A test device and method for simulating mud-water balance shield cutter head mud cake treatment and excavation face stability

Abstract

The present invention provides a test device for simulating the treatment of mud cake formation on a slurry shield cutter head and the stability of an excavation surface, comprising a soil excavation surface system (9), a mud circulation cabinet (13) and a shield machine simulation system (19); the soil excavation surface system (9) is movably connected to the shield machine simulation system (19); the mud circulation cabinet (13) is connected to the soil excavation surface system (9) or the shield machine simulation system (19) through a pipeline. The present invention also provides a method for the test device for simulating the treatment of mud cake formation on a slurry shield cutter head and the stability of an excavation surface. During the test process of the present invention, soil and mud to be tested are added to the soil excavation surface system, the shield machine simulation system cuts the soil, and the mud circulation cabinet completes mud and water separation and transportation, simulating the excavation process of the slurry shield. The device provides reference and reference for engineering practice from the two aspects of mud cake treatment and maintaining the stability of the shield excavation surface.

Description

Technical Field

[0001] The invention relates to a test device and method for simulating mud-water balance shield cutter head mud cake processing and excavation face stability, belonging to the technical field of underground tunnel shield excavation model test. Background Art

[0002] Modern shield tunneling machines have the functions of excavating and cutting soil, transporting soil and ballast, assembling tunnel linings, measuring and guiding deviation correction, etc. Shield tunneling machines have been widely used in tunnel projects such as subways, railways, highways, and hydropower. Since the use of tunnel boring machines has the advantages of fast excavation speed, good tunnel forming, small surrounding rock disturbance, high degree of mechanization, and small impact on the surrounding environment, it has become the main method of tunnel construction and is widely used in underground engineering construction in the transportation, urban construction, water conservancy, energy and other industries in various countries around the world. However, during the shield excavation process, due to the nature of the soil material itself, the configuration of the shield machine, and the construction conditions, the problem of mud cake will occur. The cutter disc mud cake is a semi-solid or solid block formed by the fine particles and debris cut off by the cutter disc re-adhering to the center or opening area of ​​the cutter disc. It increases the workload of the cutter disc, causes a sudden change in excavation parameters, and significantly reduces construction efficiency. Therefore, solving the problem of cutter disc mud cake has important engineering practical significance.

[0003] The problem of mud cake on the cutterhead of shield machine is a common and extremely difficult problem to solve on construction sites. In order to solve the problem, it is necessary to first understand the formation conditions and mechanism of mud cake. Domestic and foreign scholars have conducted a lot of research on the problem of mud cake on the cutterhead of shield machine.

[0004] However, there are the following problems: the tests based on the construction site are greatly restricted due to the limitations of equipment conditions and environment, and the indoor tests on the research of mud cake mechanism are mostly simple mechanical pull-out tests, which cannot well simulate the mud cake formation process under complex conditions. The few model tests that can simulate the shield excavation process have problems such as poor system reliability, difficult operation, difficult cleaning, and loose integration of device measurements with the mud cake problem. There are also few research devices specifically for the mud cake problem of mud-water balance shield in a mud environment. At present, there is almost no device for this aspect, and it is urgent to design a shield cutter head mud cake research device that can solve the above problems.

[0005] Another problem is that in the process of solving the problem of mud cake on the cutter disc of shield tunneling, it is also a big problem to keep the excavation surface stable. According to the survey, most engineering units will inject mud dispersants into the cutter disc excavation surface when dealing with the problem of mud cake. Mud dispersants are surfactants with two opposite properties of lipophilicity and hydrophilicity in the molecule. They can evenly disperse those inorganic and organic solid and liquid particles that are difficult to dissolve in liquids, and at the same time prevent the sedimentation and coagulation of particles, forming amphiphilic reagents required for stable suspensions. According to engineering practice, dispersants can effectively solve the problem of mud cake, but according to different formations and working conditions, there is no unified evaluation standard for the ratio and type selection. In addition, the use of dispersants will cause a sudden drop in the viscosity of the mud on the shield excavation surface, seriously affecting construction safety and causing major safety hazards.

[0006] The stability of the shield excavation face is mainly maintained by two indicators. The first is the specific gravity. During the excavation process, the specific gravity of the incoming mud should not be too high or too low. Too high will affect the transportation capacity of mud and water and reduce the excavation speed. Too low will be detrimental to the stability of the excavation face. The specific gravity of mud and water should range from 1.05g / m³ to 1.15g / m³. The other is viscosity. From the perspective of the suspension requirements of soil particles, the matching of the mud and water treatment system, and the maintenance of the stability of the excavation face, the gel strength (static shear force) of the mud and water is required to be moderate; from the perspective of fluidity, the kinematic viscosity should not be too high. The viscosity range of mud and water should be maintained at 20~35s. As mentioned above, most existing technologies do not consider the influence of the specific gravity and viscosity of mud and water during the use of dispersants. Since the stability of the shield excavation face will affect the construction safety, when considering the treatment of the mud cake on the shield cutter head, the influence of dispersants and other reagents on the specific gravity and viscosity of mud and water should also be considered. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a test device for simulating the treatment of mud cake on the cutter head of a slurry balance shield and the stability of the excavation face. During the test, the formation mechanism of the shield mud cake and the corresponding solution measures can be studied, providing a basis for the treatment of the cutter head mud cake in actual engineering.

[0008] At the same time, the present invention provides a method for simulating the test device for the treatment of mud cake on the cutter head of a slurry balance shield and the stability of the excavation face. The method can simulate actual working conditions such as mud and water circulation on the excavation face, stress states of different strata, and shield cutter head excavation, thereby providing a basis and method for the treatment of mud cake on the cutter head in actual engineering.

[0009] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0010] A test device for simulating the treatment of mud cake on the cutter head of a slurry balance shield and the stability of the excavation face, comprising a soil layer excavation face system, a mud circulation cabinet and a shield machine simulation system;

[0011] The soil excavation surface system is movably connected to the shield machine simulation system;

[0012] The mud circulation cabinet is connected to the soil excavation surface system or the shield machine simulation system through pipelines.

[0013] The soil excavation surface system and the shield machine simulation system are both placed on a workbench supported by columns;

[0014] The soil excavation surface system comprises a soil chamber and a mud chamber separated by a removable plate, and a movable chamber door is hinged at the top of the soil chamber;

[0015] The stratum pressurizing device is installed above the soil bin chamber and is used to pressurize the soil in the soil bin chamber;

[0016] The opposite surface of the mud chamber and the shield machine simulation system is provided with a shield guide flange;

[0017] The side of the mud chamber is connected to the pipeline of the mud circulation cabinet through a mud inlet valve and a mud outlet valve;

[0018] A feed hopper A is installed at the front side of the mud chamber, and a switchable partition 1 is provided at the feed port of the feed hopper A, and the partition 1 is controlled by the feed switch A;

[0019] A mud specific gravity and viscosity sensor is installed inside the mud chamber, and the mud specific gravity and viscosity sensor is connected to the digital display screen on the front side of the mud chamber. An excavation face alarm indicator light is installed on the right side of the digital display screen; the excavation face alarm indicator light is connected to the mud specific gravity and viscosity sensor.

[0020] The stratum pressurizing device includes a pressure transmission plate for contacting the soil in the soil bin chamber, the pressure transmission plate is connected to the pressure frame A through a pressure transmission screw, the pressure frame A is located above the soil bin chamber, and the pressure frame B is located below the soil bin chamber. Both ends of the pressure frame A and the pressure frame B are connected by a vertical rod 1, and a pressure transmission lever is hinged on the upper surface of the pressure frame B. A balance hammer is provided at one end of the pressure transmission lever, and a hanging plate is suspended at the other end of the pressure transmission lever, and a weight is placed in the hanging plate. Vertical rods 2 are symmetrically connected to the lower surface of the workbench near the mud chamber, and a connecting plate located below the pressure transmission lever is connected between the two vertical rods 2. An adjusting handwheel is connected to the connecting plate through rotation of a screw, and the top surface of the screw conflicts with a constraint baffle movably connected to the vertical rod 2.

