A shield cutter adhesion test device coupled with electroosmosis-rotation-drawing

Abstract

The present application relates to the technical field of shield tunneling, and discloses a device for adhesion test of shield cutterhead by coupling electroosmosis, rotation and pulling, which comprises a soil sample box for containing soil samples, a pulling system for providing vertical pulling movement, a sliding table driven by the pulling system, a rotating system fixed on the sliding table, a cutterhead assembly driven by the rotating system, an electroosmosis system for applying a controllable electric field between the cutterhead assembly and the soil samples, and a data acquisition and control system connected with the above-mentioned systems. The device integrates pulling, rotation, electroosmosis and measurement and control functions, applies electroosmosis technology to the adhesion reduction and anti-mud cake of the shield cutterhead interface, and combines with the existing spoil improvement technology, so that the process of electroosmosis adhesion reduction, rotation shearing and pulling detachment can be continuously completed in one test, thereby providing reliable test basis and theoretical support for the anti-mud cake of the cutterhead, the electroosmosis assisted adhesion reduction and the optimization of spoil improvement parameters in the shield construction process.

Description

Technical Field

[0001] This invention relates to the field of tunnel boring machine (TBM) technology, and in particular to a test device for TBM cutterhead adhesion using electroosmosis-rotation-pull-out coupling. Background Technology

[0002] Shield tunneling, with its advantages of high mechanization, good safety performance, and minimal susceptibility to environmental interference, has become a key construction technology in urban underground space development and tunnel engineering. However, when tunneling in highly cohesive strata, soil adhesion easily occurs on the surfaces of the shield cutterhead, soil chamber, and screw conveyor system. The accumulated soil on the cutterhead surface forms a "mud cake," which not only significantly reduces the cutterhead's cutting efficiency but can also cause problems such as poor muck removal from the soil chamber, blockage of the screw conveyor, and even serious engineering failures.

[0003] To address the mud cake problem, mechanical flushing and chemical soil amendment are commonly used methods in engineering projects. While mechanical flushing can partially remove the attached soil, it suffers from drawbacks such as discontinuous operation, limited cleaning range, delayed treatment, and interference with construction space. Chemical soil amendment technology injects foaming agents, dispersants, and other amendment materials into the excavation face or soil chamber to transform highly cohesive soil into a plastic state with a certain degree of fluidity, thereby reducing the adhesion between the soil and equipment interface. Although this method is widely used, it still faces challenges such as high consumption of chemicals, high cost, and complex effects on soil properties.

[0004] In recent years, electroosmosis technology, as a method for regulating soil moisture and interfacial properties based on an applied electric field, has been widely studied in fields such as soft soil foundation reinforcement and soil dehydration. For cohesive soils, the electric field can drive the directional migration of pore water and ions, changing the local water content and particle arrangement of the soil, thereby affecting the water film thickness and contact state at the soil-metal interface, thus reducing the adhesion between clay and metal. Therefore, applying electroosmosis technology to reduce adhesion and prevent mud cake at the cutterhead interface of tunnel boring machines, and combining it with existing slag improvement technologies, holds promise for providing a new technical approach.

[0005] However, existing research mainly focuses on the consolidation and reinforcement mechanisms of electroosmotic drainage and the macroscopic mechanical properties of the improved soil. Studies on the adhesion behavior at the clay-cutterhead interface under electroosmosis are still relatively limited. In particular, the electrode arrangement (such as position, spacing, and polarity combination) directly affects the electric field distribution, seepage path, and interfacial response, thus significantly influencing adhesion force. However, specialized experimental equipment and evaluation methods are currently lacking. Conventional electroosmosis tests often place the cathode and anode on opposite sides of the soil sample, which differs significantly from the electrode arrangement conditions in actual shield tunneling. Therefore, there is an urgent need to develop electrode arrangement schemes that more closely reflect engineering realities and to systematically study the impact of different arrangement methods on the viscosity reduction effect of electroosmosis.

[0006] On the other hand, current experimental methods for studying the adhesion properties of soil-structure interfaces mainly include direct shear tests, interfacial friction tests, and pull-out tests. These methods mostly only measure normal adhesion force or shear strength under static conditions, failing to consider the rotational cutting effect during the actual tunneling process of the shield cutterhead. Furthermore, existing devices generally lack coupled electric field effects, making it impossible to compare the interfacial adhesion performance before and after electroosmosis treatment, thus failing to accurately reflect the interfacial behavior under electroosmosis-mechanical coupling conditions.

