Construction method and application of damage assessment system for open tunnel lining structure subjected to rockfall impact

Abstract

The present invention discloses a method for constructing a damage assessment system for an open-cut lining structure caused by rockfall impact and its application. In view of the defect of the prior art that there is a lack of a graphical assessment system, the present invention provides a method for constructing a damage assessment system for an open-cut lining structure caused by rockfall impact. First, a rockfall impact damage constitutive model for the lining structure expressed by damage factors is constructed, and a three-dimensional finite element model of a rockfall-open-cut is constructed; then, the dynamic response and damage evolution stage characteristics of the rockfall impact and the lining structure are analyzed, and a macroscopic damage stage evolution model expressed by a macroscopic damage index and the arch deflection is constructed; the ratio of the arch deflection to the allowable deflection is used as a damage assessment index to determine the damage evaluation criteria; then, the main control variables of the damage are screened through simulation tests and dimensional analysis; finally, a quantitative damage assessment system of the generalized P-I graphical method is established. The present invention solves the macroscopic process and measurement problems of damage to concrete arch structures under impact loads, and provides new ideas for research and technology development of such problems.

Description

Technical Field

[0001] The present invention relates to damage assessment technology for civil engineering structures, and in particular to a method for measuring structural damage distribution characteristics and constructing a structural damage assessment system by using strain response data of an arched concrete structure subjected to a rolling stone impact load, and the application of the method. The invention belongs to the fields of electrical digital data processing technology suitable for specific functions, impact test technology of structural components, and geological disaster monitoring technology. Background Art

[0002] As a passive protection facility, the open tunnel of the main transportation line in mountainous areas is always under the threat of landslide and rockfall disasters, and is extremely vulnerable to direct impact damage from rolling stones. The key to the safety of the open tunnel structure is the safety of the open tunnel lining. After the open tunnel is damaged by the impact of rolling stones, the identification and assessment of the degree of damage to the lining structure is a necessary and even primary link in emergency response to disasters and post-disaster recovery and reconstruction.

[0003] The pressure-impulse curve (PI curve) is a simple and efficient tool for impact damage assessment, but in the existing technology it has always been limited to assessing the degree of damage to structural components under the action of explosion loads, and has never been used for lining damage caused by impact loads. The main reasons for this situation are four aspects: First, although explosion loads and impact loads are both accidental loads on buildings, the types of shock waves, movements and their destructive properties are completely different. The former will further generate diffraction overpressure loads after generating reflected overpressure loads on buildings, while the latter will not. Therefore, the general principle of load analysis and calculation is that the former calculates dynamic loads equivalent to static loads, or directly performs dynamic analysis according to the explosion time course; the latter analyzes and calculates according to the mass, speed, impact time and point of action of the impactor. This makes it difficult to use impact load test data to construct curve evaluation tools. Second, the dynamic response of building structures under impact loads and explosion loads is completely different. A more intuitive manifestation of the difference between explosion loads and impact loads at the principle level is that shock wave loading technology can effectively simulate explosion loads and is used for explosion mechanics research, but cannot simulate impact loads. Third, the existing impact damage measurement methods calculated using engineering algorithms are mostly based on single component targets or regular overall targets. The various indicators used in the methods cannot be applied to the target measurement and evaluation of arch structures, and therefore cannot solve similar technical problems in open hole linings (concrete arch structures). Finally, the key to establishing a PI graphical curve evaluation tool is to screen out the main control variables through scientific and reliable means, but there is currently no reliable screening solution. Limited by these basic differences, the current research on rolling stone damage to open hole lining structures is mostly focused on the dynamic response of open holes, and no effective graphical damage assessment tools have been developed.

[0004] The existing technology "Research on early warning standards for rockfall impact damage of open-cut structures with double-ear wall based on acceleration signals" (Li Dongming, Chengdu University of Technology, 2017) discloses a method for assessing damage after a rolling stone impacts an open-cut lining structure. This method takes the tensile damage factor as the basis, uses the damage factor provided by the ABAQUS concrete damage constitutive model as a microscopic quantitative index for evaluating the degree of structural damage, and uses statistical means to take the average value of the damage factor of all units in the arch of the model as a quantitative index of the degree of damage of the entire open-cut structure; on this basis, the corresponding relationship between different rolling stone diameters (or rolling stone masses), different initial impact velocities and the degree of open-cut damage is obtained; at the same time, a univariate quartic polynomial function model between the kinetic energy of the rolling stone impact and the mean value of the arch unit damage factor (quantitative index of the degree of damage) is constructed. The main defects of this evaluation method are that, on the one hand, it only counts the tensile damage of the arch in one research case, and there is no tensile damage calculation model and damage degree classification system for the open hole lining structure; on the other hand, the method relies on the arch settlement data or acceleration signal, which is difficult to obtain directly in actual rolling stone cases, and it is difficult to reproduce without relying on a specially built laboratory measurement system, which limits the promotion and use of the technical solution in research or production practice, and cannot accumulate sufficient data for building an evaluation system. In short, this technology is only suitable for damage measurement for special research cases, and cannot solve the problem of building a damage assessment system. Summary of the invention