[0021] The mud circulation cabinet includes the first filtration area, mud flocculation area, second filtration area and mud sedimentation area from top to bottom; each area is separated by a detachable grille. A detachable observation port is set on one side of each area;

[0022] The first filter area is connected to the soil excavation surface system or the shield machine simulation system through a mud input pipe, a liquid flow meter is installed on the mud input pipe, a removable coarse particle filter is arranged in the first filter area, and the first filter area is connected to the mud flocculation area through a PVC pipe;

[0023] A feed hopper B is installed on the side of the mud flocculation zone, and a switchable partition 2 is provided at the feed port of the feed hopper B, and the partition 2 is controlled by the feed switch B; a magnetic stirrer is installed below the mud flocculation zone, and a rotor is placed on the magnetic stirrer. The mud flocculation zone is connected to the second filtration zone through a PVC pipe 2;

[0024] The second filter area is provided with a removable fine-particle filter screen, and the second filter area is connected to the mud sedimentation area through a PVC pipe.

[0025] The mud settling area is connected to the soil excavation surface system or the shield machine simulation system through a mud output pipe and a mud circulation pump, a second liquid flow meter is installed on the mud output pipe, and a second mud specific gravity viscosity sensor is arranged inside the mud settling area;

[0026] A slurry inlet valve and a slurry outlet valve are arranged on the side of the mud chamber. When the mud chamber is connected to the mud circulation cabinet, the mud input pipe passes through the slurry inlet valve, and the mud output pipe passes through the slurry outlet valve.

[0027] The shield machine simulation system includes a simulated shield shell, a simulated cutterhead and a power device;

[0028] The simulated cutter head is connected to the power device via a rotating spindle;

[0029] The simulated shield is a detachable soil box, and the simulated cutterhead is connected to the simulated shield; a simulated segment barrel is arranged inside the simulated shield, and two water pipe channels are arranged at the rear end of the simulated segment barrel, and the water pipe channels are movably connected to the mud output pipe and the mud input pipe respectively; the rotating main shaft passes through the simulated segment barrel and a waterproof rubber bearing is arranged at the junction of the simulated segment barrel;

[0030] An embedded pressure sensor is installed at the center of the simulated cutter head, and the pressure sensor is connected to a computer;

[0031] A heating plate is welded on the back of the simulated cutter head, and the heating plate is controlled by a temperature controller, and the temperature controller is placed on a workbench;

[0032] The power device includes a servo motor connected to the rotating main shaft, and a torque speed sensor and a coupling are arranged on the rotating main shaft; the torque speed sensor is connected to a computer;

[0033] The servo motor is controlled by a servo motor control box arranged on the workbench;

[0034] The servo motor is connected to the motor fixing device, the motor fixing device is welded to the supporting frame, the supporting frame is arranged on the sliding rack below, there are teeth on both sides of the sliding rack, the sliding rack is gear-connected with the dual-axis stepping motor arranged on the workbench, a pulley is arranged on the lower surface of the sliding rack, and a linear guide rail compatible with the pulley is arranged on the workbench.

[0035] When the water pipe channel is not connected to the mud circulation cabinet, the water pipe channel is sealed by screwing in a waterproof screw.

[0036] The length ratio of the soil bin chamber to the mud chamber is 5:1; the front side of the soil bin chamber and the upper side of the mud chamber are both visible materials; the bottom ends of the soil bin chamber and the mud chamber are both equipped with slurry discharge valves; a pressure transmission screw pin is provided on the pressure transmission plate, and the pressure transmission screw is screwed into the pressure transmission screw pin.

[0037] A method for simulating the test device for mud-water balance shield cutter head mud cake treatment and excavation face stability, the excavation face mud-water circulation simulation includes the following steps:

[0038] Step 1: Unscrew the waterproof screw on the water pipe channel at the rear end of the simulated shield shell in the shield machine simulation system, connect the mud input pipe and mud output pipe on one side of the mud circulation cabinet to the water pipe channel respectively, and then insert the coarse particle filter and the fine particle filter into the first filter area and the second filter area respectively;

[0039] Step 2: Open the feed funnel B (feed switch B) on one side of the mud circulation cabinet, pour in the shield mud sampled on site, start the mud circulation pump, and close the mud inlet valve and the mud outlet valve on one side of the mud chamber;

[0040] Step 3: Observe the values ​​of liquid flow meter 1 and liquid flow meter 2 on the mud inlet pipe and mud outlet pipe, and continuously adjust the mud circulation pump. When the values ​​of liquid flow meter 1 and liquid flow meter 2 are stable and similar, the excavation surface is in a balanced state of mud and water circulation.

[0041] A method for simulating the test device for the mud-water balance shield cutter head mud cake treatment and excavation face stability, the simulation of different stratum stress states includes the following steps:

[0042] Step 1: Close the slurry discharge valve at the bottom of the soil chamber in the soil excavation surface system, place the extractable plate between the mud chamber and the soil chamber, and tighten the waterproof rubber gasket between the mud chamber and the extractable plate;

[0043] Step 2: Remove the pressure frame A above the soil bin in the soil excavation surface system, open the movable bin door, pour the soil taken on site into the soil bin, and compact it;

[0044] Step 3: Place the pressure frame A on the pressure transmission plate and screw the pressure transmission screw into the pressure transmission screw pin. According to the different formation stresses that need to be simulated in the test plan, add weights to the hanging plate on one side of the pressure transmission lever. Use the adjustment handwheel to adjust the height of the restraint baffle so that the pressure transmission lever is in a balanced state. Pressure is applied to the soil through the pressure transmission plate.

[0045] A method for simulating the test device for the mud-water balance shield cutter head mud cake treatment and excavation face stability, wherein the shield cutter head excavation simulation comprises the following steps:

[0046] Step 1: Gently push the simulated shield shell in the shield machine simulation system along the linear guide rail on the workbench and insert it into the shield guide flange on the side of the mud chamber;

[0047] Step 2: Turn on the dual-axis stepper motor and adjust the dual-axis stepper motor so that the simulated shield shell moves forward at a speed of 0.5 to 1.5 cm / s. When it contacts the soil in the soil bin chamber, the pressure sensor at the front end of the simulated cutter head transmits a pressure signal to the computer.

[0048] Step 3: When the excavation face pressure value is stable, turn on the servo motor and adjust the speed to 1-5 rpm to simulate the cutter head rotating to cut the soil and simulate the shield tunneling excavation process.

