Device and method for testing grouting effect of subway shield tunnel

Abstract

A testing device for the grouting effect of a subway shield tunnel includes a device box, a channel lining, a dense clay layer, a sandy silt layer, a silty clay layer, a tunnel system, and a measurement system. The dense clay layer, sandy silt layer, and silty clay layer are arranged sequentially from top to bottom within the device box. The channel lining is located in the middle above the dense clay layer. The tunnel system is arranged between the sandy silt layer and the silty clay layer. The measurement system includes a displacement sensor, a water-sensitive soil moisture sensor, and an earth pressure cell. The displacement sensor is installed on the top surface of the dense clay layer on both sides of the channel lining. The water-sensitive soil moisture sensor is arranged between the channel lining and the tunnel system. The earth pressure cell is located within the silty clay layer. A method for testing the grouting effect of a subway shield tunnel is also provided. This invention not only enables the testing of the grouting effect of subway shield tunnels but is also simple, easy to operate, inexpensive, and has a short cycle time.

Description

Technical Field

[0001] This invention belongs to the field of tunnel engineering technology and relates to a testing device and method for the grouting effect of subway shield tunnels. It is mainly applicable to the testing and research of the grouting effect of subway shield tunnels and its disturbance effect on riverbed. Background Technology

[0002] Tunnel construction mainly involves tunnel excavation, segment assembly, and grouting. Grouting is a crucial process for maintaining ground balance and controlling ground settlement, ensuring uniform soil pressure and the stability of the lining structure composed of segments. The disturbance caused by tunnel boring machines (TBMs) excavating and grouting beneath a riverbed can lead to uplift or settlement of the upper riverbed, easily creating seepage channels. This increases soil moisture content and reduces soil strength. Inadequate control measures can result in riverbed collapse or water inrush, potentially even submerging the TBM and rendering it unusable, causing significant economic losses and serious negative social impacts. Existing testing devices and methods have the following main shortcomings: 1) The grouting and curing process requires a long period, making rapid testing of grouting effects impossible; 2) Only a uniform grouting method can be used for the entire grouting layer, making it impossible to control the specific location of grouting and achieve precise control of the grouting area and orientation; 3) It is impossible to control the amount of grout injected into different areas of the grouting layer, and cannot handle complex grouting conditions such as over-grouting, under-grouting, and combinations thereof. Summary of the Invention

[0003] To overcome the shortcomings of existing tunnel grouting testing devices and methods, which cannot quickly test grouting effects, accurately control grouting areas and orientations, or simultaneously consider complex working conditions such as over-grouting, under-grouting, and their combinations, this invention provides a testing device and method for the grouting effect of subway shield tunnels. This invention effectively overcomes the deficiencies of conventional tunnel grouting testing devices and methods. It not only enables the testing of grouting effects in subway shield tunnels but is also simple, easy to operate, inexpensive, and quick.

[0004] The technical solution adopted by this invention to solve its technical problem is:

[0005] A testing device for the grouting effect of a subway shield tunnel includes a device box, a riverbed lining, a dense clay layer, a sandy silt layer, a silty clay layer, a tunnel system, and a measurement system. The dense clay layer, sandy silt layer, and silty clay layer are arranged sequentially from top to bottom inside the device box. The riverbed lining is located in the middle above the dense clay layer. The tunnel system is arranged between the sandy silt layer and the silty clay layer. The measurement system includes a displacement sensor, a water-sensitive soil moisture sensor, and an earth pressure cell. The displacement sensor is installed on the top surface of the dense clay layer on both sides of the riverbed lining. The water-sensitive soil moisture sensor is arranged between the riverbed lining and the tunnel system. The earth pressure cell is located within the silty clay layer.

[0006] Furthermore, the tunnel system includes a tunnel segment layer, a grouting layer, and a high-elasticity wear-resistant rubber fixing layer. The high-elasticity wear-resistant rubber fixing layer is arranged outside the grouting layer, and the grouting layer is arranged outside the tunnel segment layer.

[0007] Furthermore, the grouting layer includes a combined airbag block, an air delivery hose, a metering control unit, a control circuit, and an air pump. The combined airbag block is attached to the outside of the tunnel. The air delivery hose is arranged in a ring around the outside of the tunnel segment layer and passes through the combined airbag block. The metering control unit is embedded in the air delivery hose. The control circuit is laid along the inside of the air delivery hose. The metering control unit is connected to the control circuit.

