A shield synchronous grouting model test system and test method

Abstract

The present invention relates to the technical field of synchronous grouting in shield tunnels and stratum stability, and more specifically to a shield synchronous grouting model test system and test method. The shield synchronous grouting model test system comprises a simulation box, a shield device, a grouting device, a power device, a ground stress loading device, a water injection device, and a monitoring device. The rear end of the shield shell is rotatably connected to a ring-shaped rotating disk with grouting holes provided on the rotating disk. The grouting device is connected to the grouting holes on the rotating disk via grouting branch pipes. The position of the grouting holes can be changed by rotating the disk, thereby enabling research on how different grouting hole arrangements affect the buoyancy behavior of the pipe segments and the deformation patterns of the surrounding strata.

Description

Technical Field

[0001] The invention relates to the technical field of shield construction simulation test, and in particular to a shield synchronous grouting model test system and a test method. Background Art

[0002] With the rapid development of municipal transportation construction, shield technology is increasingly being used. However, during construction, deformation of the segments and surrounding ground often occurs due to inadequate simultaneous grouting. In severe cases, this can lead not only to surface subsidence and cracking, but also to a range of other problems, including segment buoyancy, water leakage through circumferential and contact joints, and segment cracking.

[0003] In order to solve the above problems, the Chinese invention patent with publication number CN118758759A combines the simulation box with the slurry supply simulation component to enable the experiment to control the grouting pressure and grouting rate of the slurry in real time for grouting, and studies the influence mechanism of different grouting pressures and grouting amounts on stratum deformation; the Chinese invention patent with publication number CN1172712A analyzes the change law of Ft under different conditions by changing different slurries or changing the different densities of slurries, and calculates and compares the influence relationship between the final generalized buoyancy and the slurry properties; the Chinese invention patent with publication number CN116717274A sets a power device outside the simulation box to pull the outer shell to move, and sets a buoyancy detection device on each segment to detect the buoyancy of each segment, so as to solve the problem that the process of reflecting the buoyancy of the shield tail of the shield machine cannot truly reflect the actual situation.

[0004] However, existing model testing systems often rely on fixed grouting holes for the segments. During the synchronous grouting process in shield tunnels, the location of the holes directly influences the grouting path, pressure distribution, and the resulting grouting layer morphology within the shield tail gap. Different grouting hole arrangements can significantly affect the buoyancy of the slurry on the segments, in turn influencing the buoyancy of the segments and the deformation of the surrounding strata. Summary of the Invention

[0005] (1) Technical issues to be resolved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a shield synchronous grouting model test system and test method, which can solve the technical problem that the existing test model cannot simulate how different grouting hole arrangements affect the floating behavior of the pipe segment.

[0007] (2) Technical solution

[0008] In order to achieve the above objectives, the main technical solutions adopted by the present invention include:

[0009] An embodiment of the present invention provides a shield synchronous grouting model test system, comprising a simulation box, a shield device, a grouting device, a power device, a ground stress loading device, a water injection device and a monitoring device; the top of the simulation box is open and is provided with a loading plate, and the interior of the simulation box is filled with model soil; the shield device comprises a shield shell and multiple pipe segments, the shield shell is a hollow cylinder and is arranged to pass through the simulation box, and the multiple pipe segments are assembled in the shield shell; the rear part of the shield shell is rotatably connected to a ring-shaped rotating disk, the rotating disk is provided with grouting holes, and the grouting device is connected to the grouting holes on the rotating disk through a grouting branch pipe; the power device is used to pull the front end of the shield shell to perform shield excavation simulation, the ground stress loading device simulates ground stress loading on the model soil through the loading plate, the water injection device simulates the water pressure environment in the model soil through the water injection pipe, and the monitoring device is used to monitor the floating displacement of the pipe segment and the deformation of the surrounding model soil.

[0010] Preferably, an annular flange is provided on the rear end surface of the shield shell; and an annular groove cooperating with the annular flange is provided on the side of the rotating disc close to the shield shell to enable the rotating disc to rotate relative to the shield shell.

[0011] Preferably, the rotating disc comprises a plurality of arc-shaped ring blocks connected end to end, an arc-shaped groove is provided on a side of the arc-shaped ring block close to the shield shell, and the arc-shaped grooves on the plurality of arc-shaped ring blocks are connected to form an annular groove.

