A model experimental device and method for grouting and sealing reinforcement of the outer ring of a shield tunnel.

Abstract

This invention discloses a model experimental device and method for grouting and sealing reinforcement of the outer ring of a shield tunnel. It includes a model box, a shield tunnel lining structure, hydraulic jacks, elastic components, a grout storage tank, a rotating shaft, fan blades, a grout storage chamber, a positioning support, a grout stop valve, a flow meter, and a pressure gauge. The model box includes an upper structure and a lower structure. The lower structure includes a first module, a second module, a third module, and a frame. The upper part of the middle sections of the first, second, and third modules is made of high-strength tempered glass. The beneficial effects of this invention are: it can meet the requirements of different grouting quantities, grouting angles, grouting depths, and grouting spacings; by adjusting the different jacking distances and the layering of two different soil materials, it can simulate adverse working conditions under uneven loads and complex geological conditions; the design of circumferential cracks in the shield tunnel lining structure, combined with a water storage tank, can effectively evaluate the effect of grouting and sealing.

Description

Technical Field

[0001] This invention relates to the technical field of shield tunnel annular grouting, and in particular to a model experimental device and method for grouting and reinforcing the outer ring of a shield tunnel for leak sealing. Background Technology

[0002] Subways, as an underground transportation mode, effectively alleviate surface traffic congestion and are an important part of regional development, with many cities in my country having them. Shield tunnel segment lining is the main structural type for subway tunnels; however, as subway tunnels age, their structural performance begins to decline, and various defects appear under the combined influence of complex external environments. Among these, water leakage is the most common. Grouting, as an effective means of reinforcing weak surrounding rock and controlling water damage, has been increasingly widely used in the treatment of water leakage in subway tunnels. However, due to the complex interaction of many factors such as the physicochemical properties of the grout, the injected medium, and the grouting environment, the grouting process is subject to significant changes, resulting in a complex mechanism that means existing grouting theories lag far behind practical needs. Therefore, there is an urgent need to increase theoretical research to provide effective guidance for grouting practice.

[0003] Research on the water-blocking and reinforcement mechanism of grouting in tunnel treatment mainly employs three methods: theoretical derivation, field tests, and model tests. Theoretical derivation often has the preconditions of ideal conditions, which differ significantly from the actual tunnel grouting process. Field tests are extremely costly, posing economic challenges. Model tests, compared to field tests, require less funding but offer higher accuracy and can reflect the actual water-blocking and reinforcement mechanism of grouting to a certain extent, thus being favored by most scholars.

[0004] Existing model tests for grouting and water plugging reinforcement of shield tunnels have the following problems: 1) They do not take into account uneven loads and complex strata in actual working conditions, making it difficult for the test results to guide the treatment of water leakage in shield tunnels under these unfavorable conditions; 2) Few studies consider the boundary effects of the shield tunnel lining structure itself, which will have a certain impact on the test results; 3) There are almost no model tests for grouting and water plugging from the inside to the outside of the shield tunnel ring. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and to meet the requirements of different grouting quantities, grouting angles, grouting depths, and grouting spacings. It can also adjust the different jacking distances and press in two different soil materials in different zones and layers to simulate adverse working conditions under uneven loads and complex strata. Furthermore, the design of circumferential cracks in the lining structure of shield tunnels, combined with a water storage tank, can effectively evaluate the effect of grouting and sealing. This invention provides a model experimental device and method for grouting and sealing reinforcement of the outer ring of shield tunnels.

[0006] The objective of this invention is achieved through the following technical solution: a model experimental device for grouting and sealing reinforcement of the outer ring of a shield tunnel, comprising a model box, a shield tunnel lining structure, a hydraulic jack, an elastic component, a grout storage tank, a rotating shaft, a fan blade, a grout storage chamber, a positioning bracket, a grout stop valve, a flow meter, and a pressure gauge. The model box comprises an upper structure and a lower structure. The lower structure comprises a first module, a second module, a third module, and a frame. The upper part of the first module, the second module, and the third module are all made of high-strength tempered glass, and the surrounding protrusions are made of metal and have reserved bolt holes.

[0007] The frame, first module, second module, and third module are sequentially connected by bolts to form the lower structure of the model box. Each lower structure is equipped with a water outlet, which is located near the bottom of the lower structure. Each water outlet is equipped with a water stop valve. A water storage tank is located on the top of the lower structure, and the upper surface of the water storage tank is flush with the top of the lower structure. The shield tunnel lining structure includes segment lining and positioning rings. The upper structure also includes a reaction plate, which is located in the middle of the upper structure. The hydraulic jack is located below the reaction plate. A support column is located at the bottom of the slurry tank, and a base is located at the bottom of the support column. Rollers are located on the base. The interior of the shield tunnel lining structure is equipped with a miniature camera, grouting pipe, and grouting plate.

[0008] In the model experimental device for grouting and sealing reinforcement of the outer ring of the shield tunnel of the present invention, the grouting pipe includes grouting pipe one, grouting pipe two, grouting branch pipe one and grouting branch pipe two. Below the grout storage tank, there are grout storage chamber one and grout storage chamber two. One end of grouting pipe one is equipped with an air compressor, and the other end is connected to grout storage chamber one and grouting branch pipe two respectively. The other end of grouting branch pipe two is connected to grout storage chamber two. The grouting branch pipe two located at the outlet of grout storage chamber two is connected to grouting pipe two. One end of grouting branch pipe one is connected to grout storage chamber one, and the other end is connected to grouting pipe two. Grouting pipe two is connected to the grouting plate.

[0009] In the model experimental device for grouting and sealing reinforcement of shield tunnel ring of the present invention, the first module is provided in multiple parts and is the main structure composed of model boxes. The second module is provided in at least 4 parts and the 4 second modules form a circular opening. A water injection hole is reserved at one-quarter height of the third module. The upper structure includes frame one and frame two, and frame one, frame two and reaction plate are connected by threads.

