Grouting body-rock body interface circulation corrosion-scouring durability experiment system and experiment method thereof

Abstract

The invention discloses a grouting body-rock body interface circulating corrosion-scouring durability experiment system and an experiment method thereof. The grouting body-rock body interface circulating corrosion-scouring durability experiment system comprises a transparent interface model unit, a circulating fluid supply unit, an automatic switching valve group and an effluent collecting and monitoring unit. The transparent interface model unit forms an interlayer space by upper and lower transparent plates; the circulating fluid supply unit comprises an acid corrosion liquid storage tank and a clear water storage tank; the automatic switching valve group periodically switches the flow path; the effluent monitoring unit collects ion concentration, particle content and seepage parameters in real time. The permeability evolution is inversed by monitoring the pressure difference change, the corrosion rate and the scouring falling amount are calculated in combination with waste liquid analysis, and an accumulated degradation index and a failure threshold value are introduced to realize intelligent judgment. According to the method, the chemical-hydraulic coupling effect in the underground environment can be truly reproduced, the interface degradation mechanism is visually revealed, the long-term durability of the grouting interface is quantitatively evaluated, and a scientific basis is provided for grouting material optimization, mix proportion optimization and engineering life prediction.

Description

Technical Field

[0001] This invention relates to the field of durability research technology for geotechnical engineering and hydraulic structures, and in particular to a cyclic dissolution-scouring durability test system and test method for the grout-rock interface. Background Technology

[0002] Rock fissure grouting is a widely used reinforcement and seepage prevention measure in geotechnical engineering and hydraulic structures. It involves injecting grout into fissures to fill voids, reduce permeability, and restore the structural integrity. In projects such as dam foundation seepage prevention, underground engineering leak sealing, tunnel lining repair, and mine roadway reinforcement, grouting not only seals leaks but also improves mechanical properties and enhances durability. After grouting, a composite interface is formed between the grout and the rock mass (or concrete substrate). The long-term stability of this interface directly determines the structural safety and seepage prevention effect.

[0003] Current research and experiments mainly focus on the diffusion characteristics, solidification performance, and sealing strength characterization after a single grouting session, while insufficient attention is paid to the long-term service degradation of the grout-rock interface. In practical engineering, this interface is situated in a complex seepage and chemical environment, subjected to the combined effects of groundwater erosion and chemical dissolution (such as acidic and saline water bodies) over a long period. This leads to gradual debonding of the grout at the interface, pore enlargement, and even the formation of seepage channels, significantly reducing the effectiveness of seepage prevention and reinforcement. However, there is currently a lack of experimental systems capable of simulating this "grouting interface-cyclic dissolution-erosion" process under laboratory conditions.

[0004] Existing durability testing apparatuses primarily target rock or concrete substrates, focusing on performance changes under environmental conditions such as freeze-thaw cycles, sulfate attack, and alternating wet and dry conditions. Their structures typically consist of a constant-temperature bath, a fluid circulation system, and a loading device. While these systems can reflect the overall degradation patterns of materials, they cannot reproduce the complex environmental effects at the interface after grouting repair. Furthermore, the experimental subjects are mostly intact block samples, lacking the ability to characterize the coupled effects of flow, dissolution, and scouring at the interface. In addition, current studies generally employ static immersion or single-fluid flushing methods, failing to realize the real-world service cycle process under alternating acid and water conditions, making it difficult to accurately assess the accelerated degradation patterns of the interface region.

[0005] The main reasons for the above problems are:

[0006] (1) Existing rock mass deterioration test systems are mostly designed for the rock or concrete blocks themselves, and fail to consider the characteristics of the rock-grout composite system formed after the grouting process, resulting in the deterioration law that cannot reflect the true service state of the interface. (2) Traditional fluid reaction systems are usually single-channel or single-medium circulation structures, which make it difficult to achieve automatic switching and circulation control between acid and water, and cannot simulate the long-term alternating acid etching-scouring combined effect in engineering. (3) The internal structure of the interface area after grouting is complex and highly heterogeneous. Most devices lack visualization and real-time monitoring modules, making it difficult to capture key deterioration behaviors such as grout debonding, pore evolution and seepage path changes at the interface. (4) In addition, some systems are still mainly controlled by steady flow or static reaction in experimental control, without considering the influence of flow velocity fluctuation and time evolution on the interface durability degradation process, which limits the quantitative assessment of interface stability in actual seepage environment.

[0007] To address the aforementioned shortcomings, this invention proposes an experimental system and method for the durability of cyclic dissolution-scouring at the grout-rock interface.