[0008] The air delivery hose is connected to the air pump, the air pump is connected to the computer, the computer is connected to the control circuit and the data acquisition instrument, and the data acquisition instrument is connected to the displacement sensor, the water-sensitive soil moisture sensor and the soil pressure cell.

[0009] Preferably, in the combined airbag block, the airbag block surrounds the tunnel clockwise and is attached to its outer surface.

[0010] The device box also includes a tunnel segment slot and a transparent baffle. One end of the tunnel is connected to the inner wall of the device box through the tunnel segment slot, and the other end of the tunnel is provided with a transparent baffle, which is installed in the baffle slot on the opposite side of the device box.

[0011] Preferably, the tunnel segment layer is formed by connecting adjacent tunnel segment units with bolts.

[0012] The water-sensitive soil moisture sensor unit is connected by strong adhesive, and the displacement sensor and soil pressure cell are buried in the soil.

[0013] A method for testing the grouting effect of subway shield tunnels includes the following steps:

[0014] Step 1: Determine the similarity ratio of the test device based on the relationship between the tunnel diameter, soil layer thickness, river water depth, and device box size;

[0015] Step 2: Determine the size, shape, and material of the test components based on the actual conditions of the tunnel;

[0016] Step 3: Determine the thickness and distribution of the test soil layer based on the geological survey report;

[0017] Step 4: Place the device box and install the tunnel segment slots and baffle slots. The test box is a transparent tempered glass box with an opening at the top and the bottom fixed to the ground. The side walls have corresponding prefabricated slots. The tunnel segment slots are used to fix the tunnel, and the baffle slots are used to install transparent baffles.

[0018] Step 5: Assemble the grouting layer. According to the engineering characteristics and testing requirements, wrap the airbag blocks clockwise around the tunnel and attach them to its outer surface; evenly arrange the metering control units on the air supply hose, and arrange the air supply hose around the tunnel in a way that runs through the combined airbag blocks; the air supply hose connects each ring of the tunnel longitudinally, and the end is connected to the air pump;

[0019] Step 6: Assemble the tunnel system. The tunnel system consists of a tunnel segment layer, a grouting layer, and a high-elasticity wear-resistant rubber fixing layer from the inside out. The high-elasticity wear-resistant rubber fixing layer is attached to the outer ring of the grouting layer.

[0020] Step 7: Connect the displacement sensor, water-sensitive soil moisture sensor, and soil pressure cell to the data acquisition instrument via data cables; connect the air pump to the combined airbag block via an air delivery hose to complete the assembly of the measurement and control system.

[0021] Step 8: Fill the device box with soil in layers and bury the earth pressure box at the predetermined corresponding position.

[0022] Step 9: When filling the soil in layers to the lower end of the tunnel slot, the assembled tunnel system is sent in through the side window of the device box and laid horizontally inside the device box.

[0023] Step 10: Continue filling the soil, and according to the thickness of the filled soil, bury the water level gauge, water-sensitive soil moisture sensor, displacement sensor soil pressure cell in the device according to the test position, spacing and quantity.

[0024] Step 11: Lay the river lining when filling the soil to the designed position of the river lining.

[0025] Step 12: Determine the tunnel grouting test parameters and adjust the inflation pressure and flow rate of the combined airbag block to meet the test grouting requirements;

[0026] Step 13: Before the experiment begins, complete the debugging of the data acquisition software, including inputting parameters of the displacement sensor, water-sensitive soil moisture sensor and soil pressure cell, and selecting the data acquisition frequency and output type; debug the air pump and control the air pressure of the combined airbag block.

[0027] Step 14: Turn on the data acquisition instrument and, through the computer control system, open the metering and control unit of all combined airbag blocks. After the interaction between the tunnel system and the surrounding soil has stabilized, record the test data to achieve rapid grouting of the entire tunnel.

[0028] Step 15: Through the computer control system, the directional control of the orientation of the combined airbag blocks of the lower half-ring tunnel system of the river lining is used to achieve precise control of the grouting orientation of the lower half-ring tunnel of the river lining.

[0029] Step 16: Using a computer control system, control the air pressure and flow rate of the under-grouting and over-grouting corresponding to the interval combination airbag blocks of the single-ring tunnel respectively, to realize the testing of the combination of under-grouting and over-grouting of the single-ring tunnel system.

