A layer advantage seepage driving group anchor corrosion test device and test method

Abstract

The application discloses a kind of layer advantage seepage driving group anchor corrosion test device and test method, including shell, simulation rock mass, seepage system and observation system, simulation rock mass is set in shell, simulation rock mass is layered rock mass with anisotropy and interface effect, multiple anchor rods are arranged on it along vertical direction, simulation rock mass simulates slope structure, simulation rock mass and anchor rod on it together form simulation anchoring system, electrolyte system is used to form layer advantage seepage environment in simulation rock mass, to simulate in rock mass permeability, hydraulic gradient and pore structure lead to the intensification of local corrosion phenomenon caused by advantage seepage path.This design not only can simulate the intensification of local corrosion phenomenon caused by advantage seepage path, effectively improve the accuracy of corrosion test, and can truly reproduce the control effect of layered structure on seepage path and corrosion process, effectively improve the engineering representativeness of corrosion test.

Description

Technical Field

[0001] This invention relates to a corrosion testing device for anchoring systems, and more particularly to a corrosion testing device and method for group anchors driven by layer-dominant seepage. Background Technology

[0002] Anchor bolts (cables) are widely used reinforcement components in geotechnical engineering projects such as slopes, tunnels, underground caverns, and foundation pits. They are subjected to complex geological environments and groundwater over long periods, and their durability directly affects the safety and lifespan of the project. Especially in layered rock masses, due to significant differences in permeability at rock layer interfaces, groundwater often forms dominant seepage channels along the bedding planes, accelerating the migration and accumulation of corrosive media, making the anchor bolt system more susceptible to localized corrosion or even group failure.

[0003] Currently, most research methods for anchor bolt corrosion problems involve using indoor corrosion testing equipment to test the corrosion behavior of a single anchor bolt in a static or simple circulating solution. This method is important for studying corrosion mechanisms due to its strong controllability and measurable parameters.

[0004] Although this experimental setup can be used to study the corrosion mechanism of a single anchor bolt, it still has the following limitations:

[0005] 1. In actual engineering, anchor corrosion is a dynamic process driven by seepage. The movement of corrosive media is controlled by rock permeability, hydraulic gradient and pore structure. Most existing tests immerse anchors in a homogeneous solution, ignoring the direct influence of the seepage field on ion transport, concentration distribution and corrosion electrochemical process. In particular, they cannot simulate the localized corrosion intensification caused by the dominant seepage path in layered rock masses.

[0006] 2. The anisotropy and interface effects of layered rock masses significantly affect the distribution of the seepage field and the corrosion behavior of the anchor bolt-rock interface. At the same time, existing tests mostly use homogeneous rock samples or simplified materials, which fail to truly reproduce the control effect of the layered structure on the seepage path and corrosion process, thus weakening the engineering representativeness of the test results.

[0007] The information disclosed in this background section is intended only to enhance understanding of the overall background of this application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of existing technologies that cannot simulate dominant seepage paths and have poor engineering representativeness, and to provide a layered dominant seepage-driven group anchor corrosion test device that can simulate dominant seepage paths and has good engineering representativeness.

[0009] To achieve the above objectives, the technical solution of the present invention is:

[0010] A layered seepage-driven group anchor corrosion test device, the corrosion test device comprising: a shell, a simulated rock mass, a seepage system, and an observation system;

[0011] The shell is a square box structure, and the simulated rock mass is set on a fixed base at the bottom of the shell. The simulated rock mass is a layered rock mass with anisotropy and interface effect, and multiple anchor rods are set on the simulated rock mass along the vertical direction.

[0012] The seepage system is used to create a bedding-dominant seepage environment within the simulated rock mass;

[0013] The observation system is used to monitor the simulated rock mass and each anchor bolt in real time and collect experimental data.

[0014] The seepage system includes a high-pressure plunger pump, an inlet pipeline, an outlet pipeline, and a waste liquid collector;

[0015] The outlet of the high-pressure plunger pump is connected to the inlet of the housing via an inlet pipe, and the outlet of the housing is connected to the waste liquid collector via a drain pipe.

[0016] Both the inlet and outlet pipes are equipped with precision regulating valves and high-sensitivity hydraulic gauges.

[0017] The high-pressure plunger pump has dual-mode control capability, which can be used to accurately control the seepage rate of the electrolyte in constant flow mode, or to simulate the seepage conditions of constant head difference in constant pressure mode, so as to form a seepage field in the shell.

[0018] The precision regulating valve is used to precisely regulate the fluid pressure in the inlet and outlet lines of the high-pressure plunger pump.

[0019] The high-sensitivity hydraulic gauge is used to accurately measure the fluid pressure in the inlet and outlet lines of the high-pressure plunger pump.

[0020] The waste liquid collector is used to collect the electrolyte that passes through the casing.

[0021] The inner wall of the shell is uniformly coated with an epoxy resin anti-corrosion coating. High-strength permeable stones are provided on the inner walls of the front and rear sides of the shell. The high-strength permeable stones are used to make the seepage field uniformly distributed in the cross-section. High-elastic latex sealing gaskets are provided on the top plate, left and right side walls and fixed base of the inner wall of the shell.

[0022] The simulated rock mass comprises multiple layers of parallel stacked rock slabs, which are made of silicate cement, calcareous sand and deionized water, and the upper and lower surfaces of the rock slabs have textures.

[0023] Multiple anchor bolts are arranged on the simulated rock mass in a matrix, quincunx, or engineering equivalent pattern.

[0024] The observation system includes an anchor bolt mechanical state monitoring device, an anchor bolt electrochemical corrosion monitoring device, a rock mass internal seepage field monitoring device, an auxiliary environmental parameter monitoring device, and a data synchronous acquisition unit;

[0025] The anchor bolt mechanical state monitoring device is a resistance strain gauge or vibrating wire tension sensor. The anchor bolt mechanical state monitoring device is set between the anchor head of each anchor bolt and the top plate of the shell, and is used to continuously record the time history change curve of the prestress of each anchor bolt during the corrosion process.

[0026] The anchor bolt electrochemical corrosion monitoring device is a multi-channel electrochemical workstation or a zero-resistance galvanometer. The anchor bolt electrochemical corrosion monitoring device uses each anchor bolt as an independent working electrode. By measuring the potentiodynamic polarization curve of each anchor bolt, the instantaneous corrosion current density of each anchor bolt is calculated, so as to realize the quantitative and in-situ assessment of corrosion rate and corrosion mechanism.

[0027] The rock mass internal seepage field monitoring device includes multiple micro pore water pressure sensors. Each of the rock mass internal seepage field monitoring devices is uniformly arranged along the three-dimensional spatial grid nodes inside the simulated rock mass. The rock mass internal seepage field monitoring device is used to sense and transmit seepage pressure data at different locations inside the simulated rock mass in real time.

[0028] The auxiliary environmental parameter monitoring device includes a pH sensor, a redox potential sensor, and an ion-selective electrode. The auxiliary environmental parameter monitoring device is installed at the liquid inlet, liquid outlet, and between each rock plate of the shell, and is used to monitor the changes in the fluid chemical environment during the seepage process in real time.

