Tunnel lining degradation similar material preparation method based on performance inversion, tunnel lining degradation similar material and application

Abstract

The invention discloses a preparation method of a tunnel lining degradation similar material based on performance inversion, the tunnel lining degradation similar material and application, and the preparation method comprises the following steps: firstly, carrying out a four-factor four-level orthogonal test based on cement, river sand, gypsum and water to obtain test block mechanical property data; establishing a tunnel lining reduced scale performance calculation model by using a multi-target-ideal point method; simulating performance degradation of the lining after N years of operation by combining a concrete incremental damage theory; and finally, inversely calculating the mix proportion of the degraded similar material through a multi-target-ideal point method. According to the preparation method, the whole-course simulation of the tunnel lining from a prototype state to a degradation state is realized, namely a reliable experimental material can be provided for tunnel maintenance. The tunnel lining degradation similar material can be accurately matched with the real degradation state of a tunnel in a specific service period; when the tunnel lining degradation similar material is used for a model test, the residual life of an existing tunnel can be more truly predicted, and the effectiveness of reinforcement measures is evaluated.

Description

Technical Field

[0001] This invention relates to the field of tunnel and underground engineering technology, and in particular to a method for preparing tunnel lining deterioration similar materials based on performance inversion, the tunnel lining deterioration similar materials, and their applications. Background Technology

[0002] During long-term operation, tunnels and underground engineering structures are subjected to continuous cyclic loads such as train vibration and ground pressure, which leads to the gradual deterioration of concrete material properties, resulting in strength reduction, crack propagation, and other phenomena, seriously threatening operational safety. Among these, scaled-down model tests in the laboratory are a key means to study the long-term performance evolution laws of such structures. The core of scaled-down model tests is that the similar materials used must be able to truly reflect the mechanical properties of the prototype structure at a specific service stage (especially after deterioration).

[0003] It should be noted that existing laboratory scaled-down model tests mainly include the following two methods, specifically:

[0004] Method 1: Similar material design method based on initial properties:

[0005] Application and concept: This method is the most commonly used. Its core objective is to make the parameters such as density, strength, and elastic modulus of the model material meet the geometric similarity ratio requirements of the prototype material in the initial (new) state of the tunnel lining.

[0006] Process and Methods: Orthogonal experimental design software was used to conduct mix proportion experiments with raw materials such as cement, sand, gypsum, and water. A large number of trial mixes were prepared, and the mechanical properties were tested using a universal testing machine. Finally, regression analysis was performed using data analysis software (such as Excel and Origin) to screen out material proportions that met the initial performance similarity requirements.

[0007] Method 2: Degradation simulation method based on macroscopic defect implantation:

[0008] Application and concept: In order to represent damage in the model, this method simulates degradation by artificially introducing macroscopic defects into the prepared similar materials, such as pre-set cracks and weak layers;

[0009] Process and Method: The process is relatively independent. First, a model representing the healthy state is prepared according to Method 1. Then, relying on the engineer's experience, CAD software is used to design the defect location. Finally, physical implantation is carried out through mechanical cutting, pre-embedded isolation materials, etc.

[0010] The aforementioned laboratory scaled-down model experiment has the following shortcomings, specifically:

[0011] Defect 1: It cannot achieve quantitative simulation of continuous degradation of material properties, resulting in poor simulation realism: The material properties prepared by existing methods are static. For example, the above method 1 can only simulate the "starting point" and cannot reflect the continuous decay of material properties during the load process. The above method 2 is a jump-type, qualitative approximation, which does not match the real micro-damage accumulation process.

[0012] Defect 2: Low accuracy and strong subjectivity in degradation simulation, lack of scientific basis: In particular, Method 2 above relies heavily on the personal experience and judgment of engineers to pre-set the shape, size and degree of defects, which cannot accurately correspond to the real state after "N years of operation", resulting in low reliability and poor repeatability of the results. Summary of the Invention

[0013] The purpose of this invention is to provide a method for preparing tunnel lining deterioration similar materials based on performance inversion, which addresses the shortcomings of existing technologies. This method can simulate the entire process of tunnel lining from prototype to deterioration state through a theoretical model that couples load history with material damage evolution. Furthermore, the tunnel lining deterioration similar materials prepared by this method can provide reliable experimental materials for tunnel maintenance.

[0014] Another objective of this invention is to provide a tunnel lining deterioration similar material that can accurately match the actual deterioration state of a tunnel during a specific service period, and can be used as a reliable experimental material for tunnel structure durability model tests. Applying this tunnel lining deterioration similar material to tunnel structure durability model tests can more realistically predict the remaining life of existing tunnels and evaluate the effectiveness of reinforcement measures.