[0049] The beneficial effects of the present invention are as follows: During the test, the soil and mud to be tested are added to the soil excavation surface system, the shield machine simulation system cuts the soil, and the mud circulation cabinet completes the separation and transportation of mud and water, simulating the excavation process of the slurry shield. By reading and analyzing the excavation parameters collected by various sensors, the formation mechanism and treatment of mud cakes under different stratum conditions in the construction of slurry shield can be systematically studied; the influence of the use of various admixtures on the mud circulation effect and the stability of the shield excavation surface can be studied. This device provides reference and reference for engineering practice from the two aspects of mud cake treatment and maintaining the stability of the shield excavation surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a schematic diagram of the structure of the present invention;

[0051] Figure 2 It is a front view of the soil excavation face system and the shield machine simulation system in the present invention;

[0052] Figure 3 It is a top view of the soil excavation surface system and the shield machine simulation system in the present invention;

[0053] Figure 4 It is an enlarged diagram of the principle of the soil excavation surface system of the present invention;

[0054] Figure 5 It is an enlarged diagram of the principle of the shield machine simulation system in the present invention;

[0055] Figure 6 It is a principle cross-sectional diagram of the mud circulation cabinet in the present invention;

[0056] Figure 7 It is a perspective view of a simulated shield shell portion in the present invention;

[0057] In the figure: 1-column; 2-slurry discharge valve; 3-workbench; 4-soil chamber; 5-movable chamber door; 6-metal hinge; 7-stratum pressurization device; 8-feeding funnel A; 9-soil excavation surface system; 10-mud chamber; 11-shield guide flange; 12-feeding funnel B; 13-mud circulation cabinet; 14-coarse particle filter; 15-magnetic stirrer; 16-fine particle filter; 17-mud and water circulation pump; 18-simulated shield shell; 19-shield machine simulation system; 20-servo motor; 21-rack; 22-servo motor control box; 23-double-axis stepper motor; 24-pressure transmission screw; 25-pressure frame A; 26-pressure transmission plate; 27-weight; 28-adjusting hand wheel; 29-constraint baffle; 30-force transmission lever; 31-pressure frame B; 32- Balance hammer; 33-removable plate; 34-feed switch A; 35-slurry inlet valve; 36-slurry outlet valve; 37-torque speed sensor; 38-rotating spindle; 39-motor fixing device; 40-temperature controller; 41-pulley; 42-linear guide; 43-pressure transmission screw pin; 44-specific gravity viscosity sensor; 45-waterproof rubber bearing; 46-digital display screen; 47-excavation face alarm indicator light; 48-liquid flow meter one; 49-mud input pipe; 50 first filter zone; 51 grid; 52-mud flocculation zone; 53-PVC pipe three; 54-mud sedimentation zone; 55-mud output pipe; 56-second filter zone; 57-rotor; 58-pressure sensor; 59-simulated cutter head; 60-heating plate; 61-water pipe channel. DETAILED DESCRIPTION

[0058] The following is a further detailed description of a test device and method for simulating mud-water balance shield cutter head mud cake processing and excavation face stability in conjunction with the accompanying drawings and specific embodiments, so that technicians in this technical field can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation method. For ordinary technicians in this technical field, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

[0059] Example 1

[0060] like Figure 1 As shown, a test device for simulating the treatment of mud cake formation on the cutter head of a slurry shield and the stability of the excavation face, the device comprises a soil excavation face system 9, a mud circulation cabinet 13 and a shield machine simulation system 19. The soil excavation face system 9 is mainly used to simulate the stratum excavated by the shield machine, and the system can also simulate strata under different stress states; the mud circulation cabinet 13 is mainly used to simulate the state of mud balance on the excavation face in the slurry shield; and the shield machine simulation system 19 is used to simulate the process of shield cutter head excavation.

[0061] like Figure 1 , Figure 2 , Figure 3 As shown, the soil excavation face system 9 is placed on the workbench 3, and the workbench 3 is supported by four columns 1, and the four columns 1 are all provided with fixing bolts to prevent relative displacement during the startup of the device. A shield machine simulation system 19 is provided on the other side of the soil excavation face system 9, and a multifunctional sensor device is provided in the shield machine simulation system 19. The data of the multifunctional sensor device can be input into the computer. The setting of the multifunctional sensor device can collect the excavation parameters during the shield process, and can better analyze the treatment of the shield cutter disc mud cake under different working conditions. The mud circulation cabinet 13 is connected to the shield machine simulation system 19 or the soil excavation face system 9 through the mud input pipe 49 and the mud output pipe 55. Different connection modes correspond to different working conditions. When connected to the soil excavation face system 9, a mud-water separation circulation material selection test based on flocculant screening or a mud-water balance excavation face stability test is carried out at this time. When connected to the shield machine simulation system 19, a mud-water balance mud cake treatment test based on dispersant screening or a mud cake production rate and mechanism research test is carried out at this time.

[0062] like Figure 1 , Figure 2 , Figure 3As shown, the soil excavation surface system 9 of the present invention includes a stratum pressurizing device 7, a soil bin chamber 4, and a mud chamber 10. The pressurizing device 7 is suspended on the other side of the workbench 3 and is erected above the soil bin chamber 4. The soil excavation surface system 9 is about 0.4m high, about 0.6m long, and about 0.3m wide. The setting of the pressurizing device 7 can transfer pressure to the soil layer by adding weights 27 according to the requirements of the test plan to simulate the stress state of different strata and meet more test conditions.

[0063] like Figure 3 As shown, the soil bin chamber 4 and the mud chamber 10 of the present invention are welded by multiple horizontal and vertical steel brackets and are in the shape of a hollow cube. The length ratio of the soil bin chamber 4 to the mud chamber 10 is 5:1. The soil bin chamber 4 and the mud chamber 10 are separated by a removable plate 33, and the removable plate 33 is preferably a removable steel plate. A slurry discharge valve 2 is installed at the bottom of the soil bin chamber 4 and the mud chamber 10. The soil excavation surface system 9 is divided into two by the removable plate 33, which can facilitate the addition of soil on site and the circulation of mud and water before the test. At the beginning of the test, the removable plate 33 can be extracted to start the operation of the soil excavation surface system 9.

[0064] like Figure 3 As shown, the front side material of the soil chamber 4 of the present invention is glass, the upper side material of the mud chamber 10 is glass, and the remaining surfaces are made of stainless steel. The provision of the glass observation window, on the one hand, can facilitate extraction and cleaning of the test equipment after the test is completed, and on the other hand, can be beneficial for observing the excavation process of the shield and the formation of mud cakes during the test. Stainless steel material can extend the service life of the device. A movable door 5 is installed on the upper side of the soil chamber 4, and the movable door 5 is hinged to the soil chamber 4 by a metal hinge 6. The openable and closable door can facilitate the addition of soil on site, and also attention should be paid to waterproofing work before the start of the test.

[0065] like Figure 3 As shown, a shield guide flange 11 is installed on one side of the mud chamber 10 of the present invention, and its diameter is one quarter of the height of the mud chamber 10, which is about 0.1m. The diameter is one quarter of the height of the mud chamber, which can ensure that in the process of simulating shield tunneling, the influence of the boundary effect is taken into account to prevent the collapse of the soil layer on the excavation surface. A waterproof rubber gasket is arranged inside the shield guide flange 11, and the side of the mud chamber 10 is connected to the mud input pipe 49 and the mud output pipe 55 through the slurry inlet valve 35 and the slurry outlet valve 36. The setting of the shield guide flange 11 can ensure that the shield simulation system runs in a straight line during the process of simulating tunneling, and the waterproof rubber gasket arranged inside can better ensure the airtightness of the entire system.

[0066] like Figure 2As shown, the stratum pressurizing device 7 of the present invention comprises a pressure transmission screw 24, a pressure transmission plate 26, a pressure transmission screw pin 43, a pressurizing frame A25, a pressurizing frame B31, a force transmission lever 30, a constraint baffle 29 and an adjustment hand wheel 28. The pressure transmission screw 24 is installed on the pressurizing frame A25 and the pressure transmission plate 26, and the pressurizing frame A25 is connected to the pressurizing frame B31 through a vertical rod 1. The force transmission lever 30 and the pressurizing frame B31 are hinged under the workbench 3, a balance hammer 32 is arranged at one end of the force transmission lever 30, and a hanging plate and a weight 27 are suspended at the other end, the force transmission lever 30 is installed on the constraint baffle 29, and an adjustment hand wheel 28 is arranged below the constraint baffle 29. The setting of the formation pressurizing device 7 can be based on the different formation stresses that need to be simulated in the test plan. A weight 27 is added to the hanging plate on one side of the force transmission lever 30, and the height of the restraint baffle 29 is adjusted using the adjustment hand wheel 28 to make the force transmission lever 30 in a balanced state. Pressure is applied to the soil layer through the pressure transmission plate 26.