[0005] The purpose of the present invention is to address the deficiencies in the prior art and to provide a method for constructing and applying a damage assessment system for open tunnel lining structures caused by rockfall.

[0006] To achieve the above objectives, the present invention first provides a method for constructing a damage assessment system for open tunnel lining structures caused by rockfall, and the technical solution is as follows.

[0007] A method for constructing a damage assessment system for open-cut lining structures caused by rockfall, characterized in that:

[0008] Step S100: construct a t The damage constitutive model DCM of the open-cut lining structure due to rockfall is expressed, and a three-dimensional finite element model of the rockfall-open-cut lining is constructed. The lining structure in the three-dimensional finite element model is constructed using the constitutive model DCM, and the macro damage index is screened. ψ , the macro damage index ψ It is an indicator that can characterize the macroscopic damage characteristics of lining structures caused by rockfall impact;

[0009] Step S200: Use the three-dimensional finite element model to carry out simulation calculations, analyze the dynamic response of the open hole lining structure under the influence of rockfall dynamic parameters and structural parameters, analyze the characteristics of the open hole lining damage evolution stage, and calculate the arch deflection in the statistical simulation data.u Macroscopic damage index ψ The second characteristic parameter is constructed by ψ and u Macroscopic damage evolution model of open-cut lining structure subjected to rockfall impact ψ - u ;

[0010] Step S300: Using the evolution model ψ - u Carry out simulation tests to analyze the evolution stages of impact damage of open-cut lining structures, and use the result data to construct a damage classification system DAS for open-cut lining structures caused by rolling stones. The DAS system includes damage classification DAC, damage assessment index DAI, and DAI classification threshold DAI. cr The damage classification DAC level structure is determined according to the analysis results of the impact damage evolution stage of the open hole lining structure;

[0011] Step S400: select p observable indicators in the event of rockfall impacting the open hole lining as candidate variables Q, wherein the candidate variables Q include observable indicators that can characterize the rockfall structure and dynamic characteristics, and observable indicators that can characterize the open hole lining structure and response characteristics. The observable indicators that can characterize the open hole lining structure and response characteristics include the arch deflection. u , the dimensional analysis method is used to construct the function of formula 1 and examine the correlation between each candidate variable Q and the index DAI, and the two main control variables x and y of the damage of the open hole lining structure due to rockfall are statistically selected.

[0012] Formula 1;

[0013] Step S500: Determine the grading thresholds DAI in the system DAS using the function of formula 1 cr The corresponding critical condition value x of the second main control variable cr With y cr , and simulate the DAI value DAI under different combinations of the two main control variables (x, y) (x,y) ; Based on DAI (x,y) Data, search for DAI at all levels cr The corresponding damage critical point (X cr , Y cr ), the damage critical point (X cr , Y cr ) is x and y satisfy the critical condition value x at the same time cr With y cr The combined working condition (x, y); the critical point of each level of damage (X cr , Y cr) is used as the basis to construct the critical damage curve CDA of the open hole lining structure corresponding to each damage classification DAC. The curve CDA is expressed according to formula 2:

[0014] Formula 2,

[0015] Where, C is constant coefficient.

[0016] The above-mentioned method for constructing a damage assessment system for open-cut lining structures caused by rockfall impact is intended to construct a graphical type of generalized PI curve-based damage assessment system for open-cut lining structures caused by rockfall impact. The key to constructing a PI curve assessment tool is to establish a mapping function that is as accurate as possible between the two main control variables in the rockfall-open-cut lining impact system and the characteristic variables that reflect the critical state of the staged quantitative change in the damage evolution process of the open-cut lining structure. To solve this technical problem, the above-mentioned construction method of the present invention firstly, based on the selected damage factor d t Design macro damage index ψ , and lining structure indicators u Combination, using finite element test data to establish ψ - u The macro damage evolution model is used to analyze and determine the critical state of the staged quantitative change and the damage index threshold of the open hole lining structure damage evolution process, and further construct the damage degree classification system DAS, which includes damage classification and damage classification based on lining structure indicators. u Damage assessment indicators and classification thresholds. Secondly, a theoretical analysis model of the rolling stone-open hole lining impact system is constructed, and observable indicators that can characterize the two-way interaction of the system's impact-response are selected as candidates for the main control variables. The mapping function between the main control variable candidates and the classification threshold is established using dimensional analysis to screen out the two main control variables x and y. Finally, based on the test data of the two main control variables under different simulation conditions, the system DAS is used as a media tool to determine the critical point at which the main control variable combination (x, y) undergoes a phased quantitative change in the lining damage evolution process, which is the critical point of each level of damage (X cr , Y cr ), by accumulating (X cr , Y cr ) data fitting curve, and obtain the damage assessment system illustrated by the generalized PI curve.

