Simulation device for mud penetration of assembled slurry shield machine in composite strata

Abstract

The present invention provides a simulation device for mud penetration of an assembled slurry shield machine in a composite stratum, the simulation device comprising a shield simulation module, an assembled mud injection module, an assembled composite soil layer simulation module and a data acquisition module; the shield simulation module comprises at least one shield simulation unit, the shield simulation unit comprises a mud bin, a shield motor and a cutterhead, the mud bin is provided with a plurality of penetration holes; a slurry collection mechanism is provided outside the mud bin, the mud bin is connected to a sampling tube, and a slurry collection pump is connected to the sampling tube; the assembled mud injection module comprises a mud injection mechanism, the shield simulation unit is placed in the composite soil layer of the simulation box, and the mud injection mechanism is connected to a slurry storage tank and a mud penetration hole. By adopting the technical solution of the present invention, simulation tests of the penetration law of slurry of slurry shield machines with different cutterhead types in composite strata can be carried out on a variety of cutterhead forms, and mud parameters of different penetration positions of the mud can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of shield construction, and in particular relates to a device for simulating mud penetration of an assembled mud-water balance shield machine in a composite stratum. Background Art

[0002] Slurry shield machines are widely used in the construction of urban subways, river crossings and undersea tunnels. With the increase in traffic volume, general diameter slurry shield machines can no longer meet the requirements of large diameter tunnels. Therefore, large diameter slurry shields came into being. With the increase in the diameter of the shield, the stratum conditions become more and more complicated during the slurry shield excavation process, and the differences in mud at different positions begin to become significant. However, the mechanism affecting the stability of the shield excavation face is very complex. The factors affecting the stability of the face, the degree and regularity of the influence of each factor, the interaction between the stratum parameters, construction parameters, and mud characteristics, the penetration of mud during the shield excavation process, the properties of mud at different positions, and the amount of penetration still need to be completed with the help of experiments.

[0003] However, the existing visualization device for simulating the penetration of slurry in the stratum of slurry shield is mainly used to simulate the general shield diameter and the relatively simple stratum. For large-diameter slurry shield, due to the influence of gravity differentiation, there are certain differences in the properties of slurry at different heights in the slurry bin, and the penetration and film-forming laws of slurry with different viscosities, densities and particle sizes in the stratum are different. The existing device cannot obtain the difference in the properties and penetration of slurry at different positions during the simulation process. Under most working conditions, the same section in the large-diameter shield process reveals a composite stratum, and there are certain differences in the permeability of different strata, which further affects the penetration and film-forming laws of slurry in the stratum; at the same time, the construction of slurry shield tunnels is also developing towards the deep part. The existing stratum simulation device has too single stratum type layout. For multi-layer stratum conditions, due to the overlapping and compaction during the layout process, mutual disturbances are likely to occur, thereby destroying the lower arranged stratum, and thus it is impossible to truly simulate the stratum conditions, and it is impossible to simulate the slurry film-forming and penetration laws when the stratum is buried deep or the stratum conditions are complex. Finally, the existing device does not consider the effect of different blade types on film formation. Summary of the invention

[0004] In response to the above technical problems, the present invention discloses a simulation device for mud penetration of an assembled slurry balance shield machine in a composite formation, which can be used in conjunction with a variety of cutterhead modules and a data acquisition system to conduct simulation tests on the penetration laws of slurry in large-diameter slurry shield machines with different cutterhead types in composite formations, and obtain mud parameters at different penetration positions of the mud.

