Experimental System and Method for Treating Sludge Cake with Ultra-High Water Pressure

Abstract

This invention discloses an experimental system and method for treating mud cakes under ultra-high water pressure. It realistically reproduces the state of slag being compressed into mud cakes under high temperature and high pressure inside a tunnel boring machine. The resulting mud cakes have high on-site reproduction accuracy and are of high value for studying actual cutterhead mud cakes. The mud cake forming device can produce mud cakes with different moisture contents, particle sizes, and temperatures. It is not limited to mud cakes formed in a single stratum but can also handle mud cakes formed in complex strata. The designed experimental method for analyzing water jet cutting of mud cakes can explore the effect of ultra-high water pressure treatment of mud cakes with specific properties under different specific conditions. It provides a good solution to the problem of on-site cutterhead mud cakes and has extremely high engineering universality and practical value.

Description

Technical Field

[0001] This invention relates to the field of shield tunnel engineering technology. More specifically, this invention relates to a test system and test method for treating mud cake under ultra-high water pressure. Background Technology

[0002] In recent years, my country's urban rail transit construction has developed rapidly, with subway line construction being particularly prominent. As one of the most important construction methods for subways, the shield tunneling method has seen its application scope gradually expand. Due to my country's vast territory and significant differences in hydrogeology across different regions, the difficulties faced by shield tunneling are becoming increasingly prominent. Among these, the formation of mud cake on the cutterhead when the shield tunnels traverse cohesive strata is a global problem that plagues the engineering community. Its occurrence affects the safety of shield tunneling, the economy of the project, and the rationality of the construction schedule. Currently, there is no technical method that can completely solve the problem of shield tunneling mud cake formation.

[0003] When a tunnel boring machine (TBM) excavates in cohesive strata, the soil is cut by the cutterhead, forming small particles. Due to the mineral composition of these particles, they tend to adhere, accumulating into clumps or adhering to the cutterhead. Under the pressure of the ground and the high temperature at the tunnel face, the adhered soil tends to consolidate and gradually hardens, forming semi-consolidated or consolidated lumps in the cutterhead or soil chamber, thus producing mud cake. Mud cake accumulates around the cutterhead, reducing its penetration depth, causing uneven wear, and even clogging the cutterhead opening. In severe cases, mud cake can clog the soil removal device, leading to excessive TBM torque, severe cutterhead wear, and difficulty in controlling the TBM's tunneling posture, significantly reducing tunneling efficiency and even causing excessive surface settlement, resulting in construction safety issues.

[0004] Many subway projects in my country have encountered the problem of mud cake formation. Currently, methods for dealing with cutterhead mud cake mainly include pre-construction measures and on-site measures. Pre-construction measures primarily involve improving the design of the tunnel boring machine (TBM) to reduce the likelihood of mud cake formation, specifically through early TBM selection and configuration optimization. On-site measures involve a series of auxiliary measures during construction to prevent mud cake formation or remove existing mud cake, including soil improvement and control of construction and tunneling parameters. However, considering the rotatability of the TBM cutterhead, traditional soaking chamber tests cannot effectively evaluate the dispersant treatment effect on cutterhead mud cake under the reciprocating action of soaking and rotation. Furthermore, the effect of the modifier on the formed mud cake cannot be directly reflected for different geological conditions. Summary of the Invention

[0005] One object of the present invention is to solve at least the above-mentioned problems and to provide at least the advantages that will be described later.

[0006] Another objective of this invention is to provide a test system and method for treating mud cake under ultra-high water pressure, in order to solve the technical problem that the existing technology has poor ability to simulate the treatment effect of mud cake formed by the cutter head.

[0007] To achieve these objectives and other advantages according to the present invention, a test system for treating mud cake under ultra-high water pressure is provided, comprising:

[0008] A clay cake making device includes a base, a pressure mold box with vertical penetration in the middle of the base, vertically telescopic material-taking cylinders symmetrically connected to opposite sides of the pressure mold box, a pressure plate at the top of the pressure mold box, a pressure mechanism connected to the base, the pressure mechanism connected downward to the pressure plate, a heating mechanism attached to the outer surface of the pressure mold box, and two vertically sliding water-filtering plates inside the pressure mold box. The dimensions of the water-filtering plates and the pressure plate are consistent with the inner cross-sectional shape of the pressure mold box, and the two water-filtering plates sandwich the slag to be made into clay cakes in the middle.

[0009] The test water tank has a support platform at one end and a detachable cutting mold box fixed at the other end. One end of the cutting mold box is open, and a mud cake is embedded in the cutting mold box with the cutting surface of the mud cake exposed at the opening. The support platform and the test water tank are connected by a moving mechanism that can drive the support platform to move toward the cutting mold box. A water jet emitter is installed on the support platform facing the opening of the cutting mold box. A rotating bolt is screwed on the support platform to fix the water jet emitter on the support platform after the rinsing angle is adjusted. A high-pressure water inlet pipe is connected to the side of the water jet emitter facing away from the cutting mold box. A detachable partition is installed between the cutting mold box and the water jet emitter inside the test water tank.

