A high-pressure environment under bentonite mud anti-dispersion performance test system

Abstract

The application provides a high-pressure environment bentonite mud anti-dispersion performance test system, which comprises a sealed test module, a pumping module, a collection module and a central control module. The sealed test module comprises a base and a test cavity, both ends of the test cavity are provided with a sealing assembly and a pressure relief assembly, the sealing assembly provides a closed pressure environment required for testing, and the pressure relief assembly maintains the pressure environment in the test cavity; the pumping module is arranged at the liquid inlet end of the test cavity to transport bentonite mud and clean water. The collection module is arranged at the liquid outlet end of the test cavity to collect and weigh the mass of the mixture after testing; the central control module is connected with the pumping module, the components in the test cavity and the collection module through PLC communication connection to control the pumping frequency, the pressure in the test cavity and the collection of the mass of the mixture during testing. The test system can simulate the hydrostatic anti-dispersion performance and the dynamic water anti-scouring capacity of the bentonite mud in the pressure environment, and provides a visual test environment throughout the process.

Description

Technical Field

[0001] This invention relates to the field of underground engineering material performance testing technology, and more specifically, to a system for testing the anti-dispersion performance of bentonite slurry under high pressure. Background Technology

[0002] Slurry-balanced shield tunneling machines (SMTs) are widely used in complex conditions such as high water pressure and flowing groundwater due to their excellent pressure control and construction safety. Their core construction principle relies on bentonite slurry to accumulate at the excavation face, forming a mud film to effectively transfer support forces. However, conventional bentonite slurry is prone to particle dispersion and slurry escape under these complex conditions, leading to a rapid decline in its basic properties. This significantly deteriorates the mud film formation process at the excavation face, seriously threatening the stability of the excavation face and tunneling safety. Therefore, it is necessary to modify and optimize conventional bentonite slurry to specifically improve its resistance to water dispersion while maintaining its thixotropic properties, in order to meet the construction requirements of slurry-balanced shield tunneling machines under high water pressure and flowing groundwater conditions.

[0003] Bentonite grout is one of the commonly used materials in shield tunneling construction. To address the issue of this type of grouting material being significantly diluted in water-rich environments, current research focuses on the simultaneous grouting of underwater concrete and shield tunneling, primarily conducting the following two types of tests: First, in a still water environment, anti-dispersion performance tests are conducted based on DL / T 5117—2000 "Test Procedure for Underwater Non-Dispersible Concrete"; second, in a dynamic water environment, erosion resistance tests are conducted based on a combination of various working conditions.

[0004] First, it must be considered that the aforementioned technological advancements are all based on visualization under normal pressure or non-visualized under pressure, while slurry-balanced shield tunneling is often used in complex geological environments characterized by "high water pressure and flowing groundwater." Furthermore, the material properties of bentonite slurry differ significantly from those of underwater concrete and the grout used in the shield tunneling process. Therefore, it is necessary to develop a pressure-resistant visualization testing system capable of simulating the aforementioned complex construction environments. Based on this system, further testing of the modified and optimized bentonite slurry under pressure will reveal its static water anti-dispersion performance and dynamic water erosion resistance, enabling a comprehensive and accurate evaluation of its anti-dispersion performance. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a testing system for the anti-dispersion performance of bentonite slurry under high pressure, so as to achieve accurate simulation and testing of the static water anti-dispersion performance and dynamic water anti-scouring performance of bentonite slurry under high pressure.

[0006] To address the aforementioned technical problems, embodiments of the present invention provide a testing system for the anti-dispersion performance of bentonite slurry under high pressure, comprising:

[0007] A sealing test module includes a base and a test chamber. The base is positioned below the test chamber and snaps into the bottom of the test chamber. The test chamber is made of plexiglass, and both ends of the test chamber are equipped with sealing components and pressure relief components. The test chamber, in conjunction with a pumping module and the sealing components, provides a closed pressurized environment for testing the anti-dispersion performance of bentonite slurry. The test chamber, in conjunction with the pumping module and the pressure relief components, maintains the pressure environment within the test chamber.