[0007] In summary, existing technologies lack a comprehensive experimental device capable of simultaneously simulating rotary cutting, electroosmosis, and pull-out adhesion, making it impossible to systematically study the influence of different electrode arrangements on the tangential and normal adhesion forces at the clay-cutterhead interface under controllable conditions. Therefore, developing a shield cutterhead adhesion experimental device with multi-field coupling of electroosmosis, rotation, and pull-out is of significant theoretical and engineering importance for revealing the electroosmosis viscosity reduction mechanism, optimizing electrode arrangement schemes, and improving the tunneling efficiency of shields in cohesive strata. Summary of the Invention

[0008] The purpose of this invention is to provide a shield cutterhead adhesion test device with electroosmosis-rotation-pull-out coupling to solve the above-mentioned technical problems existing in the prior art.

[0009] To achieve the above objectives, the present invention provides the following solution: a shield cutterhead adhesion test device with electroosmosis-rotation-pull-out coupling, comprising: a soil sample box, mounted on a support base, for holding soil samples; a pull-out system, fixed to the support base, providing vertical pull-out motion and driving the slide table to rise and fall; a slide table, connected to the power output end of the pull-out system; a rotation system, fixedly mounted on the slide table, providing rotational motion and driving the cutterhead assembly to rotate; a cutterhead assembly, connected to the power output end of the rotation system, simulating a shield cutterhead and contacting the soil sample; an electroosmosis viscosity reduction system, the electrical output end of which is connected to the cutterhead assembly and an anode arranged on the cutterhead assembly, respectively, for applying a controllable electric field between the cutterhead assembly and the soil sample; and a data acquisition and control system, connected to the pull-out system, rotation system, and electroosmosis viscosity reduction system.

[0010] Optionally, the drawing system includes a drawing servo motor, a first coupling, a linear screw, a vertical guide rail, and a slider assembly; the drawing servo motor drives the linear screw to rotate through the first coupling; the slider assembly is threadedly engaged with the linear screw and slidably connected to the vertical guide rail; the slide table is fixedly connected to the slider assembly.

[0011] Optionally, the rotation system includes a rotary servo motor, a second coupling, and a rotary spindle; the rotary servo motor is fixed on the slide, and its output shaft is connected to the rotary spindle through the second coupling.

[0012] Optionally, the cutter head assembly includes an insulating rod and a simulated cutter head; the upper end of the insulating rod is connected to the lower end of the rotating spindle; the upper end of the simulated cutter head is detachably connected to the lower end of the insulating rod.

[0013] Optionally, the simulated cutter head includes a hollow connecting rod and cutter head spokes fixed thereon; the cutter head spokes are provided with a plurality of anode holes for inserting anode rods; the anode holes communicate with the inner cavity of the hollow connecting rod through channels inside the cutter head spokes.

[0014] Optionally, the electroosmotic viscosity reduction system includes a programmable DC regulated power supply, an anode, a cathode, and a conductive slip ring; the anode includes an anode rod that can be inserted into the anode hole; the cathode is formed by the simulated cutter head; the conductive slip ring is disposed at the connection between the simulated cutter head and the hollow connecting rod, and is used to maintain the electrical circuit conduction when the cutter head rotates.

[0015] Optionally, an insulating ring is provided between the anode rod and the anode hole, the height of which is higher than the thickness of the simulated cutter head and lower than the length of the anode rod.

[0016] Optionally, the anode rods are arranged on the spokes of the simulated cutterhead according to a preset arrangement scheme; the preset arrangement scheme includes at least one of inner ring arrangement, inner and outer double ring arrangement, inner and outer symmetrical arrangement, or inner and outer offset arrangement.

[0017] Optionally, the cutterhead spokes are provided with removable end plates, and the opening ratio of the simulated cutterhead can be adjusted by replacing or adding / removing the removable end plates.

[0018] Optionally, the data acquisition and control system includes a torque sensor and an S-force sensor, which are mounted on the rotating spindle.