[0067] The adjusting hand wheel 28 is contact-connected with the constraint baffle 29 through a circular shaft, and the circular shaft is screwed into the metal plate at the bottom of the constraint baffle 29 and fixed to the two vertical poles on both sides. The constraint baffle 29 can be flexibly moved in the vertical direction along the two vertical poles on both sides. When the adjusting hand wheel 28 is rotated, the adjusting hand wheel 28 drives the circular shaft to screw in or out of the metal plate at the bottom of the constraint baffle 29, thereby pushing the constraint baffle 29 to rise or fall in the vertical direction.

[0068] like Figure 3 As shown, a feed hopper A8 is installed at the front side of the mud chamber 10 of the present invention, and a switchable partition 1 is provided at the feed port of the feed hopper A8, and the partition 1 is controlled by a feed switch A34. The feed hopper A8 is arranged on the side of the mud chamber 10, and clean water can be poured into it before the test to detect the sealing of the device, and mud dispersant, foaming agent and other additives can also be added in the shield cutter head mud cake treatment test.

[0069] like Figure 4As shown, a mud specific gravity and viscosity sensor 44 is installed inside the mud chamber 10 of the present invention. The model of the mud specific gravity and viscosity sensor 44 is VLO-M1. This type of sensor is small in size and has high sensitivity. It can detect specific gravity and viscosity at the same time, and can effectively detect the mud specific gravity and mud viscosity at a certain moment of the mud shield excavation face. The VLO-M1 mud specific gravity and viscosity sensor is connected to the digital display screen 46 on the front side of the mud chamber 10, and an excavation face alarm indicator light 47 is installed on the right side of the digital display screen 46. The digital display screen 46 can directly reflect the mud specific gravity and mud viscosity of the excavation face at this time, which is intuitive and fast. The mud density and mud viscosity indicators play a decisive role in the stability of the excavation face. Therefore, an excavation face alarm indicator 47 is installed. According to the experience of slurry shield construction, when the mud density exceeds the range of 1.05g / m³~1.15g / m³, or the mud viscosity exceeds the range of 20~35s, the installed excavation face alarm indicator 47 will flash red, indicating that the shield excavation face may lose stability at this time, causing certain construction safety hazards. The test personnel should stop the test or take measures to maintain the stability of the excavation face.

[0070] like Figure 6 As shown, the mud circulation cabinet 13 of the present invention includes a first filtering area 50, a mud flocculation area 52, a second filtering area 56, and a mud sedimentation area 54. The mud circulation cabinet 13 has a bottom area of ​​0.8 m 2 , a cuboid with a height of about 1.5m. The height ratio of each area from top to bottom is 1:1.5:1:2. The space between the mud flocculation area 52 and the mud sedimentation area 54 is relatively large, which is conducive to the flocculation and sedimentation. Each area is separated by a removable grille 51. A removable observation glass port is provided on one side of each area. The setting of multi-zone filtration areas in the vertical direction can not only save the space of the device, but also complete the mud and water separation more quickly and efficiently. The vertical setting between different areas can save the installation of redundant mud pumps, and the mud transportation between different areas can be completed by gravity. The setting of the grille 51 can facilitate disassembly and cleaning and maintenance of the device.

[0071] like Figure 6As shown, the first filter area 50 of the present invention is connected to the soil excavation surface system 9 through a mud input pipe 49, and a liquid flow meter 1 48 is installed on the mud input pipe 49. A removable coarse-grained filter screen 14 is provided in the first filter area 50, and the mesh diameter of the coarse-grained filter screen 14 is 0.8 mm. The first filter area 50 is connected to the mud flocculation area 52 through a PVC pipe 1. The function of the first filter area 50 is mainly to filter large-diameter stone particles in the mud and complete the preliminary filtering task. The liquid flow meter 1 48 can detect the mud flow rate at this time, and compare it with another liquid flow meter 2 on the mud output pipe 55. When the values ​​of the two liquid flow meters are stable and similar, it can be considered that the mud circulation device is running stably at this time.

[0072] like Figure 6 As shown, the mud flocculation zone 52 of the present invention is equipped with a feed hopper B12 on the side, and the feed port of the feed hopper B12 is provided with a switchable partition 2, and the partition 2 is controlled by the feed switch B. A magnetic stirrer 15 is installed below the mud flocculation zone 52, and the model of the magnetic stirrer 15 is SN-MS-20L. A rotor 57 with a diameter of 15 cm is placed on the magnetic stirrer 15, and the magnetic stirrer 15 is controlled by the rotor switch on the side. The mud flocculation zone 52 is connected to the second filter zone 56 through PVC pipe 2. The mud flocculation zone 52 is the core area in the mud and water separation. The space is large. By adding flocculants, the mud and water can be effectively separated and the specific gravity of the input mud can be reduced. By adding flocculants through the feed funnel B12, the flocculant screening test can be completed, and a set of solutions for efficiently completing the mud and water separation cycle can be obtained. The magnetic stirrer 15 is different from the traditional mechanical stirrer. The device saves volume and does not need to consider the problem of water seepage in the machine. It has high reliability and strong stirring force. Therefore, in order to simplify the device and improve reliability, the magnetic stirrer 15 is selected.

[0073] like Figure 6 As shown, the second filter area 56 of the present invention is provided with a removable fine particle filter 16, and the mesh diameter of the fine particle filter 16 is 0.2 mm. The second filter area 56 is connected to the mud sedimentation area 54 through a PVC pipe 3 53. The second filter area 56 is mainly used to filter the floccules and some small particles of sand precipitated in the mud flocculation area, so as to further reduce the specific gravity of the mud.

[0074] like Figure 6As shown, the mud sedimentation area 54 of the present invention is connected to the soil excavation surface system 9 through a mud output pipe 55 and a mud water circulation pump 17. A liquid flow meter 2 is installed on the mud output pipe 55, and a mud specific gravity viscosity sensor of model VLO-M1 is arranged inside the mud sedimentation area 54. The mud sedimentation area 54 is mainly used to complete the last step of sedimentation. The space is large and can store more filtered mud water to complete mud water separation and transportation. Liquid flow meter 2 can detect the mud flow rate at this time, and form a comparison with another liquid flow meter 1 on the mud input pipe 49. When the values ​​of the two liquid flow meters are stable and similar, it can be considered that the mud circulation device is running stably at this time.

[0075] like Figure 5 As shown, the shield machine simulation system 19 of the present invention includes a simulated shield shell 18, a simulated cutter head 59 and a power device. The simulated cutter head 59 is connected to the power device through a rotating main shaft 38.

[0076] like Figure 5 As shown, the simulated shield shell 18 of the present invention is a detachable soil box, and the simulated cutter head 59 is connected to the simulated shield shell 18 by screws and nuts. A simulated segment tube is arranged inside the simulated shield shell 18, and two water pipe channels 61 are arranged at the rear end of the simulated segment tube. The water pipe channels 61 can be connected to the mud input pipe 49 and the mud output pipe 55, and the water pipe channels 61 can be sealed by screwing in the screws. When the mud input pipe 49 and the mud output pipe 55 are connected to the soil layer excavation surface system 9, the water pipe channels 61 can be sealed by screwing in the screws to prevent leakage. When the working condition is switched, the screws are unscrewed, the mud input pipe 49 and the mud output pipe 55 are inserted, and other tests can be performed after fixing. A waterproof rubber bearing 45 is arranged at the junction of the rotating main shaft 38 and the simulated shield shell 18. The simulated shield shell 18 provides protection when the shield cutter head is excavating, and can also collect the soil cut by excavation. By weighing, the treatment effect of the cutter head mud cake problem can be judged. The waterproof rubber bearing 45 can effectively prevent mud from overflowing from the rear end of the simulated shield shell 18, so that it forms a closed whole.