[0010] In the model experimental device for grouting and sealing reinforcement of the outer ring of the shield tunnel of the present invention, the upper end of the elastic element is fixed to the bottom end of the hydraulic jack, and the lower end of the elastic element is provided with a loading plate and is detachably connected to the loading plate. The loading plate is provided with an annular groove that cooperates with the bottom of the hydraulic jack. The side wall of the annular groove is provided with a card. The lower end of the elastic element is provided with a rotatable snap-fit, so that the loading plate can be moved up and down in the vertical direction. The top surface of the loading plate is provided with reinforcing ribs, and the bottom of the loading plate is provided with cylindrical protrusions.

[0011] In the model experimental device for grouting and sealing reinforcement of the outer ring of the shield tunnel of the present invention, the grouting pipe is also equipped with a grout stop valve and a pressure gauge; the water storage tank is a rectangular structure with graduations, and a fixing component and a water injection hole are provided on one side surface of the water storage tank. The fixing component is fastened to the third module by bolts. The size and height of the water injection hole are consistent with the water injection hole in the third module, and a water pipe is provided between the two. At least 6 hydraulic jacks are provided and are evenly arranged below the reaction plate.

[0012] In the model experimental device for grouting and sealing reinforcement of the outer ring of the shield tunnel of the present invention, the base is also provided with multiple arc-shaped grooves; the inside of the grout storage tank is also provided with a rotating shaft, the rotating shaft is provided with fan blades, the bottom of the grout storage tank is provided with grout outlet one and grout outlet two, and below the grout outlet one and grout outlet two are respectively provided with grout pipe one and grout pipe two, which are respectively connected to grout storage chamber one and grout storage chamber two. The grout storage chamber one and grout storage chamber two are hollow cylinders with scales engraved on their surfaces. The grout storage chamber one and grout storage chamber two are made of high-strength glass. The grout storage chamber one and grout storage chamber two are fixed inside the arc-shaped grooves.

[0013] In the model experimental device for grouting and sealing reinforcement of the shield tunnel ring of the present invention, the positioning ring is provided with 16 reserved holes in the middle and has two grooves on both sides. The size of the segment lining is consistent with the size of the groove on the positioning ring and can be inserted into the positioning ring. Several segments lining are inserted into several positioning rings to form a shield tunnel lining structure. The grouting plate also includes annular supports and diagonal braces. There are two annular supports. Both annular supports are provided with fixing holes. The diameter of the fixing holes is the same and consistent with the diameter of the reserved holes of the positioning ring. The annular supports are concave structures and are used in conjunction with the positioning ring and can be snapped together. The grouting pipe is provided with grouting branches and the grouting branches are fixed on the grouting plate and the positioning ring. The reserved holes where the grouting branches are not inserted are blocked with rubber plugs.

[0014] In the model experimental device for grouting and sealing reinforcement of the outer ring of the shield tunnel of the present invention, the grouting branch is equipped with a flow meter and a mining connector, one end of the mining connector is connected to the grouting branch, and the other end of the mining connector is connected to a grouting rod. The mining connector is fixed in a reserved hole, and the grouting rod has at least three different length specifications. The end of the grouting rod is provided with several grouting holes, and the positioning ring is used in conjunction with the grouting plate.

[0015] In the model experimental device for grouting and sealing reinforcement of the outer ring of a shield tunnel according to the present invention, a displacement gauge is provided on the positioning bracket, and there are 4 displacement gauges, two in the horizontal direction and two in the vertical direction; annular strain gauges are also provided on the positioning ring, and there are 8 annular strain gauges, which are evenly distributed on the positioning ring. The annular strain gauges are staggered from the reserved holes on the positioning ring. The annular strain gauges include transverse strain gauges and longitudinal strain gauges. Earth pressure cells are also provided on the shield tunnel lining structure. The earth pressure cells and longitudinal strain gauges are on the same cross section and fixed at a distance of D / 2 and D from the positioning ring. There are 4 earth pressure cells and 6 longitudinal strain gauges. The longitudinal strain gauges and earth pressure cells are evenly distributed on the surface of the tunnel lining. The radius of the circular opening is the same as the outer diameter of the shield tunnel lining structure, and several miniature cameras are provided. The tunnel lining material is made of natural rubber tubing.

[0016] In the method of a model experimental device for grouting and sealing reinforcement of the outer ring of a shield tunnel according to the present invention, it includes the following steps:

[0017] S1: Review literature to determine the experimental design;

[0018] S2: Determine the size of the shield tunnel lining structure based on the similarity ratio designed in the experimental scheme; determine the assembly form of the shield tunnel lining based on the grouting spacing designed in the experimental scheme, including the number of positioning rings and the length of the segment lining; determine the number and layout angle of the grouting branches based on the grouting quantity and grouting angle designed in the experimental scheme; determine the length of the grouting rod based on the grouting depth designed in the experimental scheme, and then assemble and connect them in sequence.

[0019] S3: After the shield tunnel lining and grouting plate are assembled, displacement gauges, strain gauges and earth pressure cells are installed. Specifically, the displacement gauges should be as close as possible to the positioning rings; the strain gauges are attached to the surface of the shield tunnel lining and connected with wires. Silicone sealing and waterproofing measures are taken at the strain gauges and wiring positions. The two wires are separated and fixed with 502 glue to prevent short circuits.

[0020] S4: Determine the size of the model box according to the experimental requirements, assemble the components in sequence, and roll a waterproof plastic film along the inner surface of the model box.