[0029] The data synchronization acquisition unit is a central data acquisition instrument. The data synchronization acquisition unit is used to collect data from the anchor bolt mechanical state monitoring device, the anchor bolt electrochemical corrosion monitoring device, the rock mass internal seepage field monitoring device, and the auxiliary environmental parameter monitoring device, and to ensure the spatiotemporal consistency of all data.

[0030] A method for testing corrosion of anchorages driven by seepage at a layered advantage, the method comprising the following steps:

[0031] S1. Based on the structure of the slope to be tested, a simulated rock mass is manufactured. Anchor holes are drilled on the manufactured simulated rock mass, and the pre-treated anchor rods are installed into the anchor holes. The simulated rock mass with the anchor rods installed is then placed inside the shell.

[0032] S2. Connect the seepage system to the inlet and outlet on the shell, and then install the observation system inside and outside the shell;

[0033] S3. Configure electrolyte for the seepage system and adjust the seepage system to the set working type and working flow rate. After the seepage system is adjusted, start the high-pressure plunger pump to conduct a corrosion test on the anchor bolt, and at the same time, the observation system collects the experimental data in real time.

[0034] S4. Construct a spatiotemporal evolution model, perform parameter sensitivity analysis on the experimental data using the spatiotemporal evolution model, and obtain the parameter sensitivity analysis results. At the same time, remove the anchor rod, scrape off the corrosion products on the anchor rod, and perform micro-macro correlation analysis to obtain the micro-macro correlation analysis results. Integrate the parameter sensitivity analysis results and the micro-macro correlation analysis results to generate a standard data report.

[0035] In S1, a similar material ratio is selected according to the structure of the slope to be tested. Cement, calcareous sand and water are weighed according to the selected material ratio. The cement and calcareous sand are poured into a forced mixer and dry-mixed for 3 minutes until uniform. Then the weighed water is added and wet-mixed for 5-8 minutes until a uniform slurry-aggregate mixture is formed.

[0036] High-elasticity latex sealing gaskets are installed on the top plate, left and right side walls, and fixed base of the inner wall of the shell. The slurry-aggregate mixture is then poured into the shell in stages. The steps for each stage of pouring are as follows:

[0037] Vibrate the slurry-aggregate mixture for 2 minutes using a vibrating table. After vibration, smooth the surface with a scraper and wait for the set time to allow the slurry-aggregate mixture to solidify and form a rock slab. After the rock slab has initially solidified, rough interfaces are engraved on the surface to enhance interlayer bonding and simulate natural layers. At this point, one layer of rock slab is manufactured.

[0038] Once all the rock slabs are manufactured, anchor holes are drilled in the manufactured simulated rock mass, and pre-treated anchor rods are installed into the anchor holes. The simulated rock mass with the anchor rods installed is then placed inside the shell.

[0039] S3 includes:

[0040] S3.1 After the high-pressure plunger pump is turned on, inject the corrosive liquid into the shell at a flow rate of 5 mL / min for 48 hours, while removing residual air in the simulated rock mass until water is continuously discharged from the outlet of the shell without bubbles.

[0041] S3.2 Set the acquisition parameters of the observation system and acquire data through the real-time observation system;

[0042] S3.3. Collect 50 mL of liquid sample from the waste liquid collector every 24 hours and analyze the changes in Cl⁻ and SO₂⁻ concentrations using an ion chromatograph. At the same time, collect pore water samples from different depths inside the simulated rock mass every 72 hours and analyze the pH and main cation concentrations using an ion chromatograph. After collection, empty the waste liquid collector.

[0043] S3.4. On the 15th day of the test, the working mode of the high-pressure plunger pump was switched from constant flow mode to constant pressure mode, and the inlet pressure was kept at 0.1MPa for 10 days to observe the changes in the seepage path.

[0044] S3.5 Integrate the data collected by the observation system, the data obtained by the ion chromatograph, and the changes in the seepage path to generate experimental data.

[0045] In step S4, the experimental data is preprocessed, including time-scale synchronization, outlier handling, and data normalization.

[0046] Corrosion kinetics analysis, seepage-corrosion coupling analysis, and synergistic failure analysis of the group anchor system were performed on the pretreated experimental data to obtain the analyzed experimental data.

[0047] The corrosion kinetic analysis includes:

[0048] The instantaneous corrosion current density was calculated using the Tafel extrapolation method based on the potentiodynamic polarization curve. :

[0049] ;

[0050] In the above formula, , The denoted terms are the Tafel slopes for the anode and cathode, where the anode is an anchor bolt and the cathode is an anchor bolt electrochemical corrosion monitoring device. Polarization resistor;

[0051] Based on corrosion current density Obtain the corresponding corrosion rate ;

[0052] The cumulative corrosion depth is calculated by integration over time period t as d(t).

[0053] ;

[0054] In the above formula, M is the molar mass of iron, ρ = 7.87 g / cm³, and F = 96485 C / mol. for Corrosion current density at any given time Let t be a specific moment within the time interval;

[0055] By fitting an equivalent circuit model using Nyquist plots of electrochemical impedance spectroscopy, the dominant corrosion control modes are identified, including charge transfer control, diffusion control, or resistance control.

[0056] The seepage-corrosion coupling analysis includes:

[0057] Based on the seepage pressure data collected by the seepage field monitoring device inside the rock mass, a continuous seepage pressure distribution cloud map is generated using the Kriging spatial interpolation method, and equipotential lines and streamlines are drawn.

[0058] A spatial rectangular coordinate system is established with one vertex of the shell as the origin and the three edges of the shell adjacent to the origin as the coordinate axes. The dominant channel index is defined. :

[0059] ;

[0060] In the above formula, for The advantage channel index of the point, for Hydraulic gradient at a point This is obtained through inversion via instantaneous pressure pulse test. A localized permeability system at a point is considered a dominant permeation channel when α > 2.0;

[0061] Corrosion-seepage correlation analysis: Calculating the corrosion rate at each anchor location and its correlation with the local hydraulic gradient. Pearson correlation coefficient:

[0062] ;

[0063] In the above formula, for Corrosion rate at each anchor bolt location at any given time. for Local hydraulic gradient at time, The average corrosion rate at all anchor locations. The local average hydraulic gradient;

[0064] The collaborative failure analysis of the anchor group system includes:

[0065] Anchor bolt state matrix construction: Construct an n×m dimensional state matrix S(t), where n is the number of anchor bolts and m is the number of monitoring parameters.

[0066] ;

[0067] In the above formula, F i (t) / F i,0 Prestress retention rate;

[0068] Overall safety assessment of the system: The overall safety factor FS(t) of the anchorage system at time t is calculated using the load-resistance reduction method.

[0069] ;

[0070] In the above formula, To account for the remaining pull-out force of the anchor bolt after corrosion damage, The actual load on the anchor bolt is obtained through finite element back analysis of the rock mass stress field;

[0071] Failure propagation network analysis: Based on the time series of abrupt changes in anchor prestress, a directed graph G(V,E) for failure propagation is constructed, where vertex V is the anchor and edge E has a weight. This represents the stress influence coefficient of anchor bolt i failure on anchor bolt j;

[0072] Based on machine learning methods, a spatiotemporal evolution model of erosion depth d is constructed. The spatiotemporal evolution model includes...

