A TBM backfill grouting model test device and test method under multi-field coupling
The multi-field coupled TBM wall backfill grouting model test device solves the problems of poor controllability of grout diffusion and difficulty in detection, realizes accurate evaluation of multi-field coupled working conditions, optimizes grouting materials and process parameters, and provides reliable test basis.
Patent Information
- Application Number
- CN202611046247.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-14
- Publication Date
- 2026-11-03
AI Technical Summary
The existing TBM wall backfill grouting process and model test technology have problems such as poor controllability of grout diffusion, difficulty in detecting hidden works, lack of multi-field coupling mechanism and insufficient full-domain non-destructive quantitative detection methods, resulting in strong subjectivity and low data accuracy in the evaluation of grouting effect.
A multi-field coupled TBM wall backfill grouting model test device is provided, including a visualization model system, a dynamic water system, a grouting system, a monitoring servo control system, an ultrasonic detection system, an image acquisition system, and a magnetic quantitative detection system. It can simulate multi-field coupled working conditions and perform full-process visualization observation and full-domain non-destructive quantitative evaluation.
It realizes the restoration of real working conditions with multi-field coupling, has the ability to visualize the whole process and perform non-destructive quantitative evaluation in the whole domain, accurately evaluates the grouting effect, provides experimental support and theoretical basis, and optimizes grouting materials and process parameters.
Smart Images
Figure CN123027869A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of underground engineering grouting technology, specifically to a test device and test method for a TBM backfill grouting model under multi-field coupling. Background Technology
[0002] During the construction of tunnel boring machines (TBMs), factors such as cutter over-excavation and surrounding rock deformation and convergence often lead to the formation of a 10-20mm annular gap between the surrounding rock and the tunnel lining. The conventional approach is to first backfill the gap with hard gravel with a particle size of 5-10mm to form a supporting framework. Then, cement-based grout or chemical grout is injected through pre-reserved grouting holes in the tunnel lining. After curing, an integral gravel backfill layer is formed. This backfill layer enhances the synergistic stress-bearing performance between the tunnel lining and the surrounding rock, inhibits the aging deformation of the surrounding rock, improves the overall stiffness and stress uniformity of the lining structure, and simultaneously seals the original fissures in the surrounding rock and the gaps behind the wall, achieving long-term water-blocking and seepage prevention in the tunnel.
[0003] However, the current TBM wall backfill grouting process and model testing technology still have significant technical shortcomings. The main problems in engineering applications and laboratory tests are as follows: (1) Poor controllability of grout diffusion: Affected by underground seepage disturbance, material ratio and grouting parameters, the grout is unevenly distributed in the pores of pea gravel, which easily leads to local voids and unbonded loose areas, reducing the integrity and structural strength of the back stone body of the lining. (2) Difficulty in detecting and evaluating hidden works: Both gravel backfilling and grouting are underground hidden works. Existing methods can only indirectly judge the grouting process by the grouting hole discharge status and grouting pressure. It is impossible to intuitively grasp the gravel movement and filling status and the spatial distribution range of grout. The grouting forming quality lacks quantitative evaluation basis. (3) Lack of research on multi-field coupling mechanism: The real underground environment has the coupling effect of multiple physical fields such as seepage field, temperature field and chemical corrosion field. The superposition of multiple fields will change the hydration characteristics of grout, consolidation rate and mechanical properties of stone body, thus affecting the grouting and water plugging effect. The existing test device has not realized the simulation of multi-field coupling working conditions, and there is no suitable quantitative grouting effect evaluation system. (4) Insufficient non-destructive quantitative testing methods: Traditional ultrasonic testing can only reflect the internal defects of the stone body and cannot accurately characterize the full-area indicators such as grout filling rate and diffusion uniformity. It is difficult to distinguish between the loose area of the gravel, the grout-rich area and the void area, resulting in strong subjectivity and low data accuracy in the evaluation of grouting effect.
[0004] Due to the aforementioned limitations, the mechanisms of grout penetration, diffusion, and consolidation in the pores of pea gravel under multi-field coupling in water-rich corrosive environments remain unclear. The causes of defects such as bonding failure and voids in loose areas cannot be precisely traced. Therefore, there is an urgent need to develop a model testing device and method capable of reproducing real-world multi-field coupling conditions, providing full-process visual observation and comprehensive non-destructive quantitative evaluation, to offer experimental support and theoretical basis for grouting material selection, process parameter optimization, and accurate evaluation of grouting effects. Summary of the Invention
[0005] The purpose of this invention is to address the problems existing in the prior art by providing a test device and test method for a TBM wall backfill grouting model under multi-field coupling.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: Firstly, a test apparatus for a TBM backfill grouting model under multi-field coupling is provided, comprising: A visualization model system, comprising a visualization model box, which includes a semi-circular arc-shaped slab-shaped pipe lining layer and a surrounding rock layer arranged in parallel, with a gravel backfill layer between them; A dynamic water system, which is connected to the visualization model system, is used to provide the visualization model system with water flows of different velocities, corrosiveness, and temperatures to construct a multi-field coupled seepage environment containing seepage fields, temperature fields, and chemical fields. The grouting system is connected to the visualization model system and is used to inject grout with different proportions into the visualization model system, adjust the grouting parameters, and quantitatively add magnetic tracer medium to the grout. A monitoring servo control system is connected to the dynamic water system and the grouting system, and is used to monitor water flow parameters and grouting parameters. The monitoring servo control system includes at least a temperature sensor, a flow rate sensor, and a pressure sensor. An ultrasonic detection system is used to perform non-contact, non-destructive internal structure detection and performance evaluation of the grouting binder in the pea gravel backfill layer. An image acquisition system is used to continuously observe the dynamic diffusion process of slurry in the pores of the pea gravel backfill layer; It also includes a magnetic quantitative detection system, which scans the entire domain of the visualization model system to collect electromagnetic response signals and inverts and analyzes the distribution content, spatial filling range, and local enrichment degree of the magnetic tracer medium in the detected area.
