Method for evaluating residual service performance and toughness of tunnel grouting reinforced surrounding rock

Abstract

The invention discloses a residual service performance and toughness evaluation method for tunnel grouting reinforcement surrounding rock, and belongs to the technical field of tunnel engineering safety and disaster prevention and reduction. The problems that in the prior art, only a single static strength index is concerned, temperature-impact coupling damage cannot be evaluated, and toughness and dynamic performance cannot be quantified are solved. The method comprises the following steps: preparing a representative sample, simulating fire high-temperature damage and dynamic impact damage, carrying out static and dynamic mechanical tests, extracting key parameters, establishing a comprehensive residual service performance index and a temperature-impact coupling toughness index, and evaluating the performance and the toughness. The comprehensive performance degradation of the grouting surrounding rock after the fire disaster under the complex load can be scientifically and systematically quantified, and accurate and reliable technical support is provided for safety evaluation, toughness repair and performance improvement design after the tunnel fire disaster.

Description

Technical Field

[0001] This invention belongs to the field of tunnel engineering safety and disaster prevention and mitigation technology, and in particular relates to a method for evaluating the remaining service performance and toughness of tunnel grouting reinforced surrounding rock. Background Technology

[0002] Tunnel fires are among the most serious disasters during tunnel operation. The high temperatures generated can cause degradation of the material properties of the grouting-reinforced surrounding rock behind the lining, leading to a significant decrease in load-bearing capacity, stiffness, and toughness. Even more serious is the possibility of extreme events within the tunnel, such as vehicle fuel tank explosions or structural component collapses, which, combined with the high temperatures, generate intense dynamic impact loads on the surrounding rock. This coupling effect of high-temperature softening and impact damage drastically alters the material's mechanical response and failure mode. As a crucial component of the tunnel-surrounding rock collaborative load-bearing system, the post-disaster performance degradation of the grouting-reinforced surrounding rock directly determines the tunnel's safety margin and functional recovery costs.

[0003] Currently, safety assessments of tunnel structures after fires largely focus on the residual strength of materials such as lining concrete under static loads, resulting in a single assessment indicator. However, existing technologies have significant shortcomings when it comes to grouting and reinforcing the surrounding rock behind the lining, which cannot be directly accessed. First, current methods primarily focus on the static indicator of residual strength, lacking quantitative assessments of material toughness and damage tolerance. Toughness, however, is a key performance indicator for measuring a structure's ability to absorb energy and prevent brittle fracture during a disaster. Second, the assessment process fails to adequately consider the dynamic impact loads that may accompany tunnel fires, completely ignoring the real disaster mechanism of temperature field coupling with impact loads, leading to discrepancies between assessment results and actual conditions. Third, existing technologies fail to systematically analyze the rate-related characteristics of materials under impact loads from a dynamic mechanical performance perspective. Finally, due to the lack of indicators for quantifying the toughness loss of grouting surrounding rock under dynamic loads, existing methods struggle to support a scientific assessment of the overall impact toughness of the tunnel, preventing engineers from developing precise repair and reinforcement plans based on comprehensive performance degradation data.

[0004] The aforementioned problems and shortcomings stem from insufficient understanding of the damage mechanisms of complex composites like grout-reinforced surrounding rock under coupled disasters, and the lack of a standardized testing and evaluation method capable of simultaneously acquiring static and dynamic mechanical properties and establishing comprehensive quantitative indicators. This makes it difficult to scientifically and systematically assess the remaining service performance and toughness of the surrounding rock in the safety assessment and repair design after a tunnel fire, thus creating potential safety hazards for the long-term operation of the tunnel. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a method for evaluating the remaining service performance and toughness of grouting-reinforced surrounding rock in tunnels. This method can scientifically and systematically quantify the comprehensive performance degradation of grouting surrounding rock under complex loads after a fire, providing accurate and reliable technical support for safety assessment, toughness repair, and performance enhancement design after a tunnel fire.