[0073] ;

[0074] In the above formula, For the predicted corrosion depth, For time period t The chloride ion concentration at the point is measured by an auxiliary environmental parameter monitoring device. The effective stress is measured by the anchor bolt mechanical state monitoring device. For temperature, A set of material property parameters;

[0075] The spatiotemporal evolution model was trained using the XGBoost algorithm. The input features included local hydraulic gradient, chloride ion concentration, effective stress, temperature and material parameters, and the output was corrosion depth.

[0076] The micro-macro correlation analysis includes sampling typical corrosion areas on the anchor bolt surface, observing the micro morphology with scanning electron microscopy, determining the elemental distribution with energy dispersive spectroscopy, and establishing the correspondence between corrosion morphology characteristics and electrochemical parameters and environmental parameters.

[0077] Before and after the experiment, rock cores were drilled at the same location in the simulated rock mass. The porosity change was measured by mercury intrusion porosimetry, and the CaO content change was analyzed by XRF to quantify the degree of calcareous sand dissolution.

[0078] The correlation between corrosion morphology characteristics, electrochemical parameters, environmental parameters, and the degree of calcareous sand dissolution is integrated to generate micro-macro correlation analysis results.

[0079] The S4 includes the standard data report, which includes the prestress time history curves and final retention rates of each anchor bolt, contour maps of the spatial distribution of corrosion rates, animations of the evolution of the seepage field, time history curves of the overall safety factor of the anchoring system, migration curves of key ion concentrations, XRD patterns of corrosion products, and semi-quantitative analysis tables of phases.

[0080] The S3 also includes an emergency response procedure, which includes stopping the seepage pump, closing all valves, and conducting a safety assessment when the prestress of any anchor bolt is detected to drop below 60% of its initial value, or the leakage rate of the corrosion testing device is >1% / h.

[0081] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0082] 1. In the layered dominant seepage-driven group anchor corrosion test device of the present invention, a slope structure is simulated by simulating a rock mass. Multiple anchors are set vertically on the simulated rock mass, and the simulated rock mass and the anchors together form a simulated anchoring system. The seepage system is used to create a layered dominant seepage environment within the simulated rock mass to simulate the localized corrosion intensification caused by the dominant seepage path due to the rock mass's permeability, hydraulic gradient, and pore structure. Therefore, this design can simulate the localized corrosion intensification caused by the dominant seepage path, effectively improving the accuracy of corrosion tests.

[0083] 2. In the layered seepage-driven group anchor corrosion test device of this invention, the simulated rock mass is made of layered rock mass with anisotropy and interface effects. The simulated rock mass includes multiple parallel stacked rock slabs, made of silicate cement, calcareous sand, and deionized water. The upper and lower surfaces of the rock slabs have textures, forming a rock mass model with obvious layered structure and controllable physical and mechanical properties. The introduction of calcareous sand allows the simulated rock mass to undergo a dissolution reaction in an acidic seepage environment, thereby dynamically simulating the permeability evolution process of natural rock mass due to dissolution, and realistically reproducing the control effect of the layered structure on the seepage path and corrosion process. Therefore, this design can realistically reproduce the control effect of the layered structure on the seepage path and corrosion process, effectively improving the engineering representativeness of the corrosion test.

[0084] 3. In the layered advantage seepage-driven group anchor corrosion test device of the present invention, experimental data is collected in real time through the observation system. Corrosion kinetic analysis, seepage-corrosion coupling analysis, and group anchor system synergistic failure analysis are performed on the pre-processed experimental data to obtain the analyzed experimental data. The parameter sensitivity analysis of the experimental data is performed through the spatiotemporal evolution model. At the same time, the micro-macro correlation analysis is performed on the corrosion products on the anchor rod to obtain the parameter sensitivity analysis results and micro-macro correlation analysis results. This realizes high-frequency, synchronous, in-situ monitoring and data fusion analysis of corrosion process, mechanical response and seepage parameters. Attached Figure Description

[0085] Figure 1 This is a schematic diagram of the structure of the device described in this invention.

[0086] Figure 2 This is a longitudinal sectional view of the device described in this invention.

[0087] Figure 3This is a cross-sectional view of the device described in this invention.

[0088] Figure 4 This is a flowchart of the method described in this invention.

[0089] Figure 5 This is the core data analysis flowchart in Embodiment 2 of the present invention.

[0090] In the diagram: 1. Shell 11. Fixed base 12. High-strength permeable stone 13. High-elasticity latex sealing gasket 14. Epoxy resin anti-corrosion coating 15. Simulated rock mass 2. Rock slab 21. Seepage system 3. High-pressure plunger pump 31. Liquid inlet pipe 32. Liquid outlet pipe 33. Waste liquid collector 34. Precision regulating valve 35. High-sensitivity hydraulic gauge 36. Observation system 4. Anchor bolt mechanical state monitoring device 41. Anchor bolt electrochemical corrosion monitoring device 42. Rock mass internal seepage field monitoring device 43. Anchor bolt 5. Detailed Implementation

[0091] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0092] Example 1:

[0093] See Figures 1 to 3 A layered rock mass corrosion test device driven by layered dominant seepage is disclosed. The corrosion test device includes: a shell 1, a simulated rock mass 2, a seepage system 3, and an observation system 4. The shell 1 is a box structure. The simulated rock mass 2 is set on a fixed base 11 at the bottom of the shell 1. The simulated rock mass 2 is a layered rock mass with anisotropy and interface effect. Multiple anchor bolts 5 are set on the simulated rock mass 2 along the vertical direction. The seepage system 3 is used to form a layered dominant seepage environment in the simulated rock mass 2. The observation system 4 is used to monitor the simulated rock mass 2 and each anchor bolt 5 in real time and collect experimental data.

[0094] The simulated rock mass 2 and the anchor rods 5 on it together form a simulated anchoring system. The seepage system 3 is used to create a layered dominant seepage environment in the simulated rock mass 2 to simulate the localized corrosion intensification caused by the dominant seepage path due to the rock mass permeability, hydraulic gradient and pore structure.

[0095] The seepage system 3 includes a high-pressure plunger pump 31, an inlet pipe 32, an outlet pipe 33, and a waste liquid collector 34;

[0096] The outlet of the high-pressure plunger pump 31 is connected to the inlet of the housing 1 through the inlet pipe 32, and the outlet of the housing 1 is connected to the waste liquid collector 34 through the drain pipe 33.

[0097] Precision regulating valves 35 and high-sensitivity hydraulic gauges 36 are installed on the liquid inlet pipe 32 and the liquid outlet pipe 33.

[0098] The high-pressure plunger pump 31 has dual-mode control capability, which can be used to accurately control the seepage rate of the electrolyte in constant flow mode, or to simulate the seepage conditions of constant head difference in constant pressure mode, so as to form a seepage field in the shell 1.

[0099] The precision regulating valve 35 is used to precisely regulate the fluid pressure of the inlet pipe 32 and the outlet pipe 33 of the high-pressure plunger pump 31.

[0100] The high-sensitivity hydraulic gauge 36 is used to accurately measure the fluid pressure in the inlet pipe 32 and outlet pipe 33 of the high-pressure plunger pump 31.

[0101] The waste liquid collector 34 is used to collect the electrolyte passing through the housing 1.