[0007] Furthermore, the segment lining layer and the surrounding rock layer are respectively made of transparent plates with a light transmittance of not less than 90%, forming a semi-circular annular column structure. Transparent plates are also provided on the end faces to form a visual model box. The segment lining layer is located on the inner side and is composed of multiple ring single structures that are sequentially spliced together. The adjacent rings are arranged in a staggered manner along the circumference. The surrounding rock layer is located on the outer side. The dimensions of the segment lining layer and the surrounding rock layer are set according to the actual engineering dimensions or geometric similarity scale. The spacing width of the pea gravel backfill layer corresponds to the actual gap size between the tunnel lining and the surrounding rock in the project or is scaled down proportionally, and the minimum spacing width is not less than 5 times the maximum particle size of the pea gravel used for backfilling. The periphery of the gravel backfill layer is provided with an annular sealing element that connects to the segment lining layer and the surrounding rock layer, so as to achieve complete sealing and waterproofing around the cavity.
[0008] Furthermore, several grouting holes are evenly arranged on the segment lining layer and connected to the grouting system through pressure-resistant grouting pipelines; water injection holes are arranged on the back of the visualization model box and connected to the dynamic water system through water injection pipelines; grout observation holes are arranged on the end side of the visualization model box, and the grouting termination time is determined by the grout concentration observed through the grout observation holes; drainage holes are provided at the bottom edge of the visualization model box and are connected to the drainage system for discharging waste liquid and residual liquid generated during the test.
[0009] Furthermore, the dynamic water system includes a water storage tank, a water pump, and a multi-purpose water pipe. The inlet of the water pump is connected to the water storage tank, and the outlet is connected to the multi-purpose water pipe. The multi-purpose water pipe includes a cooling water pipe, a heating water pipe, a normal temperature water pipe, and a main water pipe. The heating water pipe, the normal temperature water pipe, and the cooling water pipe are each equipped with independent on / off valves and converge into the main water pipe. The main water pipe is connected to the water injection hole of the visualization model box. The heating water pipe integrates a heater, the cooling water pipe integrates a cooler, and the main water pipe is connected in series with a flow rate regulator and a flow rate sensor.
[0010] Furthermore, the water pump configured in the dynamic water system provides a water flow velocity of not less than 4 m / s to meet the differentiated water injection requirements of the single-hole or multi-hole visualization model box; the dynamic water system adjusts the pH value of the solution by adding acidic or alkaline substances to the water, and controls the degree of water corrosion by doping with soluble corrosive salt ions, simulating the erosion behavior of different chemical corrosion conditions on grouting materials and solidified bodies.
[0011] Furthermore, the grouting system includes a grout tank, a grouting pump, and grouting pipelines. The grout tank has a built-in stirring device to prevent the magnetic powder from settling and stratifying with the grout. The discharge end of the grout tank is connected to the inlet end of the grouting pump through the grouting pipe, and the discharge end of the grouting pump is connected to the grouting hole of the visualization model box through the grouting pipelines. The grouting pipeline is equipped with a flow velocity sensor and a pressure sensor (such as a pressure gauge and a grouting flow meter) connected in series to collect grouting pressure and grouting flow parameters in real time; the grouting pump provides a rated grouting pressure of not less than 10 MPa to meet the high-pressure grouting simulation requirements under different geological conditions.
[0012] Furthermore, the ultrasonic detection system is detachably installed on the outer surface of the visualization model box, including a paired ultrasonic transmitter and an ultrasonic receiver, for non-destructive monitoring of the entire process of nucleation, growth and morphological distribution of the grouting cementitious body in the pea gravel backfill layer; The front and back of the visualization model box are equipped with an orthogonal grid detection system. The grid nodes are ultrasonic detection points, and the distance between adjacent ultrasonic detection points is no more than 10cm. Supplementary detection points with the same spacing are arranged on both sides of the visualization model box. The ultrasonic detection points and the supplementary detection points together form a multi-dimensional acoustic detection network covering the gravel backfill layer. The ultrasonic transmitter and the ultrasonic receiver are arranged in pairs at the ultrasonic detection points and the supplementary detection points, respectively.
[0013] Furthermore, the image acquisition system includes an industrial camera with a full-frame resolution of no less than 2560×2048 pixels and a maximum shooting frame rate of no less than 10,000 frames per second. The industrial camera is mounted directly above the transparent base plate of the visualization model box, and after field-of-view calibration, the imaging range completely covers the entire area of the visualization model box, continuously capturing the dynamic diffusion, seepage migration, and morphological evolution of the slurry in the pore network of the pea gravel backfill layer, providing visualized raw data for the analysis of the permeation mechanism.
[0014] Furthermore, the magnetic quantitative detection system is equipped with a high-frequency ground-penetrating radar detection module. The high-frequency ground-penetrating radar detection module performs a full-domain continuous electromagnetic scan along the outer surface of the visualization model box according to a preset gridded path, and collects full-domain electromagnetic response signals. Based on the strong electromagnetic reflection characteristics of the magnetic tracer medium in the slurry, the background data processing terminal analyzes the spatial distribution content of the magnetic tracer medium in the detection area, the actual filling range of the slurry, and the degree of local enrichment through an inversion algorithm. Based on the analysis results, the overall filling rate of the slurry, the lateral / longitudinal diffusion uniformity, and the void sealing rate are quantitatively calculated.