[0012] Preferably, a connecting hole communicating with the arcuate groove is provided on the circumference of the arcuate ring block; a connecting groove is provided on the outer circumference of the annular flange of the shield shell; and the rotating disc is connected to the connecting groove on the annular flange through a connecting piece passing through the connecting hole.

[0013] Preferably, two adjacent pipe segments are detachably connected.

[0014] Preferably, the grouting main pipe of the grouting device is connected to multiple grouting branch pipes, the grouting branch pipes are sequentially connected to conversion joints, branch grouting pumps and regulating valves, and the ends of the grouting branch pipes are connected to the grouting holes.

[0015] Preferably, the grouting device includes a slurry storage box, in which an agitator driven to rotate by a brushless motor is installed, and the slurry storage box is connected to a plurality of liquid distribution pipes.

[0016] Preferably, the water injection device includes a water reservoir, a water pump and a water injection pipe connected in sequence; the bottom of the simulation box is provided with a simulated buried depth material layer, a water-proof layer and a permeable layer from bottom to top; the water injection pipe is inserted into the simulated buried depth material layer from the outside of the simulation box, and a plurality of water injection holes are evenly distributed on the upper part of the water injection pipe.

[0017] Preferably, the monitoring device includes a pressure gauge, a displacement gauge and a pore pressure gauge; the pressure gauge and the displacement gauge are installed on the inner wall of the pipe segment, and the pore pressure gauge is installed in the model soil around the pipe segment.

[0018] The present invention also provides a shield synchronous grouting model test method, which uses the above-mentioned shield synchronous grouting model test system to conduct the test, comprising the following steps:

[0019] S01: Install the simulation box and fill it with simulated burial depth material layer, aquiclude layer and permeable layer in sequence;

[0020] S02: Install water injection device;

[0021] S03: Install the shield device, connect multiple segments in sequence to form a pipe ring, fix the pressure gauge and displacement gauge on the inner wall of the segment, position the shield shell in the simulation box, set the assembled pipe ring in the shield shell, adjust the layout of the grouting holes on the rotating disk at the rear end of the shield shell, and connect the power unit to the front end of the shield shell;

[0022] S04: Install grouting device;

[0023] S05: Fill the simulation box with model soil in layers, ensuring that the aquiclude and permeable layers are located below the soil mass. Bury a piezometer in the model soil and install a loading plate on top of the model soil. The loading plate is connected to the ground stress loading device.

[0024] S06: Apply water pressure, and the water injection device injects water into the simulation box through the water injection pipe;

[0025] S07: The ground stress loading device transfers the load evenly to the model soil through the loading plate and stops loading after the required ground stress environment is reached;

[0026] S08: Start the power unit, pull the shield outward for horizontal excavation, and adjust the flow rate of the grouting device at the same time. The grouting holes on the rotating disc inject grouting liquid into the gap at the rear end of the shield through the grouting pipe to achieve synchronous grouting. When the shield moves out of the segment to be grouted, the grouting is stopped. When the shield is completely out of the way, the power unit is turned off and the excavation process is stopped.

[0027] S09: After grouting is completed, data is collected through the monitoring device;

[0028] S10: Repeat the above steps, adjust the simulated burial depth material, change the position of the grouting hole by rotating the rotating disk, set different ground stress pressures, types of mortise and tenon structures, water pressures, types and proportions of slurries, grouting volumes, grouting pressures, shield shell excavation speeds, and grouting hole layout parameters, and complete the synchronous grouting test during shield tunneling under different conditions.

[0029] (3) Beneficial effects

[0030] The beneficial effects of the present invention are:

[0031] The present invention provides a shield synchronous grouting model test system, which includes a simulation box, a shield device, a grouting device, a power device, a ground stress loading device, a water injection device and a monitoring device. Since the rear end of the shield shell is rotatably connected to a ring-shaped rotating disk, the rotating disk is provided with grouting holes. The grouting device is connected to the grouting holes on the rotating disk through grouting branch pipes. The position of the grouting holes can be changed by the rotating disk, so that it is possible to study how different grouting hole arrangements affect the floating behavior of the pipe segment and the deformation law of the surrounding strata.