[0102] The inner wall of the shell 1 is uniformly coated with an epoxy resin anti-corrosion coating 14. High-strength permeable stones 12 are provided on the inner walls of the front and rear sides of the shell 1. The high-strength permeable stones 12 are used to make the seepage field uniformly distributed in the cross section. High-elastic latex sealing gaskets 13 are provided on the top plate, left and right side walls and fixed base 11 of the inner wall of the shell 1.

[0103] The simulated rock mass 2 includes multiple layers of parallel stacked rock slabs 21. The rock slabs 21 are made of silicate cement, calcareous sand and deionized water. The upper and lower surfaces of the rock slabs 21 have textures.

[0104] Multiple anchor bolts 5 are arranged on the simulated rock mass 2 in a matrix, quincunx, or engineering equivalent pattern.

[0105] The anchor rods are made of commonly used engineering steel. Their lower ends are bonded and fixed to the rock borehole wall by injecting special grouting material, while the upper ends pass through the pre-reserved sealing interface on the top plate of the box body. An anchor head, gasket, and torque wrench are connected to the outside to apply and precisely control the initial prestress of each anchor rod, so as to truly simulate the active reinforcement state of the anchor rod.

[0106] The observation system 4 includes an anchor bolt mechanical state monitoring device 41, an anchor bolt electrochemical corrosion monitoring device 42, a rock mass internal seepage field monitoring device 43, an auxiliary environmental parameter monitoring device, and a data synchronous acquisition unit.

[0107] The anchor bolt mechanical state monitoring device 41 is a resistance strain gauge or vibrating wire tension sensor. The anchor bolt mechanical state monitoring device 41 is set between the anchor head of each anchor bolt 5 and the top plate of the shell 1, and is used to continuously record the time history change curve of the prestress of each anchor bolt 5 during the corrosion process.

[0108] The anchor bolt electrochemical corrosion monitoring device 42 is a multi-channel electrochemical workstation or a zero-resistance galvanometer. The anchor bolt electrochemical corrosion monitoring device 42 uses each anchor bolt 5 as an independent working electrode. By measuring the potentiodynamic polarization curve of each anchor bolt, the instantaneous corrosion current density of each anchor bolt is calculated, thereby realizing the quantitative and in-situ assessment of corrosion rate and corrosion mechanism.

[0109] The anchor bolt electrochemical corrosion monitoring device 42 can also measure the corrosion potential or electrochemical impedance spectrum of each anchor bolt.

[0110] Measuring corrosion potential, potentiodynamic polarization curves, and electrochemical impedance spectroscopy constitutes a systematic set of electrochemical testing methods. Their core purpose is to quantitatively diagnose and evaluate the corrosion state, rate, and microscopic mechanisms of anchor bolts from different dimensions, particularly to reveal the spatiotemporal non-uniformity and evolution of anchor group corrosion under the unique environment of "seepage-driven" corrosion. Specifically:

[0111] Corrosion potential: By monitoring the potential of each anchor bolt relative to the reference electrode, the thermodynamic probability and relative activity of corrosion can be determined. In a group anchor system, anchor bolts with more negative potentials generally have a greater tendency to corrode. Combined with spatial location, a "corrosion potential distribution cloud map" can be drawn, which visually shows which areas of anchor bolts are first to enter an active corrosion state under the influence of seepage paths, serving as a starting point for studying the spatial heterogeneity of corrosion.

[0112] Potentiodynamic polarization curves: By applying a small-range potential scan to the anchor bolt and measuring the current response, techniques such as Tafel extrapolation can be used to accurately calculate the instantaneous corrosion current density, thereby directly obtaining a quantitative corrosion rate. This is key to upgrading the degree of corrosion from qualitative description to quantitative analysis. By comparing the corrosion rates of anchor bolts at different locations and time points, the driving and amplification effects of dominant seepage paths on the corrosion rate can be quantitatively analyzed, establishing a quantitative correlation between the seepage field and the corrosion field.

[0113] Electrochemical impedance spectroscopy (EIS): This technique probes the impedance response at the corrosion electrode / solution interface by applying a small AC perturbation. By fitting the impedance spectrum to an equivalent circuit, parameters such as charge transfer resistance, solution resistance, and the resistance and capacitance of the coating or corrosion product film can be determined. Its core function is to reveal the microscopic mechanisms and control steps of corrosion in a seepage environment, helping to determine whether seepage alters the corrosion mechanism.

[0114] In summary, these three elements constitute a complete electrochemical monitoring chain: corrosion potential characterizes whether corrosion will occur and where it will occur first; polarization curves characterize how fast corrosion occurs; and impedance spectroscopy reveals why corrosion occurs in this way.

[0115] In the seepage-corrosion coupling study of this patent, this method can transform abstract corrosion into scientific data that can be spatiotemporally located, quantified and compared, and analyzed mechanistically. Ultimately, this data is used to construct a spatiotemporal evolution model of corrosion, assess the remaining life of anchor bolts, and provide direct electrochemical criteria for engineering early warning, perfectly supporting the achievement of the invention's objectives.

[0116] The rock mass internal seepage field monitoring device 43 includes multiple micro pore water pressure sensors. Each of the rock mass internal seepage field monitoring devices 43 is uniformly arranged along the three-dimensional spatial grid nodes inside the simulated rock mass 2. The rock mass internal seepage field monitoring device 43 is used to sense and transmit seepage pressure data at different locations inside the simulated rock mass 2 in real time.

[0117] The auxiliary environmental parameter monitoring device includes a pH sensor, a redox potential sensor, and an ion-selective electrode. The auxiliary environmental parameter monitoring device is installed between the liquid inlet and liquid outlet of the shell 1 and between each rock plate 21, and is used to monitor the changes in the fluid chemical environment during the seepage process in real time.

[0118] The data synchronization acquisition unit is a central data acquisition instrument. The data synchronization acquisition unit is used to collect data from the anchor bolt mechanical state monitoring device 41, the anchor bolt electrochemical corrosion monitoring device 42, the rock mass internal seepage field monitoring device 43, and the auxiliary environmental parameter monitoring device, and to ensure the spatiotemporal consistency of all data.

[0119] Example 2:

[0120] See Figure 4 A method for testing corrosion of anchorages driven by seepage at different levels, the method comprising the following steps:

[0121] S1. Based on the structure of the slope to be tested, a simulated rock mass 2 is manufactured. Anchor holes are drilled on the manufactured simulated rock mass 2, and the pre-treated anchor rods 5 are installed into the anchor holes. The simulated rock mass 2 with the anchor rods 5 installed is placed inside the shell 1.

[0122] S2. Connect the seepage system 3 to the inlet and outlet of the shell 1, and then install the observation system 4 inside and outside the shell 1.

[0123] S3. Prepare electrolyte for seepage system 3, and adjust seepage system 3 to the set working type and working flow rate. After the seepage system 3 is adjusted, start high pressure plunger pump 31 to conduct corrosion test on anchor 5, and at the same time, observation system 4 collects experimental data in real time.

[0124] S4. Construct a spatiotemporal evolution model, perform parameter sensitivity analysis on the experimental data using the spatiotemporal evolution model, and obtain the parameter sensitivity analysis results. At the same time, remove anchor rod 5, scrape off the corrosion products on anchor rod 5, and perform micro-macro correlation analysis to obtain the micro-macro correlation analysis results. Integrate the parameter sensitivity analysis results and the micro-macro correlation analysis results to generate a standard data report.