[0006] To achieve the above objectives, the present invention provides a method for evaluating the remaining service performance and toughness of tunnel grouting-reinforced surrounding rock, comprising:

[0007] The surrounding rock aggregate was collected from the engineering site and screened. Indoor pressure grouting simulation was carried out using grouting materials to prepare standard cylindrical samples.

[0008] The standard cylindrical samples were grouped, placed in a high-temperature environment and heated to different target temperatures and held at that temperature to simulate high-temperature damage from a fire, and then cooled to room temperature.

[0009] Dynamic impact compression tests at different strain rates were conducted on high-temperature treated specimens using a dynamic impact testing system to obtain dynamic stress-strain curves.

[0010] Static compression tests under confining pressure were conducted on another set of specimens after high-temperature treatment using a static triaxial testing machine to obtain static stress-strain curves.

[0011] Based on the dynamic stress-strain curves and static stress-strain curves, the peak strength, elastic modulus, ductility coefficient, and energy absorption parameters for static and dynamic stress-strain are extracted.

[0012] Based on the extracted static and dynamic peak strength, elastic modulus, ductility coefficient and energy absorption parameters, a first index for comprehensively evaluating remaining service performance and a second index for evaluating temperature-impact coupling toughness are constructed respectively.

[0013] The damage level and performance degradation trend of the grouting-reinforced surrounding rock are evaluated based on the values ​​of the first and second indicators.

[0014] Optionally, the preparation of standard cylindrical specimens includes:

[0015] The actual graded rock blocks obtained after screening are used as aggregates and filled into the mold.

[0016] A grout similar to that used in the engineering prototype was injected into the mold under pressure to fill the voids in the aggregate, forming a grouting stone body.

[0017] After curing the grouting stone body, it is drilled, cut and polished to make a cylindrical sample that meets the test standards.

[0018] Optionally, heating to different target temperatures in a high-temperature environment includes:

[0019] After grouping the samples, they were placed in a high-temperature furnace;

[0020] Each group of samples was heated to a different target temperature at a set heating rate;

[0021] After reaching the target temperature, maintain the temperature for a period of time to ensure that the sample is heated evenly.

[0022] Optionally, dynamic impact compression testing may include:

[0023] The specimen was impacted using a split Hopkinson bar test system;

[0024] Adjust the impact conditions to ensure the test strain rate covers 50 s. -1 up to 800 s -1 The range.

[0025] Optionally, static compression tests under confining pressure conditions may include:

[0026] The test confining pressure is set according to the actual burial depth of the tunnel and the ground stress conditions;

[0027] The specimen is placed in a triaxial pressure chamber, and the confining pressure is applied first, followed by an axial load until the specimen fails.

[0028] Optional, the extracted parameters include:

[0029] Extract static peak strength, static elastic modulus, static ductility coefficient, and static energy absorption capacity;

[0030] Extract dynamic peak strength, dynamic elastic modulus, dynamic ductility coefficient, and dynamic energy absorption capacity;

[0031] Calculate the ratio of dynamic strength to static strength, which serves as the dynamic increase factor.

[0032] Optionally, constructing the first metric includes:

[0033] The ratios of static strength and elastic modulus at high temperature relative to the reference value at room temperature, the ratio of dynamic strength and elastic modulus relative to the reference value at room temperature, and the ratio of dynamic increase factor relative to the reference value at room temperature are weighted and summed.

[0034] Optionally, constructing a second metric includes:

[0035] The ratios of the static ductility coefficient and the dynamic ductility coefficient after high temperature relative to the reference value at room temperature, as well as the ratios of the static energy absorption capacity and the dynamic energy absorption capacity relative to the reference value at room temperature, are weighted and summed.