[0021] S5: Prepare two different similar soil materials to simulate heterogeneous strata. The preparation of similar soil materials mainly considers the unit volume weight, cohesion, internal friction angle, Poisson's ratio and elastic modulus of the soil. Based on the similarity ratio and the physical and mechanical parameters of the geological survey data, fly ash and river sand are used as the main materials, and a certain proportion of barite powder, quartz sand, petrolatum and rosin are added to simulate the material. The deviation of the physical parameters of the model soil is controlled within 2%. In particular, in order to highlight the characteristics of heterogeneous strata, it is necessary to ensure that the elastic modulus value of one of the similar soil materials is 2.5 times or more than that of the elastic modulus value of the other soil material.

[0022] S6: Mix the two different soil materials evenly and load them into the model box in the left and right sections at the same time, in 10cm layers. Use manual compaction to bury them to the same level as the bottom of the circular openings 1-7. During this process, use the ring cutter method to take samples to control the compaction degree. In addition, this invention can also fill different soils in the upper and lower sections to simulate the working conditions of uneven soft and hard strata.

[0023] S7: Several circumferential cracks are made on the shield tunnel lining structure. The crack length is D / 16, where D is the outer diameter of the shield tunnel lining structure, and the crack width is 0.5×d90, where d90 is the particle diameter corresponding to 90% of the soil on the gradation curve. The cracks are set at the waist of the shield tunnel lining and then placed on the compacted soil. The shield tunnel lining structure is waterproofed. Specifically, one end near the circular opening protrudes slightly from the model box, and the contact point with the model box is sealed with a waterproof rubber pad and glue. The other end is sealed with a waterproof bag. The positioning ring and the segment lining insertion joint are also sealed with glue.

[0024] S8: Continue to bury the soil until the designed height, using the same method as above; then assemble the other experimental components in sequence to form the experimental system.

[0025] S9: Adjust the 6 hydraulic jacks to compress the elastic element. After the elastic element is compressed, it will apply a vertical force to the loading plate. The value of the force is kx, where k is the stiffness coefficient and x is the compression amount. Change the ejection distance of different jacks to obtain different load values, thereby simulating uneven load conditions.

[0026] S10: Pour enough water into the water tank until the water level in the model box is at the same level as the water level in the water tank. Record the water level height h0 at this moment. Record the water level height h1 again after 24 hours. The amount of water leakage in the model box in one day can be calculated by the height difference and the geometric dimensions of the water tank.

[0027] S11: Continue adding water to the water storage tank to the original height, prepare and stir the grout in the grout storage tank, open the grout stop valve one to let the grout enter the grout storage chamber, and place some iron oxide of different colors that do not react with the grout in different grout storage chambers. After the grouting volume required by the design is reached, close the grout stop valve one, record the initial monitoring data at this moment, turn on the air compressor to inject the grout into the soil. During this process, record the monitoring data every 10 seconds. Manual recording is done outside the model box, and several miniature cameras are used to record inside the shield tunnel lining structure until the grouting is completed. 24 hours later, record the height of the water storage tank at this moment and calculate the leakage of the model box in one day after grouting.

[0028] S12: Open the water stop valve to drain the water from the model box, then remove the upper structure of the model box, excavate the soil in the model box in sections along the excavation section perpendicular to the shield tunnel lining structure, record the grout diffusion traces in different sections, and take samples of the reinforced area with standard specimens to conduct uniaxial compressive strength, shear strength and permeability tests, compare them with the material properties of the unreinforced soil, and finally remove the other components in sequence;

[0029] S13: Based on comprehensive measurement data, conduct an analysis of the grouting and sealing reinforcement patterns outside the shield tunnel ring.

[0030] The present invention has the following advantages:

[0031] 1. In this model experimental device, by adjusting the different jacking distances and pressing in two different soil materials in sections and layers, unfavorable working conditions under uneven loads and complex strata were simulated.

[0032] 2. The design of circumferential cracks in the shield tunnel lining structure of this model experimental device, combined with a water storage tank, can effectively evaluate the effect of grouting and leak sealing.

[0033] 3. The positioning clasp in this model experimental device, together with the grouting plate, grouting branch, mining joint and grouting rod, can meet the requirements of different grouting quantities, different grouting angles, different grouting depths and different grouting spacings.

[0034] 4. The model box of the present invention has an assembled structure, which can meet the experimental requirements of different sizes and can be reused multiple times.

[0035] 5. The model experimental device of the present invention can simulate a variety of complex working conditions and has a simple structure. It can detect, monitor and record a large amount of data. By analyzing the regularity of the results, it can enrich the grouting theory and has high scientific value. Attached Figure Description

[0036] Figure 1 This is a cross-sectional view of the external grouting device of the present invention;

[0037] Figure 2 This is a three-dimensional schematic diagram of the model box of the present invention;

[0038] Figure 3 This is a front view of the lower structure of the model box of the present invention;

[0039] Figure 4 This is a right view of the lower structure of the model box of the present invention;

[0040] Figure 5 This is a schematic diagram showing the connection between frame one and the first module in this invention;

[0041] Figure 6 This is a schematic diagram showing the connection between frame one and frame two in this invention;

[0042] Figure 7 This is a schematic diagram of the water storage tank structure in this invention;

[0043] Figure 8 This is a schematic diagram of the shield tunnel lining structure of the present invention;

[0044] Figure 9 This is a schematic diagram of the positioning ring structure in this invention;

[0045] Figure 10 This is a schematic diagram of the grouting disc structure in this invention;

[0046] Figure 11 This is a schematic diagram of the connection between the grouting branch and the positioning retaining ring of the present invention;

[0047] Figure 12 This is a diagram showing the arrangement of displacement gauges in this invention;

[0048] Figure 13 This is a diagram showing the arrangement of the pressure cell and strain gauges in this invention;

[0049] Figure 14 This is a schematic diagram of the excavation cross-section of the present invention;

[0050] Figure 15 This is a schematic diagram of the top structure of the loading plate of the present invention;

[0051] Figure 16 This is a schematic diagram of the bottom structure of the loading plate of the present invention;

[0052] Figure 17 for Figure 15 A magnified view of a portion of point A in the middle;

[0053] Figure 18 This is a schematic diagram of the working method of the present invention.