[0030] Step 17: End the test and disassemble the test apparatus.

[0031] Furthermore, the method also includes the following steps:

[0032] Step 18: Repeat steps 14, 15, and 16 to test the complex conditions of tunnel segment grouting required for different engineering scenarios.

[0033] The beneficial effects of the present invention are mainly reflected in: (1) it can shorten the time required for tunnel grouting and maintenance process and realize rapid testing of tunnel grouting process; (2) it can control the specific area of ​​grouting and realize precise control of grouting direction; (3) it can control the amount of grouting in different areas of grouting layer and realize complex working conditions such as over-grouting, under-grouting and their combination. Attached Figure Description

[0034] Figure 1 This is a front view of a test device for testing the grouting effect of a subway shield tunnel.

[0035] Figure 2 This is a side view of the device.

[0036] Figure 3 This is a top view of the device.

[0037] Figure 4 This is a detailed structural diagram of the tunnel segment layer and the grouting layer.

[0038] Figure 5 This is a cross-sectional view of the tunnel segment layer and the grouting layer.

[0039] Figure 6 This is a detailed drawing of the combined airbag block.

[0040] Figure 7 This is a schematic diagram of the grouting layer.

[0041] Figure 8 This is a schematic diagram of the circuit connection of the measurement system.

[0042] The components include: 1. Device box; 2. River water; 3. Riverbed lining; 4. Dense clay layer; 5. Sandy silt layer; 6. Silt clay layer; 7. Tunnel segment layer; 8. Grouting layer; 9. High-elasticity wear-resistant rubber fixing layer; 10. Displacement sensor; 11. Water-sensitive soil moisture sensor; 12. Earth pressure cell; 13. Water level gauge; 14. Tunnel segment slot; 15. Transparent baffle; 16. Baffle slot; 17. Combined airbag block; 17-1. Airbag block 1; 17-2 17-3. Airbag block 2, 17-4. Airbag block 4, 17-5. Airbag block 5, 17-6. Airbag block 6, 17-7. Airbag block 7, 17-8. Airbag block 8, 17-9. Airbag block 9, 17-10. Airbag block 10, 17-11. Airbag block 11, 17-12. Airbag block 12; 18. Gas delivery hose; 19. Metering and control unit; 20. Control circuit; 21. Air pump; 22. Data acquisition instrument; 23. Computer system. Detailed Implementation

[0043] The present invention will now be further described with reference to the accompanying drawings.

[0044] Reference Figures 1 to 8 A testing device for the grouting effect of a subway shield tunnel includes a device box 1, a riverbed lining 3, a dense clay layer 4, a sandy silt layer 5, a silty clay layer 6, a tunnel system, and a measurement system. The dense clay layer, sandy silt layer, and silty clay layer are arranged sequentially from top to bottom inside the device box. The riverbed lining is located in the middle above the dense clay layer. The tunnel system is arranged between the sandy silt layer and the silty clay layer. The measurement system includes a displacement sensor, a water-sensitive soil moisture sensor, and an earth pressure cell. The displacement sensor is installed on the top surface of the dense clay layer on both sides of the riverbed lining. The water-sensitive soil moisture sensor is arranged between the riverbed lining and the tunnel system. The earth pressure cell is located within the silty clay layer.

[0045] The tunnel system includes a tunnel segment layer 7, a grouting layer 8, and a high-elasticity wear-resistant rubber fixing layer 9. The high-elasticity wear-resistant rubber fixing layer 9 is arranged outside the grouting layer 8, and the tunnel segment units of the tunnel segment layer 7 are connected by bolts.

[0046] The tunnel system also includes a tunnel segment slot 14 and a transparent baffle 15. One end of the tunnel segment layer 7 is connected to the inner wall of the device box 1 through the tunnel segment slot 14, and the other end of the tunnel segment layer 7 is provided with a transparent baffle 15. The transparent baffle 15 is connected in the baffle slot 16 on the opposite side of the device box 1.

[0047] The grouting layer includes a combined airbag block 17, an air supply hose 18, a metering control unit 19, a control circuit 20, and an air pump 21. The combined airbag block 17 is attached to the outside of the tunnel segment layer 7. The air supply hose 18 is arranged in a loop around the outside of the tunnel segment layer 7 and passes through the combined airbag block 17. The metering control unit 19 is installed on the air supply hose 18, and the control circuit 20 is laid along the inside of the air supply hose 18.