[0032] The present invention provides a shield synchronous grouting model test method to realize multi-point synchronous grouting during shield tunneling, and simulate and analyze the pipe segment floating and surface settlement during shield tunneling under different water pressures, burial depths and complex geology. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic structural diagram of the shield synchronous grouting model test system of the present invention;

[0034] Figure 2 A front cross-sectional view of a shield synchronous grouting model test system during tunneling according to the present invention (including a grouting device);

[0035] Figure 3 A front cross-sectional view of the shield synchronous grouting model test system of the present invention in an initial state;

[0036] Figure 4 for Figure 3 A magnified schematic diagram of part A;

[0037] Figure 5 It is a structural diagram of a rotating disk;

[0038] Figure 6 This is the left view of the shield synchronous grouting model test system (the rear side plate, bracket and circular clamp are not shown).

[0039] [Description of Reference Numerals]

[0040] 1: simulation box; 2: model soil; 3: reservoir; 4: water pump; 5: water injection pipe; 6: valve; 7: simulated buried depth material layer; 8: water injection hole; 9: pressure water level observation pipe; 10: shallow water level observation pipe; 11: jack; 12: loading plate; 13: aquiclude; 14: permeable layer; 15: rotating disc; 16: grouting hole; 17: non-grouting segment; 18: circular fixture; 19: slurry; 20: bracket; 21: vertical bar; 22: shield; 23: liquid distribution pipe; 24: Brushless motor; 25: Agitator; 26: Slurry storage box; 27: Monitor; 28: Grouting pump; 29: Flow meter; 30: Grouting main pipe; 31: Branch grouting pump; 32: Regulating valve; 33: Annular flange; 34: Annular groove; 35: Grouting branch pipe; 36: Pressure gauge; 37: Displacement meter; 38: Pore pressure gauge; 39: Square head bolt; 40: Connector; 41: Connecting hole; 42: Segment to be grouted; 43: Insert plate; 44: Brush; 45: Pulley; 46: Conversion joint. DETAILED DESCRIPTION

[0041] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation methods in conjunction with the accompanying drawings.

[0042] Example 1

[0043] As shown in Figure 1, this embodiment provides a shield synchronous grouting model test system, which includes a simulation box 1, a water injection device, a grouting device, a ground stress loading device, a monitoring device, a shield device and a power device.

[0044] As shown in Figure 2, the shield apparatus primarily comprises a shield shell 22 and multiple ring segments. Shield shell 22 is composed of a hollow cylinder welded together from multiple annular steel plates. Shield shell 22 is located within simulation chamber 1. The segments are heterogeneous tubes, and adjacent rings are connected by bolts and a tenon-and-groove structure. The tenon-and-groove structure consists of mating protrusions and grooves, which are positioned on the end faces of two adjacent segments. The protrusions and grooves can be either rectangular or circular, fitting together. Bolt type can be selected based on test conditions.

[0045] The multi-ring segments are assembled in the shield 22, and a plurality of pulleys 45 are installed on the inner wall of the shield 22 to support the outer wall of the segments. In order to ensure the accuracy of the test, the rear rings of the multi-ring segments need to extend outside the rear end of the shield 22. In the initial state, the segments inside the shield 22 are defined as the segments to be grouting 42, and the segments outside the shield 22 are defined as the segments not to be grouting 17. In order to fix the segments not to be grouting 17, as shown in FIG. Figure 2As shown, a circular clamp 18 is provided on the outer side of the non-grouting pipe segment 17, which is fixed by a bracket 20, and a plurality of square head bolts 39 are threadedly connected to the side wall of the circular clamp 18. Bolt holes are reserved on the non-grouting pipe segment 17. When the non-grouting pipe segment 17 enters the circular clamp 18, the square head bolts 39 are screwed into the bolt holes of the non-grouting pipe segment 17, thereby achieving the fixation of the non-grouting pipe segment 17.

[0046] like Figure 3 As shown, the rear portion of the shield shell 22 is rotatably connected to a ring-shaped rotating disc 15, and the shield shell 22 and the rotating disc 15 are coaxially arranged. In order to achieve stable rotation between the rotating disc 15 and the shield shell 22, an annular flange 33 is provided on the rear end surface of the shield shell 22, and an annular groove 34 that cooperates with the annular flange 33 is provided on the side of the rotating disc 15 close to the shield shell 22.