[0054] In the diagram, 1. Model box, 1-1 First module, 1-2 Second module, 1-3 Third module, 1-4 Water injection hole, 1-5 Frame 1, 1-6 Frame 2, 1-7 Circular opening, 1-8 Reaction plate, 1-9 Water storage tank, 1-10 Water pipe, 1-11 Fixing component, 1-12 Water outlet, 1-13 Water stop valve, 2. Shield tunnel lining structure, 2-1 Segment lining, 2-2 Positioning clasp, 2-2-1 Reserved hole, 3. Hydraulic jack, 4. Elastic component, 5. Loading plate, 6. Base, 7. Roller, 8. Support column, 9. Slurry storage tank, 10. Rotating shaft, 11. Fan blade, 12. Slurry outlet pipe 1, 13. Slurry stop valve 1, 14. Slurry storage bin 1, 15. Groove, 16. Air compressor 17 Grouting pipe, 18 Grout stop valve II, 19 Pressure gauge, 20 Grouting disc, 20-1 Ring support, 20-2 Diagonal brace, 20-3 Fixing hole, 21 Grouting branch, 22 Rubber plug, 23 Mining joint, 24 Positioning support, 25 Displacement gauge, 26 Ring strain gauge, 27 Longitudinal strain gauge, 28 Earth pressure cell, 29 Flow meter, 30 Miniature camera, 31 Grouting rod, 32 Grouting hole, 33 Bolt, 34 Excavation section, 35 Soil I, 36 Soil II, Grouting pipe I, 37 Grouting pipe II, 38 Grouting branch pipe I, 39 Grouting branch pipe II, 40 Grout storage bin II, 41 Ring groove, 42 Card, 43 Reinforcing rib, 44 Cylindrical protrusion, 45. Detailed Implementation

[0055] The present invention will be further described below with reference to the accompanying drawings. The scope of protection of the present invention is not limited to the following description:

[0056] like Figures 1-17 As shown, a model experimental device for grouting and sealing reinforcement of the outer ring of a shield tunnel includes a model box 1, a shield tunnel lining structure 2, a hydraulic jack 3, an elastic element 4, a grout storage tank 9, a rotating shaft 10, a fan blade 11, a grout storage chamber, a positioning bracket 24, a grout stop valve, a flow meter 29, and a pressure gauge 19. The model box 1 includes an upper structure and a lower structure. The lower structure includes a first module 1-1, a second module 1-2, a third module 1-3, and a frame. The upper part of the middle of the first module 1-1, the second module 1-2, and the third module 1-3 are all made of high-strength tempered glass, and the protrusions around them are made of metal with pre-drilled bolt holes to facilitate splicing.

[0057] The frame, first module 1-1, second module 1-2 and third module 1-3 are connected in sequence by bolts 33 to form the lower structure of model box 1. The lower structure is provided with water outlets 1-12, and the water outlets 1-12 are close to the bottom of the lower structure. Each water outlet 1-12 is provided with a water stop valve 1-13. The top of the lower structure is provided with a water storage tank 1-9, and the upper surface of the water storage tank 1-9 is flush with the top of the lower structure. The shield tunnel lining structure 2 includes segment lining 2-1 and positioning ring 2-2. The upper structure also includes a reaction plate 1-8, which is set in the middle of the upper structure. The hydraulic jack 3 is set below the reaction plate 1-8. The bottom of the slurry tank 9 is provided with a support column 8, and the bottom of the support column 8 is provided with a base 6. The base 6 is provided with rollers 7. The interior of the shield tunnel lining structure 2 is provided with a miniature camera 30, a grouting pipe 17 and a grouting plate 20.

[0058] Grouting pipe 17 is provided with grouting pipe 1 37, grouting pipe 2 38, grouting branch pipe 1 39 and grouting branch pipe 2 40. Grouting storage tank 9 is provided with grouting storage chamber 1 14 and grouting storage chamber 2 41 below it. One end of grouting pipe 1 37 is provided with an air compressor 16, and the other end is connected to grouting storage chamber 1 14 and grouting branch pipe 2 40 respectively. The other end of grouting branch pipe 2 40 is connected to grouting storage chamber 2 41. Grouting branch pipe 2 40 located at the outlet of grouting storage chamber 2 41 is connected to grouting pipe 2 38. One end of grouting branch pipe 1 39 is connected to grouting storage chamber 1 14, and the other end is connected to grouting pipe 2 38. Grouting pipe 2 38 is connected to grouting plate 20.

[0059] The first module 1-1 has multiple units and is the main structure composed of model boxes 1. The second module 1-2 has at least 4 units, and the 4 second modules 1-2 form a circular opening 1-7. The third module 1-3 has a water injection hole 1-4 reserved at one-quarter of its height. The upper structure includes frame one 1-5 and frame two 1-6, and frame one 1-5, frame two 1-6 and reaction plate 1-8 are connected by threads, thereby ensuring the rapid assembly and splicing of the lower structure.

[0060] The upper end of the elastic element 4 is fixed to the bottom end of the hydraulic jack 3, and the lower end of the elastic element 4 is provided with a loading plate 5, which is detachably connected to the loading plate 5. The loading plate 5 is provided with an annular groove 42 that cooperates with the bottom of the hydraulic jack 3. The side wall of the annular groove 42 is provided with a card 43. The lower end of the elastic element 4 is provided with a rotatable snap-fit, which allows the loading plate 5 to move up and down vertically. The top surface of the loading plate 5 is provided with a reinforcing rib 44, and the bottom of the loading plate 5 is provided with a cylindrical protrusion 45. The cylindrical protrusion 45 is provided to increase the mutual cooperation between the soil.