[0008] A pumping module is located at the inlet end of the test chamber and communicates with the test chamber, and is used to transport bentonite slurry and clean water;

[0009] A data collection module, located at the drain end of the test chamber and connected to the test chamber, is used to collect and weigh the mass of the mixture after testing; and

[0010] The central control module is connected to the pumping module, the components in the test chamber, and the acquisition module via PLC communication. It is used to control the pumping frequency during the test, observe the pressure in the test chamber, and read the mass of the mixture after the test.

[0011] In one embodiment, the base includes:

[0012] Support blocks are symmetrically arranged below the test chamber, with the top of the support blocks engaging with the bottom of the test chamber; and

[0013] A bracket is disposed below the support block and detachably connected to the bottom of the support block.

[0014] In one embodiment, the liquid inlet end is provided with a slurry inlet reserved hole, a water inlet reserved hole, a pressure relief reserved hole and a liquid inlet end center reserved hole, and a first liquid inlet end pressure gauge is installed on the liquid inlet end center reserved hole;

[0015] The drain end is provided with a slurry discharge reserved hole, a drainage reserved hole and a center reserved hole of the drain end, and a first drain end pressure gauge is installed on the center reserved hole of the drain end.

[0016] In one embodiment, the pumping module includes:

[0017] The slurry pump has one end connected to the bentonite slurry tank via a slurry inlet pipe, and the other end connected to the slurry inlet pre-drilled hole via a slurry inlet pipe; and

[0018] The water pump has one end connected to the clean water tank via an inlet pipe, and the other end connected to the water inlet pre-reserved hole via an inlet pipe.

[0019] In one embodiment, the pumpable flow rate range of the slurry pump is 0.18 m³ / s. 3 / h~0.9m3 The pump's flow rate is 0.4 m³ / h, with a variable frequency range of 10Hz to 50Hz. 3 / h~1.8m 3 / h, with a variable frequency range of 10Hz~50Hz.

[0020] In one embodiment, the slurry inlet pipeline is equipped with a slurry inlet valve and a slurry inlet flow meter, and the water inlet pipeline is equipped with a water inlet valve and a water inlet flow meter.

[0021] In one embodiment, the acquisition module includes:

[0022] A storage box is located at the drain end of the test chamber. A drain outlet and a slurry outlet are provided on one side of the storage box. The drain outlet is connected to a pre-drainage hole via a drain pipe, and the slurry outlet is connected to a pre-drainage hole via a slurry outlet pipe.

[0023] A weighing platform is installed at the bottom of the storage box.

[0024] In one embodiment, the drainage pipeline is equipped with a drainage valve and a drainage flow meter, and the slurry discharge pipeline is equipped with a slurry discharge valve.

[0025] In one embodiment, the pressure relief assembly includes:

[0026] A first pressure relief assembly is disposed at the liquid inlet end of the test chamber and communicates with the test chamber through a pressure relief pre-drilled hole on the liquid inlet end; and

[0027] The second pressure relief component is located at the drain end of the test chamber and communicates with the test chamber through a pre-drainage hole on the drain end.

[0028] In one embodiment, the first pressure relief component includes:

[0029] The inlet valve is fixedly connected to the pressure relief reserved hole to adjust the opening degree of the pressure relief reserved hole;

[0030] A safety valve at the inlet end is located on the other side of the valve at the inlet end; and

[0031] A second inlet pressure gauge is installed between the inlet valve and the inlet safety valve, and is connected to the pressure relief port through the inlet valve; and / or

[0032] The second pressure relief assembly includes:

[0033] A drain safety valve is installed at the pre-drained hole, and one end of the drain safety valve is connected to one end of the drain pipe; and

[0034] The second drain end pressure gauge is installed on the drain end safety valve and is connected to the drain reserved hole.