[0015] Secondly, based on the aforementioned test device for TBM backfill grouting model under multi-field coupling, a test method for TBM backfill grouting model under multi-field coupling is provided, the test method comprising the following steps: Preparation of modified grouting slurry containing magnetic tracer medium; Gravel is filled into the visualization model box to form the gravel backfill layer; The dynamic water system is activated to create a multi-field coupled seepage environment with different flow velocities, temperatures, and corrosion characteristics; Start the grouting system and inject grout into the visualization model box in a stepped manner until all grouting holes are grouted. The image acquisition system is activated to continuously acquire image data of the diffusion and migration of grout during the grouting process. After grouting is completed, the waste liquid and residual liquid in the visualization model box are discharged, all pipeline interfaces are sealed, and the box is left to stand for standard curing for 28 days. It also includes multi-method combined detection and evaluation: Ultrasonic pre-detection: The original ultrasonic background signal of the pea gravel backfill layer is collected by the ultrasonic detection system before grouting; during the grouting process and curing period, the ultrasonic detection system is triggered at a set frequency to collect the ultrasonic wave shape, wave velocity and attenuation parameters at each measuring point, and the cementitious body formation process and internal defect distribution are reconstructed in real time. Magnetic quantitative detection: After curing, the magnetic quantitative detection system is used to perform a grid scan along the entire area of the visualization model box to collect electromagnetic response signals. Based on the electromagnetic reflection characteristics of the magnetic tracer medium, its spatial distribution content, filling range and enrichment degree are inverted, and the slurry filling rate, diffusion uniformity and void sealing rate are quantitatively calculated. By combining the diffusion and transport image data, the ultrasonic pre-detection data, and the magnetic quantitative detection data, a comprehensive and quantitative evaluation of the TBM wall backfill grouting effect under multi-field coupled seepage environment is completed.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This multi-field coupled TBM wall backfill grouting model test device can reproduce the real working conditions of multi-field coupling, and has the ability to visualize the whole process and perform full-domain non-destructive quantitative evaluation. Combined with magnetic tracer-ground penetrating radar quantitative detection technology, it provides experimental support and theoretical basis for grouting material selection, process parameter optimization, and accurate evaluation of grouting effect, filling the gap in existing model test quantitative detection technology; 2. Through the setting of the visualization model box, this test device can not only simulate the real TBM wall backfilling situation, but also has a transparent visualization function. Combined with the image acquisition system, it can capture the seepage path, diffusion form and transport law of grout in the pores of pea gravel under multi-field coupled working conditions without obstruction, solving the problem that traditional hidden processes cannot be visualized and observed; 3. The dynamic water system and the component system can realistically reproduce the multi-physics field coupled working conditions. Furthermore, grouting simulation is conducted, enabling independent control of three parameters: flow rate, temperature, and chemical corrosion. This accurately simulates the superimposed environment of in-situ seepage, temperature, and chemical fields in underground engineering, reproducing the real physicochemical processes of grout hydration, erosion, and consolidation. The experimental data closely matches actual engineering conditions. 4. This experimental device also uses magnetic powder added to the grout as a tracer medium, combined with ground-penetrating radar electromagnetic scanning inversion technology, breaking through the limitations of traditional qualitative detection. It can non-destructively and quantitatively obtain core indicators such as grout filling rate, diffusion uniformity, and void sealing rate, achieving digital and precise evaluation of grouting effects. 5. This experimental method integrates visualized image data, ultrasonic defect data, radar quantitative data, and operating parameters, systematically revealing the grout diffusion mechanism, the causes of void defects, and the laws of material degradation under multi-field coupling. It provides reliable indoor experimental basis for optimizing new grouting material formulations, calibrating intelligent grouting process parameters, and predicting grouting effects on engineering sites. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the overall experimental device for backfill grouting model of TBM wall under multi-field coupling according to the present invention; Figure 2 This is a schematic diagram of the layout of water injection holes on the back of the visualization model box provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the layout of grouting holes on the front of the visualization model box provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the three-in-one temperature control device provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the grouting scheme provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the ultrasonic test point locations provided in an embodiment of the present invention; In the diagram: 1. Grout tank; 2. Grouting pump; 3. Grouting pipeline; 4. Vibration-resistant pressure gauge; 5. Grouting flow meter; 6. Visual model box; 7. Surrounding rock layer; 8. Gravel backfill layer; 9. Segment lining layer; 10. Grouting hole; 11. Water storage tank; 12. Water pump; 13. Multi-purpose water pipe; 1301. Heating water pipe; 1302. Normal temperature water pipe; 1303. Cooling water pipe; 14. Flow rate regulator; 15. Electromagnetic flow meter; 16. Main water pipe; 17. Drainage hole; 18. Fine-tuning bracket; 19. Grout observation hole; 20. Water injection hole; 21. Industrial camera; 22. Grid node; 23. Supplementary detection point; 24. Ultrasonic transmitter; 25. Ultrasonic receiver. Detailed Implementation
[0018] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0019] In the description of this invention, it should be noted that the terms "middle," "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0020] Example 1: A test device for backfill grouting model of TBM wall under multi-field coupling is provided, combined with Figures 1-3 As shown, it includes: a visualization model system, a dynamic water system, a grouting system, a monitoring servo control system, an ultrasonic detection system, an image acquisition system, and a magnetic quantitative detection system; The visualization model system includes a visualization model box 6, which includes a semi-circular arc-shaped plate-shaped pipe lining layer 9 and a surrounding rock layer 7 arranged in parallel, with a gravel backfill layer 8 set between them. The dynamic water system is connected to the visualization model system and is used to provide the visualization model system with water flows of different velocities, corrosiveness, and temperatures to construct a multi-field coupled seepage environment containing seepage fields, temperature fields, and chemical fields. The grouting system is connected to the visualization model system and is used to inject grout with different proportions into the visualization model system, control grouting parameters such as grouting pressure and grouting flow rate, and can quantitatively add magnetic powder to the grout as a magnetic tracer medium. The monitoring servo control system is connected to the dynamic water system and the grouting system, and is used to monitor water flow parameters and grouting parameters. The monitoring servo control system includes at least a temperature sensor, a flow rate sensor, and a pressure sensor. The ultrasonic detection system is used to perform non-contact, non-destructive internal structure detection and performance evaluation of the grouting binder in the pea gravel backfill layer. The image acquisition system is used to continuously observe the dynamic diffusion process of slurry in the pores of the pea gravel backfill layer; The magnetic quantitative detection system scans the entire domain of the visualization model system to collect electromagnetic response signals, and then analyzes the distribution content, spatial filling range, and local enrichment degree of the magnetic tracer medium within the detected area.
