numerical simulation technology for hydraulic structures. The method includes: obtaining the initial porosity φ0 of the concrete structure to be tested; obtaining the porosity and deterioration depth of the concrete specimen after different numbers of wet-dry cycles to obtain a porosity and deterioration depth group list A; establishing an initial concrete structure model corresponding to the concrete structure to be tested; adding a load G to the initial concrete structure model according to the actual stress state of the concrete structure to be tested to obtain a target concrete structure model X0; and performing finite element simulation on X0 according to A to obtain the maximum number of wet-dry cycles corresponding to the concrete structure to be tested. This invention can accurately simulate the maximum number of wet-dry cycles of hydraulic structures under real stress conditions.

Description

Technical Field

[0001] This invention relates to the field of numerical simulation technology for hydraulic structures, and in particular to a numerical simulation method for hydraulic structures under wet-dry cycles. Background Technology

[0002] Hydraulic structures are primarily made of concrete. Due to the unique nature of their working environment, concrete structures are frequently subjected to wet-dry cycles, which have multifaceted effects on the concrete structure. Physically, the volumetric expansion and contraction caused by alternating wet and dry cycles induces internal micro-cracks, reduces structural density, increases porosity (φ), leading to decreased concrete strength, altered elastic modulus, and increased structural deformation. Furthermore, the depth of these deteriorations (d) accumulates with each wet-dry cycle, gradually reducing the durability and safety of the concrete structure and threatening its long-term stable use. Therefore, accurately simulating the maximum number of cycles a concrete structure can undergo under wet-dry conditions to assess its durability has become a pressing technical problem. Summary of the Invention

[0003] To address the aforementioned technical problems, the technical solution adopted by this invention is as follows:

[0004] According to the numerical simulation method for hydraulic structures under wet-dry cycles provided in this application, the method includes the following steps:

[0005] S100, obtain the initial porosity φ0 of the concrete structure to be tested;

[0006] S200, obtain the porosity and degradation depth of the concrete specimen after different numbers of wet-dry cycles, to obtain a porosity and degradation depth group list A = (A1, A2, ..., A...). i A n ), i=1, 2,...,n; among them, A i Let A be the porosity and degradation depth of a concrete specimen after i wet-dry cycles, where n is the maximum number of wet-dry cycles performed on the concrete specimen; i =(φ i d i ); φ i and d i The values ​​are, in order, the porosity and degradation depth of the concrete specimen after i cycles of wet and dry treatment; the concrete material of the concrete specimen is the same as that of the concrete structure to be tested.

[0007] S300, Establish the initial concrete structure model corresponding to the concrete structure to be tested; wherein, the initial concrete structure model includes a deteriorated area and a non-deteriorated area, and the porosity of the concrete corresponding to the initial concrete structure model is φ0.

[0008] S400, add load G to the initial concrete structure model according to the actual stress state of the concrete structure to be tested, and obtain the target concrete structure model X0.

[0009] S500, based on A, perform finite element simulation on X0 to obtain the maximum number of wet-dry cycles corresponding to the concrete structure under test.

[0010] Furthermore, step S500 includes the following steps:

[0011] S510, obtain the preset value N=1 and the intermediate model QR=X0;

[0012] S520, import the QR into the preset finite element calculation software, and set the QR surface to d. N The deep region is classified as a degraded region, and the remaining regions of QR are classified as undegraded regions; proceed to S530;

[0013] S530 sets the porosity of the concrete in the QR deterioration zone to φ. N The porosity of the undeteriorated concrete is set to φ0, and a load G is added for simulation; enter S540;

[0014] S540, If QR is not destroyed after this simulation, then export the concrete structure model after this simulation to obtain the Nth concrete structure model X. N If the condition is met, proceed to S550; otherwise, determine the number of wet-dry cycles for the concrete structure to be tested as N.

[0015] S550, obtain N=N+1 and QR=X N Enter S520.

[0016] Furthermore, step S100 includes the following steps:

[0017] S110, Collect concrete sample DW from the concrete structure to be tested;

[0018] S120, obtain the volume V and dry weight m of DW. d and moist weight m s ;

[0019] S130, according to V, m d and m s Determine φ0 = (m s -m d ) / (V×ρ); where ρ is the density of water.

[0020] Furthermore, step S200 includes the following steps:

[0021] S210, set up 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 ); where B i B is the number of the i-th concrete specimen; i =i;

[0022] S220, for B i The concrete specimen was subjected to i wet-dry cycles to obtain the corresponding concrete porosity φ. i and degradation depth d i .

[0023] Furthermore, the concrete specimen is cube-shaped.

[0024] Furthermore, the preset finite element calculation software includes ABAQUS and ANSYS CivilFEM.