[0008] A search revealed that Chinese patent document CN119935840A, published on May 6, 2025, discloses a temperature-controlled fracture network grouting experimental device and method. This method focuses on the grouting process itself, particularly the diffusion behavior of the two-component grout, the immediate evaluation of the sealing effect, and the influence of temperature on the grouting process. This application, however, focuses on the durability degradation of the simulated interface under the alternating effects of chemical corrosion and water erosion during long-term service after grouting, and provides a dynamic and quantitative assessment of this degradation. Summary of the Invention

[0009] The purpose of this invention is to provide an experimental system and method for the cyclic dissolution-scouring durability of the grout-rock interface, so as to simulate the alternating acid etching-scouring process of the interface after grouting under controllable fluid, chemical and temperature conditions, and to achieve dynamic and quantitative durability analysis.

[0010] To achieve the above objectives, this application provides a grout-rock interface cyclic dissolution-scouring durability testing system, comprising: A transparent interface model unit includes two parallel transparent plates, a first transparent plate and a second transparent plate, with an interlayer space between the two plates for accommodating the grouting body, and the surfaces of the opposite sides of the first transparent plate and the second transparent plate for simulating the rock mass interface. A circulating fluid supply unit, comprising an acidic solvent storage tank and a clean water storage tank, which are respectively connected to the inlet of the transparent interface model unit via pipelines; An automatic switching valve group is installed on the pipeline between the acidic solvent storage tank and the clean water storage tank and the transparent interface model unit. It is used to periodically switch the injection of acidic solvent and clean water into the transparent interface model unit alternately, so as to implement the coupling effect of cyclic dissolution and water flow scouring on the solidified grout-rock interface. An effluent collection and monitoring unit is connected to the outlet of the transparent interface model unit and is used to collect the effluent and monitor its ion concentration or solid particle content. The experimental system is used to dynamically evaluate the bonding durability between the grout and the simulated rock mass interface after the grout in the transparent interface model unit has completely solidified.

[0011] The transparent interface model unit also includes an outlet and a dissolution and scouring inlet disposed on the front and rear sides between the first transparent plate and the second transparent plate, as well as a first baffle and a second baffle disposed on the left and right sides; a gasket for controlling the initial crack opening is disposed between the first transparent plate and the second transparent plate.

[0012] It also includes a clamping unit, which includes an upper clamping plate, a lower clamping plate, a front fixing plate, a rear fixing plate, a left clamping plate, and a right clamping plate. The upper clamping plate, the lower clamping plate, the front fixing plate, the rear fixing plate, the left clamping plate, and the right clamping plate are connected by bolts to form a clamping cavity, and the transparent interface model unit is located in the clamping cavity.

[0013] It also includes a grouting unit, which includes a grouting pump and a grout storage tank. The feed end of the grouting pump is connected to the grout storage tank. A grouting port is provided on the first transparent plate, and the discharge end is connected to the grouting port through a pipe. The grout storage tank is used to hold the grouting liquid.

[0014] The automatic switching valve group includes a high-pressure pump and a multi-channel valve. The acidic solvent storage tank and the clean water storage tank are respectively connected to the inlet of the multi-channel valve through pipelines. The outlet of the multi-channel valve is connected to the inlet of the high-pressure pump through a pipeline. The outlet of the high-pressure pump is connected to the inlet of the transparent interface model unit through a pipeline. A pressure sensor is installed on the pipeline at the outlet of the high-pressure pump.

[0015] It also includes a visualization monitoring unit, which includes a camera and a computer. The camera is communicatively connected to the computer and is positioned above and / or below the transparent interface model unit. The camera is used to record dynamic images of the slurry diffusion, interface dissolution and scouring process, and saves them to the computer in real time.

[0016] A method for testing the durability of cyclic dissolution-scouring at the grout-rock interface, employing the aforementioned cyclic dissolution-scouring durability testing system, includes the following steps: S1. Inject grout into the interlayer space of the transparent interface model unit, and form a grout-rock interface model after the grout has completely solidified; S2. Start the circulating fluid supply unit, and inject acidic dissolving liquid and clean water into the grouting body-rock interface model alternately according to a preset cycle through the automatic switching valve group to perform multiple rounds of dissolution and scouring circulation; collect inlet pressure, flow rate, pH value of effluent, calcium ion concentration and suspended particle concentration in real time during each cycle; S3. Based on the collected data, calculate the interface dissolution rate for the current round. and amount of erosion and shedding And update the cumulative degradation index. ; In the formula: These are the weighting coefficients. n This is the current cycle number; S4. Determine the cumulative degradation index. Has the preset durability failure threshold been reached? : like If so, the next dissolution-flushing cycle will continue. like If the test fails, the test is terminated, and the number of cycles at this point is recorded as the durability life index of the grout-rock interface. S5. Based on the aforementioned durability life index and degradation evolution law, evaluate the long-term applicability of the grouting material in the target service environment.