[0047] like Figure 5 As shown, to facilitate the production of the rotating disc 15, the rotating disc 15 includes multiple arc-shaped ring blocks connected end to end. The arc-shaped ring blocks are provided with an arc-shaped groove on the side close to the shield 22. The arc-shaped grooves on the multiple arc-shaped ring blocks are connected to form an annular groove 34. In order to make the rotating disc 15 move together with the shield 22, after adjusting the position of the grouting holes 16 on the rotating disc 15 by rotating it, the rotating disc 15 and the shield 22 are connected by the connecting piece 40. Figure 4 As shown, a connecting hole 41 is provided around the circumference of the arcuate ring block, communicating with the arcuate groove. A connecting groove is provided on the outer circumference of the annular flange 33 of the shield shell 22. The rotating disk 15 is connected to the connecting groove on the annular flange 33 via a connecting member 40 that passes through the connecting hole 41. After the simulation is completed, the connecting member 40 is removed, the relative position of the rotating disk 15 and the shield shell 22 is rotated, and the connecting member 40 is reinstalled. The shield shell 22 is then returned to its initial position for the next test simulation.

[0048] like Figure 1As shown, the simulation box 1 serves as a test chamber and consists of a removable front, rear, left, and right panels, along with a bottom panel. The front, rear, left, and right panels are all visible acrylic panels, allowing test personnel to clearly observe the interior of the simulation box 1. The top of the simulation box 1 is open and is used to fill the model soil 2. An opening is provided on the front panel, through which an insert plate 43 is removably connected. Insert plate 43 is provided with a guide cylinder that allows the shield 22 to be removed. A brush 44 is attached to the inner side of the guide cylinder to prevent the shield 22 from dislodging a small amount of model soil 2. A simulated burial depth material layer 7, a water-proof layer 13, and a permeable layer 14 are laid in order from bottom to top on the bottom of the simulation box 1. The simulated burial depth material layer 7 is composed of, but not limited to, a cementitious material or a compressible fluid. By adjusting the selection and proportion of the burial depth material, different segment burial depths can be simulated. The aquiclude 13 and aquitard 14 are selected based on their permeability. The aquitard 14 is composed of, but not limited to, sand or gravel, and the aquiclude 13 is composed of, but not limited to, clay or silt. The remaining soils are adjusted based on the test content. The shield shell 22 is then installed within the simulation chamber 1. When the shield shell 22 is positioned within the simulation chamber 1, the front end of the shield shell 22 penetrates the guide tube on the front sidewall of the simulation chamber 1, allowing the brush 44 to contact the outer wall of the shield shell 22. The rear end of the shield shell 22 penetrates the rear sidewall of the simulation chamber 1. The model soil 2 is then filled from the open opening of the simulation chamber 1 until the model soil 2 completely covers the shield shell 22.

[0049] The ground stress loading device includes components such as a loading plate 12 and a jack 11. The loading plate 12 is formulated according to the rectangular size of the upper opening of the simulation box 1 and can be embedded in the model soil 2 in the simulation box 1 to ensure that the loading plate 12 and the model soil 2 can contact each other. It is used to receive the load transmitted from the jack 11 on the upper part of the loading plate 12, so that the load is evenly transferred to the model soil 2, so that the ground stress loading device can simulate the ground stress loading of the model soil 2 through the loading plate 12.

[0050] like Figure 6 As shown, the water injection device includes a reservoir 3, a pump 4, a valve 6, an injection pipe 5, a pressure water level observation pipe 9, and a shallow water level observation pipe 10. The reservoir 3, pump 4, and injection pipe 5 are sequentially connected. The valve 6 is located on the main water pipe. The injection pipe 5 extends from the outside of the simulation box 1 into the simulated buried depth material layer 7. Multiple injection holes 8 are evenly spaced along the top of the injection pipe 5. The left and right side walls of the simulation box 1 are connected to the pressure water level observation pipe 9 and the shallow water level observation pipe 10, respectively.