[0025] Furthermore, after step S500, the method further includes the following steps:

[0026] S600, based on the maximum wet-dry cycle number NUM corresponding to the concrete structure under test. max and the average duration t of a single wet-dry cycle p Determine the service life limit T=NUM for the concrete structure to be tested. max ×t p .

[0027] The present invention has at least the following beneficial effects:

[0028] The numerical simulation method for hydraulic structures under wet-dry cycles of the present invention obtains the initial porosity of the concrete structure to be tested and establishes an initial concrete structure model including deteriorated and non-deteriorated regions based on wet-dry cycle test data of concrete specimens of the same material. After applying loads under actual stress conditions, finite element simulation is performed. This method can accurately quantify the cumulative effect of concrete porosity and deterioration depth during wet-dry cycles, thereby effectively solving the problem of physical property deterioration in concrete caused by wet-dry cycles, such as volume expansion and contraction, microcrack development, increased porosity, and strength degradation. Through the coupled analysis of experimental data and structural models, the material degradation law at the specimen scale is extended to the actual structural scale, realizing accurate simulation of the maximum number of wet-dry cycles of hydraulic structures under real stress conditions.

[0029] In addition, this invention fully considers the consistency of concrete material, 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 mismatch. It provides a scientific quantitative basis for evaluating the durability of concrete structures, effectively solves the long-standing problem of structural durability and safety assessment in the engineering field, and has important engineering significance for ensuring the long-term stable operation of hydraulic structures. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A flowchart illustrating a numerical simulation method for hydraulic structures under wet-dry cycles, provided in an embodiment of the present invention.

[0032] Figure 2 This is a schematic diagram of a concrete structure model provided in an embodiment of the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] It should be noted that, based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Furthermore, this device and / or practice the method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.

[0035] The following will refer to Figure 1 The flowchart shown introduces a numerical simulation method for hydraulic structures under wet-dry cycles.

[0036] The numerical simulation method for hydraulic structures under wet-dry cycles may include the following steps:

[0037] S100, obtain the initial porosity φ0 corresponding to the concrete structure to be tested.

[0038] In this embodiment, the concrete structure to be tested can be any concrete structure in a wet-dry cycle environment, such as an aqueduct structure. Initial porosity is a fundamental parameter of concrete material, directly affecting its 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.

[0039] Furthermore, step S100 may include the following steps:

[0040] S110, collect concrete samples (DW) from the concrete structure to be tested.

[0041] S120, obtain the volume V and dry weight m of DW. d and moist weight m s .

[0042] Dry weight can be obtained by measuring the weight of the concrete sample after drying, while wet weight can be obtained by measuring the weight of the concrete sample after immersing it in water.

[0043] S130, according to V, m d and m s Determine φ0 = (m s -m d ) / (V×ρ); where ρ is the density of water.

[0044] In this embodiment, it can be understood that water can be absorbed in the pores of concrete. The difference between the wet weight and the dry weight is the mass of 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 concrete. This method can obtain key parameters through simple physical measurements (weight and volume), and is easy to operate and low in cost. Based on the principle of mass conservation, the calculation results are reliable, providing accurate initial material properties for subsequent models.

[0045] S200, obtain the porosity and degradation depth of the concrete specimen after different numbers of wet-dry cycles, to obtain a porosity and degradation depth group list A = (A1, A2, ..., A...). i A n ), i=1, 2,...,n; among them, A i Let A be the porosity and degradation depth of a concrete specimen after i wet-dry cycles, where n is the maximum number of wet-dry cycles performed on the concrete specimen; i =(φ i d i ); φ i and d iThe values ​​are, in order, the porosity and degradation depth of the concrete specimen after i cycles of wet and dry treatment; the concrete material of the concrete specimen is the same as that of the concrete structure to be tested.

[0046] In this embodiment, different numbers of wet-dry cycle experiments, such as 1, 2...n times, were conducted on concrete specimens of the same material as the structure under test. The porosity and deterioration depth after each cycle were recorded. List A reflects the quantitative relationship between the number of wet-dry cycles and the degree of concrete deterioration, which is the key input data for subsequent simulations.

[0047] Furthermore, step S200 may include the following steps:

[0048] S210, set up 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 ); where B i B is the number of the i-th concrete specimen; i =i.

[0049] S220, for B i The concrete specimen was subjected to i wet-dry cycles to obtain the corresponding concrete porosity φ. i and degradation depth d i .

[0050] In this embodiment, the specimen and the structure under test are made of the same material to ensure the engineering relevance of the experimental data; each group of specimens is subjected to only i cycles, such as B1 only once and B2 only twice, to avoid cumulative errors caused by repeated cycles of the same specimen (such as the specimen being partially damaged after multiple cycles, resulting in distorted subsequent data); by controlling variables through grouped experiments, it is ensured that the porosity and degradation depth data corresponding to each number of cycles are independent and accurate; parallel experiments of multiple groups of specimens can reduce random errors and improve data reliability.