[0036] Technical Effects of this Invention: This invention discloses a method for evaluating the remaining service performance and toughness of grout-reinforced surrounding rock in tunnels, overcoming the limitations of existing technologies that only focus on a single static strength index. By coupling dynamic impact damage and high-temperature damage, it shifts from a single static high-temperature assessment to a more realistic temperature-impact coupled comprehensive assessment, representing a more advanced concept and a more comprehensive evaluation dimension. The innovatively established two dimensionless comprehensive indices can simultaneously quantify service performance and toughness characteristics, avoiding the problems of complex parameters and difficult calibration in traditional constitutive models, making the evaluation process more intuitive and efficient. By comparing static and dynamic mechanical performance parameters, the influence of high-temperature damage on material rate-related properties can be revealed, uncovering coupled damage mechanisms that cannot be observed in single-factor tests. The established index system can adjust weights according to different engineering characteristics, adapting to various geological conditions and fire intensities, providing an efficient and practical evaluation tool for the full-condition safety analysis and performance prediction of post-disaster tunnel structures, thus providing accurate and reliable technical support for safety assessment, toughness repair, and performance enhancement design after tunnel fires. Attached Figure Description

[0037] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0038] Figure 1 This is a flowchart illustrating a method for evaluating the remaining service performance and toughness of tunnel grouting-reinforced surrounding rock according to an embodiment of the present invention.

[0039] Figure 2 This is a diagram showing the changes in the apparent morphology of the grouting stone body after being subjected to different temperatures according to an embodiment of the present invention.

[0040] Figure 3 This is a static stress-strain curve of the grouting stone body in an embodiment of the present invention at a temperature of 25°C;

[0041] Figure 4 This is a static stress-strain curve of the grouting stone body in an embodiment of the present invention at a temperature of 200℃;

[0042] Figure 5 This is a static stress-strain curve of the grouting stone body in an embodiment of the present invention at a temperature of 400℃;

[0043] Figure 6 This is a static stress-strain curve of the grouting stone body in an embodiment of the present invention at a temperature of 600℃;

[0044] Figure 7 This is a graph showing the variation of CRPI and TIRI indices with temperature in an embodiment of the present invention. Detailed Implementation

[0045] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0046] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0047] like Figure 1 As shown in the figure, this embodiment provides a method for evaluating the remaining service performance and toughness of tunnel grouting reinforced surrounding rock, including:

[0048] The surrounding rock aggregate was collected from the engineering site and screened. Indoor pressure grouting simulation was carried out using grouting materials to prepare standard cylindrical samples.

[0049] The standard cylindrical samples were grouped, placed in a high-temperature environment and heated to different target temperatures and held at that temperature to simulate high-temperature damage from a fire, and then cooled to room temperature.

[0050] Dynamic impact compression tests at different strain rates were conducted on high-temperature treated specimens using a dynamic impact testing system to obtain dynamic stress-strain curves.

[0051] Static compression tests under confining pressure were conducted on another set of specimens after high-temperature treatment using a static triaxial testing machine to obtain static stress-strain curves.

[0052] Based on the dynamic stress-strain curves and static stress-strain curves, the peak strength, elastic modulus, ductility coefficient, and energy absorption parameters for static and dynamic stress-strain are extracted.

[0053] Based on the extracted static and dynamic peak strength, elastic modulus, ductility coefficient and energy absorption parameters, a first index for comprehensively evaluating remaining service performance and a second index for evaluating temperature-impact coupling toughness are constructed respectively.

[0054] The damage level and performance degradation trend of the grouting-reinforced surrounding rock are evaluated based on the values ​​of the first and second indicators.

[0055] Furthermore, the preparation of standard cylindrical specimens includes:

[0056] The actual graded rock blocks obtained after screening are used as aggregates and filled into the mold.

[0057] A grout similar to that used in the engineering prototype was injected into the mold under pressure to fill the voids in the aggregate, forming a grouting stone body.

[0058] After curing the grouting stone body, it is drilled, cut and polished to make a cylindrical sample that meets the test standards.

[0059] Specifically, the implementation process of this embodiment is as follows:

[0060] First, fragmented mudstone and sandstone were collected as aggregates from the surrounding rock in the area affected by the tunnel fire or from areas with similar geological conditions. The collected fragments were then sieved, and based on the sieve results, they were configured into a particle aggregate that accurately reflects the gradation of the in-situ surrounding rock. In this embodiment, the aggregate particle size was controlled at 0-10 mm, with approximately 50% of the particles being 2-5 mm in diameter, to simulate a moderate degree of crushing.