[0010] Preferably, the moving mechanism includes:

[0011] A pair of guide rails are fixed to the upper end of the test water tank and are set perpendicular to the surface of the mud cake to be cut. The guide rails extend toward the cutting mold box to the partition.

[0012] A slide rod is arranged perpendicular to the extension direction of the guide rail and its two ends are slidably connected to a pair of guide rails, and the support is connected to the bottom of the slide rod;

[0013] A telescopic rod is installed horizontally and perpendicular to the surface of the mud cake to be cut. The telescopic end of the telescopic rod is fixedly connected to the side of the support platform, and the fixed end of the telescopic rod is connected to the side of the test water tank facing the cutting mold box.

[0014] Preferably, both the pressurizing mold box and the cutting mold box are rectangular structures. The cutting mold box has an adjacent and detachable first side plate and a second side plate. Fastening bolts are provided on the first side plate and the second side plate, and the first side plate and the second side plate are surrounded and fastened to the outside of the mud cake by the fastening bolts.

[0015] Preferably, the base includes a pair of parallel support blocks, the distance between the pair of support blocks being slightly greater than the dimension of the pressure mold box in the corresponding direction. The pressure mechanism includes a pair of parallel portal frames, the bottom ends of each portal frame being fixed to a support block respectively. A fixing plate is connected between the tops of the pair of portal frames. The pressure mechanism is a pressure cylinder, with the pressure cylinder connected downwards to the fixing plate. The pressure plate is fixed to the bottom of the telescopic end of the pressure cylinder. The cylinder body of each material-taking cylinder is fixed to a support block and located between the pair of portal frames. The telescopic end of the material-taking cylinder is arranged upwards and a fixing rod is connected between it and the corresponding side of the pressure mold box. A base plate is also slidably connected between the pair of support blocks. The base plate has the same height as the support blocks and its length in the sliding direction is greater than the length of the pressure mold box.

[0016] Preferably, the filter plate is made of rubber and has filter holes arranged in an array on the filter plate.

[0017] This invention also provides a test method for an ultra-high water pressure treatment system for mud cake, comprising the following steps:

[0018] S1. Using the forming mud cake making device, press the mud cake. Place a bottom plate at the bottom of the pressure mold box to support the bottom of the pressure mold box. Then, place the first filter plate in the pressure mold box in sequence, add the slag to be made into mud cake, and cover the slag with the second filter plate. Use the pressure mechanism to set the pressure and pressure time to drive the pressure plate to press down the filter plate on the upper side. During the pressure process, open the heating mechanism to set the temperature. Finally, a formed mud cake sample is obtained.

[0019] S2. Take out the mud cake sample and transfer it to the cutting mold box for limiting and fixing. Leave the surface of the mud cake sample to be cut at the opening of the cutting mold box.

[0020] S3. Fix the cutting mold box to one end inside the test water tank, and make the surface to be cut face the opposite end inside the test water tank, and place the partition in front of the surface to be cut.

[0021] S4. Install the moving mechanism and the support platform in the test water tank, install and adjust the scouring angle of the water jet launcher on the support platform, adjust the distance between the water jet launcher and the mud cake sample using the moving mechanism, and control the scouring pressure of the water jet launcher through the high-pressure water inlet pipeline.

[0022] S5. Remove the partition, turn on the water jet switch, and use the water jet launcher to conduct a water jet cutting test on the surface of the mud cake sample to be cut.

[0023] 8. Preferably, the method further includes step S6, evaluating the effect of the ultra-high pressure water jet cutting the surface of the mud cake, specifically,

[0024] A1. Calculation of surface area change of mud cake: After the cutting mold box containing the mud cake sample is placed in the test water tank, the area of ​​the surface to be cut is determined as S0 according to the opening size of the cutting mold box. After determining the water jet rinsing pressure P and rinsing angle α, the water jet switch is turned on to rinsing and cutting the surface to be cut. At a cutting time t, the rinsing surface of the mud cake sample is scanned using a three-dimensional laser scanner to obtain the contour curve of the rinsing surface of the mud cake sample, and the remaining area S of the rinsing surface is calculated. The specific surface area A is also calculated.

[0025] A2. Calculation of mud cake volume change: Based on the opening size of the cutting mold box, determine the volume of the formed mud cake as V0. Under the same water jet rinsing pressure P and rinsing angle α as in step A1, turn on the water jet switch. Within the rinsing time t, use a three-dimensional laser scanner to scan the overall contour of the mud cake sample, obtain the corresponding contour curve, calculate the remaining volume V of the rinsed mud cake, and calculate the specific volume B.