[0019] Compared with the prior art, the present invention discloses at least the following beneficial effects: This invention integrates a pull-out system, a rotation system, and a data acquisition and control system to construct a comprehensive test platform capable of realistically simulating the tunneling conditions of a shield cutterhead in cohesive strata. Furthermore, it integrates an electroosmotic viscosity reduction system, providing a new technical means for cutterhead mud cake prevention. The device achieves precise vertical displacement and desorption of the cutterhead assembly through the pull-out system, and drives the cutterhead to simulate actual cutting motion through the rotation system. The combination of these two systems allows the experiment to synchronously or sequentially reproduce the rotational shearing of the cutterhead in the soil and the subsequent pull-out separation process, thus more realistically reflecting the dynamic mechanical behavior of the cutterhead-soil interface during shield tunneling. Based on this, the electroosmotic viscosity reduction system integrated into the cutterhead assembly can directly apply a controllable electric field to the cutterhead-soil contact interface, achieving in-situ coupling of electroosmotic and mechanical effects. This allows for direct and real-time study of the influence of the electric field on the interface adhesion characteristics. The entire experimental process is uniformly coordinated and monitored by the data acquisition and control system, ensuring the synchronous acquisition and high-precision control of rotation parameters, pull-out parameters, electroosmotic parameters, and measured data such as torque and axial force. This integrated structural design enables the device to continuously complete multiple stages such as electroosmosis treatment, rotational shearing, and pull-out desorption in a single test. This avoids the interface disturbances and errors caused by changing devices or conducting step-by-step tests in traditional methods, significantly improving test efficiency, data consistency, and the reliability of results. It provides an effective technical means for in-depth research on the adhesion behavior of shield cutterheads under the electroosmosis-mechanical coupling mechanism. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall structure of the test apparatus provided in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the connection between the bottom of the soil sample box and the base in an embodiment of the present invention; Figure 3 For the present invention Figure 1 A magnified view of a section at point A in the middle; Figure 4 For the present invention Figure 3 A magnified view of a section at point B in the middle; Figure 5 This is a diagram showing the layout scheme of the simulated cutterhead anode holes in an embodiment of the present invention, wherein (a) is the inner ring layout, (b) is the inner and outer double ring layout, (c) is the inner and outer symmetrical layout, and (d) is the inner and outer offset layout; Figure 6A schematic diagram of a simulated cutterhead with other aperture ratios provided by the present invention; Figure 7 Schematic diagram of other blade spoke ratios provided by the present invention; Figure 8 This is a comparison diagram of tangential adhesion forces in different embodiments of the present invention; Figure 9 This is a comparison diagram of the normal adhesion forces in different embodiments of the present invention; Figure 10 This is a comparison chart of the amount of material adhering to the cutter head under different electrode arrangement schemes according to the present invention.

[0022] Reference numerals: 1. Support base; 2. Soil sample box; 3. Pulling system; 4. Slide table; 5. Rotation system; 6. Cutter head assembly; 7. Electroosmosis viscosity reduction system; 9. Eccentric groove structure; 10. Pulling servo motor; 11. First coupling; 12. Linear lead screw; 13. Vertical guide rail; 14. Slider assembly; 15. Rotary servo motor; 16. Second coupling; 17. Rotary spindle; 18. Insulating rod; 19. Simulated cutter head; 20. Hollow connecting rod; 21. Cutter head spokes; 22. Programmable DC regulated power supply; 23. Anode; 24. Anode rod; 25. Wire; 26. Insulating ring; 27. Cathode; 28. Conductive slip ring; 29. ​​Torque sensor; 30. S-shaped force sensor; 31. Pulling servo driver; 32. Rotary servo driver; 33. Control console; 34. Removable sealing plate. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1 Reference Figures 1 to 10 As shown in the figure, this embodiment provides a shield cutterhead adhesion test device with electroosmosis-rotation-pull-out coupling. It is mainly used to study the influence of electroosmosis on the adhesion behavior of clay-cutterhead interface under the mechanical conditions of simulating the actual rotation cutting and pull-out of shield cutterhead. It is especially suitable for evaluating the influence of different electrode arrangements on the interface adhesion reduction effect.

[0026] The experimental apparatus includes a support base 1, a soil sample box 2, a pull-out system 3, a slide table 4, a rotation system 5, a cutter head assembly 6, an electroosmosis viscosity reduction system 7, and a data acquisition and control system.