[0061] Then, using the same PO 42.5 ordinary Portland cement as the original tunnel design, the grout was prepared at a water-cement ratio of 0.8:1. The prepared aggregate was filled into a self-made steel mold, and the grout was injected into the mold at a pressure of 2MPa using a pressure grouting machine to ensure that the grout fully filled the gaps between the aggregates, simulating the on-site pressure grouting process.

[0062] After grouting, the sample was cured for 28 days under standard curing conditions (temperature 20±2℃, relative humidity above 95%). After curing, a core sample was drilled from the large stone body using a diamond drill bit. After cutting, end face grinding and other finishing processes, a standard cylindrical sample with a size of Φ50mm×100mm was finally made. Its flatness and perpendicularity met the rock mechanics test standards recommended by ISRM.

[0063] Furthermore, heating to different target temperatures in a high-temperature environment includes:

[0064] After grouping the samples, they were placed in a high-temperature furnace;

[0065] Each group of samples was heated to a different target temperature at a set heating rate;

[0066] After reaching the target temperature, maintain the temperature for a period of time to ensure that the sample is heated evenly.

[0067] Specifically, the implementation process of this embodiment is as follows:

[0068] The standard cylindrical samples were grouped and placed in a high-temperature furnace. They were heated to different target temperatures and kept at these temperatures to simulate the different maximum temperature conditions experienced by the grouting surrounding rock during a fire. They were then allowed to cool naturally to room temperature. The appearance and physical records of high and low temperature damage were recorded. The color changes, crack development, and pore expansion of each group of samples after high-temperature treatment were recorded, and their mass loss rate was calculated by weighing.

[0069] The prepared standard samples were divided into 4 groups, with at least 3 parallel samples in each group to ensure the reliability of the test results. Each group of samples was placed in an RX3-45-9 type box-type resistance furnace.

[0070] The furnace temperature was increased to four target temperatures: 25℃ (room temperature control group), 200℃, 400℃, and 600℃, at a heating rate of 5℃ / min. After reaching the target temperature, the temperature was maintained for 2 hours to ensure uniform heating inside and outside the sample, simulating the continuous high-temperature action of a fire.

[0071] After the temperature control period, the power was turned off, and the sample was allowed to cool naturally to room temperature with the furnace. This process avoids secondary damage to the microstructure of the sample caused by the quenching effect. After cooling, the sample was removed for observation and weighing. The degradation of apparent properties was recorded as follows: Figure 2 As shown; Physical parameters to be measured: Weigh each group of samples using an electronic balance (accuracy 0.01g) and calculate their mass loss rate.

[0072] Furthermore, dynamic impact compression testing includes:

[0073] The specimen was impacted using a split Hopkinson bar test system;

[0074] Adjust the impact conditions to ensure the test strain rate covers 50 s. -1 up to 800 s -1 The range.

[0075] Specifically, the implementation process of this embodiment is as follows:

[0076] Using a split Hopkinson bar test system, the treated specimens were subjected to different strain rates (e.g., 100 s). -1 ~500 s -1 The dynamic impact compression test under SHPB simulates the impact loads such as explosions during a fire, and obtains its dynamic stress-strain curve; the strain rate range of the SHPB test should cover the strain rate range that may be caused by tunnel explosion impact, preferably 50s. -1 up to 800 s -1 .

[0077] Dynamic impact tests were conducted using the SHPB split Hopkinson bar system. Based on one-dimensional elastic wave theory, the dynamic stress, strain, and strain rate of the specimens were calculated. By adjusting the impact gas pressure, complete dynamic stress-strain curves for specimens at different temperature groups under different strain rates were obtained. The results show that with increasing temperature, the dynamic peak strength and elastic modulus of the material decrease significantly, while the peak strain and ductility increase.