[0026] A3. The effect of ultra-high water pressure flushing of mud cake is evaluated by the magnitude of the two parameters, specific surface area A and specific volume B, and the optimal water jet flushing pressure P, flushing angle α, and flushing time t are determined.

[0027] Preferably, the method also includes monitoring the moisture content of the mud cake sample. After the mud cake is prepared, the mud cake sample is taken out, and four points are evenly selected on the left and right sides of the mud cake sample to measure the moisture content. The measurement method is to use a soil moisture sensor probe for testing. After the test is completed, the average value of the eight measuring points is taken as the moisture content of the mud cake.

[0028] Preferably, it also includes temperature monitoring and control of the mud cake sample. The mud cake sample is pressed into shape at a temperature T by the heating mechanism to simulate the effect of different temperatures during friction in the shield tunneling process. During the pressing process, the temperature gun is used to continuously detect the temperature from the top of the mud cake. When the measured temperature and the set temperature T remain basically unchanged for a certain period of time, the mud cake temperature control is completed. At the same time, when the mud cake sample is water-jet cut, heat-resistant gloves are used to move the mud cake sample.

[0029] The present invention has at least the following beneficial effects: The ultra-high water pressure cutting mud cake test system of the present invention truly reproduces the state of slag and soil being compressed into mud cakes under high temperature and high pressure inside the tunnel boring machine. The resulting finished mud cake has high on-site reproduction, which is of high value for studying actual cutterhead mud cakes. The mud cake forming device can produce mud cakes with different moisture contents, different particle sizes, and different temperatures. At the same time, it is not limited to mud cakes formed in a single stratum, but can also deal with the problem of mud cakes formed in composite strata, with wide applicability. The present invention also designs a set of test methods for analyzing water jet cutting mud cakes, which can study the effect of water jet cutting mud cakes under different water pressures, study the treatment effect of water jets and mud cakes at different distances, and analyze the effect of water jets on mud cakes at different cutting angles. It provides a good solution to the problem of on-site cutterhead mud cakes and has extremely high engineering applicability and practical value.

[0030] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the molding mud cake making device of the present invention;

[0032] Figure 2 This is a schematic diagram of the structure of the filter plate of the present invention;

[0033] Figure 3 This is a schematic diagram of the cutting mold box of the present invention;

[0034] Figure 4 This is a schematic diagram of the experimental system for treating mud cake under ultra-high water pressure according to the present invention;

[0035] Figure 5 This is a schematic diagram showing the arrangement of moisture content measuring points according to the present invention;

[0036] Figure 6 This is a planar schematic diagram of the surface to be cut of the mud cake sample of the present invention;

[0037] Figure 7 This is a planar schematic diagram of the surface to be cut of the mud cake sample of the present invention during water jet cutting;

[0038] Instruction manual drawing reference numerals: 1. Support block, 2. Fixing rod, 3. Material handling cylinder, 4. Gantry frame, 5. Fixing plate, 6. Pressurizing cylinder, 7. Base, 8. Surface to be cut, 9. Pressurizing plate, 10. Pressurizing mold box, 11. Heating mechanism, 12. Cutting mold box, 13. Fixing groove, 14. Fastening bolt, 15. Guide rail, 16. Sliding rod, 17. Support platform, 18. Water jet emitter, 19. Partition plate, 20. High-pressure water inlet pipe, 21. Test water tank, 22. Telescopic rod, 23. First side plate, 24. Second side plate, 25. Filter hole, 26. Filter plate. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0040] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] like Figure 1 , Figure 2 , Figure 4 As shown, the present invention provides an experimental system for treating mud cake under ultra-high water pressure, comprising:

[0042] The device for making shaped mud cakes includes a base 7, a pressure mold box 10 with vertical penetration in the middle of the base 7, vertically telescopic material-taking cylinders 3 symmetrically connected to opposite sides of the pressure mold box 10, a pressure plate 9 above the pressure mold box 10, a pressure mechanism connected to the base 7, the pressure mechanism connected downward to the pressure plate 9, a heating mechanism 11 attached to the outer surface of the pressure mold box 10, and two vertically sliding filter plates 26 inside the pressure mold box 10. The dimensions of the filter plates 26 and the pressure plate 9 are consistent with the inner cross-sectional shape of the pressure mold box 10. The two filter plates 26 sandwich the slag to be made into mud cakes in the middle.