[0017] S2 also includes the following steps: S2.1. Through automatic valve group control, acid is first injected into the grout-rock interface model at a set flow rate. It flows through the fractures to the outlet of the transparent interface model unit. After the acid comes into contact with the grout-rock interface, a chemical reaction occurs, causing local dissolution and pore enlargement. At this time, the pressure P1 at the inlet of the grout-rock interface model and the pressure P2 at the outlet are set to atmospheric pressure. The change of ΔP = P1-P2 over time is recorded synchronously. Under the condition that the flow rate Q remains constant, the permeability is calculated according to Darcy's law. The decrease of ΔP indicates the increase of fracture permeability k, reflecting the process of seepage channel expansion caused by dissolution. S2.2 After the set erosion time is reached, the automatic switching valve group switches to the clean water channel, allowing clean water to flush the fissures at the same flow rate. This process simulates the alternating action of the grout being eroded by acid and then flushed by seepage in an engineering environment. The changes in inlet and outlet pressure and flow fluctuations are continuously monitored. If ΔP increases over time, it indicates that the fissure channel is partially blocked due to grout shedding or redistribution of deposits. If ΔP decreases, it indicates that the flushing has caused further expansion of the channel or grout debonding. S2.3 The automatic switching valve group automatically cycles between the acid and clean water channels according to the set program. Each cycle includes two stages: dissolution and flushing. The ΔP–Q curve of each stage is recorded, the permeability change curve k(t) is calculated in real time, and the permeability recovery or decay trend is plotted.

[0018] After completing the set number of cycles, the ΔP–Q data is exported, and the average permeability change rate during the entire cycle is calculated using the curve integral method. The permeability increment Δk is proportional to the content of slurry particles in the outlet waste liquid, so the permeability increment Δk is used as an evaluation index for interface durability. Specifically: if Δk is consistently greater than 0, it indicates that the grouting interface structure is damaged and the durability is reduced; if Δk is less than or equal to 0, it indicates that the system has reached an equilibrium state under the action of scouring, and the sealing structure has durability.

[0019] The outlet liquid enters the waste liquid bottle through a conduit. Samples are taken periodically and the ion concentration and particle content are analyzed using a liquid chromatograph. Combined with the waste liquid mass recorded by an electronic balance, the amount of slurry detachment and the dissolution rate are quantitatively calculated to establish the degradation law of the slurry-rock interface under cyclic dissolution-scouring conditions.

[0020] Compared with the prior art, the above-conceptual technical solution conceived in this application has the following beneficial effects: 1. Existing technologies focus on the grout diffusion behavior, immediate sealing effect, and the influence of temperature on setting during the grouting process, addressing the problem of how to effectively grout. This application, however, shifts the research focus to the long-term service stage after grouting is completed, specifically addressing the core engineering concern of how long grouted structures can withstand complex groundwater environments. This fills the gap in existing experimental technologies for long-term durability assessment and achieves a paradigm shift from construction performance to service performance research.

[0021] 2. This application achieves, for the first time in the laboratory, a programmed and adjustable parameter-controlled dissolution-scouring cycle loading through the coordinated control of acidic solvent storage tank, clean water storage tank and automatic switching valve group. It faithfully reproduces the deterioration stress path of the actual underground environment, and significantly improves the environmental representativeness of accelerated aging test and the reliability of engineering extrapolation.

[0022] 3. This application uses upper and lower transparent plates to clamp the grouting body, directly constructing and studying the bonding interface between the grouting body and the rock mass. The upper and lower transparent plates have textures with preset roughness to simulate different rock mass interface morphologies, closely resembling the key weak points in actual engineering where debonding, leakage and failure occur. This design is closer to the real failure mechanism, making the experimental results more engineering-oriented and valuable for guidance.

[0023] These three applications not only support high-speed camera recording of the entire microscopic evolution process, such as interface debonding and pore expansion, but also construct a quantitative evaluation system through online monitoring of multiple parameters, including pressure, flow rate, ion concentration, and particle content: real-time inversion of permeability based on Darcy's law. ; Calculate the dissolution rate With scouring and shedding Propose cumulative degradation indicators and penetration rate increment As a durability criterion, an engineering failure threshold is introduced. The intelligent termination mechanism. This data-driven and criterion-based control method transforms durability assessment from experience-based judgment to scientific quantification, significantly improving the objectivity, comparability, and engineering applicability of the results.

[0024] 4. This application systematically solves the fundamental defect of existing grouting test technology in being unable to evaluate long-term service performance by focusing on four innovative dimensions: interface durability, simulating real alternating action, constructing a quantitative evaluation system, and outputting engineering-usable indicators. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0026] Figure 1 This is a schematic diagram of the experimental system of the present invention.

[0027] Figure 2 This is a schematic diagram of the transparent interface model unit in this invention.