[0051] First, fill the reservoir 3 with water, start the water pump 4, open the valve 6, and let water enter the water injection pipe 5. Then, water enters the simulation box 1 from the water injection hole 8 at the top of the water injection pipe 5. Observe the water level of the pressure water level observation pipe 9 to obtain the water pressure of the model soil 2 and understand the pressure changes of the deep water. Then observe the shallow water level observation pipe 10 to monitor the changes in the shallow water level in the soil layer. After reaching the predetermined water pressure, close the valve 6 and the water pump 4, and perform water pressure environment simulation through the water injection device.

[0052] The power device includes a servo motor and a telescopic rod. A vertical bar 21 is welded and fixed to the front end of the shield shell 22. The driving end of the telescopic rod is connected to the servo motor, and the telescopic end of the telescopic rod is connected to the vertical bar 21. The telescopic rod is driven by the servo motor to drive the shield shell 22 to advance. When the shield shell 22 is completely out of the simulation box 1, the servo motor is turned off.

[0053] like Figure 2 As shown, the grouting device consists of a slurry storage box 26, a monitor 27, a grouting pump 28, a flow meter 29, a grouting main pipe 30, a branch grouting pump 31, a regulating valve 32, and multiple grouting branch pipes 35. The slurry storage box 26 is equipped with a monitor 27, which can detect the state of the slurry 19 in the slurry storage box 26 in real time, including parameters such as the pressure, temperature, and liquid level of the slurry 19, to ensure that the slurry 19 is always in the best state. A grouting pump 28 and a flow meter 29 are installed between the grouting main pipe 30 and the slurry storage box 26 to observe the grouting flow and adjust the grouting pressure. The grouting main pipe 30 is connected to multiple grouting branch pipes 35, each of which is connected in sequence to a conversion joint 46, a branch grouting pump 31, and a regulating valve 32. The number of branch grouting pipes corresponds to the number of grouting holes 16 on the rotating disc 15, and the ends of the grouting branch pipes 35 are connected to the grouting holes 16 of the rotating disc 15. The grouting main pipe 30 and the plurality of grouting branch pipes 35 constitute the grouting pipes of the grouting device.

[0054] In this embodiment, there are six grouting holes 16, and the number of grouting branch pipes 35 corresponds to six. Each grouting branch pipe 35 is sequentially installed with a conversion joint 46, a sub-grouting pump 31, and a regulating valve 32. By adjusting the sub-grouting pump 31 and the regulating valve 32 on each grouting branch pipe 35, the grouting pressure of different grouting holes 16 can be controlled. During each test, the rotating disk 15 is adjusted to adjust the different layout positions of the grouting holes 16. Adjusting the conversion joint 46 of the sub-grouting pipe can connect to the slurry storage box 26 with different ratios to conduct test observations. During grouting, the grouting pump 28 is first started to flow into the grouting main pipe 30. Then, the sub-grouting pump 31 and the regulating valve 32 are opened to flow into the grouting branch pipe 35. When the shield 22 just escapes the multi-ring pipe segment to be grouted, the grouting pump 28 is turned off to stop grouting, and then the opening at the front end of the simulation box 1 is sealed.

[0055] The existing model test system also has a problem that affects the test. The slurry 19 of the grouting device is prepared in advance, and the grouting device injects grout into the simulation box 1 through the slurry pipe. Whether it is double slurry or single slurry, initial setting is prone to occur when it is stationary or flowing at a low speed, resulting in blockage and inability to carry out normal test simulation.

[0056] like Figure 2 As shown, an agitator 25 is installed in the slurry storage box 26, and a brushless motor 24 is installed on the top outer side of the slurry storage box 26. The output shaft of the brushless motor 24 is connected to the agitator 25 to drive the agitator 25 to stir the slurry 19. At the same time, three liquid distribution pipes are connected to the slurry storage box 26.

[0057] like Figure 6 As shown, the monitoring device includes a pressure gauge 36, a displacement gauge 37, and a pore pressure gauge 38. The pressure gauge 36 and displacement gauge 37 are installed on the inner wall of the segment 42 to be grouted, and the pore pressure gauge 38 is installed in the model soil 2 surrounding the segment 42 to be grouted. The pressure gauge 36 is used to detect the grouting pressure applied to the segment 42 to be grouted, and the displacement gauge 37 is used to detect the displacement of the segment 42 to be grouted. The displacement data obtained can be used to obtain data on the segment's floating, convergence, and misalignment. The pore pressure gauge 38 is used to detect the pore water pressure around the segment 42 to be grouted.