[0017] Based on the above-mentioned method for constructing a damage assessment system for rockfall impact on open tunnel lining structures, the present invention further provides an optimization and improvement plan. Each optimization and improvement plan can be implemented simultaneously or separately without affecting the technical logic connection of the plan.

[0018] Optimization 1: Using vault deflection u Allowable deflection of lining structure u dThe ratio D (Formula 3) is used as a specific damage assessment index DAI scheme. The present invention has found through preliminary theoretical analysis and experimental tests that concrete arch structures represented by lining structures show two characteristics in the strain of rolling stone impact load: on the one hand, in the entire arch structure, when the maximum displacement of the arch exceeds a certain value, the damage value will increase exponentially; on the other hand, in the exponential increase stage of the damage value, the damage is not concentrated in the impacted part, but is scattered throughout the arch structure and connected into a surface, causing the structure to lose its bearing capacity and reach a level that cannot be repaired. These two characteristics meet the allowable deflection u d Based on this finding, the present invention considers introducing the allowable deflection u d It can effectively measure the deformation characteristics of large arched concrete structures under rolling stone impact loads, especially the damage characteristics. u Relative to the allowable deflection u d This optimization scheme is the first to allow deflection u d The damage assessment measurement of concrete arch structures caused by impact loads is introduced as a damage observation variable.

[0019] Formula 3,

[0020] In the formula, u - Arch deflection (mm), u d - Allowable deflection of lining structure (mm).

[0021] Furthermore, based on the previous analysis data, the present invention further determines the u d The empirical expression (Formula 4) can be used to quickly calculate the D value. In Formula 4, w is the inner width of the arch structure, in mm.

[0022] Formula 4.

[0023] Optimization 2. Provide the tensile damage calculation model TDC as a specific form of the damage constitutive model DCM of the open hole lining structure due to rockfall.

[0024] The concrete damage plasticity model is used to simulate the continuous and plastic damage of concrete, and it is assumed that its failure is controlled by the tensile cracking of concrete. Thus, the tensile damage calculation model TDC is constructed as the specific expression of the damage constitutive model DCM of the open hole lining structure of the present invention. The model TDC represents the tensile damage process of the open hole lining structure as two stages, including: stage one, elastic deformation stage; stage two, tensile damage stage. The model TDC represents the tensile damage process of concrete in the form of a function as the equation group 5.

[0025] Formula 5-1,

[0026] Formula 5-2,

[0027] Formula 5-3,

[0028] In the model TDC, σ t - Concrete tensile stress (MPa), d t - concrete tensile damage factor, E0 - concrete lossless elastic modulus (MPa), ε t - tensile strain of concrete, ε pl - Equivalent plastic strain of concrete under tension, ε ck - Concrete cracking strain, the units of variables and the determination methods are the same as the concrete damage plasticity model.

[0029] Optimization 3: Using the tensile damage calculation model TDC definition to construct macro damage indicators ψ Based on the model TDC, the macro damage index ψ Designed for lining structures N Damage factor d t The mean value of (Formula 6-1),

[0030] Formula 6-1.

[0031] Further using the model TDC, the damage factor d t It can be defined as the damage value φ of the open hole lining structure component point expressed according to Formula 6-2.

[0032] Formula 6-2,

[0033] In the formula, φ( i , t )-No. i The damage value of a lining structure component at time t, dimensionless.

[0034] Optimization 4. Provide the basic structure of the DAS system for grading the degree of damage to open-cut lining structures caused by rockfall.

[0035] Utilizing a large amount of preliminary test data, the present invention specifically provides a 4-level grading design coded as DS1 to DS4 for the grading system DAS, as shown in Table 1.