[0078] Furthermore, static compression tests under confining pressure conditions include:

[0079] The test confining pressure is set according to the actual burial depth of the tunnel and the ground stress conditions;

[0080] The specimen is placed in a triaxial pressure chamber, and the confining pressure is applied first, followed by an axial load until the specimen fails.

[0081] Specifically, the implementation process of this embodiment is as follows:

[0082] Another set of parallel samples after high temperature were subjected to conventional triaxial compression tests using a rock triaxial testing machine. The confining pressure was set according to the tunnel burial depth and ground stress conditions. Complete static stress-strain curves of the grouting stone body under different temperature conditions were obtained.

[0083] A triaxial rock testing system was used for the test. Based on the actual burial depth of the tunnel, 10 MPa was selected as the confining pressure to simulate the stress state under its service environment. The heated specimen was placed in the triaxial pressure chamber, and the set confining pressure was applied until stability was achieved. Then, an axial load was applied at a controlled displacement rate of 0.5 mm / min until the specimen completely failed. The testing system automatically recorded the axial stress, axial strain, and radial strain throughout the loading process, and plotted a complete stress-strain curve, as shown below. Figures 3-6 As shown in the figure, this curve fully reveals the material's service performance throughout the entire process, from compaction, elasticity, yielding to post-peak softening.

[0084] Furthermore, the extracted parameters include:

[0085] Extract static peak strength, static elastic modulus, static ductility coefficient, and static energy absorption capacity;

[0086] Extract dynamic peak strength, dynamic elastic modulus, dynamic ductility coefficient, and dynamic energy absorption capacity;

[0087] Calculate the ratio of dynamic strength to static strength, which serves as the dynamic increase factor.

[0088] Specifically, the implementation process of this embodiment is as follows:

[0089] Key parameters for evaluating service performance are comprehensively extracted from the static and dynamic stress-strain curves, including static and dynamic peak strength, static and dynamic elastic modulus, static and dynamic peak strain, static and dynamic ductility coefficient, and area under the stress-strain curve; in particular, the changes in material rate-related properties after a fire are quantified by calculating the dynamic increase factor (DIF).

[0090] like Figures 3-6 As shown, where Figure 3 This is a static stress-strain curve of the grouting stone body in an embodiment of the present invention at a temperature of 25°C; Figure 4 This is a static stress-strain curve of the grouting stone body in an embodiment of the present invention at a temperature of 200℃; Figure 5 This is a static stress-strain curve of the grouting stone body in an embodiment of the present invention at a temperature of 400℃; Figure 6 This is a static stress-strain curve of the grouting stone body at 600℃, according to an embodiment of the present invention; Figures 3-6 Extract key indicators for assessing remaining service performance and damage toughness:

[0091] Static parameter: Static peak intensity (σ) c Static elastic modulus (E); Static peak strain (ε) c Static yield strain (ε) y ); Static ductility coefficient (μ); Static energy absorption (W).

[0092] Dynamic parameter: Dynamic peak intensity (σ) dc Dynamic elastic modulus (E) d Dynamic peak strain (ε) dc ); Dynamic ductility coefficient (μ) d Dynamic energy absorption (W) d ); Dynamic addition factor (DIF).

[0093] Establish the Comprehensive Remaining Service Performance Index (CRPI) and the Temperature-Shock Coupled Toughness Index (TIRI).

[0094] Furthermore, the construction of the first indicator includes:

[0095] The ratios of static strength and elastic modulus at high temperature relative to the reference value at room temperature, the ratio of dynamic strength and elastic modulus relative to the reference value at room temperature, and the ratio of dynamic increase factor relative to the reference value at room temperature are weighted and summed.

[0096] Furthermore, the construction of the second indicator includes:

[0097] The ratios of the static ductility coefficient and the dynamic ductility coefficient after high temperature relative to the reference value at room temperature, as well as the ratios of the static energy absorption capacity and the dynamic energy absorption capacity relative to the reference value at room temperature, are weighted and summed.