[0058] In this embodiment, the model soil 2 can be limestone, mudstone, siltstone, quartz sandstone, etc., or can be clay layers such as silt, silt sand, silty clay, medium-coarse sand, gravel sand, medium sand, silty fine sand, and silty silt. The permeable layer 14 is composed of sand or gravel soil, and the impermeable layer 13 is composed of clay or silty soil.

[0059] Example 2

[0060] Based on the shield synchronous grouting model test system of Example 1, this embodiment provides a shield synchronous grouting model test method, and the specific steps are as follows:

[0061] S01: Install the simulation box 1, and fill the simulation box 1 with the simulated buried depth material layer 7, the impermeable layer 13 and the permeable layer 14 in sequence;

[0062] S02: Install the water injection device. Use the water pump 4 to connect the water reservoir 3 and the water injection pipe 5. The valve 6 controls the water flow into the simulation box 1. There are water injection holes 8 on the water injection pipe 5 to inject water evenly. The pressure water level observation pipe 9 is placed between the aquiclude 13 and the permeable layer 14 to observe the water pressure in the simulation box 1. The shallow water level observation pipe 10 is placed on the upper part of the aquiclude 13 to monitor the water level.

[0063] S03: Install the shield device, connect the multi-ring segments (including the segments to be grouted 42 and the segments not to be grouted 17) with bolts and a mortise and tenon structure, fix the pressure gauge 36 and the displacement gauge 37 to the inner wall of the segments to be grouted 42, position the shield shell 22 in the simulation box 1, fix the assembled pipe rings in the shield shell 22, adjust the layout of the grouting holes 16 on the rotating disk 15 at the rear end of the shield shell 22, and connect the servo motor to the vertical bar 21 at the front end of the shield shell 22 via a telescopic rod;

[0064] S04: Install the grouting device, connect the grouting main pipe 30 to the slurry storage box 26, install a grouting pump 28 and a flow meter 29 on the grouting main pipe 30, install the monitor 27 on the slurry storage box 26, connect the grouting main pipe 30 to six grouting branch pipes 35, install a conversion joint 46, a branch grouting pump 31, and a regulating valve 32 on the grouting branch pipes 35, the number of grouting holes 16 is six, the number of grouting branch pipes 35 is six, and the ends of the grouting branch pipes 35 are connected to the grouting holes 16 of the rotating disk 15;

[0065] S05: Fill the simulation box 1 with model soil 2 in layers, ensuring that the aquiclude 13 and the permeable layer 14 are located below the model soil 2. Bury a piezometer 38 in the model soil 2. Install a loading plate 12 on the top of the simulation box 1. Install a jack 11 on the loading plate 12. The loading plate 12 and the jack 11 constitute a ground stress loading device.

[0066] S06: Apply water pressure, turn on the pump 4, pump water out of the reservoir 3, open the valve 6, let water enter the water injection pipe 5, and inject it into the simulation box 1 through the water injection hole 8. Observe that the pressure water level observation pipe 9 reaches the specified water pressure, close the valve 6, turn off the pump 4, and stop water injection;

[0067] S07: Turn on the jack 11 and apply the load downward. The ground stress loading device transfers the load evenly to the model soil 2 through the loading plate 12, and stops loading after the desired ground stress environment is reached.

[0068] S08: Start the power device to pull the shield shell 22 outward for horizontal excavation. At the same time, adjust the flow rate of the grouting device and inject slurry into the gap between the tail end of the shield shell 22 and the model soil 2 through the slurry delivery pipe to achieve synchronous grouting. When the shield shell 22 moves out of the grouting segment 42 to be grouted, stop grouting. When the shield shell 22 is completely out of the way, then seal the opening at the front end of the simulation box 1 and turn off the servo motor to stop the excavation process.