[0036] Table 1 Classification system for damage degree of open-cut lining structure caused by rockfall

[0037]

[0038] Optimization 5. Among the candidate variables Q, observable indicators that can characterize the structure and dynamic characteristics of the rolling stone include the mass of the rolling stone m , impact speed v , Contact head form factor N * , impact angle θ Among them, the contact head shape factor N * It can be determined according to the prior art ZL2022103972851.

[0039] Optimization VI. Among the candidate variables Q, the observable indicators that can characterize the open hole lining structure and response characteristics include the compressive strength index of the soil, density ρ s ,thickness T s , Arch deflection u Furthermore, the compressive strength index of the soil is preferably the compressive strength of the soil R * . This variable can be determined according to the prior art ZL 2022103972851.

[0040] Optimization 7: Select the π theorem for dimensional analysis and set m , v , T s are mutually unrelated parameters, N * , θ , R * , ρ s , u is the relevant parameter. Furthermore, the π theorem calculation model expressed by equations 7-1, 7-2, and 7-3 is constructed to perform variable regression analysis.

[0041] Formula 7-1,

[0042] Formula 7-2,

[0043] Formula 7-3.

[0044] Optimization 8: Using linear interpolation, according to the condition of formula 8, DAI (x,y) Search for critical points of damage at all levels (X cr , Y cr ), where C is the same constant coefficient as in Formula 2.

[0045] Formula 8.

[0046] Another object of the invention is to provide an application solution for the method of constructing the above-mentioned method for assessing the damage of open tunnel lining structures caused by rockfall.

[0047] An application of the above-mentioned method for constructing a damage assessment system for an open-cut lining structure caused by rock rolling, characterized in that it is used in quantitative assessment of damage to an open-cut lining structure caused by rock rolling.

[0048] The above application solutions may include two types of solutions.

[0049] Monitoring and early warning scheme: For the open-cut tunnels to be monitored, a monitoring terminal / sensor unit is installed on the arch of the lining structure to collect the real-time deflection data of the arch, and a monitoring terminal / sensor unit is installed in the upper space of the open-cut tunnel to collect the geometric characteristics and movement data of the rolling stones; preset the real-time deflection early warning conditions; when the real-time deflection meets the early warning conditions, issue an early warning message; obtain the geometric characteristics and movement data of the rolling stones and input them into the critical damage curve CDA of the rolling stone impact open-cut tunnel lining structure to determine the degree of damage; calculate the ratio D according to the real-time deflection, and calculate the damage according to the classification threshold DAI cr Determine the damage level; compare the damage levels determined by CDA and ratio D, determine the damage level based on the higher principle, and determine the open hole damage morphology description and repairability recommendations.

[0050] Post-disaster assessment program: After the rockfall damages the open tunnel, conduct on-site investigation to obtain the geometric characteristics and movement data of the rockfall and the maximum deflection data of the lining structure; determine the degree of damage based on the rockfall geometric characteristics and movement data using the critical damage curve CDA of the open tunnel lining structure caused by the rockfall impact; calculate the ratio D based on the maximum deflection and use the classification threshold DAI cr Determine the damage level; compare the damage levels determined by CDA and ratio D, determine the damage level based on the higher principle, and determine the open hole damage morphology description and repairability recommendations.