[0028] Figure label: Transparent interface model unit 1, first transparent plate 101, second transparent plate 102, grouting port 103, outlet 104, erosion inlet 105, first stop block 106, second stop block 107, upper clamping plate 108, lower clamping plate 109, front fixing plate 110, rear fixing plate 111, left side clamping plate 112, right side clamping plate 113, gasket 114; 2. Grouting pump; 3. Grouting tank; 4. Acidic solvent storage tank; 5. Clean water storage tank; 6. High-pressure pump; 7. Multi-channel valve; 8. Pressure sensor; 9. First vertical support rod; 10. Second vertical support rod; 11. Horizontal support rod; 12. Fixing block; 13. Camera; 14. Computer; 15. Waste liquid bottle; 16. Liquid chromatograph. Detailed Implementation

[0029] To more clearly illustrate the purpose, technical solution, and beneficial effects of this application, a further detailed description of this application is provided below in conjunction with illustrations and specific embodiments. It should be specifically noted that the specific embodiments described below are only for illustrating the technical content of this application and do not constitute a limitation on the scope of protection of this application.

[0030] Regarding the explanation of terminology: In this application, "and / or" is used to describe the relationship between related objects, covering three possible situations: taking "A and / or B" as an example, it can indicate the situation where only A exists, A and B exist simultaneously, or only B exists; the symbol " / " indicates the "or" relationship between related objects, such as "A / B" which refers to A or B.

[0031] Regarding the description of the embodiments: The terms "exemplary" and "for example" appearing in this application are only used to illustrate the technical solutions through specific examples. It should be particularly emphasized that any implementation method or design scheme marked as "exemplary" or "for example" should not be construed as having an advantage over other solutions. Such expressions are only used to present the technical concepts more intuitively.

[0032] Example 1: See Figure 1 This invention provides a cyclic dissolution-scouring durability test system for the grout-rock interface, comprising: Transparent interface model unit 1 includes two parallel transparent plates 101 and 102, with a sandwich space between the two plates for accommodating the grouting body, and the surfaces of the first transparent plate 101 and the second transparent plate 102 on opposite sides are used to simulate the rock mass interface. The circulating fluid supply unit includes an acidic solvent storage tank 4 and a clean water storage tank 5, which are respectively connected to the inlet of the transparent interface model unit through pipelines. An automatic switching valve group is installed on the pipeline between the acidic solvent storage tank 4 and the clean water storage tank 5 and the transparent interface model unit. It is used to periodically switch the injection of acidic solvent and clean water into the transparent interface model unit to implement the coupled effect of cyclic dissolution and water scouring on the solidified grout-rock interface. The effluent collection and monitoring unit is connected to the outlet of the transparent interface model unit and is used to collect the effluent and monitor its ion concentration or solid particle content. The experimental system is used to dynamically evaluate the bonding durability between the grout and the simulated rock mass interface after the grout in the transparent interface model unit has completely solidified.

[0033] In this embodiment, the transparent interface model unit 1 is used to construct a controllable and observable physical model of the grout-rock interface. The surfaces of the first transparent plate 101 and the second transparent plate 102 on opposite sides can be processed into smooth surfaces or textures with a preset roughness to simulate different rock interface morphologies. The transparent interface model unit 1, as the direct object of the dissolution-scouring fluid action, bears the bonding interface between the grout and the simulated rock mass. Utilizing transparent materials and in conjunction with a high-speed camera or microscopic imaging system, the transparent interface model unit 1 can record the microscopic evolution process of the interface under cyclic action in real time and in situ, such as crack initiation, grout spalling, and seepage path reconstruction.

[0034] The circulating fluid supply unit provides two fluid media with different properties: acidic dissolving solution and clean water. These two fluid media are stored separately in independent acidic dissolving solution tank 4 and clean water tank 5, respectively. Flow rate and pressure are precisely controlled by pumps, providing a stable and adjustable fluid source for subsequent alternating dissolution-scouring cycles. The circulating fluid supply unit simulates the real chemical environment of groundwater. The acidic dissolving solution reproduces typical chemical erosion conditions such as carbonic acid erosion caused by CO2 dissolution in groundwater or acidic mine drainage. The clean water injection simulates the carrying and shearing scouring effects of groundwater flow on loose particles at the interface. By adjusting parameters such as the pH value, ion concentration, and flow rate of the dissolving solution, the service environment of different geological regions, such as karst areas and acidic mining areas, can be simulated, improving the engineering adaptability of the experiment.

[0035] An automatic switching valve assembly is installed on the pipeline between the acidic solvent storage tank 4, the clean water storage tank 5, and the transparent interface model unit 1. Under program control, such as by a PLC or computer, it automatically switches the fluid path according to a preset time cycle, achieving seamless alternation between the dissolution and scouring stages. It supports setting parameters such as dissolution duration, scouring duration, and total number of cycles. The automatic switching valve assembly is used to simulate the intermittent and alternating occurrence of dissolution and scouring in nature. By shortening the cycle period or increasing the dissolution intensity, it can accelerate the interface degradation process on a laboratory scale, providing a data basis for lifetime prediction.