[0069] In step S08, the various components of the required slurry 19 can also be delivered to the slurry storage box 26 through various liquid distribution pipes. When a single slurry 19 is required, one liquid distribution pipe is injected with cement slurry, and the other two liquid distribution pipes are respectively injected with different additive solutions. When slurry 19 is required, one liquid distribution pipe is injected with liquid A and one liquid distribution pipe is injected with liquid B. The combination of liquid A and liquid B can be cement slurry and water glass, water glass and acid curing agent, etc. The required slurry 19 is stirred and mixed by the agitator 25. The agitator 25 can fully mix the slurry 19 and prevent coagulation. The power device is started to pull the shield shell 22 outward for horizontal excavation. At the same time, the flow rate of the grouting device is adjusted, and grouting is injected into the shield tail gap through the grouting pipe to achieve synchronous grouting.

[0070] S09: After grouting is completed, data is collected through monitoring devices to summarize the rising, staggering, and convergence patterns of the segments, and to collect shield tail clearance data;

[0071] S10: Repeat the above steps, adjust the simulated burial depth material, change the grouting points to achieve multi-point synchronous grouting, set different ground stress pressure, type of mortise and tenon structure, water pressure, slurry 19 type and ratio, grouting amount, grouting pressure, shield shell 22 excavation speed, grouting hole 16 layout parameters, and complete the synchronous grouting test during shield tunnel excavation under different conditions.

[0072] In this embodiment, the grouting device is connected to the grouting holes 16 on the rotating disc 15 through the grouting branch pipe 35. The position of the grouting hole 16 can be changed by the rotating disc 15. By adjusting the branch grouting pumps 31 and the regulating valves 32 on each grouting branch pipe 35, the grouting pressure of different grouting holes 16 can be controlled. In each test, the rotating disc 15 is adjusted to adjust the different layout positions of the grouting holes 16, so that it is possible to study the effects of different grouting hole 16 arrangements or different grouting amounts on the floating behavior of the pipe segment and the deformation law of the surrounding strata.

[0073] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0074] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0075] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0076] In the description of this specification, the terms "one embodiment", "some embodiments", "embodiments", "examples", "specific examples" or "some examples" refer to the specific features, structures, materials or characteristics described in conjunction with the embodiment or example and included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and features of different embodiments or examples, unless they are mutually inconsistent.

[0077] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A shield synchronous grouting model test system, characterized in that: It includes a simulation box (1), a shield device, a grouting device, a power device, a ground stress loading device, a water injection device and a monitoring device; The top of the simulation box (1) is open and provided with a loading plate (12), and the interior of the simulation box (1) is filled with model soil (2); The shield device comprises a shield shell (22) and a plurality of pipe segments, the shield shell (22) is a hollow cylinder and is arranged to pass through the simulation box (1), and the plurality of pipe segments are assembled in the shield shell (22); The rear portion of the shield shell (22) is rotatably connected to a ring-shaped rotating disc (15), the rotating disc (15) is provided with a grouting hole (16), and the grouting device is connected to the grouting hole (16) on the rotating disc (15) via a grouting branch pipe (35); The power device is used to pull the front end of the shield shell (22) to simulate shield tunneling, the ground stress loading device simulates ground stress loading on the model soil (2) through the loading plate (12), the water injection device simulates the water pressure environment in the model soil (2) through the water injection pipe (5), and the monitoring device is used to monitor the floating displacement of the pipe segment and the deformation of the surrounding model soil (2) after the position of the grouting hole (16) is changed by the rotating disc (15); An annular flange (33) is provided on the rear end surface of the shield shell (22); An annular groove (34) that cooperates with the annular flange (33) is provided on one side of the rotating disc (15) close to the shield shell (22) to enable the rotating disc (15) to rotate relative to the shield shell (22); A connecting hole (41) communicating with the annular groove is provided on the circumference of the rotating disc (15); A connecting groove is provided on the outer periphery of the annular flange (33) of the shield shell (22); The rotating disc (15) is connected to the connecting groove on the annular flange (33) via a connecting piece (40) passing through the connecting hole (41).

2. The shield synchronous grouting model test system according to claim 1 is characterized in that: The rotating disc (15) comprises a plurality of arc-shaped ring blocks connected end to end, an arc-shaped groove is provided on one side of the arc-shaped ring block close to the shield shell (22), and the arc-shaped grooves on the plurality of arc-shaped ring blocks are connected to form the annular groove (34).