[0077] like Figure 7 As shown, the center of the cutter head of the simulated cutter head 59 of the present invention is equipped with an embedded pressure sensor 58, and the model of the embedded pressure sensor 58 is AT8103. The signal of the pressure sensor 58 can be output to the computer. The setting of the pressure sensor 58 can be used as a parameter of shield tunneling, and whether the excavation face is unstable at this time can be judged by whether the value is stable within a certain range.

[0078] like Figure 7As shown, the simulated cutter disc 59 of the present invention is welded with a cast aluminum heating plate 60 on the back, and the cast aluminum heating plate 60 is controlled by a temperature controller 40, and the temperature controller 40 is placed on the workbench 3. According to research, the increase in the temperature of the cutter disc is one of the main reasons for the formation of mud cakes, which will be hardened on the disc and difficult to handle. The temperature controller 40 can heat the cutter disc to study the influence of temperature on the formation of mud cakes on the cutter disc at different temperatures.

[0079] like Figure 5 As shown, the power device of the present invention includes a rotating spindle 38, a servo motor 20, a servo motor control box 22, a motor fixing device 39, and a dual-axis stepping motor 23.

[0080] like Figure 5 As shown, the rotating spindle 38 of the present invention is connected in series with the torque speed sensor 37 and the servo motor 20, and connected through a coupling. The model of the torque speed sensor 37 is DYN-210, and the signal of the torque speed sensor 37 can be output to a computer. The torque speed sensor 37 can simultaneously detect the speed and torque fed back to the rotating spindle 38 under this working condition during the excavation process, and use them as the excavation parameters of the shield to determine the mud cake generation at this time. For example, if the torque and speed decrease, it can be considered that the cutter head has generated a mud cake at this time, and the rate of mud cake generation can also be determined based on the amplitude of the torque and speed changes.

[0081] like Figure 5 As shown, the model of the servo motor 20 of the present invention is HC 300, and the servo motor 20 is controlled by a servo motor control box 22. Compared with ordinary motors, the servo motor 20 has a large torque. The servo motor 20 can be positioned by pulses through the use of the servo motor control box 22 to form a pulse closed loop, thereby accurately controlling the rotation of the motor to simulate the cutter head excavation effect under different speeds. The servo motor 20 is connected to the motor fixing device 39 by screws. The motor fixing device 39 is welded to the support frame, and a sliding rack 21 is arranged below the support frame. There are tooth plates on both sides of the rack 21. The rack 21 is geared with the dual-axis stepper motor 23, and the rack 21 can move in the horizontal direction. The motor fixing device 39 can protect the servo motor 20 from being affected by other effects. Through the setting of the rack 21, when the dual-axis stepper motor 23 is turned on, the simulated cutter head 59 can move along a straight line to simulate the movement process of the shield machine.

[0082] like Figure 5As shown, the lower surface of the rack 21 of the present invention is provided with a pulley 41, and a linear guide 42 is provided on the workbench 3. The linear guide 42 is fixed to the workbench 3 by screws, and the pulley 41 can move horizontally along the linear guide 42. The installation of the linear guide 42 can ensure that the simulated shield 18 moves along a straight line, and avoid external factors such as eccentric loads affecting the test results.

[0083] The device of the present invention includes a soil excavation face system 9, a mud circulation cabinet 13 and a shield machine simulation system 19. The soil excavation face system 9 is placed on a workbench 3, and the workbench 3 is supported by four columns 1. A shield machine simulation system 19 is provided on the other side of the soil excavation face system 9, and a multifunctional sensor device is provided in the shield machine simulation system 19, and the data of the multifunctional sensor device can be input into a computer. The mud circulation cabinet 13 is connected to the shield machine simulation system 19 or the soil excavation face system 9 through a mud input pipe 49 and a mud output pipe 55. Different connection methods correspond to different test conditions. During the test, the soil and mud to be tested are added to the soil excavation face system 9, and the shield machine simulation system 19 cuts the soil. At the same time, the mud circulation cabinet 13 completes the separation and transportation of mud and water, simulating the excavation process of the mud-water balance shield. By reading and analyzing the excavation parameters collected by various sensors, the formation mechanism and treatment of mud cake under different formation conditions in slurry shield construction can be systematically studied; the influence of various admixtures on the mud circulation effect and the stability of the shield excavation face can be studied. This device provides reference and reference for engineering practice from two aspects: mud cake treatment and maintaining the stability of the shield excavation face.

[0084] Example 2

[0085] The test device for simulating mud-water balance shield cutter head mud cake treatment and excavation face stability of Example 1 can be used to carry out the following four types of test contents, that is, the methods for carrying out the following four types of experiments. The order of the following tests can be freely adjusted, and the test conditions can be added by oneself on the basis of meeting the actual engineering conditions.

[0086] Test 1: Mud-water separation cycle material selection test, including the following test steps:

[0087] Step 1: Weigh flocculation polymers of the same type but different masses or of different types but the same mass, or prepare flocculants of the same type but different concentrations or of different types but the same concentration for later use, and let stand for 60 minutes.

[0088] Step 2: Close the slurry discharge valve 2 at the bottom of the mud chamber 10 in the soil excavation surface system 9, close the feed switch A34 of the feed hopper A8 on the side of the mud chamber 10, the slurry inlet valve 35 and the slurry outlet valve 36, place the extractable plate 33 between the mud chamber 10 and the soil bin chamber 4, and tighten the waterproof rubber gasket between the mud chamber 10 and the extractable plate 33. Gently push the simulated shield shell 18 in the shield machine simulation system 19 along the linear guide rail 42 on the workbench 3, insert it into the shield guide flange 11 on the side of the mud chamber 10, and then check the waterproofness of the system to form a closed space between the mud chamber 10 and the simulated shield shell 18.

[0089] Step 3: Connect the mud input pipe 49 and the mud output pipe 55 on one side of the mud chamber 10 to the mud circulation cabinet 13 respectively, then insert the coarse particle filter 14 and the fine particle filter 16 into the first filter area 50 and the second filter area 56 respectively, close the feed switch B of the feed funnel B12 on one side of the mud and water circulation cabinet 13, and then check the waterproofness of the system.

[0090] Step 4: Open the feed switch B of the feed funnel B12 on one side of the mud circulation cabinet 13, pour in the shield mud sampled on site, start the mud water circulation pump 17, open the mud inlet valve 35 and the mud outlet valve 36 on one side of the mud chamber 10, observe the values ​​of the liquid flow meters on the mud inlet pipe 49 and the mud outlet pipe 55, and continuously adjust the mud water circulation pump 17. When the values ​​are stable and similar, record the mud specific gravity and viscosity values ​​on the digital display screen 46 of the mud chamber 10, which are recorded as G. S1 With V 1 .

[0091] Step 5: Turn on the switch of the magnetic stirrer 15 on the mud circulation cabinet 13, so that the rotor 57 of the mud flocculation area 52 starts to rotate and stir the mud, and then add various flocculants and flocculation polymers prepared in step 1 through the feed funnel B12. After the degree on the digital display screen 46 stabilizes, record the G of each group. S With V.

[0092] Step 6: According to the test plan, select the optimal type and ratio of flocculants or flocculant polymers suitable for the on-site mud, and come up with a solution suitable for mud-water separation circulation.