[0051] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The method for constructing a damage assessment system for an open-cut lining structure caused by a rolling rock impact is a method for testing damage to an open-cut lining structure caused by a rolling rock impact. The constructed test system is used to collect test signals that can reflect the interactive relationship between the rolling rock impact and the response of the open-cut lining structure, and data is obtained by analyzing and processing the obtained signals to construct a generalized PI curve assessment tool for assessing the degree of damage to the open-cut lining structure caused by the rolling rock impact. Compared with the prior art, which can only construct a PI curve assessment tool for the degree of damage to concrete structural components under blast loads, but has not been able to construct such an assessment tool for the damage to concrete arch structures under impact loads, the present invention solves this technical problem. (2) The main reason why the prior art has not been able to solve the aforementioned technical problems is that, when setting up the experimental research system, the focus of the measurement of the response of the open hole lining structure under the rock rolling impact load is limited to the measurement of the local deformation of the arch structure (such as the arch crown settlement). Therefore, the problem solved is limited to obtaining the arch crown settlement and crack expansion (both are local damage characteristics of the structure), as well as the qualitative description of the damage degree classification. It is impossible to screen out the effective main control variables required for damage assessment using the graphical method, nor is it possible to establish an assessment criterion. In short, the prior art solution may be limited to the phenomenon that the rock rolling impact has a clear impact site, and the research scope is placed on the key parts of the lining structure, so it is impossible to solve the problem of establishing a graphical method assessment tool. Different from the prior art, the present invention adopts a macro research perspective, starting from constructing a damage constitutive model DCM of the open hole lining structure expressed by the damage factor, and then constructing a macro damage evolution model of the lining structure under the rock rolling impact. ψ - u , and then use the simulation test data to obtain the quantitative results of the stage characteristics of macro damage evolution, and determine the damage master variable through dimensional analysis, gradually solving the key problems in the process of constructing the generalized PI curve graphical method evaluation tool. (3) The core of establishing the master variable screening method is to follow the technical concept of the macro research perspective and construct the concrete arch structure damage assessment index DAI. The prior art has not raised this problem. The present invention has found through preliminary research that the concrete arch structure shows two characteristics in the rolling stone impact load strain: on the one hand, under the impact load, the arch displacement is indeed an important observation indicator, but more important than the degree of change of this indicator is that when the maximum displacement of the arch reaches a certain level, the damage value will show a different change trend from the previous period, that is, an exponential increase; on the other hand, in the exponential increase stage of the damage value, the structural damage is not concentrated in the impact part, or concentrated in the local area that can be predicted only from the structural mechanics analysis, but is scattered throughout the arch structure and connected into a damage surface. It is precisely because of the appearance of the damage surface, rather than the increase in the number of local damage, that the arch structure loses its bearing capacity as a whole, and then reaches a level that cannot be repaired. Since these two characteristics satisfy the allowable deflection ud The structural strain characteristics represented by the index, so the present invention innovatively introduces the allowable deflection u d Characterize the deformation characteristics of large arched concrete structures such as lining structures under rolling stone impact loads, especially to effectively measure the damage. u and allowable deflection u d By combining direct proportional indicators, the present invention constructs a simple, effective and macro-significant damage assessment index DAI, which fundamentally solves the problem of characterizing the damage process of arched concrete structures under rockfall impact loads. (4) The present invention solves the macroscopic process and measurement problems of damage to concrete arched structures under impact loads, provides a basis for constructing other types of damage assessment chart tools, and provides new ideas for research and technology development on such issues. (5) The present invention also provides an application scheme for the method of constructing a damage assessment system for open-cut lining structures under rockfall impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram of the process of constructing a damage assessment system for open tunnel lining structures subjected to rockfall impact.

[0053] Figure 2 It is a diagram of the TDC tensile damage calculation model.

[0054] Figure 3 This is a three-dimensional finite element model of the first embodiment.

[0055] Figure 4 is a sample calculation (showing a rolling stone impacting the lining).

[0056] Figure 5 is the correlation between the arch deflection and the mean damage value.

[0057] Figure 6 The macroscopic damage evolution model of open-cut lining structure under rockfall ψ - u .

[0058] Figure 7 is the condition of different (d, v) combinations of double-ear wall open hole (D cr , V cr )data.

[0059] Figure 8 It is the critical damage curve of double-ear wall open hole lining structure impacted by rolling stones.

[0060] Fig. 9 This is the three-dimensional finite element model of the second embodiment.

[0061] Fig.10 It is different from the single pressure type Mingdong (d , v )DAI under combined working conditions (d,v) .

[0062] Fig.11 It is the critical damage curve of single-pressure open-cut lining structure under rock rolling impact.

[0063] The numbers in the accompanying drawings are:

[0064] 1 side wall; 2 steel bars; 3 arch ring; 4 invert; 5 sand cushion layer; 6 concrete backfill layer; 7 open hole lining structure; 8 surrounding rock. DETAILED DESCRIPTION

[0065] The preferred embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0066] Embodiment 1

[0067] like Figures 1 to 8 As shown, the method of the present invention is used to construct a rockfall damage assessment system for a certain open hole lining structure. The open hole is a double-ear wall open hole.

[0068] Figure 1 It is a schematic diagram of the process of constructing a damage assessment system for open tunnel lining structures subjected to rockfall impact.

[0069] 1. Constructing macroscopic damage index of rockfall impact on open tunnel lining structure ψ

[0070] 1.1 Construction of DCM damage constitutive model for rockfall impact on open tunnel lining structure

[0071] In this example, the tensile damage calculation model TDC (Equation 5) is used as a specific expression of the damage constitutive model DCM of the open tunnel lining structure subjected to rockfall impact according to the present invention.

[0072] Figure 2 It is a diagram of the TDC tensile damage calculation model.