[0035] The above-described solution of the present invention has at least the following beneficial effects:

[0036] (1) The test chamber of the test system of the present invention is made of organic glass tube with a transparency of up to 92%. Unlike conventional visualization materials, the deformation of the inner wall of the organic glass tube is less than 0.7 mm under a pressure of 1.0 MPa, and the pressure fluctuation is less than 5%. With the sealing component, it can provide a stable pressure environment for the anti-dispersion performance test of bentonite mud. It solves the contradiction between the high transparency and insufficient pressure resistance of the test chamber, and breaks through the technical problem of difficulty in directly observing the mud dispersion morphology under simulated water-rich and pressurized environment. It realizes real-time visualization recording of the anti-dispersion process of bentonite mud under pressure.

[0037] (2) The testing system of the present invention integrates two independent pumping devices, both of which are adjustable in pressure and frequency, and is connected to the storage tank and the plexiglass tube. It can simulate various working conditions under complex geological environments and can accurately control the injection flow rate and pressure of mud and water respectively. It can not only perform "static water pressure resistance test", but also accurately control the dynamic water flow rate in the plexiglass tube by adjusting the frequency of the booster pump and the valve opening to perform "dynamic water pressure resistance test", so as to realize the comprehensive testing and evaluation of the anti-dispersion performance of bentonite mud under different flow rate conditions.

[0038] (3) The intelligent weighing system equipped in the testing system of the present invention changes the traditional qualitative analysis mode that relies solely on visual observation or post-test sampling. The system can record the changes in the mass of the suspension in real time during the test, and combined with the data from the flow meter and pressure gauge, it can accurately calculate the loss of mud, providing quantitative data support for evaluating the anti-dispersion performance of mud.

[0039] (4) The testing system of the present invention can avoid the problem of untimely response of the safety valve due to the pressure difference between the inlet and outlet ends by adding safety pressure relief components at the top of the inlet and outlet ends. When the test pressure exceeds 1.2MPa, it will automatically release pressure to prevent the test chamber from failing due to excessive pressure in the pipe caused by misoperation or pipeline blockage, thus ensuring the accuracy and safety of the entire process of bentonite slurry pressure resistance and anti-dispersion performance test. Attached Figure Description

[0040] Figure 1 This is a three-dimensional simulation diagram of the overall structure of the testing system provided in this embodiment of the invention;

[0041] Figure 2 This is a schematic diagram of the overall structure of the test system provided in an optional embodiment of the present invention;

[0042] Figure 3 This is a front view of the inlet sealing flange provided in an optional embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of the specific structure of the connection between the liquid inlet sealing flange and the test chamber and pumping module provided in an optional embodiment of the present invention;

[0044] Figure 5 This is a front view of the drain end sealing flange provided in an optional embodiment of the present invention;

[0045] Figure 6 This is a schematic diagram of the specific structure of the connection between the drain end sealing flange and the test chamber and the acquisition module provided in an optional embodiment of the present invention.

[0046] Explanation of icon numbers:

[0047] 1. Test chamber; 2. Main control cabinet; 3. Clean water tank; 4. Bentonite slurry tank; 5. Agitator motor; 6. Slurry inlet pump; 7. Water inlet pump; 8. Storage box; 9. Weighing platform; 10. Slurry inlet pipeline; 11. Slurry inlet valve; 12. Slurry inlet flow meter; 13. Water inlet pipeline; 14. Water inlet valve; 15. Water inlet flow meter; 16. First inlet pressure gauge; 17. Inlet valve; 18. Inlet safety valve; 19. Second inlet pressure gauge; 20. Positioning. 21. Drainage pipe; 22. Drainage valve; 23. Drainage flow meter; 24. Discharge end safety valve; 25. Second discharge end pressure gauge; 26. Slurry discharge pipe; 27. Slurry discharge valve; 28. First discharge end pressure gauge; 29. ​​Slurry inlet reserved hole; 30. Water inlet reserved hole; 31. Inlet end center reserved hole; 32. Pressure relief reserved hole; 33. Discharge end center reserved hole; 34. Drainage reserved hole; 35. Slurry discharge reserved hole; 36. Bracket; 37. Support block. Detailed Implementation