[0021] This multi-field coupled TBM wall backfill grouting model test device can reproduce the real working conditions of multi-field coupling, and has the ability to visualize the whole process and perform non-destructive quantitative evaluation in the whole domain. Combined with magnetic tracer-ground penetrating radar quantitative detection technology, it provides experimental support and theoretical basis for grouting material selection, process parameter optimization and grouting effect accurate evaluation, filling the gap in existing model test quantitative detection technology.
[0022] This experimental device, through the setting of the visualization model box, can not only simulate the backfilling situation behind the wall of a real TBM, but also has a transparent visualization function. Combined with the image acquisition system, it can capture the seepage path, diffusion form and transport law of slurry in the pores of pea gravel under multi-field coupled working conditions without obstruction, thus solving the problem that traditional hidden processes cannot be visualized and observed.
[0023] The dynamic water system and the component system can realistically reproduce the multi-physics field coupling working condition and perform grouting simulation. They can achieve independent control of three parameters: flow rate, temperature, and chemical corrosion. They can accurately simulate the superimposed environment of in-situ seepage field, temperature field, and chemical field in underground engineering, and reproduce the real physical and chemical processes of grout hydration, erosion, and consolidation. The test data are consistent with the actual engineering situation.
[0024] This experimental device also uses magnetic powder added to the grout as a tracer medium, combined with ground-penetrating radar electromagnetic scanning inversion technology, to break through the limitations of traditional qualitative detection. It can obtain the core indicators of grout filling rate, diffusion uniformity and void sealing rate in a non-destructive and quantitative manner, and realize the digital and precise evaluation of grouting effect.
[0025] Furthermore, the segment lining layer 9 and the surrounding rock layer 7 are respectively made of transparent plates (such as acrylic plates) with a light transmittance of not less than 90%, forming a semi-circular cylindrical structure. The end faces are also provided with transparent plates to form a visualization model box 6. The segment lining layer 9 is located on the inner side and is composed of multiple ring single structures that are sequentially joined together. The adjacent rings are arranged in a staggered manner along the circumferential direction. The surrounding rock layer 7 is located on the outer side. The dimensions of the segment lining layer and the surrounding rock layer are set according to the actual engineering dimensions or geometric similarity scale. The space between the segment lining layer and the surrounding rock layer is a gravel backfill layer. The spacing width of the gravel backfill layer corresponds to the actual gap size between the segment lining and the surrounding rock in the project or is scaled down proportionally. The minimum spacing width is not less than 5 times the maximum particle size of the gravel used for filling. The periphery of the pea gravel backfill layer 8 is provided with an annular sealing element that connects to the segment lining layer and the surrounding rock layer. The transparent plates are also sealed together to achieve full sealing and waterproofing around the cavity, avoiding interference with test accuracy caused by seepage and leakage under dynamic water conditions.
[0026] Furthermore, a plurality of grouting holes 10 are evenly arranged on the segment lining layer 9, which are connected to the grouting system through pressure-resistant grouting pipelines; water injection holes 20 are arranged on the back of the visualization model box 6, which are connected to the dynamic water system through water injection pipelines; grout observation holes 19 are arranged on the end side of the visualization model box 6, and the grouting termination time is determined by the grout concentration of the grout observed through the grout observation holes 19; drainage holes are provided at the bottom edge of the visualization model box, which are connected to the drainage system for discharging waste liquid and residual liquid generated during the test.
[0027] In this embodiment, the segment lining layer 9 and the surrounding rock layer 7 of the visualization model box 6 are both integrally formed from high-transparency acrylic sheets, and the whole is a semi-circular annular column structure. Among them, the inner segment lining layer 9 is composed of five five-ring single structures of the same size, which are sequentially spliced together. The adjacent single rings are arranged in an engineering prototype staggered joint manner along the circumference to avoid the stress defects of through joints. The inner diameter of the segment lining layer is 600mm, the width of a single ring is 120mm, the total axial length of the model box is 600mm, and each segment has three grouting holes 10 evenly opened along the circumference. The diameter of the grouting holes is uniformly 12mm. A total of 15 grouting holes 10 with independent switch valves are set in the five-ring segments.
[0028] The outer diameter of the outer rock layer 7 of the visualization model box 6 is 720mm, and the total axial length is 600mm, which is consistent with the segment lining layer. The annular gap between the inner segment lining layer 9 and the outer rock layer 7 constitutes the gravel backfill layer 8, and the backfill layer is designed to have a size of 6cm (circumferential width) × 60cm (axial length).
[0029] All grouting holes 10 are connected to the grouting pump 2 of the grouting system via high-pressure grouting pipelines 3; such as Figure 2 As shown, three water injection holes 23 are arranged at the center of the leftmost segment on the back of the visualization model box 6. The water injection holes 23 are connected to the high-pressure water pump 12 of the dynamic water system through the water supply pipeline 16. Three slurry observation holes 19 are evenly arranged on the right side of the visualization model box 6. During the test, the concentration, viscosity, and color changes of the slurry flowing out of the observation holes can help determine the timing of grouting termination. One drainage hole 17 is arranged at the center of the bottom of each of the five single-ring segments, for a total of five drainage holes 17. The diameter of the drainage holes is uniformly 2cm. Corrosion waste liquid, excess slurry, and accumulated water generated during the test can be quickly discharged under gravity to avoid residual liquid affecting the curing and testing accuracy of the specimens.