[0036] The effluent collection and monitoring unit is connected to the outlet of transparent interface model unit 1 and is used to collect the effluent after each cycle. This unit can integrate various online or offline monitoring methods, including: ion concentration sensors, turbidimeters or particle counters, pH meters, conductivity meters, and other auxiliary water quality parameter monitoring devices, as well as filtration devices and weighing equipment for quantitative analysis of the mass of eroded material. The effluent collection and monitoring unit is used to quantitatively characterize the degree of interface degradation, including calcium ion concentration reflecting the chemical dissolution of the cement-based grout and suspended particle content reflecting the mechanical erosion of the interface material. The collected data is used to calculate the interface dissolution rate. Scrubber shedding amount and cumulative degradation indicators This provides a direct basis for the adaptive termination of the experiment, such as stopping when the failure threshold is reached, and offers a scientific criterion for such termination.

[0037] In this embodiment, the transparent interface model unit 1, the circulating fluid supply unit, the automatic switching valve group, and the effluent collection and monitoring unit together constitute an integrated experimental platform for environmental simulation, quantitative evaluation of the action application process, and observation. This not only solves the problem that existing technologies cannot study the long-term durability after grouting, but also improves the scientific nature and engineering practicality of grouting interface performance evaluation through visualization, quantification, and intelligent means.

[0038] In this embodiment, see Figure 2 The transparent interface model 1 also includes an outlet 104 and a dissolution and scouring inlet 105 disposed on the front and rear sides between the first transparent plate 101 and the second transparent plate 102, as well as a first baffle 106 and a second baffle 107 disposed on the left and right sides; a gasket 114 for controlling the initial crack opening is disposed between the first transparent plate 101 and the second transparent plate 102.

[0039] Furthermore, it also includes a clamping unit, which comprises an upper clamping plate 108, a lower clamping plate 109, a front fixing plate 110, a rear fixing plate 111, a left clamping plate 112, and a right clamping plate 113. The upper clamping plate 108, lower clamping plate 109, front fixing plate 110, rear fixing plate 111, left clamping plate 112, and right clamping plate 113 are connected by bolts to form a clamping cavity. The transparent interface model unit is located within the clamping cavity, thereby limiting and fixing the transparent interface model unit. During the experiment, the fluid flowing out of outlet 104 is collected in waste liquid bottle 15 for subsequent component analysis.

[0040] In this embodiment, see Figure 1 The automatic switching valve assembly includes a high-pressure pump 6 and a multi-channel valve 7. The acidic solvent storage tank 4 and the clean water storage tank 5 are connected to the inlet of the multi-channel valve 7 via pipelines. The outlet of the multi-channel valve 7 is connected to the inlet of the high-pressure pump 6 via a pipeline. The outlet of the high-pressure pump 6 is connected to the dissolution and scouring inlet 105 of the transparent interface model unit via a pipeline. A pressure sensor 8 is installed on the pipeline at the outlet of the high-pressure pump 6. The pressure sensor 8 is used to detect changes in pipeline pressure in real time, reflecting changes in fracture permeability.

[0041] Example 2: Based on Example 1, see Figure 1 The experimental system also includes a grouting unit, which is used to inject grout into the transparent interface model unit 1.

[0042] Specifically, the grouting unit includes a grouting pump 2 and a grout storage tank 3. The inlet end of the grouting pump 2 is connected to the grout storage tank 3. A grouting port 103 is provided on the first transparent plate 101, and the outlet end is connected to the grouting port 103 through a pipe. The grout storage tank 3 is used to hold the grouting liquid. After grouting is completed, the grouting port 103 is sealed with a threaded plug.

[0043] Example 3: Based on Example 1 or Example 2, see Figure 1 The experimental system also includes a visualization monitoring unit. The visualization monitoring unit includes a camera 13 and a computer 14. The camera 13 is communicatively connected to the computer 14 and is positioned above and / or below the transparent interface model unit. The camera 13 is used to record dynamic images of the slurry diffusion, interface dissolution and scouring process, and saves them in real time on the computer 14.

[0044] The camera 13 is fixed to the upper and / or lower side of the transparent interface model unit 1 by the fixing block 12 and the horizontal support rod 11. The fixing block 12 is supported by the first vertical support rod 9 and the second vertical support rod 10. The height, left and right position and front and back angle of the camera 13 can be adjusted.

[0045] Example 4: This application also proposes a test method for the durability of cyclic dissolution-scouring at the grout-rock interface. The test method uses the cyclic dissolution-scouring durability test system for the grout-rock interface described in Example 1, 2, or 3, and includes the following steps: S1. Inject grout into the interlayer space of transparent interface model unit 1, and form a grout-rock interface model after the grout has completely solidified.

[0046] Specifically, first connect the outlet of grouting pump 2 to grouting port 103 using a grouting pipe. Turn on grouting pump 2 to inject grout into the interlayer space of transparent interface model unit 1. After the grout is completed, seal grouting port 103 and wait for the grout to solidify.

[0047] S2. Start the circulating fluid supply unit, and inject acidic dissolving fluid and clean water into the grouting body-rock interface model alternately according to a preset cycle through the automatic switching valve group to perform multiple rounds of dissolution and scouring circulation; collect in real time the inlet pressure, flow rate, pH value of the outflow, calcium ion concentration and suspended particle concentration during each cycle.