[0048] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0049] In the description of this invention, it should be understood that the terms "comprising / including," "consisting of," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a product, apparatus, process, or method that comprises a list of elements includes not only those elements but may also include, where necessary, other elements not expressly listed, or elements inherent to such a product, apparatus, process, or method. Without further limitation, an element defined by the phrases "comprising / including," "consisting of," does not exclude the presence of additional identical elements in the product, apparatus, process, or method that includes said element.

[0050] It should also be understood that the terms "upper", "lower", "front", "rear", "left", "right", "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 the present invention and simplifying the description, and do not indicate or imply that the device, component or structure referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation of the present invention.

[0051] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0052] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0053] See Figure 1 and Figure 2 The present invention provides a system for testing the anti-dispersion performance of bentonite slurry under high pressure, which may include a sealing test module, a pumping module, a data acquisition module and a central control module.

[0054] The sealing test module includes a base and a test chamber 1. The base is positioned below the test chamber 1 and snaps into the bottom of the test chamber 1 to support it. Here, the test chamber 1 is an acrylic glass chamber and serves as the core experimental site for testing the anti-dispersion performance of bentonite slurry. It provides the water-rich, high-pressure environment required for the test, thus meeting the complex environmental requirements of simulating the underground construction of a slurry-water balance shield tunnel. Sealing components and pressure relief components are respectively installed at both ends of the test chamber 1. The test chamber 1, in conjunction with the pumping module and the sealing components at both ends, provides the necessary closed, pressurized environment for testing the anti-dispersion performance of bentonite slurry. The test chamber 1, in conjunction with the pumping module and the pressure relief components at both ends, can automatically activate to relieve pressure when the internal pressure exceeds a safety threshold, preventing failure of the test chamber 1 under extreme conditions. Furthermore, it avoids the problem of delayed response of the safety valve due to pressure differences at the inlet and outlet ends, ensuring the accuracy and safety of the test. The pumping module is located at the inlet of test chamber 1 and communicates with it. It is used to deliver bentonite slurry and clean water, and to provide the required pressure and flow rate for the test. The data acquisition module is located at the outlet of test chamber 1 and communicates with it. It is used to collect and weigh the mixture after the test. The central control module is connected to the pumping module, the components in test chamber 1, and the data acquisition module via PLC communication. It is used to control the pumping frequency, the pressure inside test chamber 1, and the mass of the mixture after the test during the test.

[0055] In this embodiment, the test chamber 1 can be an acrylic glass chamber with a transparency of up to 92% and a material capable of withstanding a pressure of 1.0 MPa. Preferably, the test chamber 1 can be a cylindrical chamber with an outer diameter of 300 mm, an inner diameter of 200 mm, and a length of 2 m. Unlike conventional visualization materials, the acrylic glass chamber exhibits an inner wall deformation of less than 0.7 mm under a pressure of 1.0 MPa, with a pressure fluctuation of less than 5%. Combined with a sealing component, this can meet the requirements for conducting anti-dispersion performance tests on bentonite slurry under stable pressure. This solves the contradiction between the high transparency and insufficient pressure resistance of the test chamber, overcomes the technical challenge of directly observing the dispersion morphology of slurry under simulated water-rich and pressurized conditions, and realizes real-time visualization and recording of the pressure-bearing anti-dispersion process of bentonite slurry. Preferably, the test chamber 1 can be a closed cylindrical chamber with a through hole at its end for connecting the pumping module, the acquisition module and other modules. When the chamber is connected to other components, multiple layers of sealing rings or gaskets can be provided at the corresponding connection points to ensure the sealing of the chamber during the test. The sealing component provided at the corresponding end can be a gasket or sealing ring provided at the through hole.