[0125] In S1, a similar material ratio is selected according to the structure of the slope to be tested. Cement, calcareous sand and water are weighed according to the selected material ratio. The cement and calcareous sand are poured into a forced mixer and dry-mixed for 3 minutes until uniform. Then the weighed water is added and wet-mixed for 5-8 minutes until a uniform slurry-aggregate mixture is formed.

[0126] High-elasticity latex sealing gaskets 13 are provided on the top plate, left and right side walls, and fixed base 11 of the inner wall of the shell 1. The slurry-aggregate mixture is poured into the shell 1 in stages. The steps for each stage of pouring are as follows:

[0127] Vibrate the slurry-aggregate mixture for 2 minutes using a vibrating table. After vibration, smooth the surface with a scraper and wait for the set time to allow the slurry-aggregate mixture to solidify and form a rock slab. After the rock slab has initially solidified, rough interfaces are engraved on the surface to enhance interlayer bonding and simulate natural layers. At this point, one layer of rock slab is manufactured.

[0128] After all the rock slabs are manufactured, anchor holes are drilled on the manufactured simulated rock mass 2, and the pre-treated anchor rods 5 are installed into the anchor holes. The simulated rock mass 2 with the anchor rods 5 installed is then placed inside the shell 1.

[0129] S3 includes:

[0130] S3.1 After the high-pressure plunger pump 31 is turned on, the corrosive liquid is injected into the shell 1 at a flow rate of 5 mL / min for 48 hours. At the same time, the residual air in the simulated rock mass 2 is removed until the liquid outlet of the shell 1 continuously outputs water without bubbles.

[0131] S3.2 Set the acquisition parameters of the observation system 4 and acquire data through the real-time observation system 4;

[0132] S3.3 Every 24 hours, collect 50 mL of liquid sample from waste liquid collector 34 and analyze the changes in Cl⁻ and SO₂⁻ concentrations using ion chromatography. At the same time, every 72 hours, collect pore water samples from different depths inside the simulated rock mass 2 and analyze the pH and main cation concentrations using ion chromatography. After collection, empty waste liquid collector 34.

[0133] S3.4 On the 15th day of the test, the working mode of the high-pressure plunger pump 31 was switched from constant flow mode to constant pressure mode, and the inlet pressure was kept at 0.1MPa for 10 days to observe the changes in the seepage path.

[0134] S3.5 Integrate the data collected by the observation system 4, the data obtained by the ion chromatograph, and the changes in the seepage path to generate experimental data.

[0135] In step S4, the experimental data is preprocessed, including time-scale synchronization, outlier handling, and data normalization.

[0136] Corrosion kinetics analysis, seepage-corrosion coupling analysis, and synergistic failure analysis of the group anchor system were performed on the pretreated experimental data to obtain the analyzed experimental data.

[0137] The corrosion kinetic analysis includes:

[0138] The instantaneous corrosion current density was calculated using the Tafel extrapolation method based on the potentiodynamic polarization curve. :

[0139] ;

[0140] In the above formula, , The slopes are the Tafel slopes for the anode and cathode, where the anode is anchor bolt 5 and the cathode is anchor bolt electrochemical corrosion monitoring device 42. Polarization resistor;

[0141] Based on corrosion current density Obtain the corresponding corrosion rate ;

[0142] The cumulative corrosion depth is calculated by integration over time period t as d(t).

[0143] ;

[0144] In the above formula, M is the molar mass of iron, ρ = 7.87 g / cm³, and F = 96485 C / mol. for Corrosion current density at any given time Let t be a specific moment within the time interval;

[0145] By fitting an equivalent circuit model using Nyquist plots of electrochemical impedance spectroscopy, the dominant corrosion control modes are identified, including charge transfer control, diffusion control, or resistance control.

[0146] The seepage-corrosion coupling analysis includes:

[0147] Based on the seepage pressure data collected by the seepage field monitoring device 43 inside the rock mass, a continuous seepage pressure distribution cloud map is generated using the Kriging spatial interpolation method, and equipotential lines and streamlines are drawn.

[0148] A spatial rectangular coordinate system is established with one vertex of shell 1 as the origin and the three sides of shell 1 adjacent to the origin as the coordinate coordinates. The dominant channel index is defined. :

[0149] ;

[0150] In the above formula, for The advantage channel index of the point, for Hydraulic gradient at a point This is obtained through inversion via instantaneous pressure pulse test. A localized permeability system at a point is considered a dominant permeation channel when α > 2.0;

[0151] The hydraulic gradient is obtained by an array of three-dimensional mesh-based seepage field monitoring devices 43 embedded within the rock mass. The calculation method includes:

[0152] a. Data acquisition: All piezometers synchronously measure the pressure head value at their location at a set frequency;

[0153] b. Spatial interpolation: At any given time, the head measurements at discrete points are used to generate a continuous head field within the simulated rock mass 2 through spatial interpolation.

[0154] c. Gradient calculation: By performing spatial numerical differentiation on the continuous head field h, the hydraulic gradient vector field at any location can be obtained.

[0155] The permeability coefficient was calculated using the instantaneous pressure pulse method. This involves actively applying a controllable fluid disturbance and observing the transient response of the pressure field within the simulated rock mass 2 to infer permeability. The specific implementation steps include:

[0156] Apply disturbance: During a stable seepage phase of the test, a short, small-amplitude pressure pulse is rapidly applied through the ISCO high-pressure plunger pump at the inlet;

[0157] Monitoring Response: Using the above-mentioned piezometer array, the pressure change curves at each measuring point over time during the propagation of pressure pulses within the rock mass were recorded at high frequency.

[0158] Inversion Calculation: Based on Darcy's law and the fluid mass conservation equation, a mathematical model describing the propagation of pressure pulses in heterogeneous porous media is established. Using the pressure-time response curves recorded at each measuring point as known conditions, a numerical inversion algorithm is used to solve for the permeability coefficient distribution field that best matches the model's calculated response with the actual monitored response. This process usually requires specialized seepage reverse analysis software;

[0159] Dynamic updates: By repeating this process at different stages of the experiment, dynamic evolution data of the permeability field over time t can be obtained. This is used to quantify changes in the permeability of rock masses caused by dissolution.

[0160] Corrosion-seepage correlation analysis: Calculating the corrosion rate at each anchor location and its correlation with the local hydraulic gradient. Pearson correlation coefficient:

[0161] ;

[0162] In the above formula, for Corrosion rate at each anchor bolt location at any given time. for Local hydraulic gradient at time, The average corrosion rate at all anchor locations. The local average hydraulic gradient;

[0163] The collaborative failure analysis of the anchor group system includes:

[0164] Anchor bolt state matrix construction: Construct an n×m dimensional state matrix S(t), where n is the number of anchor bolts and m is the number of monitoring parameters.

[0165] ;

[0166] In the above formula, Fi(t) / Fi,0 is the prestress retention rate;

[0167] Overall safety assessment of the system: The overall safety factor FS(t) of the anchorage system at time t is calculated using the load-resistance reduction method.