[0093] Step 7: Open the slurry discharge valve 2 on one side of the mud chamber 10, and let clean water in through the feed funnel B12 to discharge the shield mud and various waste liquids. Then disassemble the mud circulation cabinet 13 and the cleaning plate of the mud chamber 10, clean the test device and maintain it for the next use.

[0094] Experiment 2: Mud cake production rate and mechanism research experiment, including the following experimental steps:

[0095] Step 1: Before the test, weigh the masses of the simulated cutter head 59 and the simulated shield shell 18, denoted as m and m respectively.1 With m 2 .

[0096] Step 2: Close the slurry discharge valve 2 at the bottom of the soil chamber 4 in the soil excavation surface system 9, place the extractable plate 33 between the mud chamber 10 and the soil chamber 4, and tighten the waterproof rubber gasket between the mud chamber 10 and the extractable plate 33. Remove the pressure frame A25 above the soil chamber 4 in the soil excavation surface system 9, open the movable chamber door 5, pour the soil taken on site into the soil chamber, and compact it.

[0097] Step 3: Place the pressure frame A25 on the pressure transmission plate 26, and screw the pressure transmission screw 24 into the pressure transmission screw pin 43. According to the different formation stresses that need to be simulated in the test plan, add weights 27 to the hanging plate on one side of the force transmission lever 30, and use the adjustment handwheel 28 to adjust the height of the constraint baffle 29 so that the force transmission lever 30 is in a balanced state, and pressure is applied to the soil layer through the pressure transmission plate 26.

[0098] Step 4: Close the slurry discharge valve 2 at the bottom of the mud chamber 10 in the soil excavation face system 9, close the feed switch A34 of the feed funnel A8 on the side of the mud chamber 10, as well as the slurry inlet valve 35 and the slurry outlet valve 36, and gently push the simulated shield shell 18 in the shield machine simulation system 19 along the linear guide rail 42 on the workbench 3, and insert it into the shield guide flange 11 on the side of the mud chamber 10. Then check the waterproofness of the system to form an enclosed space between the mud chamber 10 and the simulated shield shell 18.

[0099] Step 5: Unscrew the waterproof screw of the water pipe channel 61 at the rear end of the shield shell 18 in the shield machine simulation system 19, connect the mud input pipe 49 and the mud output pipe 55 on one side of the mud circulation cabinet 13 to the water pipe channel 61 at the rear end of the shield shell, and then respectively insert the coarse particle filter 14 and the fine particle filter 16 into the first filter area 50 and the second filter area 56. Close the feed switch B of the feed funnel B12 on one side of the mud circulation cabinet 13, and then check the waterproofness of the system.

[0100] Step 6: Pull out the removable plate 33 between the mud chamber 10 and the soil bin chamber 4, open the feed switch B of the feed funnel B12 on one side of the mud circulation cabinet 13, pour in the shield mud sampled on site, start the mud and water circulation pump 17, open the slurry inlet valve 35 and the slurry outlet valve 36 on one side of the mud chamber 10, observe the values ​​of the liquid flow meters on the mud inlet pipe 49 and the mud outlet pipe 55, and continuously adjust the mud and water circulation pump 17 to make the values ​​stable.

[0101] Step 7: Turn on the dual-axis stepper motor 23 to make the simulated shield shell 18 move forward slowly. When it contacts the soil, the pressure sensor 58 at the front of the simulated cutter head 59 will transmit a pressure signal. When the pressure value of the excavation surface is stable, turn on the servo motor 20 and adjust the speed. The simulated cutter head 59 rotates at a speed of 1 to 5 rpm to cut the soil, simulating the shield tunneling excavation process.

[0102] The speed at which the simulated shield 18 slowly advances is preferably 0.5 to 1.5 cm / s.

[0103] Step 8: After the excavation is completed, take out the simulated shield 18, separate the simulated shield 18 and the simulated cutter head 59 with a screwdriver, weigh the masses of the simulated cutter head 59 and the simulated shield 18, and record them as m respectively. 3 With m 4 , the mass of the mud cake in this formation is M=m 3 +m 4 -m 1 +m 2 .

[0104] Step 9: The initial simulated cutter head 59 rotation speed, pressure, temperature and other working conditions can be adjusted. According to the above operation steps and formulas, the formation mechanism and formation law of the shield cutter head mud cake under various external conditions can be studied.

[0105] Test 3: Mud-water balance excavation surface stability test, including the following test steps:

[0106] Step 1: Prepare mud dispersants or foaming agents of the same type but different concentrations and different types and the same concentration for standby use, and let them stand for 60 minutes. It is recommended that the concentration of the same type of dispersants or foaming agents be configured in a gradient pattern within a certain range.

[0107] Step 2: Close the slurry discharge valve 2 at the bottom of the mud chamber 10 in the soil excavation surface system 9, close the feed switch A34 of the feed hopper A8 on the side of the mud chamber 10, the slurry inlet valve 35 and the slurry outlet valve 36, place the extractable plate 33 between the mud chamber 10 and the soil bin chamber 4, and tighten the waterproof rubber gasket between the mud chamber 10 and the extractable plate 33. Gently push the simulated shield shell 18 in the shield machine simulation system 19 along the linear guide rail 42 of the workbench 3, insert it into the shield guide flange 11 on the side of the mud chamber 10, and then check the waterproofness of the system to form a closed space between the mud chamber 10 and the simulated shield shell 18.

[0108] Step 3: Connect the mud input pipe 55 and the mud output pipe 49 on one side of the mud chamber 10 to the mud circulation cabinet 13 respectively, then insert the coarse particle filter 14 and the fine particle filter 16 into the first filter area 50 and the second filter area 56 respectively, close the feed switch B of the feed funnel B12 on one side of the mud circulation cabinet 13, and then check the waterproofness of the system.

[0109] Step 4: Pull out the removable plate 33 between the mud chamber 10 and the soil chamber 4, open the feed switch B of the feed funnel B12 on one side of the mud circulation cabinet 13, pour in the shield mud sampled on site, start the mud water circulation pump 17, open the mud inlet valve 35 and the mud outlet valve 36 on one side of the mud chamber 10, observe the values ​​of the liquid flow meters on the mud inlet pipe 49 and the mud outlet pipe 55, and continuously adjust the mud water circulation pump 17. When the values ​​are stable and close, record the mud specific gravity and viscosity values ​​on the mud chamber digital display screen 46, which are recorded as G S2 With V 2 .

[0110] Step 5: Open the feed switch A34 of the feed hopper A8 on one side of the mud chamber 10, and let the dispersant and foaming agent prepared in step 1 enter through the feed hopper A8. After the reading on the digital display screen 46 stabilizes, record the G of each group. S When the excavation face alarm indicator 47 turns red, it means that the dispersant or foaming agent configured under the test condition will cause the excavation face to become unstable, which will pose a great safety hazard to the shield construction, and the concentration under this gradient should be eliminated.

[0111] Step 6: According to the test plan, select the type of dispersant or foaming agent suitable for the on-site mud and the ratio range that can maintain the stability of the excavation surface, providing a reference for the construction safety of the shield excavation process.

[0112] Step 7: Open the slurry discharge valve 2 on one side of the mud chamber 10, and let clean water in through the feed funnel B12 to discharge the shield mud and various waste liquids. Then disassemble the mud circulation cabinet 13 and the cleaning plate of the mud chamber 10, clean the test device and maintain it for the next use.

[0113] Test 4: Mud-water balance mud cake treatment test, including the following test steps:

[0114] Step 1: Before the test, weigh the masses of the simulated cutter head 59 and the simulated shield shell 18, denoted as m and m respectively. 1 With m 2 Prepare mud dispersants or foaming agents of the same type but different concentrations or different types but the same concentrations for later use and let them stand for 60 minutes.