[0073] 1.2 Construction of the 3D finite element model of the rolling stone-double-ear wall open hole

[0074] For a certain Myeongdong, a Myeongdong 3D finite element model was constructed based on a typical Myeongdong design scheme. To simplify the calculation, the Myeongdong finite element model includes a sand cushion layer 5, a concrete backfill layer 6, and a lining structure 7. The lining structure 7 is a concrete-reinforced concrete (RC) structure constructed using the TDC model. Table 2 shows the material model and parameters of the Myeongdong model. The Myeongdong finite element model further adds a rolling stone part to form a rolling stone-Myeongdong 3D finite element model. Figure 3 It is a three-dimensional finite element model of the first embodiment. In the figure, (a) is the lining structure of the double-ear wall type open hole and the arrangement of the steel bar layer, and (b) is the three-dimensional finite element model of the rolling stone-double-ear wall type open hole.

[0075] Table 2 Material model and its parameter settings

[0076]

[0077] 1.3 Construction of macro damage index ψ

[0078] Damage factor d t It is defined as the damage value φ of the open hole lining structure component point expressed according to formula 6-2, and the macro damage index expressed according to formula 6-1 is constructed ψ .

[0079] 2. Constructing a macroscopic damage evolution model of open-cut lining structure subjected to rockfall ψ - u

[0080] The finite element model of the rolling stone-double-ear wall open hole structure was used to carry out simulation calculations, analyze the dynamic response of the lining structure under the influence of the rolling stone dynamic parameters and structural parameters, analyze the characteristics of the open hole lining damage evolution stage, and statistically simulate the arch deflection in the calculation data. u Macroscopic damage index ψ The second characteristic parameter is constructed by ψ and u Macroscopic damage evolution model of open-cut lining structure subjected to rockfall impact ψ - u .

[0081] Figure 4 is a calculation sample (showing a rolling stone impacting the lining), Figure 5 is the correlation between the arch deflection and the mean damage value, Figure 6 The macroscopic damage evolution model of open-cut lining structure under rockfall ψ - u .

[0082] 3. Constructing the DAS system for the classification of the degree of damage to the lining structure of open tunnels caused by rockfall

[0083] Utilizing the Model ψ - u Carry out simulation tests to analyze the evolution stages of impact damage of open-cut lining structures, and use the result data to construct a damage classification system DAS for open-cut lining structures caused by rolling stones. The system DAS includes damage classification DAC, damage assessment index DAI, and DAI classification threshold DAI. cr .

[0084] The damage classification DAC level structure is determined based on the analysis results of the impact damage evolution stage of the open hole lining structure. ψ - uThe evolution process is divided into four stages according to the stage characteristics of the evolution process shown, that is, the damage grading DAC level structure of the system DAS is designed to be 4 levels from DS1 to DS4. The description of the damage grading DAC is shown in Table 1.

[0085] The damage assessment index DAI is the arch deflection u Allowable deflection of lining structure u d The ratio D (Formula 3).

[0086] DAI Rating Threshold DAI cr They are the lower limits of each level from DS1 to DS4, respectively. u 1=0, u 2 = 3 mm, u 3 = 12 mm, u 4 = 40 mm, where u 4= u d .

[0087] Table 3 is the DAS rating threshold DAI of the system cr .

[0088] Table 3 System DAS rating threshold DAI cr

[0089]

[0090] 4. Screening of main control variables for rockfall damage in lining structures

[0091] 4.1 Determine the candidate variable Q

[0092] Based on the existing research on rockfall impact lining events, the candidate variable Q of the main control variable is selected. The candidate variable Q includes observable indicators that can characterize the rockfall structure and dynamic characteristics, and observable indicators that can characterize the open hole lining structure and response characteristics. Among them, the observable indicators that can characterize the open hole lining structure and response characteristics need to include the arch deflection u Table 4 is a list of candidate variables Q.

[0093] Table 4 Alternative variables Q

[0094]

[0095] In Table 4, the contact head shape factor N * It is an indicator to quantify the impact of irregular rolling stones on the contact head, and the compressive strength of the soil R * It is the compressive strength index of the soil specifically selected in this example, and both are determined according to the existing technology ZL 2022103972851.

[0096] 4.2 Screening the main control variables

[0097] The dimensional analysis method is used to construct the function of formula 1, and the correlation between each candidate variable Q and the indicator DAI is examined. Specifically, firstly, the basic expression of dimensional analysis is used to establish formula 9-1 (where L, M, and T represent the basic dimensions of length, mass, and time, respectively), and the setting is m , v , T s are mutually unrelated parameters, N * , θ , R * , ρ s , u As the relevant parameters, the π theorem is used to solve and the π theorem calculation model expressed by the equation group of Formula 5 is constructed; the intensity parameter correlation analysis is performed and the specific expression of Formula 7-2 is constructed as Formula 9-2, and finally the mapping function between each alternative variable Q and the indicator DAI is obtained, that is, Formula 1 is specifically expressed as Formula 10-1 and Formula 10-2.