[0051] Furthermore, the concrete specimen is cube-shaped.

[0052] In wet-dry cycle tests, cubic specimens exhibit uniform stress and consistent degradation across all surfaces (e.g., the depth of water penetration extends uniformly along the vertical direction of the surface), facilitating the measurement of degradation depth. Furthermore, the cubic shape makes processing and fixing easier, simplifying experimental operations.

[0053] The standardized shape of the cubic specimen reduced experimental errors, ensured the comparability of porosity and degradation depth data, and provided more reliable input for subsequent simulations.

[0054] S300, Establish the initial concrete structure model corresponding to the concrete structure to be tested; wherein, the initial concrete structure model includes a deteriorated area and a non-deteriorated area, and the porosity of the concrete corresponding to the initial concrete structure model is φ0.

[0055] In this embodiment, the initial concrete structure model needs to distinguish between deteriorated areas (initially there may be no actual deterioration, but space is reserved for subsequent iterations) and non-deteriorated areas, and the initial porosity is uniformly set to φ0. This model is the starting point for simulation and must be consistent with the geometric dimensions and boundary conditions of the actual structure.

[0056] The degradation depth of concrete structures changes with the increase of wet-dry cycles. Therefore, the concrete structure model can be simplified into degraded and undegraded regions. The difference between the degraded and undegraded regions lies in their porosity. Figure 2 As shown.

[0057] S400, add load G to the initial concrete structure model according to the actual stress state of the concrete structure to be tested, and obtain the target concrete structure model X0.

[0058] In this embodiment, the concrete structure under test will be subjected to loads such as self-weight, water pressure, and temperature stress in practical 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.

[0059] S500, based on A, perform finite element simulation on X0 to obtain the maximum number of wet-dry cycles corresponding to the concrete structure under test.

[0060] Based on the experimental data in List A, the deterioration region and porosity of the model were iteratively updated using finite element software to simulate the damage process of the structure under different wet-dry cycles, and finally the maximum number of cycles that the structure could withstand before failure was determined.

[0061] Furthermore, step S500 may include the following steps:

[0062] S510, obtain the preset value N=1 and the intermediate model QR=X0.

[0063] The initial number of simulations is N=1, and the intermediate model QR is set as the target model X0, which is the initial model after the actual load is applied.

[0064] S520, import the QR into the preset finite element calculation software, and set the QR surface to d. N The deep region is classified as a degraded region, and the remaining regions of QR are classified as undegraded regions; proceed to S530.

[0065] Set the surface of the intermediate model QR to dN The depth region is divided into deteriorated regions. For example, the deterioration depth after one dry-wet cycle is d1, and the rest is the undeteriorated region.

[0066] Furthermore, the preset finite element calculation software includes ABAQUS and ANSYS CivilFEM.

[0067] It should be noted that those skilled in the art can use ABAQUS or ANSYS CivilFEM to perform finite element simulations as needed, which will not be elaborated here.

[0068] S530 sets the porosity of the concrete in the QR deterioration zone to φ. N The porosity of the undeteriorated concrete is set to φ0, and a load G is added for simulation; then enter S540.

[0069] The porosity of the deteriorated region is set as φ N (Experimental values ​​after N wet-dry cycles), the undeteriorated area maintains the initial porosity φ0, and finite element calculations are performed after applying an actual load G.

[0070] S540, If QR is not destroyed after this simulation, then export the concrete structure model after this simulation to obtain the Nth concrete structure model X. N If the test proceeds to S550, then the number of wet-dry cycles for the concrete structure to be tested is determined to be N.

[0071] If the simulated model's structure remains intact, such as without cracks or stress exceeding limits, then save the current model as the Nth concrete structure model X after the Nth iteration. N Continue iterating; if damaged, then N is the maximum number of wet and dry cycles.

[0072] S550, obtain N=N+1 and QR=X N Enter S520.

[0073] N increases by 1, and the intermediate model QR is updated to X. N That is, the model after the previous simulation is repeated from S520 to S540 until the structure is damaged.

[0074] In this embodiment, the cumulative effect of concrete deterioration under wet-dry cycles is realistically reflected through iterative simulation driven by experimental data, such as increased porosity and expanded deterioration depth. The successive approximation method avoids the error of assuming all deterioration at once and improves the simulation accuracy.

[0075] Furthermore, after step S500, the method may further include the following steps:

[0076] S600, based on the maximum wet-dry cycle number NUM corresponding to the concrete structure under test. max and the average duration t of a single wet-dry cycle p Determine the service life limit T=NUM for the concrete structure to be tested. max ×t p .

[0077] In this embodiment, the average duration t of a single dry-wet cycle p This can be obtained through experiments or analysis of a large amount of historical data; the number of wet and dry cycles needs to be converted into actual time in order to provide a direct basis for engineering 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.