[0061] The grouting pipe 2 38 is also equipped with a grout stop valve 2 18 and a pressure gauge 19; the water storage tank 1-9 is a rectangular structure with graduations. On one side surface of the water storage tank 1-9, there is a fixing part 1-11 and a water injection hole 1-4. The fixing part 1-11 is fastened to the third module 1-3 by bolts 33. The size and height of the water injection hole 1-4 are the same as those of the water injection hole 1-4 in the third module 1-3, and a water pipe 1-10 is provided between the two. There are at least 6 hydraulic jacks 3, which are evenly arranged below the reaction plate 1-8.

[0062] The base 6 is also provided with multiple arc-shaped grooves 15; the inside of the slurry storage tank 9 is also provided with a rotating shaft 10, and the rotating shaft 10 is provided with a fan blade 11. The bottom of the slurry storage tank 9 is provided with a slurry outlet 1 and a slurry outlet 2. Below the slurry outlet 1 and the slurry outlet 2, there are respectively a slurry outlet pipe 12 and a slurry outlet pipe 2 connected to the slurry storage bin 14 and the slurry storage bin 2 41. The slurry storage bin 14 and the slurry storage bin 2 41 are hollow cylinders with scales engraved on their surfaces. The slurry storage bin 14 and the slurry storage bin 2 are made of high-strength glass and are fixed inside the arc-shaped grooves 15.

[0063] The positioning ring 2-2 also has 16 reserved holes 2-2-1 in the middle, and the two sides are grooved. The size of the segment lining 2-1 is consistent with the size of the groove on the positioning ring 2-2, and it can be inserted into the positioning ring 2-2. Several segment linings 2-1 are inserted into several positioning rings 2-2 to form the shield tunnel lining structure 2; the grouting plate 20 also includes annular supports 20-1 and diagonal braces 20-2, and there are two annular supports 20-1. Each of the components is provided with a fixing hole 20-3, the fixing hole 20-3 having the same diameter and consistent with the diameter of the reserved hole 2-2-1 of the positioning ring. The annular bracket 20-1 has a concave structure and is used in conjunction with the positioning ring 2-2, and can be snapped together. The grouting pipe 28 is provided with a grouting branch 21, and the grouting branch 21 is fixed on the grouting plate 20 and the positioning ring 2-2. The reserved hole 2-2-1 where the grouting branch 21 is not inserted is blocked with a rubber plug, thereby ensuring the authenticity and effectiveness.

[0064] The grouting branch 21 is equipped with a flow meter 29 and a mining connector 23. One end of the mining connector 23 is connected to the grouting branch 21, and the other end of the mining connector 23 is connected to a grouting rod 31. The mining connector 23 is fixed in the reserved hole 2-2-1, and the grouting rod 31 has at least three different length specifications. Several grouting holes 32 are provided on the end of the grouting rod 31. The positioning ring 2-2 is used in conjunction with the grouting plate 20.

[0065] The positioning bracket 24 is equipped with displacement gauges 25, and there are 4 displacement gauges 25, two in the horizontal direction and two in the vertical direction. The positioning ring 2-2 is also equipped with annular strain gauges 26, and there are 8 annular strain gauges 26, which are evenly distributed on the positioning ring 2-2. The annular strain gauges 26 are staggered from the reserved holes 2-2-1 on the positioning ring 2-2. The annular strain gauges 26 are equipped with transverse strain gauges and longitudinal strain gauges 27. The shield tunnel lining structure 2 is also equipped with earth pressure boxes 28. The earth pressure boxes 28 and the longitudinal strain gauges 27 are on the same cross section and are fixed at positions D / 2 and D away from the positioning ring 2-2. There are 4 earth pressure boxes 28 and 6 longitudinal strain gauges 27. The longitudinal strain gauges 27 and the earth pressure boxes 28 are evenly distributed on the surface of the tunnel lining 2-1. The radius of the circular opening 1-7 is the same as the outer diameter of the shield tunnel lining structure 2, and there are several miniature cameras 30. The tunnel lining 2-1 is made of natural rubber tubing.

[0066] like Figure 18 As shown, a method for a model experimental device for grouting and reinforcing the outer ring of a shield tunnel includes the following steps:

[0067] S1: Review literature to determine the experimental design;

[0068] S2: Determine the size of the shield tunnel lining structure 2 based on the similarity ratio designed in the experimental scheme; determine the assembly form of the shield tunnel lining 2 based on the grouting spacing designed in the experimental scheme, including the number of positioning rings 2-2 and the length of the segment lining 2-1; determine the number and layout angle of the grouting branches 21 based on the grouting quantity and grouting angle designed in the experimental scheme; determine the length of the grouting rod 31 based on the grouting depth designed in the experimental scheme, and then assemble and connect them sequentially.

[0069] S3: After the shield tunnel lining 2 and grouting plate 20 are assembled, the displacement gauge 25, strain gauge and earth pressure cell 28 are installed. Specifically, the displacement gauge 25 should be as close as possible to the positioning ring 2-2; the strain gauge is attached to the surface of the shield tunnel lining and connected with wires. Silicone sealing and waterproofing measures are taken at the strain gauge and wiring positions. The two wires are separated and fixed with 502 glue to prevent short circuit.

[0070] S4: Determine the size of model box 1 according to the experimental requirements, assemble each component in sequence, and roll a waterproof plastic film along the inner surface of model box 1.