[0168] ;

[0169] In the above formula, To account for the remaining pull-out force of the anchor bolt after corrosion damage, The actual load on the anchor bolt is obtained through finite element back analysis of the rock mass stress field;

[0170] Failure propagation network analysis: Based on the time series of abrupt changes in anchor prestress, a directed graph G(V,E) for failure propagation is constructed, where vertex V is the anchor and edge E has a weight. This represents the stress influence coefficient of anchor bolt i failure on anchor bolt j;

[0171] The weight The results were obtained through stress redistribution analysis, and the specific steps are as follows:

[0172] Define adjacent units and influence range: Taking the failed anchor i as the center, an influence radius R is preset according to the average anchor spacing d (usually R=1.5d to 2d). Other anchor j within this radius range are defined as adjacent units of anchor i, forming the target set for load redistribution.

[0173] Calculate the load distribution weighting coefficient: The distribution ratio of the failure load of anchor i to each adjacent anchor j is calculated using a weighting function based on distance and stiffness, including:

[0174] ;

[0175] In the formula, The proportionality coefficient for anchor j to share the load released by anchor i. Let i be the spatial distance between anchors i and j. β is the axial stiffness of anchor j (which can be reduced according to its material parameters and corrosion status), and β is the distance attenuation index (usually taken as 1 or 2). Represents the set of adjacent elements of anchor rod i;

[0176] ③ Determine edge weights and construct the network: The load ΔFi released by the failure of anchor i is distributed according to the weight coefficient αij, and the weight of the directed edge i→j is determined. It is directly defined as this allocation coefficient, that is:

[0177] ;

[0178] This weight quantitatively characterizes the direct impact of anchor failure i on anchor j; by traversing all anchors and potential failure events, a complete weighted directed failure propagation network graph G(V,E,W) can be constructed.

[0179] Through the above steps, the complex stress redistribution mechanism in the rock and soil mass is transformed into a deterministic calculation model based on spatial proximity and component properties, thereby realizing a structured and quantitative analysis of the failure chain effect of the group anchor system, which is used to identify key anchors and weak propagation paths.

[0180] See Figure 5 Based on machine learning methods, a spatiotemporal evolution model of erosion depth d is constructed, wherein the spatiotemporal evolution model includes,

[0181] ;

[0182] In the above formula, For the predicted corrosion depth, For time period t The chloride ion concentration at the point is measured by an auxiliary environmental parameter monitoring device. The effective stress is measured by the anchor bolt mechanical state monitoring device 41. For temperature, A set of material property parameters;

[0183] The spatiotemporal evolution model was trained using the XGBoost algorithm. The input features included local hydraulic gradient, chloride ion concentration, effective stress, temperature and material parameters, and the output was corrosion depth.

[0184] The micro-macro correlation analysis includes sampling typical corrosion areas on the surface of anchor bolt 5, observing the micro morphology with scanning electron microscopy, determining the elemental distribution with energy dispersive spectroscopy, and establishing the correspondence between corrosion morphology characteristics and electrochemical parameters and environmental parameters.

[0185] Before and after the experiment, rock cores were drilled at the same location in simulated rock mass 2. The porosity change was determined by mercury intrusion porosimetry, and the CaO content change was analyzed by XRF to quantify the degree of calcareous sand dissolution.

[0186] The correlation between corrosion morphology characteristics, electrochemical parameters, environmental parameters, and the degree of calcareous sand dissolution is integrated to generate micro-macro correlation analysis results.

[0187] The S4 includes the standard data report, which includes the prestress time history curves and final retention rates of each anchor bolt, contour maps of the spatial distribution of corrosion rates, animations of the evolution of the seepage field, time history curves of the overall safety factor of the anchoring system, migration curves of key ion concentrations, XRD patterns of corrosion products, and semi-quantitative analysis tables of phases.

[0188] The time history curves of prestress and the final retention rate of each anchor bolt: The data are directly obtained from the axial force data collected in real time by the anchor bolt mechanical state monitoring device 41 at the upper end of each anchor bolt. The time history curve is a graphical result directly drawn from the original time series data collected by the anchor bolt mechanical state monitoring device 41 after filtering and time scale alignment. The final retention rate is obtained by calculating the ratio of the anchor bolt prestress to the initial design prestress at the end of the test.

[0189] Corrosion rate spatial distribution contour map: The core data comes from the instantaneous corrosion current density of each anchor rod measured by the anchor rod electrochemical corrosion monitoring device 42 through potentiodynamic polarization curve testing and calculated by Tafel extrapolation method. The spatial distribution cloud map is generated by spatial interpolation method with the spatial coordinates of each anchor rod 5 as the location information and its corrosion current density as the attribute value.

[0190] Animation of seepage field evolution: The data comes from the time-series data recorded by the rock mass seepage field monitoring device array 43, which is arranged in a spatial grid inside the rock mass. The animation is composed of seepage spatial distribution cloud maps (generated by interpolation based on sensor data) at different times (such as every 24 hours) in a time sequence, which intuitively shows the change process of the seepage field over time.

[0191] The overall safety factor time history curve of the anchoring system is a comprehensive analysis result, and its calculation relies on two types of core monitoring data: one is the real-time prestress of each anchor rod 5, and the other is the corrosion status data of each anchor rod 5.

[0192] The key ion concentration migration curves are derived from the chemical composition analysis data of liquid samples collected periodically from the drain outlet. The concentrations of ions such as Cl⁻ and SO₄²⁻ are mainly determined using an ion chromatograph. The migration curves are plotted with time on the x-axis and the specific ion concentration measured in each sampling on the y-axis, reflecting the dynamic process of the corrosive medium migrating out of the test system with seepage.

[0193] The XRD patterns and semi-quantitative phase analysis table of the corrosion products are presented. The data comes from the microscopic analysis of the removed anchor rods after the experiment. Specifically, X-ray diffraction was used to analyze the phase composition of the scraped corrosion products.

[0194] The S3 also includes an emergency response procedure, which includes stopping the seepage pump, closing all valves, and conducting a safety assessment when the prestress of any anchor bolt 5 is detected to drop below 60% of its initial value, or when the leakage rate of the corrosion testing device is >1% / h.

[0195] Example 3:

[0196] Example 3 is basically the same as Example 1, except that:

[0197] Shell 1 is a sealed enclosure with internal net dimensions of 1.8 m (length) × 1.6 m (width) × 1.2 m (height) welded from 316L stainless steel plate with a thickness of 10 cm. This structure ensures that the enclosure has sufficient structural strength and durability under long-term fluid pressure (usually ≤1 MPa) and acidic corrosion environment.

[0198] Simulated rock mass 2 is made by mixing and casting ordinary silicate cement, calcareous sand with a specific particle size (0.5-2 mm) and deionized water in a specific mass ratio, for example, a mass ratio of 1:3:0.7.

[0199] Through layered compaction and directional curing processes, a rock mass model with obvious layered structure and controllable physical and mechanical properties is formed. The key is that the introduction of calcareous sand allows the rock mass to undergo a dissolution reaction in an acidic seepage environment, thereby dynamically simulating the permeability evolution process of natural rock mass caused by dissolution.

[0200] The anchor rod 5 is made of commonly used steel in engineering. Its lower end is bonded and fixed to the rock hole wall of the simulated rock mass 2 by injecting special grouting material. Its upper end passes through the sealing interface reserved in the top plate of the shell 1 and is connected to the anchor head, gasket and torque wrench to apply and precisely control the initial prestress of each anchor rod 5, so as to truly simulate the active reinforcement state of the anchor rod 5.