[0043] The test water tank 21 has a support platform 17 at one end and a detachable cutting mold box 12 fixed at the other end. One end of the cutting mold box 12 is open, and the mud cake is embedded in the cutting mold box 12 with the cutting surface 8 of the mud cake left at the opening. The support platform 17 and the test water tank 21 are connected by a moving mechanism that can drive the support platform 17 to move toward the cutting mold box 12. A water jet emitter 18 is provided on the opening of the support platform 17 facing the cutting mold box 12. A rotating bolt is screwed on the support platform 17 to fix the water jet emitter 18 on the support platform 17 after the rinsing angle is adjusted. The water jet emitter 18 is connected to a high-pressure water inlet pipe 20 on the side facing away from the cutting mold box 12. A detachable partition 19 is provided between the cutting mold box 12 and the water jet emitter 18 inside the test water tank 21.

[0044] When using, combine Figure 1 As shown, the shaped mud cake making device is first placed on the workbench. The pressure plate 9 is lifted by the pressure mechanism, and the material taking cylinder 3 extends upward, driving the pressure mold box 10 to move upward. Then, a base plate is placed under the pressure mold box 10 or a better workbench surface is used. The material taking cylinder 3 retracts, causing the pressure mold box 10 to descend until it touches the base plate or the structural surface of the workbench. The base plate must be shaped and sized to completely cover the bottom of the pressure mold box 10. Then, the first filter plate 26 is placed at the bottom of the pressure mold box 10. A mass of m of slag is added into the pressure mold box 10, and another filter plate 26 is placed on top of the slag. The mud cake filtration pressure is set, and the pressure mechanism is slowly moved downward. Under a specific pressure, pressure is applied for a certain period of time. During the pressure process, the heating mechanism 11, such as an electric conductivity heating device, is turned on, so that a shaped mud cake sample can be made at a specific temperature and for a specific time.

[0045] After preparing the mud cake sample under specific conditions, the pressurizing mechanism is moved upward to leave space for the mud cake sample to be removed. At the same time, the material taking cylinder 3 is started to move upward, which drives the pressurizing mold box 10 to move upward. The mud cake sample does not move relative to this, thus exposing the pressed mud cake sample. After the mud cake sample is fully exposed, the mud cake sample and mud cake filter plate 26 are taken out. The cutting mold box 12 is opened, and the mud cake sample is placed inside the cutting mold box 12. The cutting mold box 12 and the mud cake sample are the same size. The side plate of the cutting mold box 12 surrounds and abuts the corresponding surface of the mud cake sample, leaving the cutting surface 8 at the opening for subsequent water jet cutting test.

[0046] Combined Figure 4As shown, a moving mechanism is first installed at one end of the test water tank 21. For easy observation, both the test water tank 21 and the partition 19 are made of transparent material. A support platform 17 is fixed on the moving mechanism, and then the water jet emitter 18 is installed on the support platform 17. The distance between the water jet emitter 18 and the cutting surface is adjusted using the moving mechanism. After adjusting the orientation of the water jet emitter 18, its position is fixed. The position of the water jet emitter 18 is switched between rotatable and non-rotatable states by loosening and tightening the rotating bolts. The water jet emitter 18 is connected to the high-pressure water inlet pipe 20, and the cutting mold box 12 is fixed. In the test water tank 21, with the opening facing the water jet tester, a fixing groove 13 can be set in the test water tank 21 to facilitate the fixing of the cutting mold box 12. A partition 19 is used to block the front end of the surface 8 to be cut of the mud cake sample to avoid interference with the mud cake sample during the installation or adjustment of the water jet flushing angle. The water pressure of the water jet emitter 18 is controlled by adjusting the water pressure of the high-pressure water inlet pipe 20. After everything is ready, the partition 19 is removed, the pressurization device of the high-pressure water inlet pipe 20 is turned on, and the water jet cutting mud cake test can be carried out. The effect of mud cake water jet cutting at a specific time t is recorded.

[0047] In the ultra-high water pressure treatment mud cake test system of this scheme, the mud cake forming device can be used to make mud cakes with different moisture contents, different pressurization pressures, different pressing times, different particle sizes, and different heating temperatures. This facilitates the subsequent water jet cutting of mud cake samples. After the mud cakes with different characteristics are made, they are transferred to the cutting mold box 12 and fixed in a specific position in the test water tank 21. With the cooperation of the moving mechanism and the support platform 17, the water jet parameters of the water jet cutter can be adjusted. Then, the water jet cutting test is carried out using the installed water jet launcher 18. This allows the optimal water jet pressure, jet angle, and jet distance for water jet cutting of mud cakes with specific characteristics to be obtained, providing technical support for the mud cake treatment design of tunnel boring machines and guiding the on-site mud cake treatment.

[0048] In another technical solution, such as Figure 4 As shown, the moving mechanism includes:

[0049] A pair of guide rails 15 are fixed to the upper end of the test water tank 21 and are arranged perpendicular to the surface 8 to be cut of the mud cake. The guide rails 15 extend toward the cutting mold box 12 to the partition 19.