[0005] To this end, the technical solution adopted by the present invention is:

[0006] A simulation device for mud penetration of an assembled slurry balance shield machine in a composite stratum, comprising a shield simulation module, an assembled mud injection module, an assembled composite soil layer simulation module and a data acquisition module;

[0007] The shield simulation module includes at least one assembled shield simulation unit, the shield simulation unit includes a mud bin, a shield motor and a cutterhead, the shield motor is connected to the cutterhead, the cutterhead is arranged on one side of the mud bin, and the mud bin is provided with a plurality of penetration holes; the penetration holes are provided with a flow meter electrically connected to the data acquisition module;

[0008] A slurry collection mechanism is provided outside the mud bin, the mud bin is connected to a sampling tube, the slurry collection mechanism comprises a slurry collection pump, and the slurry collection pump is connected to the sampling tube;

[0009] The assembled composite soil layer simulation module comprises a simulation box without a cover, one side of the simulation box is a transparent plate, a plurality of unit stratum boxes are arranged in the simulation box, and a removable drawer plate is arranged at the bottom of each unit stratum box;

[0010] A pressure plate is provided on the top of the simulation box, an air bag is provided above the pressure plate, a top plate is provided above the air bag, the air bag is connected to an air compressor, a plurality of soil pressure gauges and water pressure gauges are provided in the simulation box, and the soil pressure gauges and water pressure gauges are electrically connected to a data acquisition module;

[0011] The assembled mud injection module comprises a mud storage tank and a mud injection mechanism, the shield simulation unit is placed in the composite soil layer of the simulation box, and the mud injection mechanism connects the mud storage tank and the mud penetration hole.

[0012] With this technical solution, during simulation, soil samples are placed in each unit stratum box, and the corresponding unit stratum boxes are stacked and placed in the simulation box according to the stratum sequence. After installation, the drawer plate is pulled out; then, pressure plates and air bags are placed in sequence on the upper part of the stratum in the simulation box, and the top plate is covered. After the required soil cover thickness is calculated, the air bags are inflated and pressurized until the upper soil of the simulation box is subjected to a pressure equal to that when the upper part is fully covered with soil; the shield simulation module is installed, and mud is proportioned according to the stratum, the prepared mud is placed in a slurry tank, and the slurry tank is connected to the mud injection mechanism; the shield motor is turned on to make the cutterhead cut the stratum, and at the same time, the mud injection mechanism connected to the gas tank is turned on to fill the mud bin with mud, and various indicators are observed. Finally, multiple groups of mud samples at different positions are obtained through a slurry pump for analysis. In this technical solution, by setting up the pumping plate, the mutual influence in the process of composite stratum layout and compaction can be eliminated. According to the actual working conditions, each unit stratum box can be used to restore and stack the stratum; and a variety of cutterhead modules can be used to simulate the permeation law of large-diameter slurry shield machines with different cutterhead types in composite strata, and obtain the mud parameters at different permeation positions of the mud. The cutterhead form can be diversified, and the shield machine size can be increased as needed. The airbag is inflated by an air compressor to squeeze the pressure plate and simulate different cover thicknesses.

[0013] As a further improvement of the present invention, the draw plate is connected to a draw-and-push drive mechanism.

[0014] As a further improvement of the present invention, the pulling and pushing driving mechanism includes a gear and a motor, a transmission mechanism that can mesh with the gear is provided on one side of the pulling plate, and the motor is connected to the transmission mechanism through the gear. With this technical solution, the pulling plate is pulled out through the pulling and pushing driving mechanism, and the interference between the layers is smaller, so that the actual restoration and stacking of the layers can be better achieved.

[0015] As a further improvement of the present invention, the side wall of the simulation box is provided with scale lines, so that the penetration depth of the mud during the excavation process can be observed.

[0016] As a further improvement of the present invention, a plurality of earth pressure gauges and water pressure gauges are arranged in a matrix form on different planes in the simulation box to meet the test requirements.

[0017] As a further improvement of the present invention, the permeable hole is provided with a hole opening and closing mechanism, and the hole opening and closing mechanism is connected to a control switch; the opening and closing size of the permeable hole is controlled by the control switch, thereby simulating the permeation effect of mud with different opening rates.

[0018] As a further improvement of the present invention, the hole opening and closing mechanism includes a hole cover plate and an opening and closing drive mechanism, the opening and closing drive mechanism is connected to the hole cover plate, and drives the hole cover plate to cover or leave the infiltration hole; the opening and closing drive mechanism is electrically connected to the control switch.