[0056] like Figure 2As shown, preferably, the base may include a bracket 36 and a support block 37; wherein, the bracket 36 is disposed below the test chamber 1, the support block 37 is symmetrically disposed between the test chamber 1 and the bracket 36, and the top of the support block 37 is engaged with the bottom of the test chamber 1, and the bottom of the support block 37 is detachably connected to the bracket 36 to support the test chamber 1; more preferably, the top of the support block 37 is configured with a groove that matches the outer diameter of the plexiglass chamber to more stably support the test chamber 1.

[0057] The pumping module and the data acquisition module are respectively located at both ends of the test chamber 1 (i.e., the inlet and outlet ends). The pumping module delivers bentonite slurry and clean water into the test chamber 1, and simultaneously applies the required pressure and water flow rate to provide the complex environment necessary for the test. Working in conjunction with the sealing and pressure relief components, it maintains a closed, stable, and safe testing environment within the test chamber 1, ensuring the accuracy and safety of the test. The data acquisition module collects the mixture within the test chamber 1 after the test, monitors the quality and performance of the mixture, and communicates with the central control module via a PLC through its built-in weighing module to achieve real-time dynamic recording.

[0058] See Figure 1 and Figure 2 Here, the central control module can be the main control cabinet 2, which serves as the operating platform during the test. It integrates the power status, start / stop status, and operating frequency adjustment switch of the pumping module. Its built-in computer is also connected to the pressure gauges, flow meters, and weighing module in the acquisition module at both ends of the test chamber 1 via PLC communication, so as to realize the real-time dynamic adjustment and observation of the working pressure and water flow rate in the test chamber 1 during the test, thereby ensuring the accuracy of the test.

[0059] See Figure 3 In an optional embodiment of the present invention, the inlet end of the test chamber 1 is provided with a slurry inlet reserved hole 29, a water inlet reserved hole 30 and a center reserved hole 31, and a first inlet end pressure gauge 16 is installed on the center reserved hole 31; the outlet end of the test chamber 1 is provided with a slurry outlet reserved hole 35, a drainage reserved hole 34 and a center reserved hole 33, and a first outlet end pressure gauge 28 is installed on the center reserved hole 33.

[0060] In this embodiment, both the first inlet pressure gauge 16 and the first outlet pressure gauge 28 are electronic pressure gauges, and both are connected to the central control module via PLC communication to monitor and read the pressure at both ends of the test chamber 1 in real time and feed it back to the central control module. Preferably, the inlet center reserved hole 31 is located at the center of the inlet end and is sealed by the first inlet pressure gauge 16; the outlet center reserved hole 33 is located at the center of the outlet end and is sealed by the first outlet pressure gauge 28 to ensure the accuracy and stability of the pressure test at both ends of the test chamber 1.

[0061] By opening a slurry inlet hole 29 and a water inlet hole 30 at the liquid inlet end of the test chamber 1, the test chamber 1 can be connected to the pumping module; by opening a drainage hole 34 and a slurry discharge hole 35 at the liquid outlet end of the test chamber 1, the test chamber 1 can be connected to the acquisition module.

[0062] See Figure 1 , Figure 2 and Figure 4 In an optional embodiment of the present invention, the pumping module may include a slurry pump 6 and a water pump 7. The slurry pump 6 has one end connected to the bentonite slurry tank 4 via a slurry inlet pipe 10, and the other end connected to a slurry inlet pre-drilled hole 29 via the same pipe, for pumping the bentonite slurry required for testing. The water pump 7 has one end connected to the clean water tank 3 via a water inlet pipe 13, and the other end connected to a water inlet pre-drilled hole 30 via the same pipe, for pumping the clean water required for testing. Here, the slurry pump 6 may be a high-pressure plunger pump, and the water pump 7 may be a booster pump.