[0015] To achieve the above objectives, the present invention is implemented through the following technical solutions.

[0016] A method for preparing tunnel lining deterioration similar materials based on performance inversion includes the following steps:

[0017] Step S1: Design an orthogonal experiment: Using cement, river sand, gypsum, and water as four factors, with four levels for each factor, an orthogonal array L16(4) is used. 5 Arrange the experimental plan and prepare the test blocks;

[0018] Step S2: Perform performance tests on each test block obtained by orthogonal experiment: After curing each test block in step S1 for 28 days, determine the compressive strength, elastic modulus, tensile strength and porosity of each test block.

[0019] Step S3: Establish a scaled model performance calculation model using the multi-objective-ideal point method: Based on the performance data of each test block obtained in step S2, and according to the performance target of the tunnel lining prototype, construct an optimization model using the multi-objective-ideal point method.

[0020] The performance targets for the tunnel lining prototype include a target value for compressive strength. Target value of elastic modulus and target value of tensile strength ;

[0021] The optimization model constructed using the multi-objective-ideal-point method takes minimizing the error between the performance of the test block and the performance of the prototype as its objective function, and the objective function is:

[0022] ;

[0023] in, The compressive strength value measured for the test block. The elastic modulus value measured for the test block. The tensile strength value measured for the test block;

[0024] The relationship between the amount of cement, river sand, gypsum and water was obtained by regression of orthogonal experimental data. The range of material usage and the allowable deviation of each performance index were used as constraints. The optimization model was solved and the performance index and optimal material mix ratio of the scaled model corresponding to the tunnel lining were obtained.

[0025] Step S4: Simulating Performance Deterioration Based on Incremental Concrete Damage Theory: Based on the performance indicators of the scaled model obtained in Step S3, the incremental concrete damage constitutive model is used to simulate the deterioration process of the tunnel lining after N years of operation. The incremental concrete damage constitutive model is based on the damage variable formula in the "Code for Design of Concrete Structures" (GB 50010-2010), considering anisotropic tensile and compressive damage. The damage evolution equation is: ;

[0026] in, As a damage variable, , These are material constants, In response, For reference strain, the operational load simulates the dynamic load of a subway train. Miner's linear cumulative damage theory is used to calculate the cumulative damage degree D_N after N years, where D_N = Σ(ni / Ni), and ni is the number of cycles for the i-th load type, and Ni is the corresponding fatigue life. Based on D_N, the performance indicators of the lining are updated to obtain the target value of the deteriorated compressive strength. Target value of elastic modulus Target value of tensile strength ;

[0027] Step S5: Back-calculate the deteriorated material mix ratio: Based on the deteriorated performance obtained in step S4... , As a new objective, the material mix proportions of the scaled-down model are calculated using the multi-objective-ideal-point method. The calculation process follows step S3, while the objective function is adjusted as follows:

[0028] ;

[0029] The relationship between the amount of cement, river sand, gypsum and water was obtained by regression of orthogonal experimental data. The range of material usage and the allowable deviation of each performance index were used as constraints. The adjusted optimization model was solved and the optimal material mix ratio of the deteriorated material corresponding to the tunnel lining was obtained.

[0030] Step S6: Preparation of similar deteriorated materials: Based on the optimal material mix ratio of the deteriorated material obtained by back-calculation in step S5, weigh cement, river sand, gypsum and water and prepare similar deteriorated material test blocks;

[0031] Step S7, Deterioration Similar Material Testing and Verification: The performance of the deterioration similar material specimens prepared in Step S6 is tested to obtain the compressive strength value of the deterioration similar material specimens. Elastic modulus value Tensile strength value ;

[0032] The compressive strength value of the above-mentioned deteriorated similar material test blocks Elastic modulus value Tensile strength value With the target value of degradation , By making comparisons, if the comparison error is less than 5%, the deteriorated similar material is judged to be qualified. The obtained deteriorated similar material is the deteriorated similar material after N years of service, and can be used for subsequent tunnel model tests.

[0033] In step S1, the cement is P.O42.5 ordinary Portland cement, the fineness modulus of the river sand is 2.3-2.8, the gypsum is α-type high-strength gypsum, and the water is purified water.

[0034] The level ranges of the four factors are as follows: cement usage is 300 kg / m³-600 kg / m³, river sand usage is 500 kg / m³-1000 kg / m³, gypsum usage is 50 kg / m³-150 kg / m³, and water usage is 150 kg / m³-300 kg / m³.

[0035] The orthogonal array L16(4) 5 It includes 16 groups of trials, with the level values ​​of each factor evenly distributed.