[0019] As a further improvement of the present invention, the shield simulation module includes a plurality of shield simulation units, which are connected to each other in sequence and connected by a connecting and fixing mechanism, and a sealing ring is provided between adjacent shield simulation units. With this technical solution, rectangular shield machines of different sizes can be assembled through the connecting and fixing mechanism outside the module, and can be configured and arranged according to test requirements to simulate large-diameter shield machines of different shapes other than those mentioned above. The cutterhead can also be replaced with other types of different rectangular shield cutterheads according to test requirements to observe the film formation rules of different cutterhead types in the stratum.

[0020] As a further improvement of the present invention, the cutter disc includes an eccentric multi-axis cutter disc, an H&V shield cutter disc, a panel cutter disc or a spoke cutter disc.

[0021] As a further improvement of the present invention, the slurry pump is connected to a sliding mechanism, and the sliding mechanism drives the slurry pump to slide, so that the slurry samples extracted by the slurry pump from the slurry sampling tube inserted into the mud bin are placed in different sampling bottles, so that the basic properties of the mud (mud density, solid content and rheological properties) can be tested at different times and positions. Further, the sliding mechanism includes a slider, a slide rail and a sliding drive mechanism, and the sliding drive mechanism drives the slider to move on the slide rail. Further, the sliding drive mechanism is a motor.

[0022] As a further improvement of the present invention, a camera is provided on one side of the simulation box.

[0023] The present invention also discloses a method for simulating mud penetration of a large-diameter slurry shield machine, which uses a simulation device for slurry penetration of a large-diameter slurry shield machine as described in any one of the above items to perform a simulation test, comprising the following steps:

[0024] Step S1, determine the thickness of each stratum according to the geological survey report, select a stratum module with a set height, and make the guardrail height of the unit stratum box consistent with the stratum thickness;

[0025] Step S2, placing the corresponding soil in the unit formation box, burying the soil pressure gauge and the water pressure gauge, and then compacting; repeating this step until all the required formations are completed;

[0026] Step S3, stacking the corresponding unit formation boxes according to the formation sequence and placing them into the simulation box, and after installation, pulling out the drawer plate;

[0027] Step S4, placing a pressure plate and an air bag on the upper part of the stratum of the simulation box in sequence, covering it with a top plate, and inflating and pressurizing the air bag after calculating the required soil cover thickness until the upper soil of the simulation box is subjected to a pressure equal to that when the upper part is fully covered with soil;

[0028] Step S5, assembling the shield simulation module and adjusting the angle between the excavation surface and the horizontal plane;

[0029] Step S6, mix the mud in combination with the already arranged strata, put the prepared mud into the mud storage tank, and connect the mud storage tank to the mud injection mechanism; check the opening rate of the current test mud permeability hole and record it, and install a partition in the mud bin according to the test target so that the cutter head area meets the test requirements;

[0030] Step S7, setting up a camera and aiming it at the formation simulation box;

[0031] Step S8, start the shield motor to make the cutterhead cut the stratum, and at the same time start the mud injection mechanism connected to the gas storage tank to fill the mud bin with mud, observe the changes of each indicator until the boundary effect appears or the values ​​of each soil pressure gauge and water pressure gauge no longer change, then stop the test, which is a set of tests;

[0032] Step S9, obtaining multiple groups of mud samples at different positions by using a slurry pump for analysis, and analyzing the diffusion characteristics of the mud in the formation by combining the camera's recording and the data of the earth pressure gauge and the water pressure gauge in the formation simulation box.

[0033] As a further improvement of the present invention, step S8 also includes repeating steps S1 to S8 with varying factors to conduct multiple groups of tests; wherein the factors are soil layer characteristics, mud characteristics, overburden pressure, cutter head type and arrangement.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] By adopting the technical solution of the present invention, simulation tests can be conducted on the permeation law of slurry in composite formations of slurry shield machines with different cutterhead types for various cutterhead forms, and the mud parameters at different permeation positions of the slurry can be obtained. Multiple tests can be conducted under the same mud ratio conditions, and the difference in the permeation of slurry under composite formations during the excavation of slurry shield machines with large diameters and different cutterhead types can be clearly observed; at the same time, the mud permeability at different positions and the mud properties at different positions can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a schematic structural diagram of a device for simulating mud penetration of an assembled slurry shield machine in a composite stratum according to an embodiment of the present invention.