[0027] The support base 1 is the basic mounting platform for the entire device, used to fix and support each subsystem. The soil sample box 2 is installed on the upper part of the support base 1 and is used to hold the test soil sample. The soil sample box 2 is preferably made of transparent or semi-transparent insulating material (such as plexiglass) to facilitate observation of the soil sample state, moisture migration around the electrodes, and interface changes during the pull-out process of the simulated cutter head 19.

[0028] Based on the above embodiments, the support base 1 is further provided with an eccentric groove structure 9 at its center, and the bottom of the soil sample box 2 is locked to the base through the eccentric groove structure 9. This connection method facilitates the quick installation and disassembly of the soil sample box 2, and effectively prevents displacement caused by force or vibration during the test, ensuring the stability and repeatability of the test.

[0029] The pulling system 3 is fixed to the upper part of the support base 1, preferably by bolts to the rear side of the base. Its function is to provide precise and controllable vertical tension and displacement to simulate the separation process between the cutter head 19 and the soil sample. The pulling system 3 includes a pulling servo motor 10, a first coupling 11, a linear screw 12, a vertical guide rail 13, and a slider assembly 14. The pulling servo motor 10 is fixed to the base via a motor support, and its drive shaft is vertically upward. The first coupling 11 connects the end of the drive shaft to the power input end of the linear screw 12, preferably using an elastic coupling or a diaphragm coupling to compensate for installation deviations, absorb vibration, and ensure a smooth pulling process. The linear screw 12 is coaxially connected to the motor via the first coupling 11. The vertical guide rail 13 is symmetrically arranged behind the linear screw 12 and parallel to it. The slider assembly 14 has an internal threaded structure that mates with the linear lead screw 12 and slides with the vertical guide rail 13 to achieve precise linear lifting and lowering motion. The slide table 4 is fixedly connected to the slider assembly 14 by bolts, thus moving together with the slider assembly 14.

[0030] The rotary system 5 is fixedly connected above the slide table 4 and rises and falls synchronously with the slide table 4. The rotary system 5 includes a rotary servo motor 15, a second coupling 16, and a rotary spindle 17. The rotary servo motor 15 is fixedly mounted on the slide table 4, and its output shaft passes downward through a through hole in the center of the slide table 4. The second coupling 16 is used to connect the output shaft of the rotary servo motor 15 and the rotary spindle 17 to ensure the coaxiality and smoothness of power transmission.

[0031] The cutterhead assembly 6 is connected to the output end of the rotating system 5 and is used to simulate the shield cutterhead. It includes an insulating rod 18 and a simulated cutterhead 19. The insulating rod 18 is made of high-strength insulating material (such as glass fiber reinforced nylon, PEEK, etc.), and its upper end is threaded to the lower end of the rotating spindle 17 to transmit axial force and torque. The upper end of the simulated cutterhead 19 is threaded to the lower end of the insulating rod 18 and can be replaced according to test requirements (such as different aperture ratios and different electrode layout schemes). The simulated cutterhead 19 specifically includes a hollow connecting rod 20 and cutterhead spokes 21. The hollow connecting rod 20 is a hollow tubular structure, with wires 25 threaded through it. The cutterhead spokes 21 are preferably four-spoke in shape, with several through-hole electrode insertion holes for inserting anode rods 24. The electrode insertion holes are connected to the hollow structure of the hollow connecting rod 20 through channels machined inside the cutterhead spokes 21, facilitating the laying and concealment of the wires 25 of the anode 23 and preventing entanglement. Furthermore, a removable sealing plate 34 can be bolted to the cutterhead spokes 21. By replacing or adding / removing the sealing plate, the opening ratio of the simulated cutterhead 19 can be easily adjusted (e.g., within the range of 30%-60%) to adapt to the actual parameters of different tunnel boring projects.