[0036] In step S2, the compressive strength and elastic modulus of each specimen are measured by a universal testing machine, the tensile strength of each specimen is measured by the splitting method, and the porosity of each specimen is measured by the water saturation method.

[0037] In step S3, the multi-objective-ideal point method further includes sensitivity analysis, which evaluates the relative importance of each performance index by changing the target weight coefficient.

[0038] The target weight coefficients are set according to the actual service conditions of the tunnel lining. The weight of compressive strength is 0.4-0.6, the weight of elastic modulus is 0.2-0.4, and the weight of tensile strength is 0.1-0.3.

[0039] In S4, the concrete incremental damage constitutive model adopts the improved Miner cumulative damage theory and introduces the nonlinear damage accumulation formula D_N = Σ(ni / Ni)^γ, where γ is the nonlinear correction coefficient with a value of 1.2-1.5, in order to improve the prediction accuracy under variable amplitude load.

[0040] Specifically, in S4, the operational load simulation includes: using a subway train load spectrum, a load frequency of 1Hz-10Hz, a stress amplitude of 0.1-0.5 times the lining compressive strength, a simulation time N of 10-50 years, and a corresponding load cycle number of 10. 6 -10 8 Second-rate.

[0041] In step S5, the back calculation process employs an iterative optimization algorithm, including a genetic algorithm or a sequential quadratic programming method, to ensure a globally optimal solution. The optimization variables are the amounts of cement, river sand, gypsum, and water, and the constraints include the conservation of total material quantity and performance boundaries.

[0042] In step S6, the preparation process of the deteriorated similar material test block further includes adding an admixture, which includes a water-reducing agent or an expansion agent, and the amount of admixture is 0.5%-2% of the cement mass.

[0043] The preparation process of the deterioration similar material test block includes: using a mechanical mixer to stir cement, river sand, gypsum, water and admixtures at a speed of 800 r / min-1200 r / min for 5-10 minutes to prepare a homogeneous slurry, which is then poured into test blocks. During pouring, a vibrating table is used to compact the slurry. The test blocks are then cured for 28 days under the following conditions: temperature 20±2℃ and humidity above 95%. This yields deterioration similar material test blocks that can be used for subsequent performance testing.

[0044] A tunnel lining deterioration similar material is prepared by the above-mentioned tunnel lining deterioration similar material preparation method based on performance inversion.

[0045] Application of a method for preparing tunnel lining deterioration similar materials based on performance inversion, as described above, in tunnel structure durability model tests.

[0046] Compared with the prior art, the present invention has the following beneficial effects, specifically:

[0047] 1. The tunnel lining deterioration similar material preparation method based on performance inversion of the present invention can quantitatively calculate the continuous deterioration process of lining material performance under specific operating years and load spectra. That is, it can improve the deterioration simulation from "qualitative and empirical" to a new level of "quantitative and theoretical". This makes the final prepared deterioration similar material able to truly reflect the actual state of the tunnel lining in service, thereby improving the accuracy and reliability of model test data. Therefore, the tunnel lining deterioration similar material preparation method based on performance inversion of the present invention can effectively overcome the limitations of the prior art, which can only simulate the initial state or rely on subjective experience to implant macroscopic defects.

[0048] 2. The tunnel lining deterioration similar material preparation method based on performance inversion of the present invention adopts the multi-objective-ideal point method for two optimization calculations. The first calculation is used to determine the initial scale ratio, and the second calculation is used to invert the final ratio of the deteriorated material. Compared with the existing technology of first preparing "healthy" materials and then "destroying" them, the present invention directly aims at "performance after N years of service" and designs the initial ratio of the material in one go. This eliminates the need for subsequent complex deterioration treatment processes and avoids repeated trial and error. This can effectively shorten the preparation cycle and save material and labor costs.

[0049] 3. The tunnel lining deterioration similar material of the present invention is prepared based on the above-mentioned tunnel lining deterioration similar material preparation method based on performance inversion. The tunnel lining deterioration similar material can accurately match the actual deterioration state of the tunnel during a specific service period.

[0050] 4. Model tests using the tunnel lining deterioration similar material of the present invention can more realistically predict the remaining life of existing tunnels and assess the effectiveness of reinforcement measures. This helps maintenance departments shift from "passive emergency response" to "proactive predictive maintenance", formulate more scientific maintenance strategies, avoid over-maintenance or under-maintenance, thereby significantly reducing the operation and maintenance costs throughout the entire life cycle and effectively preventing safety accidents. Attached Figure Description

[0051] The present invention will be further described below with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention.