[0037] Figure 2 It is a schematic diagram of the structure of the shield simulation module of an embodiment of the present invention; wherein (a) is a stereogram, (b) is a front view, and (c) is a right view.

[0038] Figure 3 It is a schematic structural diagram of a unit formation box according to an embodiment of the present invention.

[0039] Figure 4 It is a schematic diagram of the combination of unit formation boxes in the simulation box according to an embodiment of the present invention.

[0040] Figure 5 The present invention is a schematic diagram of the structure of different arrangements and combinations of shield simulation modules according to an embodiment of the present invention; (a) and (b) are front views of different cutterhead surface arrangements, and (c) and (d) are side views of stepped arrangements.

[0041] Figure 6 Schematic diagrams of the structures of different cutter discs that can be selected in the embodiments of the present invention; (a) is an eccentric multi-axis cutter disc, (b) is an H&V shield cutter disc, (c) is a panel cutter disc, and (d) is a spoke cutter disc.

[0042] Reference numerals include:

[0043] 1-Rectangular shield simulation module, 2-Assembled mud injection module, 3-Assembled composite soil layer simulation module;

[0044] 11-mud bin, 12-rectangular cutter disc, 13-mud penetration hole, 14-mud pump, 15-sampling bottle, 16-slide rail, 17-sampling tube, 18-connecting mechanism;

[0045] 21-slurry storage tank, 22-air compressor, 23-air storage tank, 24-slurry delivery pipe;

[0046] 31 - simulation box, 32 - transparent organic glass, 33 - unit formation box, 34 - pumping plate, 35 - gear, 36 - conveyor belt, 37 - pressure plate, 38 - air bag, 39 - top plate, 40 - air compressor, 41 - soil pressure gauge and water pressure gauge. DETAILED DESCRIPTION

[0047] The preferred embodiments of the present invention are described in further detail below.

[0048] like Figure 1 As shown, a simulation device for mud penetration of an assembled slurry balance shield machine in a composite stratum includes a rectangular shield simulation module 1, an assembled mud injection module 2, an assembled composite soil layer simulation module 3 and a data acquisition module; the dotted line in the figure is the data line.

[0049] like Figure 2 As shown, the rectangular shield simulation module 1 is composed of a plurality of assembled shield simulation units connected, which are five shield simulation units in this embodiment. The five shield simulation units are connected to each other in sequence and fixedly connected by a connecting mechanism 18. A sealing ring is provided between adjacent shield simulation units to maintain the airtightness between adjacent units. The number and connection method of the shield simulation units can be set as needed.

[0050] The single shield simulation unit is a cube as a whole, which includes a mud bin 11, a shield motor, a rectangular cutter head 12 and a slurry collection mechanism. The rectangular cutter head 12 is installed on one side of the mud bin 11, and a mud penetration hole 13 is provided on the mud bin 11 behind the rectangular cutter head 12. The penetration hole is provided with a hole opening and closing mechanism, and the hole opening and closing mechanism is connected to the control switch; the opening and closing size of the penetration hole is controlled by the control switch, so as to simulate the penetration effect of mud with different opening rates. A flow meter is installed at each mud penetration hole 13, and the flow meter is connected to the data acquisition module, and the penetration amount of the mud during the grouting process can be recorded by controlling the computer. The slurry collection mechanism includes a slurry collection pump 14, a sampling tube 17, a sliding mechanism, and a sampling bottle 15. The slurry collection pump 14 is connected to the sampling tube 17; the slurry collection pump 14 is connected to the sliding mechanism, and the sliding mechanism drives the slurry collection pump 14 to slide, and the mud in the sampling tube 17 is extracted and placed in different sampling bottles 15. During the test, the sliding mechanism is controlled to drive the slurry pump 14 to slide, so that the slurry samples drawn by the slurry pump 14 from the sampling tube 17 inserted into the mud bin 11 are placed in different sampling bottles 15, so that the basic properties of the mud (mud density, solid content and rheological properties) can be tested at different times and locations.