[0071] S5: Prepare two different similar soil materials to simulate heterogeneous strata, such as Soil 1 (35) and Soil 2 (36). The preparation of similar soil materials mainly considers the unit volume weight, cohesion, internal friction angle, Poisson's ratio, and elastic modulus of the soil. Based on the similarity ratio and the physical and mechanical parameters of the geological survey data, fly ash and river sand are used as the main materials, and a certain proportion of barite powder, quartz sand, petrolatum, and rosin are added to simulate the material. The deviation of the physical parameters of the model soil is controlled within 2%. In particular, in order to highlight the heterogeneous characteristics of the strata, it is necessary to ensure that the elastic modulus value of one of the similar soil materials is 2.5 times or more than that of the elastic modulus value of the other soil material.

[0072] S6: Mix the two different soil materials evenly and load them into the model box 1 in the left and right sections at the same time, in 10cm layers. Use manual compaction to bury them to the same level as the bottom of the circular openings 1-7. During this process, use the ring cutter method to take samples to control the compaction degree. In addition, this invention can also fill different soils in the upper and lower sections to simulate the working conditions of uneven soft and hard strata.

[0073] S7: Several circumferential cracks are made on the shield tunnel lining structure 2. The crack length is D / 16, where D is the outer diameter of the shield tunnel lining structure, and the crack width is 0.5×d90, where d90 is the particle diameter corresponding to 90% of the soil on the gradation curve. The cracks are set at the waist of the shield tunnel lining structure 2 and then placed on the compacted soil. The shield tunnel lining structure 2 is waterproofed. Specifically, one end near the circular opening 1-7 protrudes slightly from the model box 1 and is sealed with waterproof rubber pads and glue at the contact point with the model box 1. The other end is sealed with a waterproof bag. The positioning ring 2-2 and the joint of the segment lining 2-1 are also sealed with glue.

[0074] S8: Continue to bury the soil until the designed height, using the same method as above; then assemble the other experimental components in sequence to form the experimental system.

[0075] S9: Adjust the 6 hydraulic jacks 3 to compress the elastic element 4. After the elastic element 4 is compressed, it will apply a vertical force to the loading plate 5. The value of the force is kx, where k is the stiffness coefficient and x is the compression amount. Change the ejection distance of different jacks to obtain different load values, thereby simulating uneven load conditions.

[0076] S10: Pour enough water into the water storage tanks 1-9 until the water surface in the model box 1 is at the same level as the water surface in the water storage tanks 1-9. Record the water surface height h0 in the water storage tanks 1-9 at this moment. Record the water surface height h1 in the water storage tanks again after 24 hours. The amount of water leakage in the model box 1 in one day can be calculated by using the height difference and the geometric dimensions of the water storage tanks 1-9.

[0077] S11: Continue to add water to the water storage tanks 1-9 to the original height, prepare and stir the grout in the grout storage tank 9, open the grout stop valve 13 to let the grout enter the grout storage chamber, and place some iron oxide of different colors that do not react with the grout in different grout storage chambers. After the grouting volume required by the design is reached, close the grout stop valve 13, record the initial monitoring data at this moment, turn on the air compressor 16 to inject the grout into the soil. During this process, record the monitoring data every 10 seconds. Manually record outside the model box 1, and record inside the shield tunnel lining structure 2 through several miniature cameras 30 until the grouting is completed. 24 hours later, record the height of the water storage tanks 1-9 at this moment, and calculate the leakage of the model box 1 in one day after grouting.

[0078] S12: Open the water stop valves 1-13 to drain the water from model box 1. Then, dismantle the upper structure of model box 1 and excavate the soil inside the model box in sections along the excavation section 34, which is perpendicular to the shield tunnel lining structure. The specific locations of the excavation sections are as follows: Figure 14 As shown, the grout diffusion traces at different cross sections were recorded, and standard specimens were taken from the reinforced area for uniaxial compressive strength, shear strength and permeability tests. The results were compared with the material properties of the unreinforced soil. Finally, the other components were removed in sequence.

[0079] S13: Based on comprehensive measurement data, conduct an analysis of the grouting and sealing reinforcement patterns outside the shield tunnel ring.