[0052] Figure 1 This is a flowchart of the method for preparing similar materials for tunnel lining deterioration based on performance inversion according to the present invention. Detailed Implementation

[0053] The present invention will now be described in conjunction with specific embodiments.

[0054] Example 1: A method for preparing tunnel lining deterioration similar materials based on performance inversion, comprising the following steps:

[0055] Step S1: Design an orthogonal experiment: Using cement, river sand, gypsum, and water as four factors, with four levels for each factor, an orthogonal array L16(4) is used. 5 Arrange the experimental plan and prepare the test blocks;

[0056] Step S2: Perform performance tests on each test block obtained by orthogonal experiment: After curing each test block in step S1 for 28 days, determine the compressive strength, elastic modulus, tensile strength and porosity of each test block.

[0057] Step S3: Establish a scaled model performance calculation model using the multi-objective-ideal point method: Based on the performance data of each test block obtained in step S2, and according to the performance target of the tunnel lining prototype, construct an optimization model using the multi-objective-ideal point method.

[0058] The performance targets for the tunnel lining prototype include a target value for compressive strength. Target value of elastic modulus and target value of tensile strength ;

[0059] The optimization model constructed using the multi-objective-ideal-point method takes minimizing the error between the performance of the test block and the performance of the prototype as its objective function, and the objective function is:

[0060] ;

[0061] in, The compressive strength value measured for the test block. The elastic modulus value measured for the test block. The tensile strength value measured for the test block;

[0062] The relationship between the amount of cement, river sand, gypsum and water was obtained by regression of orthogonal experimental data. The range of material usage and the allowable deviation of each performance index were used as constraints. The optimization model was solved and the performance index and optimal material mix ratio of the scaled model corresponding to the tunnel lining were obtained.

[0063] Step S4: Simulating Performance Deterioration Based on Incremental Concrete Damage Theory: Based on the performance indicators of the scaled model obtained in Step S3, the incremental concrete damage constitutive model is used to simulate the deterioration process of the tunnel lining after N years of operation. The incremental concrete damage constitutive model is based on the damage variable formula in the "Code for Design of Concrete Structures" (GB 50010-2010), considering anisotropic tensile and compressive damage. The damage evolution equation is: ;

[0064] in, As a damage variable, , These are material constants, In response, For reference strain, the operational load simulates the dynamic load of a subway train. Miner's linear cumulative damage theory is used to calculate the cumulative damage degree D_N after N years, where D_N = Σ(ni / Ni), and ni is the number of cycles for the i-th load type, and Ni is the corresponding fatigue life. Based on D_N, the performance indicators of the lining are updated to obtain the target value of the deteriorated compressive strength. Target value of elastic modulus Target value of tensile strength ;

[0065] Step S5: Back-calculate the deteriorated material mix ratio: Based on the deteriorated performance obtained in step S4... , As a new objective, the material mix proportions of the scaled-down model are calculated using the multi-objective-ideal-point method. The calculation process follows step S3, while the objective function is adjusted as follows:

[0066] ;

[0067] The relationship between the amount of cement, river sand, gypsum and water was obtained by regression of orthogonal experimental data. The range of material usage and the allowable deviation of each performance index were used as constraints. The adjusted optimization model was solved and the optimal material mix ratio of the deteriorated material corresponding to the tunnel lining was obtained.

[0068] Step S6: Preparation of similar deteriorated materials: Based on the optimal material mix ratio of the deteriorated material obtained by back-calculation in step S5, weigh cement, river sand, gypsum and water and prepare similar deteriorated material test blocks;

[0069] Step S7, Deterioration Similar Material Testing and Verification: The performance of the deterioration similar material specimens prepared in Step S6 is tested to obtain the compressive strength value of the deterioration similar material specimens. Elastic modulus value Tensile strength value ;

[0070] The compressive strength value of the above-mentioned deteriorated similar material test blocks Elastic modulus value Tensile strength value With the target value of degradation , By making comparisons, if the comparison error is less than 5%, the deteriorated similar material is judged to be qualified. The obtained deteriorated similar material is the deteriorated similar material after N years of service, and can be used for subsequent tunnel model tests.

[0071] In step S1, the cement is P.O42.5 ordinary Portland cement, the fineness modulus of the river sand is 2.3-2.8, the gypsum is α-type high-strength gypsum, and the water is purified water.

[0072] The level ranges of the four factors are as follows: cement usage is 300 kg / m³-600 kg / m³, river sand usage is 500 kg / m³-1000 kg / m³, gypsum usage is 50 kg / m³-150 kg / m³, and water usage is 150 kg / m³-300 kg / m³.

[0073] The orthogonal array L16(4) 5 It includes 16 groups of trials, with the level values ​​of each factor evenly distributed.