[0048] Preset cycle duration of the dissolution phase Duration of the scouring phase Based on the dynamic settings of the groundwater chemical characteristics and hydraulic conditions of the target project, in this embodiment... , .

[0049] S3. Based on the collected data, calculate the interface dissolution rate for the current round. and amount of erosion and shedding And update the cumulative degradation index. ; In the formula: These are the weighting coefficients. n This represents the current cycle round.

[0050] Dissolution rate The calcium content of the grout is calculated by the ratio of the increase in calcium ions in the effluent per unit time to the theoretical calcium content of the grout.

[0051] Washout amount The mass of the solid residue is obtained by filtering the effluent and weighing it.

[0052] S4. Determine the cumulative degradation index. Has the preset durability failure threshold been reached? : like If so, the next dissolution-flushing cycle will continue. like If the test fails, the test is terminated, and the number of cycles at this point is recorded as the durability life index of the grout-rock interface.

[0053] Among them, durability failure threshold According to the engineering safety level setting, when the interface permeability increases by more than 10 times the initial value, or the inlet pressure decreases by more than 50%, the corresponding... Triggered.

[0054] S5. Based on the aforementioned durability life index and degradation evolution law, evaluate the long-term applicability of the grouting material in the target service environment.

[0055] It also includes continuously imaging the interface area through the high-speed camera system of camera 13 during the test, and actively shortening the subsequent cycle to capture the accelerated degradation stage when the rate of expansion of the interface debonding area exceeds the preset critical value.

[0056] This method not only accurately reproduces complex service environments, but also transforms the interface degradation process into quantifiable, comparable, and engineering-applicable scientific indicators through data fusion and intelligent criteria, thus solving the technical bottleneck that existing grouting test methods cannot assess long-term durability.

[0057] Example 5: In S2 of Example 4, the following steps are also included: S2.1. Through automatic valve group control, acid is first injected into the grout-rock interface model at a set flow rate. It flows through the fractures to the outlet of the transparent interface model unit. After the acid comes into contact with the grout-rock interface, a chemical reaction occurs, causing local dissolution and pore enlargement. At this time, the pressure P1 at the inlet of the grout-rock interface model and the pressure P2 at the outlet are set to atmospheric pressure. The change of ΔP = P1-P2 over time is recorded synchronously. Under the condition that the flow rate Q remains constant, the permeability is calculated according to Darcy's law. The decrease of ΔP indicates the increase of fracture permeability k, reflecting the process of permeability channel expansion caused by dissolution.

[0058] S2.2 After the set dissolution time is reached, the automatic switching valve group switches to the clean water channel, so that the clean water flushes the cracks at the same flow rate; this process simulates the alternating action of the grout being eroded by acid and then flushed by seepage in the engineering environment; continuously monitor the changes in inlet and outlet pressure and flow fluctuations; if ΔP increases with time, it indicates that the crack channel is partially blocked due to grout shedding or redistribution of deposits; if ΔP decreases, it indicates that the flushing has caused the channel to expand further or the grout to debond.

[0059] S2.3 The automatic switching valve group automatically cycles between the acid and clean water channels according to the set program. Each cycle includes two stages: dissolution and flushing. The ΔP–Q curve of each stage is recorded, the permeability change curve k(t) is calculated in real time, and the permeability recovery or decay trend is plotted.

[0060] After completing the set number of cycles, the ΔP–Q data is exported, and the average permeability change rate during the entire cycle is calculated using the curve integral method. The permeability increment Δk is proportional to the content of slurry particles in the outlet waste liquid, so the permeability increment Δk is used as an evaluation index for interface durability. Specifically: if Δk is consistently greater than 0, it indicates that the grouting interface structure is damaged and the durability is reduced; if Δk is less than or equal to 0, it indicates that the system has reached an equilibrium state under the action of scouring, and the sealing structure has durability.

[0061] The outlet liquid enters the waste liquid bottle 15 through a conduit. Samples are taken periodically and the ion concentration and particle content are analyzed using a liquid chromatograph 16. Combined with the waste liquid mass recorded by an electronic balance, the amount of slurry detachment and the dissolution rate are quantitatively calculated to establish the degradation law of the slurry-rock interface under cyclic dissolution-scouring conditions.

[0062] By automatically switching between acid and clean water flow paths using a multi-channel valve, the timing and parameters of the dissolution and scouring stages are precisely controlled, effectively simulating the intermittent and alternating effects in the groundwater environment caused by seasonal changes, reservoir scheduling, or rainfall infiltration. This avoids the oversimplification of complex underground environments by traditional single immersion or constant flow scouring tests, making the experimental results closer to engineering practice and improving the representativeness and extrapolation reliability of the test.