[0080] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A model experimental device for grouting and reinforcing the outer ring of a shield tunnel, characterized in that: It includes a model box, a shield tunnel lining structure, hydraulic jacks, elastic components, a slurry storage tank, a rotating shaft, fan blades, a slurry storage bin, a positioning bracket, a slurry stop valve, a flow meter, and a pressure gauge. The model box includes an upper structure and a lower structure. The lower structure includes a first module, a second module, a third module, and a frame. The upper part of the middle of the first module, the second module, and the third module is made of high-strength tempered glass, and the surrounding protrusions are made of metal with pre-drilled bolt holes. The frame, first module, second module, and third module are sequentially connected by bolts to form the lower structure of the model box. Each lower structure is equipped with a water outlet, which is located near the bottom of the lower structure. Each water outlet is equipped with a water stop valve. A water storage tank is located on the top of the lower structure, and the upper surface of the water storage tank is flush with the top of the lower structure. The shield tunnel lining structure includes segment lining and positioning rings. The upper structure also includes a reaction plate, which is located in the middle of the upper structure. The hydraulic jack is located below the reaction plate. A support column is located at the bottom of the slurry tank, and a base is located at the bottom of the support column. Rollers are located on the base. The interior of the shield tunnel lining structure is equipped with a miniature camera, a grouting pipe, and a grouting plate. The grouting pipe includes grouting pipe one, grouting pipe two, grouting branch pipe one, and grouting branch pipe two. Below the grout storage tank, there are grout storage chamber one and grout storage chamber two. One end of grouting pipe one is equipped with an air compressor, and the other end is connected to grout storage chamber one and grouting branch pipe two respectively. The other end of grouting branch pipe two is connected to grout storage chamber two. The grouting branch pipe two located at the outlet of grout storage chamber two is connected to grouting pipe two. One end of grouting branch pipe one is connected to grout storage chamber one, and the other end is connected to grouting pipe two. Grouting pipe two is connected to the grouting plate. The first module has multiple modules and is the main structure composed of model boxes. The second module has at least four modules, and the four second modules form a circular opening. The third module has a water injection hole reserved at one-quarter of its height. The upper structure includes frame one and frame two, and frame one, frame two and the reaction plate are connected by threads. The positioning ring has 16 reserved holes in the middle and is grooved on both sides. The size of the segment lining is consistent with the size of the groove on the positioning ring and is inserted into the positioning ring. Several segment linings are inserted into several positioning rings to form a shield tunnel lining structure. The grouting plate also includes annular supports and diagonal braces. There are two annular supports. Both annular supports have fixing holes with the same diameter, which is consistent with the diameter of the reserved holes on the positioning ring. The annular supports have a concave structure and are used in conjunction with the positioning ring and can be snapped together. The grouting pipe has grouting branches, which are fixed on the grouting plate and the positioning ring. The reserved holes where the grouting branches are not inserted are plugged with rubber plugs. Two different soil materials were prepared to simulate heterogeneous strata during the experiment: the two different soil materials were mixed evenly and then loaded into the model box in the left and right or upper and lower sections. The materials were then manually compacted to the same level as the bottom of the circular opening. During the process, the compaction degree was controlled by taking samples using the ring cutter method. Several circumferential cracks are made on the shield tunnel lining structure. The crack length is D / 16, where D is the outer diameter of the shield tunnel lining structure, and the crack width is 0.5×d90, where d90 is the particle diameter corresponding to 90% of the soil on the gradation curve. The cracks are set at the waist of the shield tunnel lining and then placed on the compacted soil. The shield tunnel lining structure is waterproofed. Specifically, one end near the circular opening protrudes slightly from the model box, and the contact point with the model box is sealed with a waterproof rubber pad and glue. The other end is sealed with a waterproof bag. The positioning ring and the segment lining insertion joint are also sealed with glue. Continue to lay the soil until the designed height, using the same method as above; then assemble the other experimental components in sequence to form the experimental system. Adjusting six hydraulic jacks to compress the elastic element, the compressed elastic element will apply a vertical force to the loading plate, the value of which is kx, where k is the stiffness coefficient and x is the compression amount; changing the ejection distance of different jacks will obtain different load values, thereby simulating uneven load conditions. Pour enough water into the water tank until the water level in the model box is at the same level as the water level in the water tank. Record the water level height h0 at this moment. Record the water level height h1 again after 24 hours. Calculate the amount of water leakage in the model box in one day by using the height difference and the geometric dimensions of the water tank. Continue adding water to the storage tank to the original height. Prepare and stir the grout in the storage tank. Open the grout stop valve to allow the grout to enter the storage chamber. Different colored iron oxides that do not react with the grout are placed in different storage chambers. After the grouting volume required by the design is reached, close the grout stop valve and record the initial monitoring data at this moment. Turn on the air compressor to inject the grout into the soil. During this process, record the monitoring data every 10 seconds. The data is recorded manually outside the model box and recorded through several miniature cameras inside the shield tunnel lining structure until the grouting is completed. 24 hours later, record the height of the storage tank at this moment and calculate the leakage of the model box in one day after grouting. Open the water stop valve to drain the water from the model box, then remove the upper structure of the model box, and excavate the soil inside the model box in sections along the excavation section perpendicular to the shield tunnel lining structure. Record the grout diffusion traces at different sections, and take samples of the reinforced area using standard specimens to conduct uniaxial compressive strength, shear strength and permeability tests. Compare the results with the material properties of the unreinforced soil, and finally remove the other components in sequence. Based on comprehensive measurement data, we conducted an analysis of the patterns of grouting and reinforcement outside the shield tunnel ring.

2. The model experimental device for grouting and sealing reinforcement of the outer ring of a shield tunnel according to claim 1, characterized in that: The upper end of the elastic element is fixed to the bottom end of the hydraulic jack, and the lower end of the elastic element is provided with a loading plate, which is detachably connected to the loading plate. The loading plate is provided with an annular groove that cooperates with the bottom of the hydraulic jack. The side wall of the annular groove is provided with a card. The lower end of the elastic element is provided with a rotating snap-fit, which allows the loading plate to move up and down vertically. The top surface of the loading plate is provided with reinforcing ribs, and the bottom of the loading plate is provided with cylindrical protrusions.

3. The model experimental device for grouting and sealing reinforcement of the outer ring of a shield tunnel according to claim 2, characterized in that: The second grouting pipe is also equipped with a second grout stop valve and a pressure gauge; the water storage tank is a rectangular structure with graduations, and a fixing part and a water injection hole are provided on one side surface of the water storage tank. The fixing part is fastened to the third module by bolts. The size and height of the water injection hole are consistent with the water injection hole in the third module, and a water pipe is provided between the two. At least 6 hydraulic jacks are provided and are evenly arranged below the reaction plate.

4. The model experimental device for grouting and sealing reinforcement of the outer ring of a shield tunnel according to claim 3, characterized in that: The base is also provided with multiple arc-shaped grooves; the inside of the slurry storage tank is also provided with a rotating shaft, the rotating shaft is provided with fan blades, the bottom of the slurry storage tank is provided with slurry outlet one and slurry outlet two, and below slurry outlet one and slurry outlet two are respectively provided with slurry pipe one and slurry pipe two, which are respectively connected to slurry storage bin one and slurry storage bin two. Slurry storage bin one and slurry storage bin two are hollow cylinders with scales engraved on their surfaces. Slurry storage bin one and slurry storage bin two are made of high-strength glass. Slurry storage bin one and slurry storage bin two are fixed inside the arc-shaped grooves.