[0051] Further, the sliding mechanism comprises a slider, a slide rail 16 and a sliding drive mechanism, and the sliding drive mechanism drives the slider to move on the slide rail 16. Further, the sliding drive mechanism is a motor.

[0052] Furthermore, the sampling bottles 15 are arranged side by side on one side of the slide rail 16 .

[0053] like Figure 1 , Figure 3 and Figure 4As shown, the assembled composite soil layer simulation module 3 includes a simulation box 31 without a cover, one side of the simulation box 31 is transparent organic glass 32, and a plurality of unit stratum boxes 33 are arranged in the simulation box 31. In order to eliminate the mutual influence during the arrangement and compaction of the composite stratum, a removable drawer plate 34 is provided at the bottom of each unit stratum box 33; a conveyor belt 36 that can be meshed with a gear 35 is installed on one side of the drawer plate 34, and the motor is connected to the conveyor belt 36 through the gear 35. Among them, the drawer plate 34 is made of thin steel plate. According to the actual working conditions, each unit stratum box 33 can be restored and stacked for actual stratum. A pressure plate 37 is provided on the top of the model box, and an air bag 38 is provided above the pressure plate 37, and a top plate 39 is provided above the air bag 38. The air bag 38 is connected to an air compressor 40, and the air compressor 40 can be adjusted by a computer to inflate, thereby squeezing the pressure plate 37 and simulating different soil cover thicknesses. The simulation box 31 is provided with a plurality of sets of soil pressure gauges and water pressure gauges 41 in a matrix form to meet the test requirements. The soil pressure gauges and water pressure gauges 41 are electrically connected to the data acquisition module. The formation simulation box 31 is marked with scale lines on the outside to observe the penetration depth of the mud during the excavation process.

[0054] like Figure 1 As shown, the assembled mud injection module 2 includes a slurry tank 21 and an air tank 23, the shield simulation unit is placed in the composite soil layer of the simulation box 31, the air tank 23 is connected to the slurry tank 21, the slurry tank 21 is connected to the mud infiltration hole 13 through a slurry delivery pipe 24, and the air tank 23 is connected to the air compressor 22.

[0055] like Figure 5 As shown, according to the test requirements, the modules can be connected through the connection devices outside to assemble into rectangular shield machines of different sizes. Figure 5 (a) and Figure 5 (b) is the front view of different cutter head layouts. Figure 5 (c) and Figure 5 (d) is a side view of a stepped arrangement, which can be configured and arranged according to the test requirements to simulate a large-diameter shield machine of a different shape than that mentioned above. In addition, the cutterhead of the shield machine can also be replaced with other types of rectangular cutterheads 12 according to the test requirements, such as Figure 6 As shown, an eccentric multi-axis cutterhead, an H&V shield cutterhead, a panel cutterhead or a spoke cutterhead can be used to observe the film formation rules of different cutterhead types in the formation.

[0056] The above test simulation device uses the following steps to simulate the slurry penetration of a large diameter slurry shield machine:

[0057] 1. Preparation before the test: prepare the auxiliary materials such as mud, soil samples, soil pressure gauge, pore water pressure gauge, etc. used for the test, and check whether all parts of the tester are normal, especially whether the air tightness of the device is good.

[0058] 2. Layout of composite strata: According to the actual development characteristics of the strata in the project area (sand type, thickness, particle size distribution, relative density, etc.), restore them in proportion to the strata simulation box. The specific operations are as follows:

[0059] Step 1: Determine the thickness of each layer according to the geological survey report, select a formation module with a suitable height, and make the guardrail height of the unit formation box consistent with the formation thickness.

[0060] Step 2: Place the corresponding soil in the unit stratum box, bury the soil pressure gauge and water pressure gauge, and then compact. Repeat this step until all the required strata are completed.