[0030] Furthermore, in combination Figure 1 and Figure 4 As shown, the dynamic water system includes a water storage tank 11, a water pump 12, and a multi-purpose water pipe 13. The inlet of the water pump 12 is connected to the water storage tank 11, and the outlet is connected to the multi-purpose water pipe 13. The multi-purpose water pipe 13 includes a cooling water pipe 1303, a heating water pipe 1301, a normal temperature water pipe 1302, and a main water pipe (i.e., water supply pipeline 16). The heating water pipe 1301, the normal temperature water pipe 1302, and the cooling water pipe 1303 are each independently equipped with a switch valve and converge into the main water pipe. The main water pipe is connected to the water injection hole of the visualization model box. The heating water pipe 1301 integrates a heater to raise the water temperature; the cooling water pipe 1303 integrates a cooler to lower the water temperature; a flow rate regulator and a flow rate sensor (such as a high-precision flow rate regulator 14 and an electromagnetic flow meter 15) are connected in series on the main water pipe to accurately control the water temperature (low temperature-normal temperature-high temperature range), flow rate and measure the flow rate in real time, ensuring that the seepage field parameters are accurate and controllable.
[0031] Furthermore, the water pump configured in the dynamic water system provides a water flow velocity of not less than 4 m / s to meet the differentiated water injection requirements of the single-hole or multi-hole visualization model box; the dynamic water system adjusts the pH value of the solution by adding acidic or alkaline substances to the water, and controls the degree of water corrosion by doping with soluble corrosive salt ions, simulating the erosion behavior of different chemical corrosion conditions on grouting materials and solidified bodies.
[0032] The chemical corrosion control method involves precisely adjusting the pH value of the solution by adding acidic substances such as hydrochloric acid and sulfuric acid or alkaline substances such as sodium hydroxide to the water body; preparing a corrosion mother solution by mixing NaCl, Na2SO4, and MgCl2 according to the ion ratio of the engineering groundwater, and then diluting it to change the Cl content in the water body. - SO4 2- Mg 2+The total concentration of corrosive ions was used to simulate the deterioration behavior of slurry and pea gravel solids under different salt and acid-base corrosion conditions.
[0033] Furthermore, the grouting system includes a grout tank 1, a grouting pump 2, and a grouting pipeline 3. The grout tank 1 has a built-in stirring device to prevent the magnetic powder from settling and stratifying with the grout. The discharge end of the grout tank 1 is connected to the inlet end of the grouting pump 2 through the grouting pipeline, and the discharge end of the grouting pump 2 is connected to the grouting hole of the visualization model box 6 through the grouting pipeline 3. A flow velocity sensor and a pressure sensor (such as a shock-resistant pressure gauge 4 and a grouting flow meter 5) are connected in series on the grouting pipeline 3 to collect grouting pressure and grouting flow parameters in real time; the grouting pump provides a rated grouting pressure of not less than 10MPa to meet the high-pressure grouting simulation requirements under different geological conditions.
[0034] The grouting system can be used to prepare magnetically modified grout and achieve parameter-controlled grouting. It can not only mix water and cementitious materials evenly, but also continuously agitate the grout to prevent the subsequent addition of micron-sized magnetic powder from settling and stratifying, thus ensuring uniform dispersion of the tracer medium throughout the entire domain.
[0035] Both the grouting pipeline 3 and the water supply pipeline 16 are made of PVC-U corrosion-resistant pipe with a pressure resistance rating of ≥10MPa. The pipelines have a uniform inner diameter of 10mm, which is suitable for high-pressure transportation and long-term circulation of corrosive water.
[0036] The monitoring servo control system integrates temperature sensors, flow rate sensors, and pressure sensors. These sensing elements are installed on the grouting pipeline 3 and the water supply pipeline 16, respectively, to collect and control parameters such as grout pressure, water temperature, water flow rate, water pH value, and corrosive ion concentration throughout the entire test process in real time, ensuring stability of the multi-field coupled working conditions throughout the entire process.
[0037] Furthermore, the ultrasonic detection system is detachably and fits onto the outer surface of the visualization model box, including a paired ultrasonic transmitter and an ultrasonic receiver, for non-destructive monitoring of the entire process of nucleation, growth, and morphological distribution of the grouting cementitious body within the pea gravel backfill layer; Combination Figure 5 and Figure 6 As shown, the front and back of the visualization model box 6 are equipped with an orthogonal grid detection system. The grid nodes 22 are ultrasonic detection points, and the distance between adjacent ultrasonic detection points is no more than 10cm. Supplementary detection points 23 with the same spacing are arranged on the two sides of the visualization model box 6. The ultrasonic detection points and the supplementary detection points together form a multi-dimensional acoustic detection network covering the gravel backfill layer. The ultrasonic transmitter 24 and the ultrasonic receiver 25 are arranged in pairs at the ultrasonic detection points and the supplementary detection points, respectively.
[0038] In this embodiment, the ultrasonic detection system uses a sound wave transmission detector, the core of which is a pair of ultrasonic transducers with a diameter of 40mm, which are divided into an ultrasonic transmitting end and an ultrasonic receiving end. They can be detachably and attached to the outer surface of the visualization model box 6, and are used to perform non-contact and non-destructive monitoring of the grouting cementitious body in the backfill layer throughout the entire process.
[0039] An orthogonal grid detection system is installed on the front and back of the visualization model box. The grid size is 10 rows × 6 columns, forming 60 pairs of standard ultrasonic detection points with a spacing of 100 mm between the points. Ten additional detection points are added on the two sides of the model box. All the detection points together form a multi-dimensional acoustic detection network that fully covers the pea gravel backfill layer 8. By collecting parameters such as ultrasonic wave velocity and attenuation coefficient, the growth morphology of the cementitious body, the distribution of internal voids and loose defects can be reconstructed in real time.
[0040] Furthermore, the image acquisition system includes at least two ultra-high-speed industrial cameras with identical parameters, one as the main acquisition camera for full-area imaging and the other for blind spot acquisition and redundancy backup. The industrial camera 21 has a full-frame resolution of no less than 2560×2048 pixels and a maximum shooting frame rate of no less than 10,000 frames / second. The industrial camera 21 is mounted directly above the transparent base plate of the visualization model box 6 via a fine-tuning bracket 18. After field of view calibration, the imaging range completely covers the entire area of the visualization model box, continuously capturing the dynamic diffusion, seepage migration and morphological evolution of slurry in the pore network of the pea gravel backfill layer, providing visualized raw data for the analysis of the permeation mechanism.