[0063] The inlet pressure difference ΔP is collected in real time by pressure sensor 8, and the permeability is calculated online according to Darcy's law. When ΔP decreases, permeability increases, reflecting the formation of preferential flow channels due to dissolution and pore enlargement or interfacial debonding; when ΔP increases, permeability decreases, indicating that erosion causes particles to detach and block cracks. This dynamic and continuous monitoring method allows changes in interfacial structural integrity to be captured and quantified in real time, far superior to traditional methods that rely solely on endpoint destructive detection.

[0064] The average permeability change rate during the entire cycle was calculated by curve integral and correlated with the slurry particle content in the outlet waste liquid. If Δk continues to increase, it indicates that the grouting interface structure is damaged and the durability is reduced. When Δk tends to stabilize, it indicates that the system has reached an equilibrium state under the action of scouring and the sealing structure has good durability.

[0065] The effluent waste liquid was sampled periodically, and the dissolution rate and erosion amount were obtained by combining liquid chromatography-16 with electronic balance. The dissolution rate can be calculated by the increase of Ca ions, and the erosion amount can be determined by the dry weight of suspended particles. This decouples the chemical and mechanical degradation mechanisms, clarifies their respective contributions to the total degradation, and provides a basis for targeted improvement to optimize grouting materials, such as improving corrosion resistance or enhancing interfacial bonding strength. It can also support the establishment of a multi-factor coupled degradation model to serve life prediction.

[0066] The method in this embodiment automatically switches between acid and clean water using a multi-channel valve, replicating the real service conditions of alternating chemical dissolution and hydraulic scouring in underground environments, thus improving the environmental representativeness of accelerated aging tests. During the experiment, the system uses Darcy's law to invert permeability evolution in real time, combined with high-precision pressure and flow monitoring to dynamically capture changes in the integrity of the interface structure. Simultaneously, high-speed imaging synchronizes macroscopic seepage response and microscopic interface damage phenomena, such as debonding, pore expansion, and channel reconstruction, achieving temporal alignment and mechanistic correlation. A durability evaluation index with the relative permeability change rate Δk as the core is proposed, and the dissolution rate and scouring amount are quantitatively separated by the ion concentration and particle content of the waste liquid. This not only achieves precise quantification of the degree of degradation but also provides an interpretable, comparable, and engineering-applicable scientific basis for grouting material optimization and life prediction.

[0067] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0068] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A grout-rock interface cyclic dissolution-scouring durability test system, characterized in that, include: Transparent interface model unit (1), the transparent interface model unit includes two parallel first transparent plates (101) and second transparent plates (102), a sandwich space is formed between the two plates to accommodate the grouting body, and the surfaces of the opposite side of the first transparent plate (101) and the second transparent plate (102) are used to simulate the rock mass interface; A circulating fluid supply unit, comprising an acidic solvent storage tank (4) and a clean water storage tank (5), which are respectively connected to the inlet of the transparent interface model unit via pipelines; An automatic switching valve group is installed on the pipeline between the acidic erosion liquid storage tank (4) and the clean water storage tank (5) and the transparent interface model unit. It is used to periodically switch the injection of acidic erosion liquid and clean water into the transparent interface model unit to implement the coupling effect of cyclic erosion and water flow scouring on the solidified grout-rock interface. An effluent collection and monitoring unit is connected to the outlet of the transparent interface model unit and is used to collect the effluent and monitor its ion concentration or solid particle content. The experimental system is used to dynamically evaluate the bonding durability between the grout and the simulated rock mass interface after the grout in the transparent interface model unit has completely solidified.

2. The grout-rock interface cyclic dissolution-scouring durability test system according to claim 1, characterized in that: The transparent interface model unit (1) also includes an outlet (104) and a dissolution and scouring inlet (105) disposed on the front and rear sides between the first transparent plate (101) and the second transparent plate (102), as well as a first baffle (106) and a second baffle (107) disposed on the left and right sides; a gasket (114) for controlling the initial crack opening is disposed between the first transparent plate (101) and the second transparent plate (102).

3. The grout-rock interface cyclic dissolution-scouring durability test system according to claim 2, characterized in that: It also includes a clamping unit, which includes an upper clamping plate (108), a lower clamping plate (109), a front fixing plate (110), a rear fixing plate (111), a left clamping plate (112), and a right clamping plate (113). The upper clamping plate (108), the lower clamping plate (109), the front fixing plate (110), the rear fixing plate (111), the left clamping plate (112), and the right clamping plate (113) are connected by bolts to form a clamping cavity, and the transparent interface model unit is located in the clamping cavity.

4. The grout-rock interface cyclic dissolution-scouring durability test system according to claim 2, characterized in that: It also includes a grouting unit, which includes a grouting pump (2) and a grout storage tank (3). The feed end of the grouting pump (2) is connected to the grout storage tank (3). A grouting port (103) is provided on the first transparent plate (101), and the discharge end is connected to the grouting port (103) through a pipe. The grout storage tank (3) is used to hold grouting liquid.