[0098] Formula 9-1,

[0099] Formula 9-2,

[0100] Formula 10-1,

[0101] Formula 10-2.

[0102] Formula 10-1 and Formula 10-2 show the correlation coefficients of the candidate variables Q: Therefore, in this example, the two main control variables x and y for damage assessment are selected as the diameter of the rolling stone d , Stone impact velocity v .

[0103] 5. Construct CDA, a critical damage curve for rockfall impact on open tunnel lining structure

[0104] 5.1 Searching for the damage critical point (D cr , V cr )

[0105] Design 2 different combinations of main control variables ( d , v ), the DAI value under different working conditions is simulated and calculated using the equation group 10, denoted as DAI (d,v) See Figure 7 . Figure 7 is the condition of different (d, v) combinations of double-ear wall open hole (Dcr , V cr ) data, DAI for each item in the figure (d,v) The data are represented by the background colors from light to dark, namely DS1 no / mild damage, DS2 moderate damage, DS3 severe damage, and DS4 complete destruction.

[0106] Based on the simulation results, the DAI of each damage rating DAC is (d,v) According to the condition of formula 8, the threshold value DAI of this level is searched. cr The critical damage point (D cr , V cr ). In this example, the variables x, y, and X in formula 6 are cr , Y cr Corresponding to d , v , D cr 、V cr Finally, based on the damage critical point (D cr , V cr ) data, and the curve is fitted according to the function of formula 2 to obtain the damage critical curve CDA corresponding to the damage classification DAC, which is a generalized PI damage curve. Figure 8 It is the critical damage curve of double-ear wall open hole lining structure impacted by rolling stones.

[0107] Embodiment 2

[0108] like Figures 9 to 11 As shown in FIG. 1 , a rolling stone impact damage assessment system for a certain open-cut lining structure is constructed using the method of the present invention. The open-cut is a single-pressure open-cut. The construction process is as follows: Figure 1 As shown, the same parts as the first embodiment are not repeated, and the text description related to conventional data means in the field is omitted.

[0109] Fig. 9 It is a three-dimensional finite element model of Example 2. In the figure, (a) is the single-pressure open hole lining structure and steel layer arrangement, and (b) is the three-dimensional finite element model of rolling stone-single-pressure open hole. The material model and parameters of the open hole model are the same as those in Table 2.

[0110] System DAS rating threshold DAI cr The same as Table 3, and the alternative variable Q is the same as Table 4.

[0111] In this example, the two main control variables x and y for damage assessment are selected, respectively, the diameter of the rolling stone d , Stone impact velocity v . Simulate and calculate the DAI value under different working conditions, denoted as DAI (d,v) See Fig.10 . Fig.10 It is different from the single pressure type Mingdong (d , v )DAI under combined working conditions (d,v) , the background color of the table in the figure has the same meaning as Figure 7 .

[0112] According to the function fitting curve of formula 2, the damage critical curve CDA corresponding to the damage classification DAC is obtained. Fig.11 . Fig.11 It is the critical damage curve of single-pressure open-cut lining structure under rock rolling impact.