[0041] Furthermore, the magnetic quantitative detection system is equipped with a high-frequency ground-penetrating radar detection module. This module performs a full-area continuous electromagnetic scan along the outer surface of the visualization model box according to a preset gridded path. During the test, micron-sized magnetic powder is quantitatively added to the grout as a passive tracer medium. Utilizing the strong electromagnetic reflection characteristics of the magnetic powder, the high-frequency ground-penetrating radar detection module collects the full-area electromagnetic response signal. The background data processing terminal analyzes the spatial distribution content of the magnetic tracer medium, the actual filling range of the grout, and the degree of local enrichment within the detection area using an inversion algorithm. Based on the analysis results, the overall filling rate, lateral / longitudinal diffusion uniformity, and void sealing rate of the grout are quantitatively calculated, achieving a full-area, non-destructive, and digital quantitative evaluation of the grouting molding effect, thus overcoming the technical shortcomings of traditional ultrasonic and visual observation methods that can only make qualitative judgments.
[0042] Example 2: Based on the multi-field coupled TBM wall backfill grouting model test device in Example 1, a multi-field coupled TBM wall backfill grouting model test method is provided.
[0043] The experimental method includes the following steps: (1) Prepare modified grouting slurry containing magnetic tracer medium; select organic grouting material, inorganic grouting material or organic-inorganic composite grouting material, prepare a base slurry with a water-cement ratio of 0.5 to 1.0:1, add magnetic powder quantitatively to the base slurry, start the built-in stirring device in the slurry tank to continuously stir, so that the magnetic powder is evenly dispersed, and obtain magnetic tracer modified grouting slurry.
[0044] In this embodiment, ordinary Portland cement with a grade ≥42.5 is preferably used to prepare single-component cement slurry, and the water-cement ratio of the base slurry is controlled at 0.5 to 0.7:1.
[0045] (2) Fill the visualization model box with gravel to form the gravel backfill layer; select hard stone gravel as backfill material, and the maximum particle size of the gravel shall not exceed 1 / 5 of the width of the gap between the lining segment and the surrounding rock; adopt a layered filling method, first complete the filling of the bottom of the visualization model box in the range of 0° to 45°, and second complete the filling of the range of 45° to 180°. After the filling is completed, compact and level the backfill layer.
[0046] In this embodiment, hard granite gravel is selected as the backfill aggregate, with the particle size strictly controlled to be 5-10mm. The aggregate performance requirements are: dry material mass ratio, chloride ion content ≤0.06%, and soundness index ≤12%. A zoned and layered filling process is adopted. The gravel filling and compaction are completed in the first stage within the 0°-45° range at the bottom of the model box, and the filling and leveling are completed in the second stage within the 45°-180° range. After the filling is completed, the tightness of the outer sealing components is checked to prevent water leakage channels.
[0047] (3) Start the dynamic water system to construct a multi-field coupled seepage environment with different flow rates, temperatures and corrosion characteristics; start the dynamic water system pump and adjust the flow rate regulator to make the water flow rate not less than 4m / s; add acid and alkali reagents to the water tank to adjust the pH value of the water according to the preset corrosion conditions, and add corrosive salts to control the ion concentration; according to the temperature conditions, selectively open the valves of the heating water pipe, cooling water pipe or normal temperature water pipe, start the corresponding temperature control equipment, and construct a multi-field coupled seepage environment with different flow rates, temperatures and corrosion characteristics.
[0048] In this embodiment, deionized water is used to prepare the basic aqueous solution. A high-pressure water pump is started, and the water flow rate is controlled within the target range of 0-2 m / s using a flow rate regulator. According to the preset corrosion conditions, NaCl, Na2SO4, and MgCl2 salts are added to adjust the ion concentration. Then, the pH value of the water is precisely adjusted using hydrochloric acid, sulfuric acid, or sodium hydroxide (acidic pH=2 / 5, neutral, and alkaline options are available). According to the temperature requirements, the valves of the heating water pipe, cooling water pipe, or room temperature water pipe are selectively opened, and the corresponding temperature control equipment is activated. After the water circulation is preheated and stabilized, a multi-field coupled seepage environment with specified flow rate, temperature, and ion concentration is formed.
[0049] (4) Start the grouting system and inject grout into the visualization model box in a step-by-step manner until all grouting holes are grouted; adopt the pure pressure step-by-step grouting process from bottom to top and control the grouting pressure of the grouting system to not exceed 0.5MPa.
[0050] In this embodiment, as Figure 5 As shown, a bottom-up stepped grouting process using pure pressure is adopted, with the grouting pressure constantly controlled within the low-pressure range of 0.2~0.3MPa. Taking the grouting holes in group A as an example, when grouting hole A1, adjacent holes A2 and A4 are blocked, and the grouting status of hole A3 is observed in real time. When grouting from hole A3 is stable and the grout changes from thin to thick, hole A3 is blocked. The observation of hole A5 continues, and the continuous grouting from hole A5 indicates that the area below hole A is filled. When thick grout overflows from the top hole A0, grouting of hole A1 is stopped, and the process is switched to hole B1 and cyclically grouted according to the same logic until all 15 grouting holes have completed the grouting operation.
[0051] (5) Turn on the image acquisition system and continuously acquire image data of the diffusion and migration of grout during the grouting process; Specifically, two ultra-high-speed industrial cameras were activated, and the camera positions and shooting angles were fine-tuned. The time synchronization calibration of the two cameras was completed to ensure that the entire field of view covered the model box cavity. The camera resolution was set to ≥2560×2048 pixels and the frame rate was set to ≥10000 frames / second. Images were continuously acquired from the start of grouting to the initial setting of the grout, and the diffusion path of the grout, the pore transport law, and the evolution characteristics of the grout-water interface were accurately recorded.