[0115] Step 2: Close the slurry discharge valve 2 at the bottom of the soil chamber 4 in the soil excavation surface system 9, place the extractable plate 33 between the mud chamber 10 and the soil chamber 4, and tighten the waterproof rubber gasket between the mud chamber 10 and the extractable plate 33. Remove the pressure frame A25 above the soil chamber 4 in the soil excavation surface system 9, open the movable chamber door 5, pour the soil taken on site into the soil chamber 4, and compact it.

[0116] Step 3: Place the pressure frame A25 on the pressure transmission plate 26, and screw the pressure transmission screw 24 into the pressure transmission screw pin 43. According to the different formation stresses that need to be simulated in the test plan, add weights 27 to the hanging plate on one side of the force transmission lever 30, and use the adjustment handwheel 28 to adjust the height of the constraint baffle 29 so that the force transmission lever 30 is in a balanced state, and pressure is applied to the soil layer through the pressure transmission plate 26.

[0117] Step 4: Close the slurry discharge valve 2 at the bottom of the mud chamber 10 in the soil excavation face system 9, close the feed switch A34 of the feed funnel A8 on the side of the mud chamber 10, as well as the slurry inlet valve 35 and the slurry outlet valve 36, and gently push the simulated shield shell 18 in the shield machine simulation system 19 along the linear guide rail 42 on the workbench 3, and insert it into the shield guide flange 11 on the side of the mud chamber 10. Then check the waterproofness of the system to form an enclosed space between the mud chamber 10 and the simulated shield shell 18.

[0118] Step 5: Unscrew the waterproof screw of the water pipe channel 61 at the rear end of the simulated shield shell 18 in the shield machine simulation system 19, connect the mud input pipe 49 and the mud output pipe 55 on one side of the mud circulation cabinet 13 to the water pipe channel 61 respectively, and then insert the coarse particle filter 14 and the fine particle filter 16 into the first filter area 50 and the second filter area 56 respectively. Close the feed switch B of the feed funnel B12 on one side of the mud circulation cabinet 13, and then check the waterproofness of the system.

[0119] Step 6: Pull out the removable plate 33 between the mud chamber 10 and the soil bin chamber 4, open the feed switch B of the feed funnel B12 on one side of the mud circulation cabinet 13, pour in the shield mud sampled on site, start the mud and water circulation pump 17, open the slurry inlet valve 35 and the slurry outlet valve 36 on one side of the mud chamber 10, observe the values ​​of the liquid flow meters on the mud inlet pipe 49 and the mud outlet pipe 55, and continuously adjust the mud and water circulation pump 17 to make the values ​​stable.

[0120] Step 7: Turn on the dual-axis stepper motor 23 to make the simulated shield shell 18 move forward slowly. When it contacts the soil, the pressure sensor 58 at the front of the simulated cutter head 59 will transmit a pressure signal. When the pressure value of the excavation surface is stable, turn on the servo motor 20 and adjust the speed. The simulated cutter head 59 rotates to cut the soil, simulating the shield tunneling excavation process.

[0121] Step 8: Open the feed switch A34 of the feed hopper A8 on one side of the mud chamber 10, and the dispersant and foaming agent configured in step 1 are introduced through the feed hopper A8. The addition of the dispersant and foaming agent can reduce the formation of mud cake.

[0122] Step 9: After the excavation is completed, take out the simulated shield 18, separate the simulated shield 18 and the simulated cutter head 59 with a screwdriver, weigh the masses of the simulated cutter head 59 and the simulated shield 18, and record them as m respectively. 3 With m 4The mass of the mud cake in this formation is M = m 3 +m 4 -m 1 +m 2 .

[0123] Step 10: You can adjust different initial cutter head speed, pressure, temperature and other working conditions. According to the above operating steps and formulas, you can study the treatment effect of dispersants and foaming agents on mud cake under various external conditions.

[0124] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0125] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0126] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the intention that the claimed invention requires more features than those expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in less than all of the features of the individual embodiments previously disclosed. Therefore, the claims that follow the detailed description are hereby expressly incorporated into the detailed description, with each claim itself serving as a separate embodiment of the present invention.

[0127] As used herein, unless otherwise specified, the use of ordinal numbers "first," "second," "third," etc. to describe common objects merely indicates that different instances of similar objects are involved, and is not intended to imply that the objects so described must have a given order in time, space, order, or in any other manner.

[0128] Although the present invention has been described according to a limited number of embodiments, it will be apparent to those skilled in the art, with the benefit of the above description, that other embodiments may be envisioned within the scope of the invention thus described. In addition, it should be noted that the language used in this specification is selected primarily for readability and teaching purposes, rather than for explaining or defining the subject matter of the present invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the present invention is illustrative, not restrictive, with respect to the scope of the present invention, which is defined by the appended claims.

[0129] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A test device for simulating the treatment of mud cake on the cutter head of a slurry balance shield and the stability of the excavation surface, characterized in that: It includes a soil excavation face system (9), a mud circulation cabinet (13) and a shield machine simulation system (19); The soil excavation surface system (9) is movably connected to the shield machine simulation system (19); The slurry circulation cabinet (13) is connected to the soil excavation surface system (9) or the shield machine simulation system (19) through pipelines: The soil excavation surface system (9) and the shield machine simulation system (19) are both placed on a workbench (3) supported by a column (1); The soil excavation surface system (9) comprises a soil chamber (4) and a mud chamber (10) separated by a removable plate (33), and a movable chamber door (5) is hingedly connected to the top of the soil chamber (4); A stratum pressurizing device (7) is installed above the soil chamber (4) and is used to pressurize the soil in the soil chamber (4); The opposing surfaces of the slurry chamber (10) and the shield machine simulation system (19) are provided with a shield guide flange (11); The side of the mud chamber (10) is connected to the pipeline of the mud circulation cabinet (13) through a mud inlet valve (36) and a mud outlet valve (35); A feed hopper A (8) is installed at the front side of the mud chamber (10), and a switchable partition 1 is provided at the feed inlet of the feed hopper A (8), and the partition 1 is controlled by a feed switch A (34); A mud specific gravity and viscosity sensor (44) is installed inside the mud chamber (10). The mud specific gravity and viscosity sensor (44) is connected to a digital display screen (46) at the front side of the mud chamber (10). An excavation face alarm indicator light (47) is installed on the right side of the digital display screen (46). The excavation face alarm indicator light (47) is connected to the mud specific gravity and viscosity sensor (44): The mud circulation cabinet (13) comprises, from top to bottom, a first filtering area (50), a mud flocculation area (52), a second filtering area (56) and a mud sedimentation area (54); each area is separated by a detachable grille (51); and a detachable observation port is provided on one side of each area; The first filter zone (50) is connected to the soil excavation face system (9) or the shield machine simulation system (19) via a mud input pipe (49), a liquid flow meter (48) is installed on the mud input pipe (49), a removable coarse particle filter (14) is provided in the first filter zone (50), and the first filter zone (50) is connected to the mud flocculation zone (52) via a PVC pipe (1); A feed hopper B (12) is installed on the side of the mud flocculation zone (52), and a switchable baffle plate 2 is provided at the feed port of the feed hopper B (12), and the baffle plate 2 is controlled by the feed switch B; a magnetic stirrer (15) is installed below the mud flocculation zone (52), and a rotor (57) is placed on the magnetic stirrer (15); the mud flocculation zone (52) and the second filtration zone (56) are connected via a second PVC pipe; A removable fine particle filter (16) is provided in the second filtering area (56), and the second filtering area (56) is connected to the mud sedimentation area (54) via a PVC pipe three (53); The mud settling area (54) is connected to the soil excavation surface system (9) or the shield machine simulation system (19) via a mud output pipe (55) and a mud circulation pump (17); a second liquid flow meter is installed on the mud output pipe (55); and a second mud specific gravity viscosity sensor is arranged inside the mud settling area (54); A mud inlet valve (35) and a mud outlet valve (36) are provided on the side of the mud chamber (10); when the mud chamber (10) is connected to the mud circulation cabinet (13), the mud inlet pipe (49) passes through the mud inlet valve (35), and the mud outlet pipe (55) passes through the mud outlet valve (36).