[0050] The slide rod 16 is arranged perpendicular to the extension direction of the guide rail 15 and its two ends are slidably connected to a pair of guide rails 15. The support 17 is connected to the bottom of the slide rod 16.

[0051] The telescopic rod 22 is set horizontally perpendicular to the surface 8 to be cut of the mud cake. The telescopic end of the telescopic rod 22 is fixedly connected to the side of the support platform 17, and the fixed end of the telescopic rod 22 is connected to the side of the test water tank 21 facing the cutting mold box 12.

[0052] The telescopic rod 22 is used to push the base 17, and the slide rod 16 connected to the base 17 moves along the length of the guide rail 15, thereby changing the position of the water jet launcher 18.

[0053] In another technical solution, such as Figure 3 As shown, the pressurizing mold box 10 and the cutting mold box 12 are both rectangular structures. The cutting mold box 12 has an adjacent and detachable first side plate 23 and a second side plate 24. Fastening bolts 14 are provided on the first side plate 23 and the second side plate 24. The first side plate 23 and the second side plate 24 are surrounded and fastened to the outside of the mud cake by the fastening bolts 14.

[0054] When transferring the mud cake sample into the cutting mold box 12, first loosen the fastening bolt 14, remove the first side plate 23 and the second side plate 24, put in the mud cake sample, adjust the position of the first side plate 23 and the second side plate 24, keep them close to the mud cake sample and keep them stable, then tighten the fastening bolt 14 to fix the position, and then fix it in the test water tank 21 through the cutting mold box 12.

[0055] In another technical solution, such as Figure 1 As shown, the base 7 includes a pair of parallel support blocks 1, the distance between the pair of support blocks 1 is slightly larger than the size of the pressure mold box 10 in the corresponding direction. The pressure mechanism includes a pair of parallel portal frames 4, the bottom ends of each portal frame 4 are respectively fixed to a support block 1, and a fixing plate 5 is connected between the tops of the pair of portal frames 4. The pressure mechanism is a pressure cylinder 6, the pressure cylinder 6 is connected downward on the fixing plate 5, the pressure plate 9 is fixed to the bottom of the telescopic end of the pressure cylinder 6, the cylinder body of each material taking cylinder 3 is fixed on a support block 1 and located between the pair of portal frames 4, the telescopic end of the material taking cylinder 3 is arranged upward and a fixing rod 2 is connected between it and the corresponding side of the pressure mold box 10. A bottom plate is also slidably connected between the pair of support blocks 1. The bottom plate has the same height as the support block 1 and its length in the sliding direction is greater than the length of the pressure mold box 10.

[0056] A portal frame 4 is connected to the base 7 as a supporting skeleton structure for the pressurizing mechanism, leaving space for the installation of the pressurizing mold box 10 and for pressurization. The material taking cylinder 3 drives the pressurizing mold box 10 to move up and down synchronously during extension and retraction via the fixed rod 2. When the mud cake may stick inside the pressurizing mold box 10, the position of the pressurizing plate 9 is fixed. The pressurizing mold box 10 is moved upward so that the pressurizing plate 9 touches the upper filter plate 26. The pressurizing mold box 10 is moved upward again so that the mud cake sample is held by the pressurizing plate 9, thereby quickly detaching from the pressurizing mold box 10. The bottom plate can be set so that the mud cake sample can fall directly onto the bottom plate, making it easy to remove the mud cake sample.

[0057] In another technical solution, such as Figure 2 As shown, the filter plate 26 is made of rubber and has filter holes 25 arranged in an array on it. During the pressurization process for making mud cake samples, the uniformly arranged filter holes 25 filter out the moisture at different locations of the mud cake when pressurized.

[0058] This invention also provides a test method for a test system for treating mud cake under ultra-high water pressure, such as... Figure 1-4 As shown, it includes the following steps:

[0059] S1. Using the molded mud cake making device, a base plate is placed at the bottom of the pressure mold box 10 to support the bottom of the pressure mold box 10. Then, the first filter plate 26 is placed in the pressure mold box 10, and sufficient amount of slag to be made into mud cake is added. The second filter plate 26 is placed on top of the slag. The pressure and time are set by the pressure mechanism to drive the pressure plate 9 to press down the upper filter plate 26. During the pressure process, the heating mechanism 11 is turned on to set a specific temperature. Finally, a molded mud cake sample is obtained. The mud cake pressing pressure is set to P, the pressure time under the specific pressure is set to t, the heating mechanism 11 is turned on during the pressure process, and the molded mud cake sample is made at a specific temperature T and a specific time t.