[0061] Step 3: stack them according to the order of the strata. After installation, start the motor connected to the conveyor belt of the drawer and slowly draw out the drawer (this process is very slow to reduce the impact on the bottom layer);

[0062] Step 4, after the pumping plate is pulled out, place the pressure plate and air bag in sequence on the upper part of the stratum, cover it with the top plate with the reserved inflation port, calculate the required covering thickness and then pressurize the air bag until the upper soil is subjected to the same pressure as when the upper part is fully covered with soil.

[0063] 3. Assembly of shield simulation modules: Select appropriate cutterhead and combination type according to test requirements, install multiple sets of shield simulation units, install sealing rings between shield simulation units (to maintain the airtightness between adjacent units), and connect them with bolts through connecting mechanisms. After the shield simulation modules are assembled, adjust the angle between the excavation surface and the horizontal plane, and then connect them through data connection lines to check the working conditions.

[0064] 4. Prepare mud: According to engineering experience and the already arranged strata, prepare the mud, put the prepared mud into the mud storage tank, check the sealing, and connect it to the gas storage tank. Check the opening rate of the current test mud penetration hole and record it. According to the test target, install partitions in the mud bin so that the cutter head area meets the test requirements.

[0065] 5. Configure monitoring equipment: set up the camera and aim it at the formation simulation box; check whether the control computer is sensitive and whether the data connection line is working properly.

[0066] 6. Test start: Turn on the shield motor to make the cutterhead cut the ground, and at the same time turn on the air compressor connected to the air tank to fill the mud bin with mud, and observe the soil pressure gauge and water pressure gauge. Changes The test is stopped until the boundary effect appears or the values ​​of the indicators no longer change. This is a set of tests.

[0067] 7. Control test: Change the soil layer characteristics, mud characteristics, overburden pressure, shield cutter head type and arrangement, etc., repeat the above steps, and conduct multiple groups of tests.

[0068] 8. End of the test: Obtain multiple groups of mud samples at different locations for analysis, and combine the records of the full-process photography system and the data of the soil pressure gauge and water pressure gauge in the formation simulation box to analyze the diffusion characteristics of the mud in the formation.

[0069] To sum up, the technical scheme described in the present invention can simulate the process of mud infiltration into composite formations during the construction of large-diameter slurry shields with various cutterhead types, and can realize real-time monitoring of the changes in pore water pressure in the soil layer, the amount of mud infiltration and the depth morphology during the mud penetration process, and the operation is simple and convenient. The present invention brings complex engineering problems into the laboratory and conducts systematic research to provide a basis for improving the stability of the excavation face of large-diameter slurry shields in actual engineering.

[0070] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A simulation device for mud penetration of an assembled slurry shield machine in a composite stratum, characterized in that: It includes a shield simulation module, an assembled mud injection module, an assembled composite soil layer simulation module and a data acquisition module; The shield simulation module includes at least one assembled shield simulation unit, the shield simulation unit includes a mud bin, a shield motor and a cutterhead, the shield motor is connected to the cutterhead, the cutterhead is arranged on one side of the mud bin, and the mud bin is provided with a plurality of penetration holes; the penetration holes are provided with a flow meter electrically connected to the data acquisition module; A slurry collection mechanism is provided outside the mud bin, the mud bin is connected to a sampling tube, the slurry collection mechanism comprises a slurry collection pump, and the slurry collection pump is connected to the sampling tube; The assembled composite soil layer simulation module comprises a simulation box without a cover, one side of the simulation box is a transparent plate, a plurality of unit stratum boxes are arranged in the simulation box, and a removable drawer plate is arranged at the bottom of each unit stratum box; A pressure plate is provided on the top of the simulation box, an air bag is provided above the pressure plate, a top plate is provided above the air bag, the air bag is connected to an air compressor, a plurality of soil pressure gauges and water pressure gauges are provided in the simulation box, and the soil pressure gauges and water pressure gauges are electrically connected to a data acquisition module; The assembled mud injection module comprises a mud storage tank and a mud injection mechanism, the shield simulation unit is placed in the composite soil layer of the simulation box, and the mud injection mechanism connects the mud storage tank and the mud penetration hole.