[0032] The electroosmotic viscosity reduction system 7 is used to apply a controllable electric field at the interface between the simulated cutterhead 19 and the soil. Its electrical output terminals are connected to the cutterhead assembly 6 and the anode rods 24 arranged on the simulated cutterhead 19. Specifically, the electroosmotic viscosity reduction system 7 includes a programmable DC regulated power supply 22, an anode 23, a cathode 27, and a conductive slip ring 28. The programmable DC regulated power supply 22 is signal-connected to the control console 33 and is used to output, adjust, and record electrical parameters such as voltage, current, and power in real time. The anode 23 includes an anode rod 24 inserted into the electrode socket of the simulated cutterhead 19. The anode rod 24 is connected to the anode 23 of the power supply via a wire 25. An insulating ring 26 is provided between the anode rod 24 and the electrode socket. The height of the insulating ring 26 is slightly higher than the thickness of the simulated cutterhead 19 but lower than the length of the anode rod 24, which ensures both insulation and effective contact between the anode rod 24 and the soil sample. The cathode 27 is formed by the simulated cutterhead 19 itself and is connected to the cathode 27 of the power supply via a wire 25. The conductive slip ring 28 is installed at the connection between the simulated cutter head 19 and the hollow connecting rod 20. Its function is to maintain the continuous conduction of the electrical circuit between the external power supply and the rotating cutter head / anode 23 when the simulated cutter head 19 rotates with the rotating system 5, and to effectively prevent the wire 25 from getting tangled during rotation.

[0033] In a preferred embodiment, to systematically study the influence of electrode arrangement on the electroosmotic viscosity reduction effect, the arrangement of the anode rods 24 on the simulated cutterhead 19 can be varied in several ways. For example... Figure 5 As shown, it demonstrates four typical layout schemes: inner circle layout ( Figure 5a), that is, all anode rods 24 are concentrated and installed near the center of the cutter head; double-ring arrangement (inner and outer rings) Figure 5 b), the anode rod is evenly distributed in two concentric rings, 24 points in total; symmetrically arranged inside and outside ( Figure 5 c), the inner and outer anode rods 24 are arranged symmetrically in the radial direction; and they are arranged with internal and external offsets ( Figure 5 d) The inner and outer anode rods 24 are offset at a certain angle in the circumferential direction. These different layout schemes can simulate different electrode arrangement strategies in actual engineering. Through comparative experiments, the influence of electric field distribution on the reduction effect of interfacial adhesion can be quantitatively analyzed.

[0034] The data acquisition and control system is responsible for monitoring and synchronously acquiring data throughout the entire testing process. It includes a torque sensor 29, an S-shaped force sensor 30, a drawing servo driver 31, a rotary servo driver 32, and a control console 33. The torque sensor 29 is fixed to the upper part of the rotating spindle 17 and is used to monitor and transmit torque data during the rotation of the cutter head in real time. The S-shaped force sensor 30 is fixed to the lower part of the rotating spindle 17 and is used to monitor and transmit axial force (normal adhesion force) data experienced by the cutter head during the drawing process in real time. The drawing servo driver 31 and the rotary servo driver 32 are respectively connected between the corresponding servo motors and the control console 33, used to receive control commands, precisely control the motor's motion state (such as speed, stroke, start / stop), and feed back the motor's operating data to the control console 33. The control console 33 (such as an industrial computer or PLC) is electrically and / or signal connected to the pull-out servo driver 31, the rotary servo driver 32, and the programmable DC regulated power supply 22, respectively. It is used to uniformly control the rotation and pull-out test parameters (such as rotation speed, time, and pull-out speed) and electroosmosis parameters (such as voltage, current, and energizing time), and to record, display, and store all physical, mechanical, and electrical parameters (such as torque, axial force, voltage, and current) collected during the test in real time, providing a complete dataset for subsequent data analysis.

[0035] It should be understood that in practical applications, the specific dimensions of the above-mentioned device, the power and accuracy of the servo motor used, the range and accuracy of the sensor, the specifications of the power supply, and other parameters can be selected and adjusted according to specific test requirements (such as soil sample size, diameter of the simulated cutterhead 19, required loading force range, etc.). These are all conventional design choices that can be made by those skilled in the art based on actual conditions and do not depart from the protection scope of this invention.