[0060] S2. Take out the mud cake sample and transfer it to the cutting mold box 12 for limiting and fixing. Leave the surface 8 of the mud cake sample to be cut at the opening of the cutting mold box 12.

[0061] S3. Fix the cutting mold box 12 to one end inside the test water tank 21, and make the surface to be cut 8 face the opposite end inside the test water tank 21, and place the partition 19 in front of the surface to be cut 8.

[0062] S4. Install the moving mechanism and the support platform 17 in the test water tank 21, install and adjust the scouring angle β of the water jet emitter 18 on the support platform 17, adjust the distance L between the water jet emitter 18 and the mud cake sample using the moving mechanism, and control the scouring pressure of the water jet emitter 18 through the high-pressure water inlet pipe 20.

[0063] S5. Remove the partition 19, turn on the water jet switch, and use the water jet launcher 18 to carry out a water jet cutting test on the surface 8 of the mud cake sample to be cut.

[0064] When the scouring angle of the water jet emitter 18 is used as a variable, the specific distance between the water jet emitter 18 and the surface 8 to be cut of the mud cake sample is adjusted simultaneously with the slide rod 16 and the guide rail 15. This allows for the determination of the water jet's effect on cutting the mud cake at different cutting angles under specific time t, specific distance L, and specific outlet water pressure P. When the distance between the water jet emitter 18 and the mud cake sample is used as a variable, it can be adjusted by the slide rod 16 and the guide rail 15. This allows for the determination of the water jet's effect on cutting the mud cake at specific time t, specific angle β, and specific pressure P under different distances. When the outlet water pressure is used as a variable, with other variable data remaining unchanged, the water jet's effect on cutting the mud cake under different outlet water jet pressures can also be determined using the above experimental method.

[0065] The experimental method in this scheme utilizes a molded mud cake making device to produce mud cake samples with different moisture contents, mud cake masses, different filtration pressures, different particle sizes, and different pressurization temperatures. This allows for a more comprehensive study of mud cake properties. Furthermore, it enables the analysis of the mud cake treatment effect during water jet cutting by using variables such as different water flow pressures, different cutting angles, and different cutting distances. This provides an excellent solution to the problem of mud cakes from cutterheads on-site and has extremely high engineering applicability and practical value.

[0066] In another technical solution, such as Figure 6-7 As shown, it also includes step S6, evaluating the effect of the ultra-high pressure water jet cutting the surface 8 of the mud cake, specifically,

[0067] A1. Calculation of surface area change of mud cake: After the cutting mold box 12 containing the mud cake sample is placed in the test water tank 21, the area of ​​the surface to be cut 8 is determined as S0 according to the opening size of the cutting mold box 12. After determining the water jet rinsing pressure P and rinsing angle α, the water jet switch is turned on to rinsing and cutting the surface to be cut 8. When the cutting time is t, the rinsing surface of the mud cake sample is scanned using a three-dimensional laser scanner to obtain the contour curve of the rinsing surface of the mud cake sample, and the remaining area S of the rinsing surface is calculated. The specific surface area A is also calculated.

[0068] A2. Calculation of mud cake volume change: Based on the opening size of the cutting mold box 12, the volume of the formed mud cake is determined to be V0. Under the same water jet rinsing pressure P and rinsing angle α as in step A1, the water jet switch is turned on. Within the rinsing time t, the overall contour of the mud cake sample is scanned using a three-dimensional laser scanner to obtain the corresponding contour curve. The remaining volume V of the rinsed mud cake is calculated, and the specific volume B is calculated.

[0069] A3. The effect of ultra-high water pressure flushing of mud cake is evaluated by the magnitude of the two parameters, specific surface area A and specific volume B, and the optimal water jet flushing pressure P, flushing angle α, and flushing time t are determined.

[0070] The water jet cutting process of the mud cake samples is monitored in real time. The morphological changes of the mud cake at a specific time t under different working conditions are recorded by weighing, video, or photography. The specific surface area A and specific volume B are then calculated to analyze the mud cake treatment and dispersion effect. The larger the combined value of specific surface area A and specific volume B, the better the mud cake treatment and dispersion effect. In this way, the optimal water jet pressure, jet angle, and jet distance under a specific mud cake are obtained, providing technical support for the mud cake treatment design of tunnel boring machines and guiding the on-site mud cake treatment.

[0071] In another technical solution, such as Figure 5 As shown, it also includes monitoring the moisture content of the mud cake sample. After the mud cake is prepared, the mud cake sample is taken out, and four points are evenly selected on the left and right sides of the mud cake sample to measure the moisture content. The measurement method is to use a soil moisture sensor probe to test. After the test is completed, the average value of the eight measuring points is taken as the moisture content of the mud cake.

[0072] By monitoring the moisture content of the mud cake samples during the mud cake production process, the waterjet cutting effect of mud cakes with different moisture contents can be studied, thus providing a more comprehensive range of mud cakes for research.