2. The test device for simulating the treatment of mud cake on the cutter head of a slurry balance shield and the stability of the excavation surface according to claim 1 is characterized in that: The stratum pressurizing device (7) comprises a pressure transmission plate (26) for contacting the soil in the soil chamber (4); the pressure transmission plate (26) is connected to a pressure frame A (25) via a pressure transmission screw (24); the pressure frame A (25) is located above the soil chamber (4); the pressure frame B (31) is located below the soil chamber (4); both ends of the pressure frame A (25) and the pressure frame B (31) are connected by a vertical rod; the upper surface of the pressure frame B (31) is hinged with a pressure transmission lever (30 ), a balance weight (32) is provided at one end of the pressure transmission lever (30), a hanging plate is suspended at the other end of the pressure transmission lever (30), a weight (27) is placed in the hanging plate, and two vertical poles are symmetrically connected to the lower surface of the workbench (3) close to the mud chamber (10), and a connecting plate located below the pressure transmission lever (30) is connected between the two vertical poles, and an adjusting hand wheel (28) is rotatably connected to the connecting plate through a screw rod, and the top surface of the screw rod conflicts with a restraining baffle (29) movably connected to the two vertical poles.

3. The test device for simulating the treatment of mud cake on the cutter head of a slurry shield and the stability of the excavation surface according to claim 2 is characterized in that: The shield machine simulation system (19) comprises a simulated shield shell (18), a simulated cutter head (59) and a power device; The simulated cutter disc (59) is connected to the power device via a rotating main shaft (38); The simulated shield (18) is a detachable soil box, and the simulated cutterhead (59) is connected to the simulated shield (18); a simulated segment barrel is arranged inside the simulated shield (18), and two water pipe channels (61) are arranged at the rear end of the simulated segment barrel, and the water pipe channels (61) are movably connected to the mud output pipe (55) and the mud input pipe (49), respectively; the rotating main shaft (38) passes through the simulated segment barrel and a waterproof rubber bearing (45) is arranged at the junction with the simulated segment barrel; An embedded pressure sensor (58) is installed at the center of the cutter head of the simulated cutter head (59), and the pressure sensor (58) is connected to a computer; A heating plate (60) is welded on the back of the simulated knife disc (59), and the heating plate (60) is controlled by a temperature controller (40), and the temperature controller (40) is placed on the workbench (3); The power device comprises a servo motor (20) connected to the rotating main shaft (38); a torque speed sensor (37) and a coupling are arranged on the rotating main shaft (38); the torque speed sensor (37) is connected to a computer; The servo motor (20) is controlled by a servo motor control box (22) arranged on the workbench (3); The servo motor (20) is connected to a motor fixing device (39), the motor fixing device (39) is welded to a supporting frame, a sliding rack (21) is arranged below the supporting frame, both sides of the sliding rack (21) are provided with tooth plates, the sliding rack (21) is gear-connected with a dual-axis stepping motor (23) arranged on the workbench (3), a pulley (41) is arranged on the lower surface of the sliding rack (21), and a linear guide rail (42) adapted to the pulley (41) is arranged on the workbench (3).

4. The test device for simulating the treatment of mud cake on the cutter head of a slurry balance shield and the stability of the excavation surface according to claim 3 is characterized in that: When the water pipe channel (61) is not connected to the mud circulation cabinet (13), the water pipe channel (61) is sealed by screwing in a waterproof screw.

5. The test device for simulating the treatment of mud cake on the cutter head of a slurry shield and the stability of the excavation surface according to claim 4 is characterized in that: The length ratio of the soil chamber (4) to the mud chamber (10) is 5:1; the front side of the soil chamber (4) and the upper side of the mud chamber (10) are both visible materials; the bottom ends of the soil chamber (4) and the mud chamber (10) are both equipped with slurry discharge valves (2); a pressure transmission screw pin (43) is provided on the pressure transmission plate (26), and the pressure transmission screw (24) is screwed into the pressure transmission screw pin (43).

6. The method of the test device for simulating the treatment of mud cake on the cutter head of a slurry balance shield and the stability of the excavation surface according to claim 5, characterized in that: The simulation of mud and water circulation on the excavation surface includes the following steps: Step 1: Unscrew the waterproof screw on the water pipe channel (61) at the rear end of the simulated shield shell (18) in the shield machine simulation system (19), connect the mud input pipe (49) and the mud output pipe (55) on one side of the mud circulation cabinet (13) to the water pipe channel (61), and then insert the coarse particle filter (14) and the fine particle filter (16) into the first filter area (50) and the second filter area (56), respectively; Step 2: Open the feed switch B of the feed funnel B (12) on one side of the mud circulation cabinet (13), pour in the shield mud sampled on site, start the mud circulation pump (17), and close the mud inlet valve (35) and the mud outlet valve (36) on one side of the mud chamber (10); Step 3: Observe the values ​​of liquid flow meter 1 (48) and liquid flow meter 2 on the mud input pipe (49) and the mud output pipe (55), and continuously adjust the mud circulation pump. When the values ​​of liquid flow meter 1 (48) and liquid flow meter 2 are stable and similar, the excavation surface is in a balanced state of mud and water circulation.

7. The method of the test device for simulating the treatment of mud cake on the cutter head of a slurry balance shield and the stability of the excavation surface according to claim 5, characterized in that: The simulation of different formation stress states includes the following steps: Step 1: Close the slurry discharge valve (2) at the bottom of the soil chamber (4) in the soil excavation surface system (9), place the extractable plate (33) between the mud chamber (10) and the soil chamber (4), and fasten the waterproof rubber gasket between the mud chamber (10) and the extractable plate (33); Step 2: Remove the pressure frame A (25) above the soil chamber (4) in the soil excavation surface system (9), open the movable chamber door (5), pour the soil taken on site into the soil chamber (4), and compact it; Step 3: Place the pressure frame A (25) on the pressure transmission plate (26), and screw the pressure transmission screw (24) into the pressure transmission screw pin (43). According to the different stratum stresses to be simulated in the test plan, add a weight (27) to the hanging plate on one side of the pressure transmission lever (30), and use the adjustment hand wheel (28) to adjust the height of the restraining baffle (29) so that the pressure transmission lever (30) is in a balanced state, and pressure is applied to the soil through the pressure transmission plate (26).

8. The method of the test device for simulating the treatment of mud cake on the cutter head of a slurry shield and the stability of the excavation surface according to claim 5, characterized in that: The shield cutterhead excavation simulation includes the following steps: Step 1: gently push the simulated shield shell (18) in the shield machine simulation system (19) along the linear guide rail (42) on the workbench (3) and insert it into the shield guide flange (11) on the side of the mud chamber (10); Step 2: Turn on the dual-axis stepper motor (23), adjust the dual-axis stepper motor (23), and make the simulated shield (18) move forward at a speed of 0.5 to 1.5 cm / s. When the simulated shield (18) contacts the soil in the soil chamber (4), the pressure sensor (58) at the front end of the simulated cutter head (59) transmits a pressure signal to the computer; Step 3: When the excavation face pressure value is stable, the servo motor (20) is turned on and the rotation speed is adjusted to 1 to 5 rpm to simulate the rotation of the cutterhead (59) to cut the soil, thereby simulating the shield tunneling excavation process.

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