3. The shield synchronous grouting model test system according to claim 2 is characterized in that: The connecting hole (41) communicating with the arc-shaped groove is provided on the circumference of the arc-shaped ring block.

4. The shield synchronous grouting model test system according to claim 1 is characterized in that: The adjacent two pipe segments are detachably connected.

5. The shield synchronous grouting model test system according to claim 1 is characterized in that: The grouting main pipe (30) of the grouting device is connected to a plurality of grouting branch pipes (35), and the grouting branch pipes (35) are sequentially connected to a conversion joint (46), a branch grouting pump (31) and a regulating valve (32), and the ends of the grouting branch pipes (35) are connected to the grouting holes (16).

6. The shield synchronous grouting model test system according to claim 5, characterized in that: The grouting device comprises a slurry storage box (26), in which an agitator (25) driven to rotate by a brushless motor (24) is installed, and the slurry storage box (26) is connected to a plurality of liquid distribution pipes (23).

7. The shield synchronous grouting model test system according to claim 5, characterized in that: The water injection device comprises a water reservoir (3), a water pump (4) and a water injection pipe (5) which are connected in sequence; The bottom of the simulation box (1) is provided with a simulated burial depth material layer (7), a water-proof layer (13) and a water-permeable layer (14) in order from bottom to top; The water injection pipe (5) is inserted into the simulated buried depth material layer (7) from the outside of the simulation box (1), and a plurality of water injection holes (8) are evenly distributed on the upper part of the water injection pipe (5).

8. The shield synchronous grouting model test system according to claim 7, characterized in that: The monitoring device includes a pressure gauge (36), a displacement gauge (37) and a piezometer (38); The pressure gauge (36) and displacement gauge (37) are installed on the inner wall of the pipe segment, and the piezometer (38) is installed in the model soil (2) around the pipe segment.

9. A shield synchronous grouting model test method, characterized in that: The shield synchronous grouting model test system according to claim 8 is used to conduct the test, comprising the following steps: S01: installing the simulation box (1), and sequentially filling the simulation box (1) with the simulated buried depth material layer (7), the water-proof layer (13), and the water-permeable layer (14); S02: Install the water injection device; S03: Install the shield device, connect the plurality of pipe segments in sequence to form a pipe ring, fix the pressure gauge (36) and the displacement gauge (37) on the inner wall of the pipe segment, position the shield shell (22) in the simulation box (1), set the assembled pipe ring in the shield shell (22), adjust the layout position of the grouting hole (16) on the rotating disk (15) at the rear end of the shield shell (22), and connect the power device to the front end of the shield shell (22); S04: Installing the grouting device; S05: filling the simulation box (1) with the model soil (2) in layers, ensuring that the aquiclude (13) and the permeable layer (14) are located below the soil, burying the piezometer (38) in the model soil (2), installing the loading plate (12) on the upper part of the model soil (2), and connecting the loading plate (12) to the ground stress loading device; S06: applying water pressure, the water injection device injects water into the simulation box (1) through the water injection pipe (5); S07: The in-situ stress loading device uniformly transfers the load to the model soil (2) through the loading plate (12), and stops loading after the desired in-situ stress environment is reached; S08: starting the power device, pulling the shield shell (22) outward to perform horizontal excavation, and adjusting the flow rate of the grouting device at the same time. The grouting holes (16) on the rotating disc (15) inject grouting liquid (19) into the gap at the rear end of the shield shell (22) through the grouting pipe to achieve synchronous grouting. When the shield shell (22) moves out of the pipe segment to be grouted, the grouting is stopped. When the shield shell (22) is completely removed, the power device is turned off to stop the excavation process. S09: After the grouting is completed, data is collected through the monitoring device; S10: Repeat the above steps, adjust the simulated burial depth material, change the position of the grouting hole (16) by rotating the rotating disk (15), set different ground stress pressures, types of mortise and tenon structures, water pressures, types and proportions of slurry (19), grouting volumes, grouting pressures, excavation speeds of the shield shell (22), and grouting hole (16) layout parameters, and complete the synchronous grouting test during shield tunnel excavation under different conditions.

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