[0036] To more clearly illustrate the experimental process of this invention, the working principle of the experimental apparatus in this embodiment is explained below: First, the prepared remolded clay or undisturbed soil sample is filled into the soil sample box 2 and compacted to a predetermined density and moisture content. According to the test plan, a specific simulated cutterhead 19 (including a specific opening ratio and electrode layout scheme) is selected and installed on the insulating rod 18, and the anode rod 24 is inserted into the corresponding electrode socket according to the selected scheme. The pulling system 3 is controlled by the control console 33 to lower the simulated cutterhead 19 until it is in full contact with the soil sample surface and a preset contact pressure is applied. Then, the programmable DC regulated power supply 22 is turned on, and a preset DC voltage is applied between the simulated cutterhead 19 (cathode) and the anode rod 24 (anode) to perform electroosmosis treatment on the soil. After a predetermined treatment time (or simultaneously with electroosmosis treatment), the rotation system 5 is started, driving the simulated cutterhead 19 to rotate at a set speed for a certain time or number of revolutions, simulating the cutting process of the shield cutterhead. The torque sensor 29 records the torque changes. After rotation, the pull-out system 3 is immediately activated to pull the simulated cutterhead 19 vertically upward at a constant speed, separating it from the soil sample. The S-shaped force sensor 30 simultaneously records the pull-out force-displacement curve, with the peak value representing the normal adhesion force under this condition. Throughout the process, the control console 33 simultaneously records time, voltage, current, torque, and pull-out force data. By comparing and analyzing data under different electroosmotic parameters, electrode layout schemes, and rotation parameters, the influence of electroosmotic-rotation coupling on the adhesion behavior of the shield cutterhead interface can be systematically studied.

[0037] Example 2 (Control group, no electroosmosis) The following section, using a specific experimental procedure, further illustrates the detailed working process of the shield cutterhead adhesion test device with electroosmosis-rotation-pull-out coupling described in Embodiment 1: S1. Test Preparation: Prepare a pre-made cohesive soil sample. Select the clay to be tested, mix it according to the experimental design ratio, and stir evenly. Then add water at the predetermined moisture content and stir evenly. The moisture content range is preferably 20%-60%. Under some test conditions, foaming agents, anti-cohesion agents, or other soil amendments can be added during the stirring process. The concentration of the amendment is preferably 0%-5%. After mixing, seal the soil sample and let it stand for 24 hours to ensure uniform moisture distribution and the formation of a stable structure. Fill the prepared cohesive soil sample into the soil sample box 2 and compact it to the predetermined density and moisture content. Fix the soil sample box 2 to the support base 1 through the eccentric groove structure 9.

[0038] S2. Electrode Layout and Installation: According to the test plan (e.g., inner ring, double ring layout, etc.), see [reference needed]. Figure 5 Insert the anode rod 24 into the corresponding electrode socket of the simulated cutter head 19 and secure it with an insulating ring 26. Then, mount the simulated cutter head 19 onto the rotating spindle 17 via the insulating rod 18.

[0039] S3. Cutterhead Preloading: Open the control system to set the test parameters, start the pull-out system 3, and slowly lower the rotating system 5 and cutterhead assembly 6 along with the slide table 4 until the cutterhead surface is in full contact with the soil sample, allowing the cutterhead to penetrate into the soil. Maintain the preset penetration depth (e.g., 1.5 mm) to ensure a stable clay-metal interface and effectively eliminate the influence of initial soil stress. During this stage, the signal measured by the S-type force sensor 30 is a compressive stress signal. Maintain this state for approximately 10 minutes to allow sufficient interfacial adhesion to form.

[0040] S4. Rotational Shear Test: The rotary servo motor 15 is started via the control console 33 to drive the simulated cutterhead 19 to rotate at a set speed, simulating the actual cutting process of the shield cutterhead. The rotational speed is preferably 0-10 r / min. Simultaneously, the advance speed is controlled by the pulling system 3, preferably 0-10 mm / min. During the test, the torque is detected and recorded by the torque sensor 29, and the changes in the interface soil sample during rotation are recorded using a high-speed camera. The rotational shear test ends after 5 minutes.

[0041] S5. Pull-out test: Start the pull-out system 3 and slowly raise the slide 4 until the normal force at the clay-cutterhead interface approaches zero (the S-type force sensor 30 reading returns to zero), then stop the movement to eliminate the compressive stress generated during the downward pressing process. Return the displacement to zero, and restart the pull-out system 3 to raise the cutterhead at a constant speed of 0-0.3 mm / s. Record the change in tension P during this process using the S-type force sensor 30 until the cutterhead is completely detached from the soil sample, ending the pull-out test.