[0048] In the combined airbag block 17, airbag block 1 (17-1), airbag block 2 (17-2), airbag block 3 (17-3), airbag block 4 (17-4), airbag block 5 (17-5), airbag block 6 (17-6), airbag block 7 (17-7), airbag block 8 (17-8), airbag block 9 (17-9), airbag block 10 (17-10), airbag block 11 (17-11), and airbag block 12 (17-12) are arranged clockwise around the tunnel segment layer 7 and attached to its outer surface.

[0049] The water-sensitive soil moisture sensor 11 is connected by strong adhesive, and the displacement sensor 10 and the soil pressure cell 12 are buried in the soil.

[0050] The device box also includes a tunnel slot 14, a transparent baffle 15, and a baffle slot 16.

[0051] A subway tunnel project in a certain city plans to use underground shield tunneling to vertically cross a river. The tunnel top will be buried at a depth of approximately 20 meters, and the deepest point of the riverbed will be approximately 15 meters from the surface. To avoid potential engineering risks at the shallowest point of the overburden layer during actual construction, the testing device and method for grouting effects in subway shield tunnels provided by this invention will be used to test for potential engineering hazards, thereby enabling the prediction of riverbed deformation during actual tunnel construction.

[0052] In this embodiment, the minimum distance between the tunnel top and the riverbed at the midpoint of the tunnel underpass section is 5m, classifying it as an ultra-shallow tunnel. The shield tunnel has an outer diameter of 6.1m, an inner diameter of 5.5m, and a ring width of 1.2m. According to the on-site geological survey report, the soil layers from top to bottom are dense clay, sandy silt, and silty clay, with thicknesses of 2m, 6m, and 8m, respectively. The soil layers in the river-underpass area have high porosity and are complex and variable, with some strata exhibiting alternating interlayer distribution and containing large crystalline slag blocks. The device box is made of transparent plexiglass, with internal dimensions of 1m × 1m × 1m. The riverbed lining 3 and the tunnel segment layer 7 are spatially perpendicular.

[0053] The implementation scheme of the present invention is as follows:

[0054] 1) Determination of the similarity ratio of the testing device. Based on the relationship between the tunnel diameter, soil layer thickness, river water depth, and device box size, the similarity ratio of the testing device was determined to be 1:50.

[0055] 2) Determine the size, shape, and material of the test components. Based on step 1), determine that the device box 1 is a cube with a side length of 1m; the deepest point of the riverbed lining 3 is about 30cm above the ground surface; the tunnel segment layer 7 is made of transparent PVC pipe with an outer diameter of 12.2cm; the combined airbag block 17 is about 0.4cm thick, about 2.4cm wide, with an inner diameter of 12.2cm and an outer diameter of 12.6cm.

[0056] 3) Determine the soil layer thickness and distribution. Based on the geological survey report, determine the soil layers required for the test. In this embodiment, the soil layers from top to bottom are dense clay layer 4, sandy silt 5, and silty clay 6. Based on the similarity ratio in step 1, the soil layer thicknesses in the device box are determined to be 4cm, 12cm, and 16cm, respectively.

[0057] 4) Place the device box 1 and install the tunnel segment slots and baffle slots. The device box 1 is a transparent tempered glass box with an opening at the top and a bottom fixed to the ground. The side walls have corresponding prefabricated slots, of which the tunnel segment slot 14 is used to fix the tunnel segments and the baffle slot 16 is used to install the transparent baffle 15.

[0058] 5) Assemble the grouting layer. According to the engineering characteristics and testing requirements, the combined airbag blocks, such as airbag block 1 (17-1), airbag block 2 (17-2), airbag block 3 (17-3), airbag block 4 (17-4), airbag block 5 (17-5), airbag block 6 (17-6), airbag block 7 (17-7), airbag block 8 (17-8), airbag block 9 (17-9), airbag block 10 (17-10), airbag block 11 (17-11), and airbag block 12 (17-12), are arranged clockwise around the tunnel segment layer 7 and attached to its outer surface; metering control units 19 are evenly arranged on the air supply hose 18, and the air supply hose 18 is laid around the tunnel segment layer 7 in a way that penetrates the combined airbag blocks 17; the air supply hose 18 connects the various rings of the tunnel longitudinally, and the end is connected to the air pump 21.