[0074] The following is a specific example to illustrate the method for preparing a tunnel lining deterioration similar material based on performance inversion in Embodiment 1. This specific example aims to prepare a scaled-down similar material (deterioration similar material) that can accurately simulate the mechanical properties (mainly compressive strength and elastic modulus) of a certain type of subway tunnel concrete lining after 30 years of operation. The initial properties of the prototype lining are: compressive strength F = 40 MPa, elastic modulus E = 30 GPa, and the scale ratio is set at 1:10. The specific steps are as follows:

[0075] Step 1: Design orthogonal experiments and establish a basic database:

[0076] Step 1.1: Determine the factors and levels: Using cement (A), river sand (B), gypsum (C), and water (D) as four factors, four levels are set for each factor. The specific level values ​​are shown in the table below (unit: kg / m³):

[0077] level Cement (A) River sand (B) Gypsum (C) Water (D) 1 300 500 50 150 2 400 700 80 200 3 500 850 110 250 4 600 1000 150 300

[0078] Step 1.2, Select L 16 (4) 5 Sixteen sets of experiments were arranged using an orthogonal array: according to the proportions listed in the table, each raw material was accurately weighed, and a mechanical mixer with a speed of 1000 r / min was used to stir for 8 minutes to prepare a homogeneous slurry, which was then poured into standard test blocks with dimensions of 70.7mm×70.7mm×70.7mm.

[0079] Step 1.3, Curing and Performance Testing: The test blocks were cured in a standard curing room (temperature 20±2℃, humidity ≥95%) for 28 days. The compressive strength (F) and elastic modulus (E) of each group of test blocks were measured using a universal testing machine. The mix proportions of the 16 test groups and the corresponding performance test results were entered into the database to form a "mix proportion-performance" mapping relationship.

[0080] Step 2: Scaled performance calculation and proportion determination based on the multi-objective-ideal point method:

[0081] Step 2.1, Set the scaling target: Based on the 1:10 geometric similarity ratio and the stress similarity relationship in similarity theory, calculate the target performance of the scaled-down similar material as follows: compressive strength ( =4 MPa) and elastic modulus ( =3GPa);

[0082] Step 2.2: Establish and solve the optimization model:

[0083] The objective function is: ;

[0084] The constraints are as follows: the amount of each material must be within the range described in step 1, with cement usage at 300 kg / m³-600 kg / m³, river sand usage at 500 kg / m³-1000 kg / m³, gypsum usage at 50 kg / m³-150 kg / m³, and water usage at 150 kg / m³-300 kg / m³.

[0085] Step 2.3, Solution: Based on the database established in Step 1, a sequential quadratic programming algorithm is used for optimization. The calculated performance is as follows: when the mix proportions are: cement 450 kg / m³, river sand 750 kg / m³, gypsum 95 kg / m³, and water 220 kg / m³. MPa The ratio that is closest to the target value (with the smallest Z value) is the optimal ratio for the initial scaled model.

[0086] Step 3: 30-year deterioration simulation based on the incremental damage theory of concrete:

[0087] Step 3.1: Input load parameters: Use the standard subway train load spectrum, with a load frequency of 5 Hz and a stress amplitude of 0.3 times the initial compressive strength of the lining (40 MPa), i.e., 12 MPa. The operating life N = 30 years, corresponding to a total load cycle count of 5 * 60 * 60 * 16 * 365 * 30 = 9.46 × 10⁻⁶. 8 Second-rate;

[0088] Step 3.2: Perform damage simulation calculations: An incremental damage constitutive model for concrete is used, and its damage evolution equation is as follows: The material constants in the damage evolution equation are taken as α=2.0 and β=1.5;

[0089] Step 3.3, Output Degraded Performance: Simulation results show that after 30 years of operation, the cumulative damage degree D of the tunnel lining... 30 =0.28, based on this, its performance parameters are updated, and the deteriorated target performance is obtained as: compressive strength. =4.0×(1-0.28)=2.88MPa, elastic modulus =3.0×(1-0.28)=2.16GPa;

[0090] Step 4: Back-calculate the mix proportion of deteriorated materials based on the multi-objective-ideal point method:

[0091] The objective function is adjusted to ;

[0092] Step 4.1, Establish the back-calculation optimization model: Here... and It is the predicted performance of similar materials under the desired ratio, and its relationship with the amount of material is obtained by database regression in step 1;

[0093] Step 4.2, Solve for the optimal mix ratio: Call the optimization algorithm again to solve the problem; the calculation shows that in order to directly prepare similar materials with performance matching "lining after 30 years of service", the optimal mix ratio is: cement 380 kg / m³, river sand 900 kg / m³, gypsum 70 kg / m³, water 240 kg / m³.