[0042] S6. Data Acquisition and Analysis: Throughout the experiment, console 33 synchronously acquires and stores data such as electroosmosis parameters (voltage, current), mechanical parameters (torque, axial force), and time. By comparing and analyzing torque and pull-out force data under different conditions (with and without electroosmosis, different electrode layout schemes, and different rotation parameters), the influence of electroosmosis technology on the adhesion force at the shield cutterhead interface can be quantitatively evaluated. After the experiment, the instrument is returned to its original position, the data is saved, the cutterhead is removed, the adhesion at the contact interface is observed and the adhesion amount is recorded, the soil sample inside soil sample box 2 is cleaned, the experiment is completed, and the device is restored to its initial state.

[0043] Example 3 (Electroosmosis Improvement Group) This embodiment provides a method for conducting tests using the shield cutterhead adhesion test device with electroosmosis-rotation-pull-out coupling described in Embodiment 1, to measure the influence of electroosmosis modification on the adhesion force of the clay-cutterhead interface under different electrode layout schemes. The test steps of the electroosmosis modification group in this embodiment are basically the same as those of the control group test in Embodiment 2, and further: When S3 forms a stable clay-metal interface, according to... Figure 5The electrode layout shown inserts the lower end of the anode rod 24 into the pre-reserved position of the electrode socket. The insertion depth of the anode rod 24, its spatial position on the cutter head, or the symmetrical / asymmetrical electrode arrangement can be adjusted according to experimental requirements to create different electrode layout patterns. The upper end of the anode rod 24 is connected to the anode 23 end of the programmable DC regulated power supply 22 via a wire 25, while the simulated cutter head 19 body is connected to the cathode 27 via a wire 25. After installation, the stability and insulation of the electrode connections are checked.

[0044] Electroosmosis treatment stage: The programmable DC regulated power supply 22 is turned on, and an electroosmosis test is conducted under a set voltage gradient or current intensity. A preset DC voltage is applied between the simulated cutterhead 19 (cathode) and the anode rod 24 (anode) to perform electroosmosis treatment. During this process, pore water undergoes directional migration under the action of the electric field, changing the water content and microstructure at the cutterhead-soil interface. Specifically, the changes in current, voltage, and duration are recorded during the energization process, and possible water migration or interface changes within the soil sample are observed.

[0045] After the preset energizing time is reached, the electroosmosis-pull-out test stage is entered. The pull-out test is carried out according to the method described in Example 2, and the pull-out force-displacement curve is recorded.

[0046] Based on the requirements, the experiment was conducted using a method of simultaneous energization, rotation, and pull-out. Under the influence of electroosmosis, the rotation system 5 was activated, causing the simulated cutterhead 19 to rotate and shear in the soil, simulating the tunneling state of the shield cutterhead under electroosmotic viscosity reduction conditions. During the experiment, torque-time, current-time, and other data were collected in real time, and changes in interface morphology were observed.

[0047] Finally, the collected torque-time, pull-out force-displacement, and current-time variation curves, as well as the parameters under different test conditions, were processed and key indicators such as tangential adhesion force, normal adhesion force, residual pull-out force, and desorption displacement were extracted. The variation characteristics of adhesion force under different electrode arrangements were also compared.

[0048] The shear strength of the soil against the metal in the tangential direction is defined as the tangential adhesion force, denoted by F. T Represented as:

[0049] In the formula: F T denoted as tangential adhesion force at the interface, T as instantaneous rotational torque, and D as the diameter of the cutter head.

[0050] The tensile strength of soil perpendicular to the contact surface between metals is defined as the normal adhesion force, denoted by F. N Represented as: F N =P / A.

[0051] In the formula: P is the maximum pull-out force that separates the cutter head from the soil sample contact surface in the vertical direction; A is the contact area in the vertical direction.

[0052] By combining the changes in sample moisture content, metal surface condition, interface failure morphology, and electrical parameters, the mechanism by which electrode arrangement affects the adhesion force at the clay-metal interface is analyzed. This allows for the evaluation of the adhesion reduction and desorption effects of electroosmosis under different strata and cutterhead during shield tunneling, providing a basis for determining a better electrode arrangement scheme.

[0053] like Figures 8 to 10 As shown, after electroosmosis modification, the normal and tangential adhesion forces and the amount of cutterhead adhesion at the clay-cutterhead interface are significantly reduced. The electrode placement position has a significant impact on the adhesion at the cutterhead interface, and electroosmosis has a significant effect on reducing adhesion and desorption at the clay-cutterhead interface.