2. The device for simulating mud penetration of an assembled slurry shield machine in a composite stratum according to claim 1, characterized in that: The draw plate is connected to a draw-and-push driving mechanism; the draw-and-push driving mechanism comprises a gear and a motor, a transmission mechanism which can mesh with the gear is provided on one side of the draw plate, and the motor is connected to the transmission mechanism via the gear.

3. The device for simulating mud penetration of an assembled slurry shield machine in a composite stratum according to claim 2, characterized in that: The side wall of the simulation box is provided with scale lines.

4. The device for simulating mud penetration of an assembled slurry shield machine in a composite stratum according to claim 1, characterized in that: The slurry pump is connected to a sliding mechanism, and the sliding mechanism drives the slurry pump to slide, so as to extract the slurry in the sampling tube and place it into different sampling bottles.

5. The device for simulating mud penetration of an assembled slurry shield machine in a composite stratum according to claim 1, characterized in that: Multiple earth pressure gauges and water pressure gauges are arranged in a matrix form on different planes in the simulation box.

6. The device for simulating mud penetration of an assembled slurry shield machine in a composite stratum according to claim 1, characterized in that: The infiltration hole is provided with a hole opening and closing mechanism, and the hole opening and closing mechanism is connected to the control switch.

7. The device for simulating mud penetration of an assembled slurry shield machine in a composite stratum according to claim 1, characterized in that: The shield simulation module comprises a plurality of shield simulation units, which are connected to each other in sequence and fixedly connected by a connecting and fixing mechanism, and sealing rings are arranged between adjacent shield simulation units.

8. The device for simulating mud penetration of an assembled slurry shield machine in a composite stratum according to claim 1, characterized in that: A camera is provided on one side of the simulation box; the cutter disc includes an eccentric multi-axis cutter disc, an H&V shield cutter disc, a panel cutter disc or a spoke cutter disc.

9. A method for simulating mud penetration of an assembled slurry shield machine in a composite stratum, characterized in that: The device for simulating mud penetration of an assembled slurry shield machine in a composite stratum according to any one of claims 1 to 8 is used, and comprises the following steps: Step S1, determine the thickness of each stratum according to the geological survey report, select a stratum module with a set height, and make the guardrail height of the unit stratum box consistent with the stratum thickness; Step S2, placing the corresponding soil in the unit formation box, burying the soil pressure gauge and the water pressure gauge, and then compacting; repeating this step until all the required formations are completed; Step S3, stacking the corresponding unit formation boxes according to the formation sequence and placing them into the simulation box, and after installation, pulling out the drawer plate; Step S4, placing a pressure plate and an air bag on the upper part of the stratum of the simulation box in sequence, covering it with a top plate, and inflating and pressurizing the air bag after calculating the required soil cover thickness until the upper soil of the simulation box is subjected to a pressure equal to that when the upper part is fully covered with soil; Step S5, assembling the shield simulation module and adjusting the angle between the excavation surface and the horizontal plane; Step S6, mix the mud in combination with the arranged stratum, put the prepared mud into the mud storage tank, and connect the mud storage tank to the mud injection mechanism; check and record the opening rate of the current test mud penetration hole, and install multiple shield modules according to the test target so that the cutterhead area meets the test requirements; Step S7, setting up a camera and aiming it at the formation simulation box; Step S8, start the shield motor to make the cutterhead cut the stratum, and at the same time start the mud injection mechanism connected to the gas storage tank to fill the mud bin with mud, observe the changes of various indicators, and stop the test until the boundary effect appears or the values ​​of the earth pressure gauge and the water pressure gauge no longer change. This is a set of tests; Step S9, obtaining multiple groups of mud samples at different positions by using a slurry pump for analysis, and analyzing the diffusion characteristics of the mud in the formation by combining the camera's recording and the data of the earth pressure gauge and the water pressure gauge in the formation simulation box.

10. The method for simulating mud penetration of an assembled slurry shield machine in a composite stratum according to claim 9, characterized in that: Step S8 also includes repeating steps S1 to S8 with varying factors to conduct multiple groups of tests; wherein the factors are soil layer characteristics, mud characteristics, overburden pressure, cutterhead type and arrangement.

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