[0201] Large areas of high-strength permeable stone 12 are embedded in the two side plates at both ends of the shell 1 along its length, serving as the infiltration surface and the infiltration boundary to ensure that the seepage field is uniformly distributed in the cross section. All inner walls of the shell 1 are filled with high-elastic latex sealing gaskets 13 between them and the outer surface of the rock mass model, effectively eliminating the fluid short-circuit effect at the contact surface between the box wall and the rock mass, and forcing the seepage to migrate strictly through the internal pore or fracture network of the rock mass.

[0202] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present invention should be included within the scope of protection set forth in the claims.

Claims

1. A surface-superior seepage-driven group anchor corrosion test device, characterized in that, The corrosion testing device includes: a shell (1), a simulated rock mass (2), a seepage system (3), and an observation system (4); The shell (1) is a square box structure. The simulated rock mass (2) is set on the fixed base (11) at the bottom of the shell (1). The simulated rock mass (2) is a layered rock mass with anisotropy and interface effect. Multiple anchor rods (5) are set on the simulated rock mass (2) along the vertical direction. The seepage system (3) is used to create a bedding-dominant seepage environment within the simulated rock mass 2; The observation system (4) is used to monitor the simulated rock mass (2) and each anchor rod (5) in real time and collect experimental data.

2. The surface-advantage seepage-driven group anchor corrosion test device according to claim 1, characterized in that, The seepage system (3) includes a high-pressure plunger pump (31), an inlet pipe (32), an outlet pipe (33), and a waste liquid collector (34). The outlet of the high-pressure plunger pump (31) is connected to the inlet of the housing (1) through the inlet pipe (32), and the outlet of the housing (1) is connected to the waste liquid collector (34) through the drain pipe (33). The inlet pipe (32) and outlet pipe (33) are each equipped with a precision regulating valve (35) and a high-sensitivity hydraulic gauge (36). The high-pressure plunger pump (31) has dual-mode control capability, which is used to accurately control the seepage velocity of the electrolyte in constant flow mode, or to simulate the seepage conditions of constant head difference in constant pressure mode, so as to form a seepage field in the shell (1). The precision regulating valve (35) is used to precisely regulate the fluid pressure of the inlet pipe (32) and outlet pipe (33) of the high-pressure plunger pump (31); The high-sensitivity hydraulic gauge (36) is used to accurately measure the fluid pressure in the inlet pipe (32) and outlet pipe (33) of the high-pressure plunger pump (31); The waste liquid collector (34) is used to collect the electrolyte passing through the housing (1).

3. The surface-advantage seepage-driven group anchor corrosion test device according to claim 1, characterized in that, The inner wall of the shell (1) is uniformly coated with an epoxy resin anti-corrosion coating (14). High-strength permeable stones (12) are provided on the inner walls of the front and rear sides of the shell (1). The high-strength permeable stones (12) are used to make the seepage field uniformly distributed in the cross section. High-elastic latex sealing gaskets (13) are provided on the top plate, left and right side walls and fixed base (11) of the inner wall of the shell (1). The simulated rock mass (2) includes multiple parallel stacked rock slabs (21), which are made of silicate cement, calcareous sand and deionized water, and have textures on the upper and lower surfaces. Multiple anchor bolts (5) are set on the simulated rock mass (2) in a matrix, quincunx, or engineering equivalent pattern.

4. The surface-advantage seepage-driven group anchor corrosion test device according to claim 1, characterized in that, The observation system (4) includes an anchor bolt mechanical state monitoring device (41), an anchor bolt electrochemical corrosion monitoring device (42), a rock mass internal seepage field monitoring device (43), an auxiliary environmental parameter monitoring device, and a data synchronous acquisition unit; The anchor mechanical state monitoring device (41) is a resistance strain gauge or vibrating wire tension sensor. The anchor mechanical state monitoring device (41) is set between the anchor head of each anchor (5) and the top plate of the shell (1) to continuously record the time history curve of the prestress of each anchor (5) during the corrosion process. The anchor bolt electrochemical corrosion monitoring device (42) is a multi-channel electrochemical workstation or a zero-resistance galvanometer. The anchor bolt electrochemical corrosion monitoring device (42) uses each anchor bolt (5) as an independent working electrode. By measuring the potentiodynamic polarization curve of each anchor bolt, the instantaneous corrosion current density of each anchor bolt is calculated, thereby realizing the quantitative and in-situ evaluation of corrosion rate and corrosion mechanism. The rock mass internal seepage field monitoring device (43) includes multiple micro pore water pressure sensors. Each of the rock mass internal seepage field monitoring devices (43) is uniformly set along the three-dimensional spatial grid nodes inside the simulated rock mass (2). The rock mass internal seepage field monitoring device (43) is used to sense and transmit seepage pressure data at different locations inside the simulated rock mass (2) in real time. The auxiliary environmental parameter monitoring device includes a pH sensor, a redox potential sensor and an ion selective electrode. The auxiliary environmental parameter monitoring device is set between the liquid inlet and liquid outlet of the shell (1) and between each rock plate (21) to monitor the changes in the fluid chemical environment during the seepage process in real time. The data synchronization acquisition unit is a central data acquisition instrument. The data synchronization acquisition unit is used to collect data collected by the anchor bolt mechanical state monitoring device (41), the anchor bolt electrochemical corrosion monitoring device (42), the rock mass internal seepage field monitoring device (43), and the auxiliary environmental parameter monitoring device, and to ensure the spatiotemporal consistency of all data.

5. A method for testing group anchor corrosion driven by dominant seepage according to any one of claims 1 to 4, characterized in that, The experimental method includes the following steps: S1. Based on the structure of the slope to be tested, a simulated rock mass (2) is manufactured. Anchor holes are drilled on the manufactured simulated rock mass (2), and the pre-treated anchor rods (5) are installed in the anchor holes. The simulated rock mass (2) with the anchor rods (5) installed is placed inside the shell (1). S2. Connect the seepage system (3) to the inlet and outlet of the shell (1), and then install the observation system (4) inside and outside the shell (1); S3. Prepare electrolyte for seepage system (3), and adjust seepage system (3) to set working type and working flow rate. After the seepage system (3) is adjusted, turn on high pressure plunger pump (31) to conduct corrosion test on anchor rod (5), and at the same time, observation system (4) collects experimental data in real time. S4. Construct a spatiotemporal evolution model, perform parameter sensitivity analysis on the experimental data through the spatiotemporal evolution model, obtain parameter sensitivity analysis results, and at the same time remove the anchor rod (5), scrape off the corrosion products on the anchor rod (5) for micro-macro correlation analysis, obtain micro-macro correlation analysis results, integrate the parameter sensitivity analysis results and micro-macro correlation analysis results to generate a standard data report.