[0054] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0055] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A test device for shield tunnel cutterhead adhesion using electroosmosis-rotation-pull-out coupling, characterized in that, include: A soil sample box (2) is installed on a support base (1) and is used to hold soil samples; The pulling system (3) is fixed to the support base (1) to provide vertical pulling motion and drive the slide (4) to rise and fall; The slide (4) is connected to the power output end of the pulling system (3); A rotating system (5) is fixedly mounted on the slide (4) to provide rotational motion and drive the cutter head assembly (6) to rotate; the rotating system (5) includes a rotating spindle (17). The cutterhead assembly (6) is connected to the power output end of the rotating system (5), simulating the shield cutterhead and contacting the soil sample; the cutterhead assembly (6) includes an insulating rod (18) and a simulated cutterhead (19); the upper end of the insulating rod (18) is connected to the lower end of the rotating main shaft (17); the upper end of the simulated cutterhead (19) is detachably connected to the lower end of the insulating rod (18); the simulated cutterhead (19) includes a hollow connecting rod (20) and cutterhead spokes (21) fixed thereon; the cutterhead spokes (21) are provided with a plurality of electrode insertion holes for inserting anode rods (24); the electrode insertion holes are connected to the inner cavity of the hollow connecting rod (20) through the channels inside the cutterhead spokes (21); An electroosmotic viscosity reduction system (7) is provided, the electrical output terminals of which are connected to the cutter head assembly (6) and the anode (23) arranged on the cutter head assembly (6) respectively, for applying a controllable electric field between the cutter head assembly (6) and the soil sample; the electroosmotic viscosity reduction system (7) includes a programmable DC regulated power supply (22), an anode (23), a cathode (27) and a conductive slip ring (28); the anode (23) includes an anode rod (24) that can be inserted into the electrode socket; the cathode (27) is composed of the simulated cutter head (19); the conductive slip ring (28) is located at the connection between the simulated cutter head (19) and the hollow connecting rod (20), for maintaining the electrical circuit conduction when the cutter head rotates; The data acquisition and control system is connected to the drawing system (3), the rotation system (5), and the electroosmotic viscosity reduction system (7) via signals. The data acquisition and control system includes a torque sensor (29) and an S-shaped force sensor (30), which are mounted on the rotating spindle (17).

2. The shield cutterhead adhesion test device with electroosmosis-rotation-pull-out coupling according to claim 1, characterized in that, The drawing system (3) includes a drawing servo motor (10), a first coupling (11), a linear screw (12), a vertical guide rail (13), and a slider assembly (14); the drawing servo motor (10) drives the linear screw (12) to rotate through the first coupling (11); the slider assembly (14) is threadedly engaged with the linear screw (12) and slidably connected to the vertical guide rail (13); the slide table (4) is fixedly connected to the slider assembly (14).

3. The shield cutterhead adhesion test device with electroosmosis-rotation-pull-out coupling according to claim 1, characterized in that, The rotating system (5) includes a rotary servo motor (15), a second coupling (16) and the rotary spindle (17); the rotary servo motor (15) is fixed on the slide (4), and its output shaft is connected to the rotary spindle (17) through the second coupling (16).

4. The shield cutterhead adhesion test device with electroosmosis-rotation-pull-out coupling according to claim 1, characterized in that, An insulating ring (26) is provided between the anode rod (24) and the electrode socket. The height of the insulating ring (26) is higher than the thickness of the simulated cutter head (19) and lower than the length of the anode rod (24).

5. The shield cutterhead adhesion test device with electroosmosis-rotation-pull-out coupling according to claim 1, characterized in that, The anode rod (24) is arranged on the spokes (21) of the simulated cutter head (19) according to a preset arrangement scheme; the preset arrangement scheme includes at least one of inner ring arrangement, inner and outer double ring arrangement, inner and outer symmetrical arrangement or inner and outer offset arrangement.

6. The shield cutterhead adhesion test device with electroosmosis-rotation-pull-out coupling according to claim 1, characterized in that, The cutterhead spokes (21) are provided with a removable sealing plate (34). The opening ratio of the simulated cutterhead (19) can be adjusted by replacing or adding / removing the removable sealing plate (34).

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