[0052] (6) After grouting is completed, drain the waste liquid and residual liquid in the visualization model box, seal all pipeline interfaces, and allow it to stand for standard curing for 28 days; In this embodiment, the specimen is cured in a sealed manner as follows: After the grouting operation is completed, the five drainage holes 17 at the bottom of the model box are opened to drain the residual corrosive waste liquid, thin slurry and accumulated water in the system under the action of gravity; all pipeline valves, grouting holes and observation holes are closed to keep the model box in a sealed state without water interference, and it is left to stand for standard curing at room temperature for 28 days to allow the magnetic modified slurry to fully hydrate and solidify, forming a stable pea gravel-slurry stone body.
[0053] (7) Implement multi-method joint detection and evaluation.
[0054] (701) Ultrasonic pre-detection: The original ultrasonic background signal of the pea gravel backfill layer is collected before grouting by the ultrasonic detection system; during the grouting process and curing period, the ultrasonic detection system is triggered at a set frequency to collect the ultrasonic wave shape, wave velocity and attenuation parameters of each measuring point, and the cementitious body formation process and internal defect distribution are reconstructed in real time. Specifically, before the grouting operation starts, the original ultrasonic background signal of the hollow gravel backfill layer is collected; during the grouting process and the 28-day curing cycle, the ultrasonic detection system is triggered at a fixed time interval of 6 hours / time to collect the ultrasonic waveform, velocity, and attenuation parameters of 60 main measuring points + 10 auxiliary measuring points, and the spatial distribution characteristics of cement growth sequence, internal voids, and loose defects are reconstructed in real time.
[0055] (702) Magnetic quantitative detection: After the curing is completed, the magnetic quantitative detection system is used to perform a grid scan along the entire area of the visualization model box to collect electromagnetic response signals. Based on the electromagnetic reflection characteristics of the magnetic tracer medium, its spatial distribution content, filling range and enrichment degree are inverted, and the slurry filling rate, diffusion uniformity and void sealing rate are quantitatively calculated. Specifically, after the specimen curing is completed, the high-frequency ground-penetrating radar module of the magnetic quantitative detection system is activated to conduct full-domain electromagnetic detection along the preset gridded scanning path of the model box and collect full-domain electromagnetic response datasets. Based on the strong electromagnetic reflection characteristics of the magnetic powder in the slurry, the built-in inversion algorithm is used to analyze the spatial distribution content of the powder, the coordinates of the slurry filling boundary, and the range of local enrichment areas, and accurately calculate the core indicators of overall filling rate, lateral / longitudinal diffusion uniformity, and void sealing rate.
[0056] (703) Combining the diffusion and transport image data, the ultrasonic pre-detection data, and the magnetic quantitative detection data, a comprehensive and quantitative evaluation of the TBM wall backfill grouting effect under multi-field coupled seepage environment is completed.
[0057] Specifically, by integrating high-speed photography visualization diffusion trajectory data, ultrasonic internal defect distribution data, and ground-penetrating radar magnetic quantitative indicators, combined with pre-set flow velocity, temperature, and corrosion ion parameters, the influence mechanism of multi-field coupling on grout penetration and diffusion, hydration consolidation, and void sealing effects is quantitatively analyzed. Ultimately, a comprehensive, accurate, and quantitative evaluation of the grouting effect of pea gravel backfill behind the TBM wall is completed, providing direct experimental basis for optimizing engineering grouting parameters.
[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A test device for backfill grouting model of TBM wall under multi-field coupling, characterized in that, include: A visualization model system, comprising a visualization model box, which includes a semi-circular arc-shaped slab-shaped pipe lining layer and a surrounding rock layer arranged in parallel, with a gravel backfill layer between them; A dynamic water system, which is connected to the visualization model system, is used to provide water flow to the visualization model system and construct a multi-field coupled seepage environment containing a seepage field, a temperature field, and a chemical field. The grouting system is connected to the visualization model system and is used to inject grout with different proportions into the visualization model system, adjust the grouting parameters, and quantitatively add magnetic tracer medium to the grout. A monitoring servo control system is connected to the dynamic water system and the grouting system, and is used to monitor water flow parameters and grouting parameters. The monitoring servo control system includes at least a temperature sensor, a flow rate sensor, and a pressure sensor. An ultrasonic detection system is used to perform non-contact, non-destructive internal structure detection and performance evaluation of the grouting binder in the pea gravel backfill layer. An image acquisition system is used to continuously observe the dynamic diffusion process of slurry in the pores of the pea gravel backfill layer; It also includes a magnetic quantitative detection system, which scans the entire domain of the visualization model system to collect electromagnetic response signals and inverts and analyzes the distribution content, spatial filling range, and local enrichment degree of the magnetic tracer medium in the detected area.
2. The multi-field coupled TBM wall backfill grouting model test device according to claim 1, characterized in that, The segment lining layer and the surrounding rock layer are both made of transparent plates with a light transmittance of not less than 90%, forming a semi-circular cylindrical structure. The end faces are also equipped with transparent plates to form a visual model box. The segment lining layer is located on the inner side and is composed of multiple ring single structures that are sequentially spliced together. The adjacent rings are arranged in a staggered manner along the circumference. The surrounding rock layer is located on the outer side. The periphery of the gravel backfill layer is equipped with an annular sealing element that connects to the segment lining layer and the surrounding rock layer.
3. The multi-field coupled TBM wall backfill grouting model test device according to claim 1, characterized in that, Several grouting holes are evenly arranged on the lining layer of the pipe segment, and connected to the grouting system through pressure-resistant grouting pipelines; water injection holes are arranged on the back of the visualization model box, and connected to the dynamic water system through water injection pipelines; grout observation holes are arranged on the end side of the visualization model box, and the grouting termination time is determined by the grout concentration at the grout observation holes; drainage holes are provided on the bottom edge of the visualization model box, which are connected to the drainage system to discharge waste liquid and residual liquid generated during the test.