5. The model experimental device for grouting and sealing reinforcement of the outer ring of a shield tunnel according to claim 4, characterized in that: The grouting branch is equipped with a flow meter and a mining connector. One end of the mining connector is connected to the grouting branch, and the other end of the mining connector is connected to a grouting rod. The mining connector is fixed in a pre-drilled hole, and the grouting rod has at least three different length specifications. The end of the grouting rod is provided with several grouting holes. The positioning ring is used in conjunction with the grouting disc.

6. The model experimental device for grouting and sealing reinforcement of the outer ring of a shield tunnel according to claim 5, characterized in that: The positioning bracket is equipped with four displacement gauges, two in the horizontal direction and two in the vertical direction. The positioning ring also has eight annular strain gauges, evenly distributed on the positioning ring. The annular strain gauges are staggered from the pre-drilled holes on the positioning ring. The annular strain gauges include both transverse and longitudinal strain gauges. The shield tunnel lining structure also has earth pressure cells, which are on the same cross-section as the longitudinal strain gauges and fixed at distances D / 2 and D from the positioning ring. There are four earth pressure cells and six longitudinal strain gauges, which are evenly distributed across the lining surface. The circular opening radius is the same as the outer diameter of the shield tunnel lining structure, and several miniature cameras are installed. The lining material is made of natural rubber tubing.

7. The method of a model experimental device for grouting and reinforcing the outer ring of a shield tunnel according to claim 6, characterized in that: It includes the following steps: S1: Review literature to determine the experimental design; S2: Determine the size of the shield tunnel lining structure based on the similarity ratio designed in the experimental scheme; determine the assembly form of the shield tunnel lining based on the grouting spacing designed in the experimental scheme, including the number of positioning rings and the length of the segment lining; The number and layout angle of the grouting branches are determined according to the grouting quantity and grouting angle designed in the experimental scheme; the length of the grouting rod is determined according to the grouting depth designed in the experimental scheme, and then they are assembled and connected in sequence. S3: After the shield tunnel lining and grouting plate are assembled, displacement gauges, strain gauges and earth pressure cells are installed. Specifically, the displacement gauges should be as close as possible to the positioning rings; the strain gauges are attached to the surface of the shield tunnel lining and connected with wires. Silicone sealing and waterproofing measures are taken at the strain gauges and wiring positions. The two wires are separated and fixed with 502 glue to prevent short circuits. S4: Determine the size of the model box according to the experimental requirements, assemble the components in sequence, and roll a waterproof plastic film along the inner surface of the model box. S5: Prepare two different soil materials to simulate heterogeneous strata. The preparation of soil materials mainly considers the unit volume weight, cohesion, internal friction angle, Poisson's ratio and elastic modulus of the soil. Based on the similarity ratio and the physical and mechanical parameters of the geological survey data, fly ash and river sand are used as the main materials, and a certain proportion of barite powder, quartz sand, petrolatum and rosin are added to simulate the material. The deviation of the physical parameters of the model soil is controlled within 2%. In order to highlight the characteristics of heterogeneous strata, it is necessary to ensure that the elastic modulus value of one soil material is 2.5 times or more than that of the elastic modulus value of the other soil material. S6: Mix the two different soil materials evenly, and load them into the model box in the left and right or upper and lower sections simultaneously. Use manual compaction to bury them to the same horizontal line as the bottom of the circular opening. During this process, use the ring cutter method to take samples to control the degree of compaction. S7: Several circumferential cracks are made on the shield tunnel lining structure. The crack length is D / 16, where D is the outer diameter of the shield tunnel lining structure, and the crack width is 0.5×d90, where d90 is the particle diameter corresponding to 90% of the soil on the gradation curve. The cracks are set at the waist of the shield tunnel lining and then placed on the compacted soil. The shield tunnel lining structure is waterproofed. Specifically, one end near the circular opening protrudes slightly from the model box, and the contact point with the model box is sealed with a waterproof rubber pad and glue. The other end is sealed with a waterproof bag. The positioning ring and the segment lining insertion joint are also sealed with glue. S8: Continue to bury the soil until the designed height, using the same method as above; then assemble the other experimental components in sequence to form the experimental system. S9: Adjust the 6 hydraulic jacks to compress the elastic element. After the elastic element is compressed, it will apply a vertical force to the loading plate. The value of the force is kx, where k is the stiffness coefficient and x is the compression amount. Change the ejection distance of different jacks to obtain different load values, thereby simulating uneven load conditions. S10: Pour enough water into the water tank until the water level in the model box is at the same level as the water level in the water tank. Record the water level height h0 at this moment. Record the water level height h1 again after 24 hours. Calculate the amount of water leakage in the model box in one day by using the height difference and the geometric dimensions of the water tank. S11: Continue adding water to the water storage tank to the original height, prepare and stir the grout in the grout storage tank, open the grout stop valve one to let the grout enter the grout storage chamber, and place some iron oxide of different colors that do not react with the grout in different grout storage chambers. After the grouting volume required by the design is reached, close the grout stop valve one, record the initial monitoring data at this moment, turn on the air compressor to inject the grout into the soil. During this process, record the monitoring data every 10 seconds. Manual recording is done outside the model box, and several miniature cameras are used to record inside the shield tunnel lining structure until the grouting is completed. 24 hours later, record the height of the water storage tank at this moment and calculate the leakage of the model box in one day after grouting. S12: Open the water stop valve to drain the water from the model box, then remove the upper structure of the model box, excavate the soil in the model box in sections along the excavation section perpendicular to the shield tunnel lining structure, record the grout diffusion traces in different sections, and take samples of the reinforced area with standard specimens to conduct uniaxial compressive strength, shear strength and permeability tests, compare them with the material properties of the unreinforced soil, and finally remove the other components in sequence; S13: Based on comprehensive measurement data, conduct an analysis of the grouting and sealing reinforcement patterns outside the shield tunnel ring.

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