[0059] 6) Assemble the tunnel system. The tunnel system consists of the tunnel segment layer 7, the grouting layer 8, and the high-elasticity wear-resistant rubber fixing layer 9 from the inside out. The high-elasticity wear-resistant rubber fixing layer 9 is 2mm thick and has a low density, and is bonded to the outer ring of the grouting layer 8; the tunnel lining segment layer 7 is 6mm thick.

[0060] 7) Assemble the measurement and control system. The displacement sensor 10, the water-sensitive soil moisture sensor 11, and the soil pressure cell 12 are connected to the data acquisition instrument 22 via data cables. The data acquisition instrument 22 is connected to the computer system 23. The air pump is connected to the combined airbag block 17 via the air delivery hose 18 and establishes a control connection with the computer system 23. The computer system 23 controls the air pressure and flow rate of the air pump.

[0061] 8) Fill the device box 1 with soil and bury the earth pressure cells. Fill the device box 1 with silty clay 6 in layers and bury the earth pressure cells 12 at the corresponding design locations.

[0062] 9) Install the tunnel system. When filling the silty clay 6 to the lower end of the tunnel segment slot 14, the assembled tunnel system is sent in through the side opening of the device box 1 and laid horizontally inside the device box 1. The spatial position of the river lining 3 and the tunnel segment layer 7 includes various working conditions such as parallel, perpendicular or oblique axes. This embodiment tests the working condition where the axis of the river lining 3 is perpendicular to the axis of the tunnel segment layer 7. The left end of the tunnel segment layer 7 is tightly connected to the tunnel segment slot 14, and the right end is tightly connected to the glass baffle 15. The inter-ring gas supply hose 18 is connected in parallel along the axis of the tunnel segment layer 7, and the terminal lead of the gas supply hose 18 and the control circuit 20 is led out from the side wall opening of the device box.

[0063] 10) Continue filling the soil in layers. During the filling process, use the corresponding measuring instruments according to... Figure 1 , Figure 2 , Figure 3 The water level gauge 13 is installed in a spatial arrangement, with its fixed end connected to the device box 1, and its probe and measuring scale extending below the water surface. Water-sensitive soil moisture sensors 11 are installed without gaps along the tunnel axis in the soil layer between the tunnel arch and the riverbed to detect river seepage. Displacement sensors 10 are evenly arranged at 5cm intervals along both sides and the bottom of the river lining 3, as well as in the soil between the tunnel segment layer and the river lining. Earth pressure cells 12 are arranged sequentially in the soil around the tunnel segment layer 7, centered on it, along both horizontal and vertical directions.

[0064] 11) When filling the soil to the designed position of the river lining, lay the river lining 3. When filling the soil to the designed position of the river lining 3, the surface of the soil and the surface of the river water 2 are both lower than the opening of the device box 1. The river water 2 is connected to an external water source through a pipe, and the relative water level of the river during the test can be changed as needed.

[0065] 12) Determine the tunnel grouting test parameters. Adjust the inflation pressure and flow rate of the combined airbag block 17 to meet the grouting requirements for the test. According to the test requirements of the embodiment, the tunnel grouting pressure is determined to be 0.12 MPa, and the single-ring grouting volume is 8 m³. 3 Based on the similarity ratio design, the air pressure injected by the air pump 21 was adjusted to 2.4 kPa, and the inflation rate of the metering control unit 19 was adjusted so that the gas inflation volume of the single-ring combined airbag block reached 0.16 m³ within a specified time. 3 This ensures that the grouting test is consistent with the actual process.

[0066] 13) Before the experiment begins, complete the debugging of the data acquisition software, including inputting relevant parameters of displacement sensor 10, water-sensitive soil moisture sensor 11 and soil pressure cell 12, selecting data acquisition frequency and output type, debugging air pump 21 and controlling the combined airbag block 17.

[0067] 14) Achieve rapid grouting across the entire tunnel grouting layer. Turn on the data acquisition instrument 22 and begin data acquisition. Through the computer system 23, activate the metering control unit 19 within all combined airbag blocks 17, ensuring the internal inflation pressure of each combined airbag block 17 reaches 2.4 kPa. Record the total flow rate of all combined airbag blocks 17 in a single ring. When the inflation reaches 0.16 m... 3 After the air pump is turned off, and the deformation of the tunnel system and the surrounding soil stabilizes, the test data is recorded to achieve rapid grouting of the entire tunnel grouting layer.