[0094] Step 5: Preparation and verification of deteriorated similar materials:

[0095] Step 5.1: Prepare deterioration-simulating materials: Based on the optimal mix ratio obtained from step 4, accurately weigh 380 kg of PO 42.5 cement, 900 kg of river sand with a fineness modulus of 2.5, 70 kg of α-type high-strength gypsum, and 240 kg of pure water (all weighed according to the proportion per cubic meter). Use a mechanical mixer to stir at 1000 r / min for 8 minutes to form a uniform slurry, and cast it into standard test blocks.

[0096] Step 5.2, Standard Curing: Place the test blocks in a standard curing room (temperature 20±2℃, humidity ≥95%) for 28 days;

[0097] Step 5.3, Performance Verification: Mechanical property tests were conducted on the cured, deteriorated, similar material specimens; the measured results were: compressive strength... =2.78MPa, elastic modulus =2.10 GPa;

[0098] Step 5.4, Result Analysis: Measured Values ​​vs. Deterioration Target Values ​​(Compressive Strength) ==2.88MPa, elastic modulus The relative errors of the lining thickness (2.16 GPa) are all less than 3%, meeting the accuracy requirement of no more than 5%. Therefore, a deteriorated similar material that can accurately simulate the mechanical state of the tunnel lining after 30 years of operation has been successfully prepared.

[0099] It should be emphasized that, for the tunnel lining deterioration similar material preparation method based on performance inversion in this embodiment, it can quantitatively calculate the continuous deterioration process of lining material performance under specific operating years and load spectra. That is, it can improve the deterioration simulation from "qualitative and empirical" to a new level of "quantitative and theoretical". This makes the final prepared deterioration similar material able to truly reflect the actual state of the tunnel lining in service, thereby improving the accuracy and reliability of model test data. Therefore, the tunnel lining deterioration similar material preparation method based on performance inversion of the present invention can effectively overcome the limitations of the prior art, which can only simulate the initial state or rely on subjective experience to implant macroscopic defects.

[0100] Furthermore, the tunnel lining deterioration similar material preparation method based on performance inversion in this embodiment uses the multi-objective-ideal point method to perform two optimization calculations. The first calculation is used to determine the initial scale ratio, and the second calculation is used to invert the final ratio of the deteriorated material. Compared with the existing technology of first preparing "healthy" materials and then trying to "destroy" them, this invention directly aims at "performance after N years of service" and designs the initial ratio of the material in one go. This eliminates the need for subsequent complex deterioration treatment processes and avoids repeated trial and error. This can effectively shorten the preparation cycle and save material and labor costs.

[0101] Example 2 differs from Example 1 in that: in step S2, the compressive strength and elastic modulus of each specimen are measured by a universal testing machine, the tensile strength of each specimen is measured by the splitting method, and the porosity of each specimen is measured by the water saturation method.

[0102] Example 3 differs from Example 1 in that: in step S3, the multi-objective-ideal point method further includes sensitivity analysis, which evaluates the relative importance of each performance index by changing the target weight coefficient;

[0103] The target weight coefficients are set according to the actual service conditions of the tunnel lining. The weight of compressive strength is 0.4-0.6, the weight of elastic modulus is 0.2-0.4, and the weight of tensile strength is 0.1-0.3.

[0104] Example 4 differs from Example 1 in that: in S4, the concrete incremental damage constitutive model adopts the improved Miner cumulative damage theory and introduces the nonlinear damage accumulation formula D_N = Σ(ni / Ni)^γ, where γ is the nonlinear correction coefficient, with a value of 1.2-1.5, to improve the prediction accuracy under variable amplitude loads.

[0105] Example 5 differs from Example 1 in that, in S4, the operational load simulation specifically includes: using a subway train load spectrum, a load frequency of 1 Hz - 10 Hz, a stress amplitude of 0.1 - 0.5 times the lining compressive strength, a simulation time N of 10 years - 50 years, and a corresponding load cycle number of 10. 6 -10 8 Second-rate.

[0106] Example 6 differs from Example 1 in that: in step S5, the back calculation process uses an iterative optimization algorithm, including a genetic algorithm or a sequential quadratic programming method, to ensure the global optimal solution; the optimization variables are the amounts of cement, river sand, gypsum, and water, and the constraints include the conservation of total material quantity and performance boundaries.