[0073] In another technical solution, the temperature monitoring and control of the mud cake sample is also included. The mud cake sample is pressed into shape at a temperature T by the heating mechanism 11 to simulate the effect of different temperatures during friction in the shield tunneling process. During the pressing process, the temperature gun is used to continuously detect the temperature from the top of the mud cake. When the measured temperature is basically unchanged from the set temperature T within a certain period of time, the mud cake temperature control is completed. At the same time, when the mud cake sample is water-jet cut, heat-resistant gloves are used to move the mud cake sample.

[0074] Temperature control of the mud cake sample is used to simulate the effects of different temperatures during friction in shield tunneling. In this scheme, the temperature control mainly involves setting the external heating temperature as T. The existing mud cake sample is pressed and formed at temperature T for a certain period of time. During the experiment, a temperature measuring gun is used to continuously probe from the top of the formed mud cake. When the measured temperature is basically unchanged from the set temperature T for a certain period of time, the mud cake temperature control can be considered complete. At the same time, when sampling for water jet cutting, heat-insulating gloves are used as much as possible to quickly carry out relevant tests to reduce heat loss of the mud cake sample during the movement process.

[0075] In summary, this invention provides an experimental system for preparing mud cakes with different moisture contents and thicknesses, and for cutting mud cakes under ultra-high water pressure. It can explore the effects of ultra-high water pressure on mud cakes with specific properties under different specific conditions. The designed mud cake preparation device realistically reproduces the state of slag being compressed into mud cakes under high temperature and pressure inside a tunnel boring machine. The resulting mud cakes have high on-site reproduction accuracy and are of high value for studying actual cutterhead mud cakes. The mud cake preparation device can produce mud cakes of different particle sizes and temperatures, and is not limited to mud cakes formed in a single stratum; it can also handle mud cake problems formed in complex strata, demonstrating broad applicability. This invention also designs an experimental method for analyzing water jet cutting of mud cakes, which can study the effects of water jet cutting of mud cakes under different water pressures, the treatment effects of water jets and mud cakes at different distances, and the effects of water jets on mud cakes at different cutting angles. It provides a good solution to the problem of on-site cutterhead mud cakes and has extremely high engineering applicability and practical value.

[0076] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A test method for ultra-high water pressure treatment of a mud cake, characterized in that, It comprises the following steps: S1, using a molding mud cake making device to press the mud cake, the molding mud cake making device comprises a base, a vertically penetrating pressure mold box is arranged in the middle of the base, opposite sides of the pressure mold box are symmetrically connected with vertically retractable material taking oil cylinders outward, a pressure plate is arranged above the pressure mold box, a pressure mechanism is connected to the base, the pressure mechanism is connected downward to the pressure plate, a heating mechanism is connected to the outer side of the pressure mold box, two vertically sliding water filtering plates are connected in the pressure mold box, the water filtering plates are made of rubber and are provided with water filtering holes in an array, the sizes of the water filtering plates and the pressure plate are consistent with the inner side cross-sectional shape of the pressure mold box, and the two water filtering plates sandwich the slag soil to be made into a mud cake in the middle; A bottom plate is placed at the bottom of the pressure mold box to resist the bottom of the pressure mold box, then a first water filtering plate is placed in the pressure mold box, the slag soil to be made into a mud cake is added, a second water filtering plate is arranged above the slag soil, the pressure mechanism is used to set the pressure and time to drive the pressure plate to press downward the upper water filtering plate, the heating mechanism is turned on to set the temperature during the pressure process, and finally a molded mud cake sample is obtained; S2, further comprising monitoring the water content of the mud cake sample, taking out the mud cake sample, and evenly selecting four points on the left and right two sides of the mud cake sample to measure the water content, the measurement method is to test by using a soil humidity sensor probe, after the test is completed, the average value of the eight measurement points of the molded mud cake is taken as the water content of the mud cake, the mud cake sample is taken out and transferred to a cutting mold box for limiting and fixing, and a cutting surface of the mud cake sample is left at the opening of the cutting mold box; S3, the cutting mold box is fixed at one end in a test water tank, a bearing platform is arranged at one end in the test water tank, and a detachable cutting mold box is fixed at the other end, one end of the cutting mold box is open, the mud cake is embedded in the cutting mold box and leaves a cutting surface of the mud cake at the opening, the bearing platform and the test water tank are connected through a moving mechanism, the moving mechanism can drive the bearing platform to move towards the cutting mold box, a water jet launcher is arranged on the bearing platform towards the opening of the cutting mold box, a rotating bolt is screwed on the bearing platform to fix the water jet launcher on the bearing platform after adjusting the flushing angle, a high-pressure water inlet pipeline is connected outward to the side of the water jet launcher away from the cutting mold box, a detachable partition plate is arranged between the cutting mold box and the water jet launcher in the test water tank, the cutting surface faces the opposite end in the test water tank, and the partition plate is placed in front of the cutting surface; S4, the moving mechanism and the bearing platform are installed in the test water tank, the flushing angle of the water jet launcher is adjusted on the bearing platform, the distance between the water jet launcher and the mud cake sample is adjusted by the moving mechanism, and the flushing pressure of the water jet launcher is controlled through the high-pressure water inlet pipeline; S5, remove the partition plate, open the water jet switch, and use the water jet launcher to carry out water jet cutting test on the cutting surface of the mud cake sample; Step S6, evaluate the effect of water jet cutting the cutting surface of the mud cake under super-high pressure water flow, specifically, A1, mud cake surface area change calculation, after the cutting mold box with the mud cake sample is placed in the test water tank, the area of the cutting surface is determined as S0 according to the opening size of the cutting mold box, after the water jet pressure P and the jet angle a are determined, the water jet switch is turned on to cut the cutting surface, the three-dimensional laser scanner is used to scan the cutting surface of the mud cake sample in the cutting time t, the profile curve of the cutting surface of the mud sample cake is obtained, the remaining area S of the cutting surface is calculated, and the specific surface area A is calculated, ; A2, mud cake volume change calculation, according to the opening size of the cutting mold box, determine the volume of the formed mud cake as V0, under the same water jet scouring pressure P, scouring angle α conditions as step A1, open the water jet switch, in the scouring time t, use three-dimensional laser scanner to scan the overall profile of the mud cake sample, get the corresponding profile curve, calculate the remaining volume V of the scoured mud cake, calculate the specific volume B, ; A3, by the comprehensive value of the specific surface area A and the specific volume B, the effect of the ultra-high water pressure scouring mud cake is evaluated, and the best water jet scouring pressure P, the scouring angle a and the scouring time t are determined.