[0068] 15) Achieve precise control of the grouting orientation of the lower half-ring tunnel of the river lining 3. Turn on the data acquisition instrument 22 and start collecting data. By controlling the switch of the metering control unit 19 inside the combined airbag block 17 of the lower half-ring tunnel system, maintain the internal inflation pressure of the combined airbag block 17 of the lower half-ring at 2.4 kPa, and record the flow rate of the combined airbag block 17 of the lower half-ring. When the inflation reaches 0.08 m... 3 After the air pump is turned off, and the deformation of the tunnel system and the surrounding soil stabilizes, the test data is recorded to achieve precise control of the grouting direction of the lower half-ring tunnel of the river lining.

[0069] 16) Achieve precise control of the interval between under-grouting and over-grouting in the single-ring tunnel system. Turn on the data acquisition instrument 22 and start collecting data. Turn on the air pump 21. Control the metering control unit 19 in airbag blocks 1 (17-1), 3 (17-3), 5 (17-5), 7 (17-7), 9 (17-9), and 11 (17-11) through the computer system 23, so that the total flow rate of these six combined airbag blocks 17 in the upper half ring is only 0.10 m³. 3 The test was conducted to assess under-grouting conditions in the tunnel system. The metering control unit 19 in airbag blocks 2 (17-2), 4 (17-4), 6 (17-6), 8 (17-8), 10 (17-10), and 12 (17-12) was controlled to ensure the total flow rate of these six combined airbag blocks 17 reached 0.22 m³ / s. 3 The test was conducted to assess the over-grouting situation of the tunnel system. After the deformation of the tunnel system and the surrounding soil stabilized, the test data was recorded to achieve precise control over the interval between under-grouting and over-grouting in the single-ring tunnel system.

[0070] 17) End the test and disassemble the test equipment. Turn off the test instruments, remove the soil from top to bottom, and take out the tunnel segment layer 7 and related measurement systems.

[0071] 18) Repeat steps 14), 15), and 16) to test the complex working conditions of tunnel segment grouting required for different engineering situations.

[0072] The embodiments described in this specification are merely illustrative examples of how to implement the inventive concept. The scope of protection of this invention should not be considered limited to the specific forms described in these embodiments; rather, it extends to equivalent technical means conceivable by those skilled in the art based on the inventive concept.

Claims

1. A device for testing the grouting effect of a subway shield tunnel, characterized in that, The test device comprises a device box, a river channel lining, a dense clay layer, a sandy silt layer, a silt clay layer, a tunnel system and a measurement system, the dense clay layer, the sandy silt layer and the silt clay layer are arranged in the device box from top to bottom, the middle part of the dense clay layer is provided with the river channel lining, the tunnel system is arranged between the sandy silt layer and the silt clay layer, the measurement system comprises a displacement sensor, a water-sensitive soil humidity sensor and a soil pressure cell, the displacement sensor is installed on the top surface of the dense clay layer on both sides of the river channel lining, the water-sensitive soil humidity sensor is arranged between the river channel lining and the tunnel system, and the soil pressure cell is located in the silt clay layer; The tunnel system comprises a tunnel segment layer, a grouting layer and a high-elasticity wear-resistant rubber fixing layer, the grouting layer comprises a combined air bag block, a gas conveying hose, a metering control unit, a control circuit and a gas pump, the combined air bag block is pasted on the outside of the tunnel, the gas conveying hose is arranged in a ring around the outer circle of the tunnel segment layer and penetrates the combined air bag block, the metering control unit is embedded on the gas conveying hose, the metering control units are uniformly arranged on the gas conveying hose, the control circuit is laid along the inside of the gas conveying hose, and the metering control unit is connected with the control circuit; the gas conveying hose is connected with the gas pump, the gas pump is connected with a computer, the computer is connected with the control circuit and a data acquisition instrument, the data acquisition instrument is connected with the displacement sensor, the water-sensitive soil humidity sensor and the soil pressure cell; in the combined air bag block, the air bag blocks are arranged in a clockwise ring around the tunnel and are pasted on the outer surface of the tunnel.

2. The device for testing the grouting effect of a subway shield tunnel according to claim 1, wherein, The high-elasticity wear-resistant rubber fixing layer is arranged outside the grouting layer, and the grouting layer is arranged outside the tunnel segment layer.