[0107] Example 7 differs from Example 1 in that: in step S6, the preparation process of the deteriorated similar material test block further includes adding an admixture, which includes a water-reducing agent or an expanding agent, and the amount of admixture is 0.5%-2% of the cement mass;

[0108] The preparation process of the deterioration similar material test block includes: using a mechanical mixer to stir cement, river sand, gypsum, water and admixtures at a speed of 800 r / min-1200 r / min for 5-10 minutes to prepare a homogeneous slurry, which is then poured into test blocks. During pouring, a vibrating table is used to compact the slurry. The test blocks are then cured for 28 days under the following conditions: temperature 20±2℃ and humidity above 95%. This yields deterioration similar material test blocks that can be used for subsequent performance testing.

[0109] Example 8: A tunnel lining deterioration similar material, which is prepared by the above-described method for preparing a tunnel lining deterioration similar material based on performance inversion.

[0110] The tunnel lining deterioration similar material in this embodiment eight is prepared based on the above-mentioned method for preparing tunnel lining deterioration similar materials based on performance inversion. This tunnel lining deterioration similar material can accurately match the actual deterioration state of the tunnel during a specific service period.

[0111] Example 9: Application of the above-described method for preparing tunnel lining deterioration similar materials based on performance inversion in tunnel structure durability model tests.

[0112] It should be noted that the model test conducted using the tunnel lining deterioration similar material of this embodiment nine can more realistically predict the remaining life of existing tunnels and assess the effectiveness of reinforcement measures. This helps maintenance departments shift from "passive emergency response" to "proactive predictive maintenance", formulate more scientific maintenance strategies, avoid over-maintenance or under-maintenance, thereby significantly reducing the operation and maintenance costs throughout the entire life cycle and effectively preventing safety accidents.

[0113] The above description is only a preferred embodiment of the present invention. For those skilled in the art, there will be changes in the specific implementation and application scope based on the ideas of the present invention. The content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing tunnel lining deterioration similar materials based on performance inversion, characterized in that, It includes the following steps, specifically: Step S1: Design an orthogonal experiment: Using cement, river sand, gypsum, and water as four factors, with four levels for each factor, an orthogonal array L16(4) is used. 5 Arrange the experimental plan and prepare the test blocks; Step S2: Perform performance tests on each test block obtained by orthogonal experiment: After curing each test block in step S1 for 28 days, determine the compressive strength, elastic modulus, tensile strength and porosity of each test block. Step S3: Establish a scaled model performance calculation model using the multi-objective-ideal point method: Based on the performance data of each test block obtained in step S2, and according to the performance target of the tunnel lining prototype, construct an optimization model using the multi-objective-ideal point method. The performance targets for the tunnel lining prototype include a target value for compressive strength. Target value of elastic modulus and target value of tensile strength ; The optimization model constructed using the multi-objective-ideal-point method takes minimizing the error between the performance of the test block and the performance of the prototype as its objective function, and the objective function is: ； in, The compressive strength value measured for the test block. The elastic modulus value measured for the test block. The tensile strength value measured for the test block; The relationship between the amount of cement, river sand, gypsum and water was obtained by regression of orthogonal experimental data. The range of material usage and the allowable deviation of each performance index were used as constraints. The optimization model was solved and the performance index and optimal material mix ratio of the scaled model corresponding to the tunnel lining were obtained. Step S4: Simulating Performance Deterioration Based on Incremental Concrete Damage Theory: Based on the performance indicators of the scaled model obtained in Step S3, the incremental concrete damage constitutive model is used to simulate the deterioration process of the tunnel lining after N years of operation. The incremental concrete damage constitutive model is based on the damage variable formula in the "Code for Design of Concrete Structures" (GB 50010-2010), considering anisotropic tensile and compressive damage. The damage evolution equation is: ; in, As a damage variable, , These are material constants, In response, For reference strain; the operational load simulates the dynamic load of a subway train, and the cumulative damage degree D_N after N years is calculated using Miner's linear cumulative damage theory, D_N = Σ(ni / Ni), where ni is the number of cycles of the i-th load and Ni is the corresponding fatigue life; the performance indicators of the lining are updated based on D_N to obtain the target value of the deteriorated compressive strength. Target value of elastic modulus Target value of tensile strength ; Step S5: Back-calculate the deteriorated material mix ratio: Based on the deteriorated performance obtained in step S4... , As a new objective, the material mix proportions of the scaled-down model are calculated using the multi-objective-ideal-point method. The calculation process follows step S3, while the objective function is adjusted as follows: ； The relationship between the amount of cement, river sand, gypsum and water was obtained by regression of orthogonal experimental data. The range of material usage and the allowable deviation of each performance index were used as constraints. The adjusted optimization model was solved and the optimal material mix ratio of the deteriorated material corresponding to the tunnel lining was obtained. Step S6: Preparation of similar deteriorated materials: Based on the optimal material mix ratio of the deteriorated material obtained by back-calculation in step S5, weigh cement, river sand, gypsum and water and prepare similar deteriorated material test blocks; Step S7, Deterioration Similar Material Testing and Verification: The performance of the deterioration similar material specimens prepared in Step S6 is tested to obtain the compressive strength value of the deterioration similar material specimens. Elastic modulus value Tensile strength value ; The compressive strength value of the above-mentioned deteriorated similar material test blocks Elastic modulus value Tensile strength value With the target value of degradation , By making comparisons, if the comparison error is less than 5%, the deteriorated similar material is judged to be qualified. The obtained deteriorated similar material is the deteriorated similar material after N years of service, and can be used for subsequent tunnel model tests.