5. A grout-rock interface cyclic dissolution-scouring durability test system according to claim 1 or 2, characterized in that: The automatic switching valve group includes a high-pressure pump (6) and a multi-channel valve (7). The acidic solvent storage tank (4) and the clean water storage tank (5) are respectively connected to the inlet of the multi-channel valve (7) through pipelines. The outlet of the multi-channel valve (7) is connected to the inlet of the high-pressure pump (6) through a pipeline. The outlet of the high-pressure pump (6) is connected to the inlet of the transparent interface model unit through a pipeline. A pressure sensor (8) is installed on the pipeline at the outlet of the high-pressure pump (6).

6. The grout-rock interface cyclic dissolution-scouring durability test system according to claim 1, characterized in that: It also includes a visualization monitoring unit, which includes a camera (13) and a computer (14). The camera (13) is connected to the computer (14) and the camera (13) is positioned above and / or below the transparent interface model unit. The camera (13) is used to record dynamic images of the slurry diffusion, interface dissolution and scouring process and saves them in real time on the computer (14).

7. A test method for the durability of cyclic dissolution-scouring at the grout-rock interface, characterized in that: The grout-rock interface cyclic dissolution-scouring durability test system according to any one of claims 1 to 6 was adopted, and the test method includes the following steps: S1. Inject grout into the interlayer space of the transparent interface model unit (1), and form a grout-rock interface model after the grout has completely solidified. S2. Start the circulating fluid supply unit, and inject acidic dissolving liquid and clean water into the grouting body-rock interface model alternately according to a preset cycle through the automatic switching valve group to perform multiple rounds of dissolution and scouring circulation; collect inlet pressure, flow rate, pH value of effluent, calcium ion concentration and suspended particle concentration in real time during each cycle; S3. Based on the collected data, calculate the interface dissolution rate for the current round. and amount of erosion and shedding And update the cumulative degradation index. ; In the formula: These are the weighting coefficients. n This is the current cycle number; S4. Determine the cumulative degradation index. Has the preset durability failure threshold been reached? : like If so, the next dissolution-flushing cycle will continue. like If the test fails, the test is terminated, and the number of cycles at this point is recorded as the durability life index of the grout-rock interface. S5. Based on the aforementioned durability life index and degradation evolution law, evaluate the long-term applicability of the grouting material in the target service environment.

8. The experimental method for the durability of cyclic dissolution-scouring at the grout-rock interface according to claim 7, characterized in that: S2 also includes the following steps: S2.

1. Through automatic valve group control, acid is first injected into the grout-rock interface model at a set flow rate. It flows through the fractures to the outlet of the transparent interface model unit. After the acid comes into contact with the grout-rock interface, a chemical reaction occurs, causing local dissolution and pore enlargement. At this time, the pressure P1 at the inlet of the grout-rock interface model and the pressure P2 at the outlet are set to atmospheric pressure. The change of ΔP = P1-P2 over time is recorded synchronously. Under the condition that the flow rate Q remains constant, the permeability is calculated according to Darcy's law. The decrease of ΔP indicates the increase of fracture permeability k, reflecting the process of seepage channel expansion caused by dissolution. S2.2 After the set erosion time is reached, the automatic switching valve group switches to the clean water channel, allowing clean water to flush the fissures at the same flow rate. This process simulates the alternating action of the grout being eroded by acid and then flushed by seepage in an engineering environment. The changes in inlet and outlet pressure and flow fluctuations are continuously monitored. If ΔP increases over time, it indicates that the fissure channel is partially blocked due to grout shedding or redistribution of deposits. If ΔP decreases, it indicates that the flushing has caused further expansion of the channel or grout debonding. S2.3 The automatic switching valve group automatically cycles between the acid and clean water channels according to the set program. Each cycle includes two stages: dissolution and flushing. The ΔP–Q curve of each stage is recorded, the permeability change curve k(t) is calculated in real time, and the permeability recovery or decay trend is plotted.

9. The experimental method for the durability of cyclic dissolution-scouring at the grout-rock interface according to claim 8, characterized in that: After completing the set number of cycles, the ΔP–Q data is exported, and the average permeability change rate during the entire cycle is calculated using the curve integral method. The permeability increment Δk is proportional to the content of slurry particles in the outlet waste liquid, so the permeability increment Δk is used as an evaluation index for interface durability. Specifically: if Δk is consistently greater than 0, it indicates that the grouting interface structure is damaged and the durability is reduced; if Δk is less than or equal to 0, it indicates that the system has reached an equilibrium state under the action of scouring, and the sealing structure has durability.

10. The experimental method for the durability of cyclic dissolution-scouring at the grout-rock interface according to claim 7, characterized in that: The outlet liquid enters the waste liquid bottle (15) through the conduit. Samples are taken at regular intervals and the ion concentration and particle content are analyzed using a liquid chromatograph (16). Combined with the waste liquid mass recorded by the electronic balance, the amount of slurry falling off and the dissolution rate are quantitatively calculated to establish the degradation law of the slurry-rock interface under cyclic dissolution-scouring conditions.

Images