2. The test method for ultra-high water pressure treatment of mud cake according to claim 1, characterized in that, The moving mechanism comprises: A pair of guide rails are fixed to the upper end of the test water tank and are arranged perpendicularly to the cutting surface of the mud cake, and the guide rails extend towards the cutting mold box to the partition plate; A slide rod is arranged perpendicularly to the extension direction of the guide rails and is slidably connected to the pair of guide rails at both ends, and the bearing platform is connected to the bottom of the slide rod; A telescopic rod is arranged perpendicularly to the cutting surface of the mud cake in the horizontal direction, and the telescopic end of the telescopic rod is fixedly connected to the side surface of the bearing platform, and the fixed end of the telescopic rod is connected to the side of the test water tank facing the cutting mold box.

3. The test method for ultra-high water pressure treatment of filter cake according to claim 1, characterized in that, The pressing mold box and the cutting mold box are both rectangular structures, the cutting mold box has a first side plate and a second side plate arranged adjacently and detachably, fastening bolts are arranged on the first side plate and the second side plate, and the first side plate and the second side plate are blocked and fastened on the outside of the mud cake by the fastening bolts.

4. The test method for ultra-high water pressure treatment of filter cake according to claim 1, characterized in that, The base comprises a pair of support blocks arranged in parallel, the distance between the pair of support blocks is slightly greater than the size of the pressing mold box in the corresponding direction, the pressing mechanism comprises a pair of door-shaped frames arranged in parallel, the bottom ends of each door-shaped frame are fixed to one support block respectively, and a fixed plate is connected between the top ends of the pair of door-shaped frames, the pressing mechanism is a pressing oil cylinder, the pressing oil cylinder is connected downward on the fixed plate, the pressing plate is fixed to the bottom of the telescopic end of the pressing oil cylinder, the cylinder body of each material taking oil cylinder is fixed to one support block and located between the pair of door-shaped frames, the telescopic end of the material taking oil cylinder is arranged upward and connected with the corresponding side of the pressing mold box through a fixed rod, and a bottom plate is slidably connected between the pair of support blocks, the height of the bottom plate is the same as that of the support blocks, and the length of the bottom plate in the sliding direction is greater than the length of the pressing mold box.

5. The test method for ultra-high water pressure treatment of filter cake according to claim 1, characterized in that, The temperature monitoring and control of the mud cake sample is also included, the mud cake sample is pressed and formed at the temperature T by the heating mechanism, the influence effect of different temperatures during the friction in the shield tunneling process is simulated, the temperature gun is used to detect the top of the mud cake during the pressing process, when the measured temperature and the set temperature T are basically unchanged within a certain time, the temperature control of the mud cake is completed, and the heat insulation gloves are used to move the mud cake sample when the mud cake sample is cut by the water jet.

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