6. The method for testing group anchor corrosion driven by layered dominant seepage according to claim 5, characterized in that: In S1, a similar material ratio is selected according to the structure of the slope to be tested. Cement, calcareous sand and water are weighed according to the selected material ratio. The cement and calcareous sand are poured into a forced mixer and dry-mixed for 3 minutes until uniform. Then the weighed water is added and wet-mixed for 5-8 minutes until a uniform slurry-aggregate mixture is formed. High-elastic latex sealing gaskets (13) are provided on the top plate, left and right side walls and fixed base (11) of the inner wall of the shell (1), and the slurry-aggregate mixture is poured into the shell (1) in stages. The single pouring steps are as follows: Vibrate the slurry-aggregate mixture for 2 minutes using a vibrating table. After vibration, smooth the surface with a scraper and wait for the set time to allow the slurry-aggregate mixture to solidify and form a rock slab. After the rock slab has initially solidified, rough interfaces are engraved on the surface to enhance interlayer bonding and simulate natural layers. At this point, one layer of rock slab is manufactured. After all the rock slabs are manufactured, anchor holes are drilled on the manufactured simulated rock mass (2), and the pre-treated anchor rods (5) are installed into the anchor holes. The simulated rock mass (2) with the anchor rods (5) installed is placed inside the shell (1).

7. The method for testing group anchor corrosion driven by layered dominant seepage according to claim 5, characterized in that: S3 includes: S3.1 After the high-pressure plunger pump (31) is turned on, the corrosive liquid is injected into the shell (1) at a flow rate of 5 mL / min for 48 hours. At the same time, the residual air in the simulated rock mass (2) is removed until the liquid outlet of the shell (1) continuously outputs water without bubbles. S3.2 Set the acquisition parameters of the observation system (4) and acquire data through the real-time observation system (4); S3.

3. Collect 50 mL of liquid sample from waste liquid collector (34) every 24 hours and analyze the changes in Cl⁻ and SO₂⁻ concentrations using ion chromatography. At the same time, collect pore water samples from different depths inside the simulated rock mass (2) every 72 hours and analyze the pH and main cation concentrations using ion chromatography. After collection, empty waste liquid collector (34). S3.

4. On the 15th day of the test, the working mode of the high-pressure plunger pump (31) was switched from constant flow mode to constant pressure mode, and the inlet pressure was kept at 0.1MPa for 10 days to observe the changes in the seepage path. S3.5 Integrate the data collected by the observation system (4), the data obtained by the ion chromatograph, and the changes in the permeation path to generate experimental data.

8. The method for testing group anchor corrosion driven by layered dominant seepage according to claim 5, characterized in that: In step S4, the experimental data is preprocessed, including time-scale synchronization, outlier handling, and data normalization. Corrosion kinetics analysis, seepage-corrosion coupling analysis, and synergistic failure analysis of the group anchor system were performed on the pretreated experimental data to obtain the analyzed experimental data. The corrosion kinetic analysis includes: The instantaneous corrosion current density was calculated using the Tafel extrapolation method based on the potentiodynamic polarization curve. : ； In the above formula, , The slopes are Tafel for the anode and cathode, where the anode is the anchor rod (5) and the cathode is the anchor rod electrochemical corrosion monitoring device (42). Polarization resistor; Based on corrosion current density Obtain the corresponding corrosion rate ; The cumulative corrosion depth is calculated by integration over time period t, d(t). ； In the above formula, M is the molar mass of iron, ρ = 7.87 g / cm³, and F = 96485 C / mol. for Corrosion current density at any given time Let t be a specific moment within the time interval; By fitting an equivalent circuit model using Nyquist plots of electrochemical impedance spectroscopy, the dominant corrosion control modes are identified, including charge transfer control, diffusion control, or resistance control. The seepage-corrosion coupling analysis includes: Based on the seepage pressure data collected by the seepage field monitoring device (43) inside the rock mass, a continuous seepage pressure distribution cloud map is generated using the Kriging spatial interpolation method, and equipotential lines and streamlines are drawn. A spatial rectangular coordinate system is established with one vertex of the shell (1) as the origin of the coordinate system and the three sides of the shell (1) adjacent to the origin of the coordinate system as the three coordinates of the coordinate system. The dominant channel index is defined. : ； In the above formula, for The advantage channel index of the point, for Hydraulic gradient at a point This is obtained through inversion via instantaneous pressure pulse test. A localized permeability system at a point is considered a dominant permeation channel when α > 2.0; Corrosion-seepage correlation analysis: Calculating the corrosion rate at each anchor location and its correlation with the local hydraulic gradient. Pearson correlation coefficient: ； In the above formula, for Corrosion rate at each anchor bolt location at any given time. for Local hydraulic gradient at time, The average corrosion rate at all anchor locations. The local average hydraulic gradient; The collaborative failure analysis of the anchor group system includes: Anchor bolt state matrix construction: Construct an n×m dimensional state matrix S(t), where n is the number of anchor bolts and m is the number of monitoring parameters. ； In the above formula, F i (t) / F i,0 Prestress retention rate; Overall safety assessment of the system: The overall safety factor FS(t) of the anchoring system at time t is calculated using the load-resistance reduction method. ； In the above formula, To account for the remaining pull-out force of the anchor bolt after corrosion damage, The actual load on the anchor bolt is obtained through finite element back analysis of the rock mass stress field; Failure propagation network analysis: Based on the time series of abrupt changes in anchor prestress, a directed graph G(V,E) for failure propagation is constructed, where vertex V is the anchor and edge E has a weight. This represents the stress influence coefficient of anchor bolt i failure on anchor bolt j; Based on machine learning methods, a spatiotemporal evolution model of erosion depth d is constructed. The spatiotemporal evolution model includes... ； In the above formula, For the predicted corrosion depth, For time period t The chloride ion concentration at the point is measured by an auxiliary environmental parameter monitoring device. The effective stress is measured by the anchor bolt mechanical state monitoring device (41). For temperature, A set of material property parameters; The spatiotemporal evolution model was trained using the XGBoost algorithm. The input features included local hydraulic gradient, chloride ion concentration, effective stress, temperature and material parameters, and the output was corrosion depth. The micro-macro correlation analysis includes taking samples from typical corrosion areas on the surface of the anchor bolt (5), observing the micro morphology with a scanning electron microscope, determining the elemental distribution with energy dispersive spectroscopy, and establishing the correspondence between corrosion morphology characteristics and electrochemical parameters and environmental parameters. Before and after the experiment, rock cores were drilled at the same location in the simulated rock mass (2). The porosity change was determined by mercury intrusion test, and the CaO content change was analyzed by XRF to quantify the degree of calcareous sand dissolution. The correlation between corrosion morphology characteristics, electrochemical parameters, environmental parameters, and the degree of calcareous sand dissolution is integrated to generate micro-macro correlation analysis results.

9. The method for testing group anchor corrosion driven by layered dominant seepage according to claim 5, characterized in that: The S4 includes the standard data report, which includes the prestress time history curves and final retention rates of each anchor bolt, contour maps of the spatial distribution of corrosion rates, animations of the evolution of the seepage field, time history curves of the overall safety factor of the anchoring system, migration curves of key ion concentrations, XRD patterns of corrosion products, and semi-quantitative analysis tables of phases.

10. The method for testing group anchor corrosion driven by layered dominant seepage according to claim 7, characterized in that: The S3 also includes an emergency response procedure, which includes stopping the seepage pump, closing all valves, and conducting a safety assessment when the prestress of any anchor bolt (5) is detected to drop below 60% of the initial value, or the leakage rate of the corrosion testing device is >1% / h.

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