3. The device for testing the grouting effect of a subway shield tunnel according to claim 1 or 2, characterized in that, The device box is further provided with a tunnel segment clamping groove and a transparent baffle, one end of the tunnel is connected with the inner wall of the device box through the tunnel segment clamping groove, the other end of the tunnel is provided with the transparent baffle, and the transparent baffle is installed in the baffle clamping groove on the opposite side of the device box.

4. The device for testing the grouting effect of a subway shield tunnel according to claim 1 or 2, characterized in that, The tunnel segment layer is connected by bolts between adjacent tunnel segment units.

5. The device for testing the grouting effect of a subway shield tunnel according to claim 1 or 2, characterized in that, The water-sensitive soil humidity sensor unit is connected by strong glue, and the displacement sensor and the soil pressure cell are embedded in the soil body.

6. The method of using the device for testing the effect of grouting of a subway shield tunnel according to claim 1, characterized in that, The method comprises the following steps: Step 1, determining the similarity ratio of the test device according to the mutual relationship among the tunnel diameter, the soil layer thickness, the river water depth and the size of the device box; Step 2, determining the size, shape and material of the test component according to the actual situation of the tunnel; Step 3, determining the thickness and distribution of the test soil layer according to the geological exploration report; Step 4, placing the device box, installing the tunnel segment clamping groove and the baffle clamping groove, the device box is a transparent tempered glass box, the upper part is open, the bottom is fixed on the ground, and the side wall has corresponding prefabricated clamping grooves, wherein the tunnel segment clamping groove is used for fixing the tunnel, and the baffle clamping groove is used for installing the transparent baffle; Step 5, assembling the grouting layer: according to the engineering characteristics and test requirements, the air bag blocks are arranged in a clockwise ring around the tunnel and are pasted on the outer surface of the tunnel; the metering control units are uniformly arranged on the gas conveying hose, and the gas conveying hose is arranged in a manner of penetrating the combined air bag block around the tunnel; the gas conveying hose longitudinally connects each ring of the tunnel, and the terminal is connected with the gas pump. Step 6, assemble the tunnel system, the tunnel system is composed of tunnel segment layer, grouting layer and high elasticity wear-resistant rubber fixing layer from inside to outside, the high elasticity wear-resistant rubber fixing layer is pasted on the outer ring of the grouting layer; Step 7, connect the displacement sensor, water-sensitive soil humidity sensor and earth pressure cell with the data acquisition instrument through the data line respectively; connect the air pump with the combined air bag block through the air conveying hose to realize the assembly of the measurement control system; Step 8, fill the soil in the device box in layers, and bury the earth pressure cell at the corresponding position; Step 9, fill the soil in layers to the position below the tunnel clamping groove, and then put the assembled tunnel system into the device box through the side window of the device box and lay it horizontally in the device box; Step 10, continue to fill the soil, and bury the water level gauge, water-sensitive soil humidity sensor, displacement sensor and earth pressure cell in the device according to the thickness of the filled soil, the test position, interval and quantity; Step 11, lay the river channel lining when the filled soil reaches the design position of the river channel lining; Step 12, determine the tunnel grouting test parameters, adjust the inflation pressure and flow of the combined air bag block to meet the test grouting requirements; Step 13, before the test starts, complete the debugging work of the data acquisition software, including the input of the parameters of the displacement sensor, water-sensitive soil humidity sensor and earth pressure cell, the selection of data acquisition frequency and output type; debug the air pump and control the air pressure of the combined air bag block; Step 14, turn on the data acquisition instrument, open all the measurement control units of the combined air bag block through the computer control system, record the test data after the interaction between the tunnel system and the surrounding soil tends to be stable, and realize the rapid grouting of the whole tunnel; Step 15, through the computer control system, realize the accurate control of the grouting direction of the lower half-ring tunnel of the river channel lining by directional control of the combined air bag block of the lower half-ring tunnel of the river channel lining; Step 16, through the computer control system, control the under-grouting and over-grouting air pressure and flow of the interval combined air bag block corresponding to the single-ring tunnel to realize the test of the under-grouting and over-grouting combined conditions of the single-ring tunnel system; Step 17, end the test and disassemble the test device.

7. The method of claim 6, wherein, The method further comprises the following steps: Step 18, repeat steps 14), 15) and 16) to test the complex conditions of the tunnel segment back grouting required by different engineering conditions.

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