Claims

1. A method for constructing a damage assessment system for open-cut lining structures caused by rockfall, characterized in that: Step S100: construct a t The damage constitutive model DCM of the open-cut lining structure due to rockfall is expressed, and a three-dimensional finite element model of the rockfall-open-cut lining is constructed. The lining structure in the three-dimensional finite element model is constructed using the constitutive model DCM, and the macro damage index is screened. ψ , the macro damage index ψ It is an indicator that can characterize the macroscopic damage characteristics of lining structures caused by rockfall impact; Step S200: Use the three-dimensional finite element model to carry out simulation calculations, analyze the dynamic response of the open hole lining structure under the influence of rockfall dynamic parameters and structural parameters, analyze the characteristics of the open hole lining damage evolution stage, and calculate the arch deflection in the statistical simulation data. u Macroscopic damage index ψ The second characteristic parameter is constructed by ψ and u Macroscopic damage evolution model of open-cut lining structure subjected to rockfall impact ψ - u ; Step S300: Using the evolution model ψ - u Carry out simulation tests to analyze the evolution stages of impact damage of open-cut lining structures, and use the result data to construct a damage classification system DAS for open-cut lining structures caused by rolling stones. The DAS system includes damage classification DAC, damage assessment index DAI, and DAI classification threshold DAI. cr The damage classification DAC is determined according to the analysis results of the impact damage evolution stage of the open hole lining structure; the damage assessment index DAI is the ratio of the arch deflection u to the allowable deflection of the lining structure. u d The ratio D is expressed according to formula 3: Formula 3, Formula 4, In the formula, u - Arch deflection, in mm, u d - Allowable deflection of lining structure, in mm, determined according to formula 4, w -Inner width of the arch structure, in mm; Step S400: select p observable indicators in the event of rockfall impacting the open hole lining as candidate variables Q, wherein the candidate variables Q include observable indicators that can characterize the rockfall structure and dynamic characteristics, and observable indicators that can characterize the open hole lining structure and response characteristics. The observable indicators that can characterize the open hole lining structure and response characteristics include the arch deflection. u , the dimensional analysis method is used to construct the function of formula 1 and examine the correlation between each candidate variable Q and the index DAI, and the two main control variables x and y of the damage of the open hole lining structure due to rockfall are statistically selected. Formula 1; Step S500: Determine the grading thresholds DAI in the system DAS using the function of formula 1 cr The corresponding critical condition value x of the second main control variable cr With y cr , and simulate the DAI value DAI under different combinations of the two main control variables (x, y) (x,y) ; Based on DAI (x,y) Data, search for DAI at all levels cr The corresponding damage critical point (X cr , Y cr ), the damage critical point (X cr , Y cr ) is x and y satisfy the critical condition value x at the same time cr With y cr The combined working condition (x, y); the critical point of each level of damage (X cr , Y cr ) is used as the basis to construct the critical damage curve CDA of the open hole lining structure corresponding to each damage classification DAC. The curve CDA is expressed according to formula 2: Formula 2, Where, C is constant coefficient.

2. The damage assessment system construction method according to claim 1, characterized in that: In step S100, the damage constitutive model DCM of the open hole lining structure due to rockfall is a tensile damage calculation model TDC, which is expressed by the equation group 5: Formula 5-1, Formula 5-2, Formula 5-3, In the formula, σ t - Concrete tensile stress, unit: MPa, d t - concrete tensile damage factor, E0 - concrete lossless elastic modulus, unit MPa, ε t - tensile strain of concrete, ε pl - Equivalent plastic strain of concrete under tension, ε ck - Concrete cracking strain; the units and determination methods of each variable are the same as those of the concrete damage plasticity model.

3. The damage assessment system construction method according to claim 2, characterized in that: The macroscopic damage index ψ Lining structure N Damage factor d t The mean value is expressed according to formula 6-1, and the damage factor d t According to formula 6-2, Formula 6-1, Formula 6-2, In the formula, φ( i , t )-No. i The lining structure component point at time t The damage value, dimensionless, N - Number of lining structure component points.

4. The damage assessment system construction method according to claim 1, characterized in that: The damage level classification system DAS for rockfall impact on open-cut lining structure includes 4 levels of damage classification DAC: 。 5. The damage assessment system construction method according to claim 1, characterized in that: In the candidate variable Q in step S400, the observable index capable of characterizing the structure and dynamic characteristics of the rolling stone includes the mass of the rolling stone m , impact speed v , Contact head form factor N * , impact angle θ The observable indicators that can characterize the open hole lining structure and response characteristics include the compressive strength index of the soil, density ρ s ,thickness T s , Arch deflection u .

6. The damage assessment system construction method according to claim 5, characterized in that: Step S400: The compressive strength index of the soil is the compressive strength of the soil. R * ; The dimensional analysis method is the π theorem, setting m , v , T s are mutually unrelated parameters, N * , θ , R * , ρ s , u are related parameters.

7. The damage assessment system construction method according to claim 6, characterized in that: Construct the π theorem calculation model expressed by the equation group 7, Formula 7-1, Formula 7-2.

8. The damage assessment system construction method according to claim 1, characterized in that: In step S500, according to the condition of formula 8, DAI (x,y) Search for critical points of damage at all levels (X cr , Y cr ), Formula 8, Where, C is constant coefficient.

9. Application of the method for constructing a damage assessment system for rockfall impact open hole lining structure according to any one of claims 1 to 8, characterized in that: It is an application in the quantitative assessment of damage to open tunnel lining structures caused by rockfall.

10. The use according to claim 9, characterized in that: Use the following table to obtain the description of the open hole damage morphology and repairability suggestions. 。

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