[0078] Converting the number of cycles obtained from simulation into actual time improves the engineering application value of the method; T can be used to intuitively assess the service life of the structure and assist in decision-making.

[0079] The method in this embodiment achieves a quantitative assessment of the durability of hydraulic structures under wet-dry cycles through a complete process of experimental data acquisition, model construction, iterative simulation, and time conversion. Its core advantages lie in the combination of experiment and simulation, the realistic reflection of cumulative degradation by iterative simulation, and the engineering applicability of the results, namely the time limit T, which provides a scientific basis for the design optimization and maintenance decisions of hydraulic structures.

[0080] By acquiring the initial porosity of the concrete structure under test and based on the wet-dry cycle test data of concrete specimens of the same material, an initial concrete structure model including deteriorated and non-deteriorated regions is established. After applying loads under actual stress conditions, finite element simulation is performed, which can accurately quantify the cumulative effect of concrete porosity and deterioration depth during wet-dry cycles. This effectively solves the problem of physical property deterioration in concrete caused by wet-dry cycles, such as volume expansion and contraction, microcrack development, increased porosity, and strength deterioration. Through the coupled analysis of experimental data and structural models, the material deterioration law at the specimen scale is extended to the actual structural scale, realizing the accurate simulation of the maximum number of wet-dry cycles of hydraulic structures under real stress conditions.

[0081] In addition, it fully considers the consistency of concrete material, 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 mismatch. It provides a scientific quantitative basis for evaluating the durability of concrete structures, effectively solves the long-standing problem of structural durability and safety assessment in the engineering field, and has important engineering significance for ensuring the long-term stable operation of hydraulic structures.

[0082] Furthermore, although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0083] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art should also understand that various modifications can be made to the embodiments without departing from the scope and spirit of the invention.

Claims

1. A numerical simulation method for hydraulic structures under wet-dry cycles, characterized in that, The method includes the following steps: S100, obtain the initial porosity φ0 of the concrete structure to be tested; S200, obtain the porosity and degradation depth of the concrete specimen after different numbers of wet-dry cycles, to obtain a porosity and degradation depth group list A = (A1, A2, ..., A...). i A n ), i=1, 2,...,n; among them, A i Let A be the porosity and degradation depth of a concrete specimen after i wet-dry cycles, where n is the maximum number of wet-dry cycles performed on the concrete specimen; i =(φ i d i ); φ i and d i The values ​​are, in order, the porosity and degradation depth of the concrete specimen after i cycles of wet and dry treatment; the concrete material of the concrete specimen is the same as that of the concrete structure to be tested. S300, Establish the initial concrete structure model corresponding to the concrete structure to be tested; wherein, the initial concrete structure model includes a deteriorated area and a non-deteriorated area, and the porosity of the concrete corresponding to the initial concrete structure model is φ0. S400, add load G to the initial concrete structure model according to the actual stress state of the concrete structure to be tested, and obtain the target concrete structure model X0. S500, based on A, perform finite element simulation on X0 to obtain the maximum number of wet-dry cycles corresponding to the concrete structure under test; Step S500 includes the following steps: S510, obtain the preset value N=1 and the intermediate model QR=X0; S520, import the QR into the preset finite element calculation software, and set the QR surface to d. N The deep region is classified as a degraded region, and the remaining regions of QR are classified as undegraded regions; proceed to S530; S530 sets the porosity of the concrete in the QR deterioration zone to φ. N The porosity of the undeteriorated concrete is set to φ0, and a load G is added for simulation; enter S540; S540, If QR is not destroyed after this simulation, then export the concrete structure model after this simulation to obtain the Nth concrete structure model X. N If the condition is met, proceed to S550; otherwise, determine the number of wet-dry cycles for the concrete structure to be tested as N. S550, obtain N=N+1 and QR=X N Enter S520.

2. The numerical simulation method for hydraulic structures under wet-dry cycles according to claim 1, characterized in that, Step S100 includes the following steps: S110, Collect concrete sample DW from the concrete structure to be tested; S120, obtain the volume V and dry weight m of DW. d and moist 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.

3. The numerical simulation method for hydraulic structures under wet-dry cycles according to claim 1, characterized in that, Step S200 includes the following steps: S210, set up 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 ); where B i B is the number of the i-th concrete specimen; i =i; S220, for B i The concrete specimen was subjected to i wet-dry cycles to obtain the corresponding concrete porosity φ. i and degradation depth d i .

4. The numerical simulation method for hydraulic structures under wet-dry cycles according to claim 1, characterized in that, The concrete specimen was cube-shaped.

5. The numerical simulation method for hydraulic structures under wet-dry cycles according to claim 1, characterized in that, The preset finite element calculation software includes ABAQUS and ANSYS CivilFEM.

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

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