[0098] Specifically, the implementation process of this embodiment is as follows:

[0099] Based on the obtained parameters, calculate the CRPI and TIRI indices at each temperature:

[0100] CRPI calculation:

[0101] For example, using weighting coefficients α=0.4, β=0.4, and γ=0.2, with 25℃ as the reference temperature, the calculation results are as follows:

[0102] 25℃: CRPI = 0.4×(45.2 / 45.2)×(8.6 / 8.6) + 0.4×(62.8 / 62.8)×(12.1 / 12.1) + 0.2×(1.39 / 1.39) = 1.000;

[0103] 200℃: CRPI = 0.4×(38.6 / 45.2)×(7.2 / 8.6) + 0.4×(51.3 / 62.8)×(9.8 / 12.1) + 0.2×(1.33 / 1.39) = 0.716;

[0104] 400℃: CRPI = 0.4×(29.5 / 45.2)×(5.1 / 8.6) + 0.4×(37.8 / 62.8)×(6.9 / 12.1) + 0.2×(1.28 / 1.39) = 0.507;

[0105] 600℃: CRPI = 0.4×(21.6 / 45.2)×(3.0 / 8.6) + 0.4×(26.1 / 62.8)×(4.2 / 12.1) + 0.2×(1.21 / 1.39) = 0.304;

[0106] TIRI calculation:

[0107] Using weighting coefficients δ=0.25, ε=0.35, ζ=0.15, and η=0.25, the calculation results are as follows:

[0108] 25℃: TIRI = 0.25×(2.4 / 2.4) + 0.35×(2.8 / 2.8) + 0.15×(0.27 / 0.27) +0.25×(0.47 / 0.47) = 1.000;

[0109] 200℃: TIRI = 0.25×(2.9 / 2.4) + 0.35×(3.2 / 2.8) + 0.15×(0.27 / 0.27) +0.25×(0.46 / 0.47) = 1.087;

[0110] 400℃: TIRI = 0.25×(4.2 / 2.4) + 0.35×(4.8 / 2.8) + 0.15×(0.27 / 0.27) +0.25×(0.43 / 0.47) = 1.428;

[0111] 600℃: TIRI = 0.25×(5.3 / 2.4) + 0.35×(6.1 / 2.8) + 0.15×(0.25 / 0.27) +0.25×(0.38 / 0.47) = 1.654.

[0112] Further applications in performance and resilience assessment: Based on the calculated CRPI and TIRI values, performance degradation curves are plotted as follows... Figure 7 As shown, a comprehensive evaluation will be conducted according to the grade evaluation standards.

[0113] This invention discloses a method for evaluating the remaining service performance and toughness of tunnel grouting reinforced surrounding rock. Compared with the prior art, the improvement of this invention lies in:

[0114] For the first time, dynamic impact damage and high-temperature damage are coupled to establish a comprehensive evaluation index system, moving from a single "static high-temperature assessment" to a "temperature-impact coupled comprehensive assessment" that is closer to the reality of disasters. The concept is more advanced and the assessment dimensions are more comprehensive.

[0115] The innovative establishment of two dimensionless comprehensive indices, CRPI and TIRI, enables the simultaneous quantification of service performance and toughness characteristics, avoiding the problems of complex parameters and difficult calibration of traditional constitutive models, and making the evaluation process more intuitive and efficient.

[0116] By comparing static and dynamic mechanical property parameters, we can reveal the influence of high-temperature damage on the rate-related properties of materials and discover coupled damage mechanisms that cannot be observed by single-factor experiments.

[0117] The established index system can adjust the weight coefficients according to different engineering characteristics, adapt to various geological conditions and fire intensities, and provides an efficient and practical evaluation tool for the full-condition safety analysis and performance prediction of post-disaster tunnel structures.