2. The method for preparing tunnel lining deterioration similar materials based on performance inversion according to claim 1, characterized in that: In step S1, the cement is P.O42.5 ordinary Portland cement, the fineness modulus of the river sand is 2.3-2.8, the gypsum is α-type high-strength gypsum, and the water is purified water; The level ranges of the four factors are as follows: cement dosage is 300 kg / m³-600 kg / m³, river sand dosage is 500 kg / m³-1000 kg / m³, gypsum dosage is 50 kg / m³-150 kg / m³, and water dosage is 150 kg / m³-300 kg / m³. The orthogonal array L16(4) 5 It includes 16 groups of trials, with the level values ​​of each factor evenly distributed.

3. The method for preparing tunnel lining deterioration similar materials based on performance inversion according to claim 1, characterized in that: In step S2, the compressive strength and elastic modulus of each specimen are determined by a universal testing machine, the tensile strength of each specimen is determined by the splitting method, and the porosity of each specimen is determined by the water saturation method.

4. The method for preparing tunnel lining deterioration similar materials based on performance inversion according to claim 1, characterized in that: In step S3, the multi-objective-ideal point method further includes sensitivity analysis, which evaluates the relative importance of each performance index by changing the target weight coefficient. The target weight coefficients are set according to the actual service conditions of the tunnel lining. The weight of compressive strength is 0.4-0.6, the weight of elastic modulus is 0.2-0.4, and the weight of tensile strength is 0.1-0.

3.

5. The method for preparing tunnel lining deterioration similar materials based on performance inversion according to claim 1, characterized in that: In S4, the concrete incremental damage constitutive model adopts the improved Miner cumulative damage theory and introduces the nonlinear damage accumulation formula D_N = Σ(ni / Ni)^γ, where γ is the nonlinear correction coefficient with a value of 1.2-1.5, in order to improve the prediction accuracy under variable amplitude load.

6. The method for preparing tunnel lining deterioration similar materials based on performance inversion according to claim 1, characterized in that: In S4, the operational load simulation specifically includes: using a subway train load spectrum, a load frequency of 1 Hz - 10 Hz, a stress amplitude of 0.1 - 0.5 times the lining compressive strength, a simulation time N of 10 years - 50 years, and a corresponding load cycle number of 10. 6 -10 8 Second-rate.

7. The method for preparing tunnel lining deterioration similar materials based on performance inversion according to claim 1, characterized in that: In step S5, the inverse calculation process employs an iterative optimization algorithm, including a genetic algorithm or a sequential quadratic programming method, to ensure a globally optimal solution. The optimization variables are the amounts of cement, river sand, gypsum, and water, and the constraints include the conservation of total material quantity and performance boundary conditions.

8. The method for preparing tunnel lining deterioration similar materials based on performance inversion according to claim 1, characterized in that: In step S6, the preparation process of the deteriorated similar material test block further includes adding an admixture, which includes a water-reducing agent or an expansion agent, and the amount of admixture is 0.5%-2% of the cement mass; The preparation process of the deterioration similar material test block includes: using a mechanical mixer to stir cement, river sand, gypsum, water and admixtures at a speed of 800 r / min-1200 r / min for 5-10 minutes to prepare a homogeneous slurry, which is then poured into test blocks. During pouring, a vibrating table is used to compact the slurry. The test blocks are then cured for 28 days under the following conditions: temperature 20±2℃ and humidity above 95%. This yields deterioration similar material test blocks that can be used for subsequent performance testing.

9. A similar material for tunnel lining deterioration, characterized in that, The tunnel lining deterioration similar material is prepared by the tunnel lining deterioration similar material preparation method based on performance inversion as described in any one of claims 1-8.

10. The application of a method for preparing tunnel lining deterioration similar materials based on performance inversion as described in any one of claims 1-8 in the durability model test of tunnel structures.

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