4. The multi-field coupled TBM wall backfill grouting model test device according to claim 1, characterized in that, The water system includes a water storage tank, a water pump, and a multi-purpose water pipe. The inlet of the water pump is connected to the water storage tank, and the outlet is connected to the multi-purpose water pipe. The multi-purpose water pipe includes a cooling water pipe, a heating water pipe, a normal temperature water pipe, and a main water pipe. The heating water pipe, the normal temperature water pipe, and the cooling water pipe are each equipped with independent on / off valves and converge into the main water pipe. The main water pipe is connected to the water inlet of the visualization model box. The heating water pipe integrates a heater, the cooling water pipe integrates a cooler, and the main water pipe is connected in series with a flow rate regulator and a flow rate sensor.
5. The multi-field coupled TBM wall backfill grouting model test device according to claim 1, characterized in that, The water pump configured in the dynamic water system provides a water flow velocity of not less than 4 m / s to meet the differentiated water injection requirements of the single-hole or multi-hole visualization model box. The dynamic water system adjusts the pH value of the solution by adding acidic or alkaline substances to the water and controls the degree of water corrosion by doping with soluble corrosive salt ions, simulating the erosion behavior of grouting materials and solidified bodies under different chemical corrosion conditions.
6. The multi-field coupled TBM wall backfill grouting model test device according to claim 1, characterized in that, The grouting system includes a grout tank, a grouting pump, and grouting pipelines. The discharge end of the grout tank is connected to the inlet end of the grouting pump through the grouting pipelines, and the discharge end of the grouting pump is connected to the grouting hole of the visualization model box through the grouting pipelines. A flow velocity sensor and a pressure sensor are connected in series on the grouting pipeline to collect grouting pressure and flow rate parameters in real time; the grouting pump provides a rated grouting pressure of not less than 10MPa to meet the high-pressure grouting simulation requirements under different geological conditions.
7. The multi-field coupled TBM wall backfill grouting model test device according to claim 1, characterized in that, The ultrasonic detection system is detachably installed on the outer surface of the visualization model box, including a paired ultrasonic transmitter and an ultrasonic receiver, for non-destructive monitoring of the entire process of nucleation, growth and morphological distribution of the grouting cementitious body in the pea gravel backfill layer; The front and back of the visualization model box are equipped with an orthogonal grid detection system. The grid nodes are ultrasonic detection points, and the distance between adjacent ultrasonic detection points is no more than 10cm. Supplementary detection points with the same spacing are arranged on both sides of the visualization model box. The ultrasonic detection points and the supplementary detection points together form a multi-dimensional acoustic detection network covering the gravel backfill layer. The ultrasonic transmitter and the ultrasonic receiver are arranged in pairs at the ultrasonic detection points and the supplementary detection points, respectively.
8. The multi-field coupled TBM wall backfill grouting model test device according to claim 1, characterized in that, The image acquisition system includes an industrial camera with a full-frame resolution of no less than 2560×2048 pixels and a maximum shooting frame rate of no less than 10,000 frames per second. The industrial camera is mounted directly above the transparent base plate of the visualization model box. After field of view calibration, the imaging range completely covers the entire area of the visualization model box, continuously capturing the dynamic diffusion, seepage migration, and morphological evolution of slurry in the pore network of the pea gravel backfill layer, providing visualized raw data for the analysis of the permeation mechanism.
9. The multi-field coupled TBM wall backfill grouting model test device according to claim 1, characterized in that, The magnetic quantitative detection system is equipped with a high-frequency ground-penetrating radar detection module. The high-frequency ground-penetrating radar detection module performs a full-domain continuous electromagnetic scan along the outer surface of the visualization model box according to a preset grid path, and collects full-domain electromagnetic response signals. The background data processing terminal analyzes the spatial distribution content of the magnetic tracer medium, the actual filling range of the slurry, and the degree of local enrichment in the detection area through an inversion algorithm. Based on the analysis results, the overall filling rate of the slurry, the uniformity of lateral / longitudinal diffusion, and the void sealing rate are quantitatively calculated.
10. The test method of the multi-field coupled TBM wall backfill grouting model test device according to any one of claims 1 to 9, characterized in that, The experimental method includes the following steps: Preparation of modified grouting slurry containing magnetic tracer medium; Gravel is filled into the visualization model box to form the gravel backfill layer; The dynamic water system is activated to create a multi-field coupled seepage environment with different flow velocities, temperatures, and corrosion characteristics; Start the grouting system and inject grout into the visualization model box in a stepped manner until all grouting holes are grouted. The image acquisition system is activated to continuously acquire image data of the diffusion and migration of grout during the grouting process. After grouting is completed, the waste liquid and residual liquid in the visualization model box are discharged, all pipeline interfaces are sealed, and the box is left to stand for standard curing for 28 days. It also includes multi-method combined detection and evaluation: Ultrasonic pre-detection: The original ultrasonic background signal of the pea gravel backfill layer is collected by the ultrasonic detection system before grouting; during the grouting process and curing period, the ultrasonic detection system is triggered at a set frequency to collect the ultrasonic wave shape, wave velocity and attenuation parameters at each measuring point, and the cementitious body formation process and internal defect distribution are reconstructed in real time. Magnetic quantitative detection: After curing, the magnetic quantitative detection system is used to perform a grid scan along the entire area of the visualization model box to collect electromagnetic response signals. Based on the electromagnetic reflection characteristics of the magnetic tracer medium, its spatial distribution content, filling range and enrichment degree are inverted, and the slurry filling rate, diffusion uniformity and void sealing rate are quantitatively calculated. By combining the diffusion and transport image data, the ultrasonic pre-detection data, and the magnetic quantitative detection data, a comprehensive and quantitative evaluation of the TBM wall backfill grouting effect under multi-field coupled seepage environment is completed.