[0118] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for evaluating the residual service performance and toughness of surrounding rock reinforced by tunnel grouting, characterized in that, The method comprises the following steps: Collecting and screening surrounding rock aggregate from an engineering site, and using grouting material to simulate indoor pressure grouting to prepare standard cylindrical samples; Grouping the standard cylindrical samples, heating them to different target temperatures in a high-temperature environment, and keeping them at the target temperatures to simulate fire high-temperature damage, and then cooling them to room temperature; Using a dynamic impact test system to conduct dynamic impact compression tests on the high-temperature treated samples at different strain rates to obtain dynamic stress-strain curves; Using a static triaxial test machine to conduct static compression tests on another group of high-temperature treated samples under confining pressure to obtain static stress-strain curves; According to the dynamic stress-strain curves and the static stress-strain curves, extracting the static and dynamic peak strengths, elastic moduli, ductility coefficients, and energy absorption parameters; Based on the extracted static and dynamic peak strengths, elastic moduli, ductility coefficients, and energy absorption parameters, constructing a first index for comprehensive evaluation of residual service performance and a second index for evaluation of temperature-impact coupling toughness; According to the numerical values of the first index and the second index, evaluating the damage level and performance degradation trend of the grouting reinforced surrounding rock.

2. The method for evaluating the residual service performance and toughness of the surrounding rock reinforced by tunnel grouting according to claim 1, characterized in that, The preparation of the standard cylindrical samples comprises the following steps: Filling the real-graded rock blocks obtained after screening into a mold as aggregate; Using a slurry similar to the engineering prototype, filling the aggregate voids in the mold under pressure to form a grouting stone body; After curing the grouting stone body, drilling, cutting, and polishing processing are performed to produce cylindrical samples that meet the test standards.

3. The method for evaluating the residual service performance and toughness of the surrounding rock reinforced by tunnel grouting according to claim 1, characterized in that, Heating the samples to different target temperatures in a high-temperature environment comprises the following steps: Grouping the samples and placing them in a high-temperature furnace; Heating each group of samples to different target temperatures at a set heating rate; After reaching the target temperature, keeping the temperature constant for a period of time to ensure uniform heating of the samples.

4. The method for evaluating the residual service performance and toughness of the surrounding rock reinforced by tunnel grouting according to claim 1, characterized in that, The dynamic impact compression test comprises the following steps: Using a split Hopkinson pressure bar (SHPB) test system to impact the samples; The impact conditions were adjusted so that the test strain rate covered a range of 50 s -1 to 800 s -1 .

5. The method for evaluating the residual service performance and toughness of the surrounding rock reinforced by tunnel grouting according to claim 1, characterized in that, The static compression test under confining pressure comprises the following steps: Setting the test confining pressure according to the actual burial depth and ground stress conditions of the tunnel; Placing the samples in a triaxial pressure chamber, first applying the confining pressure, and then applying an axial load until the sample fails.

6. The method for evaluating the residual service performance and toughness of the surrounding rock reinforced by tunnel grouting according to claim 1, characterized in that, The parameter extraction comprises the following steps: Extracting the static peak strength, static elastic modulus, static ductility coefficient, and static energy absorption capacity; Extracting the dynamic peak strength, dynamic elastic modulus, dynamic ductility coefficient, and dynamic energy absorption capacity; Calculating the ratio of dynamic strength to static strength as a dynamic increase factor.

7. The method for evaluating the residual service performance and toughness of the surrounding rock reinforced by tunnel grouting according to claim 1, characterized in that, The construction of the first index comprises the following steps: Weighted summing the ratios of the static strength and elastic modulus after high-temperature treatment to the reference values at room temperature, the ratios of the dynamic strength and elastic modulus to the reference values at room temperature, and the ratio of the dynamic increase factor to the reference value at room temperature.

8. The method for evaluating the residual service performance and toughness of the surrounding rock reinforced by tunnel grouting according to claim 1, characterized in that, The construction of the second index comprises the following steps: Weighted summing the ratios of the static ductility coefficient and the dynamic ductility coefficient after high-temperature treatment to the reference values at room temperature, and the ratios of the static energy absorption capacity and the dynamic energy absorption capacity to the reference values at room temperature.

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