[0063] In this embodiment, the slurry pump 6 and the water pump 7 are independent of each other and both can be pressure-adjustable and frequency-variable to simulate various working conditions under complex geological environments, and to precisely control the injection flow rate and pressure of the slurry and water respectively. Through the slurry pump 6 (high-pressure plunger pump) and the water pump 7 (booster pump), not only can the "static water pressure resistance to dispersion test" be performed, but also the "dynamic water pressure resistance to scouring test" can be performed by precisely controlling the dynamic water flow rate in the plexiglass cavity by adjusting the frequency of the booster pump and the opening of the pipeline valves, thus achieving a comprehensive test and evaluation of the anti-dispersion performance of bentonite slurry under different flow rate conditions.

[0064] Preferably, the bentonite slurry tank 4 is equipped with a stirring device, which consists of an adjustable-speed stirring motor 5 and stirring blades (placed inside the bentonite slurry tank 4). The adjustable-speed stirring motor 5 plays a crucial role; its speed control device is located in the main control cabinet 2, with a speed adjustment range of 0 rpm to 1400 rpm, to prepare and stir the bentonite slurry required for testing in real time. It should be noted that the operating frequency range of the stirring motor 5 is 0 to 50 Hz, and it has a linear relationship with the speed of the stirring blades.

[0065] See Figure 2 and Figure 4 In an optional embodiment of the present invention, a slurry inlet valve 11 and a slurry inlet flow meter 12 are provided on the slurry inlet pipeline 10, and a water inlet valve 14 and a water inlet flow meter 15 are provided on the water inlet pipeline 13. Preferably, the slurry inlet valve 11 is located at the slurry inlet pre-reserved hole 29, the water inlet valve 14 is located at the water inlet pre-reserved hole 30, the slurry inlet flow meter 12 is located on the slurry inlet valve 11, and the water inlet flow meter 15 is located on the water inlet valve 14 to monitor the slurry inlet flow rate and the water inlet flow rate. Preferably, both the slurry inlet valve 11 and the water inlet valve 14 can be electric valves, and both the slurry inlet flow meter 12 and the water inlet flow meter 15 can be electronic flow meters.

[0066] Here, the power supply status, start / stop status, and operating frequency switches of the slurry pump 6, water pump 7, and stirring motor 5 are respectively connected to the central control module via PLC communication; at the same time, the slurry valve 11, water valve 14, slurry flow meter 12, and water flow meter 15 are respectively connected to the central control module via PLC communication, so as to realize real-time dynamic observation and adjustment of the working pressure and dynamic water flow rate in the test chamber 1 during the test.

[0067] In an optional embodiment of the present invention, the pumpable flow rate range of the slurry pump 6 is 0.18 m³ / s. 3 / h~0.9m 3 The frequency of the feed pump 6 is linearly related to the injection rate of the bentonite slurry, with a variable frequency range of 10Hz to 50Hz. The pumpable flow rate of the water pump 7 is 0.4m³ / h. 3 / h~1.8m 3 / h, with a variable frequency range of 10Hz~50Hz. Here, the operating frequency of the inlet pump 7 is linearly related to the dynamic water flow rate required for the test conditions. By connecting the slurry pump 6 and the water pump 7, which have pressure regulation and frequency conversion functions, to the bentonite mud tank 4, the clear water tank 3, and the test chamber 1, the corresponding dynamic water flow rate can be obtained by adjusting the operating frequency of the pumping device during the test, thereby ensuring the accuracy of the test simulation.

[0068] Here, by setting up the water inlet pipe 13 and the slurry inlet pipe 10, the water inlet channel and the slurry inlet channel of the test system are made independent of each other, and the water inlet pump 7 and the slurry inlet pump 6, which can be infinitely variable in frequency, are selected respectively. The corresponding dynamic water flow velocity is obtained by changing the pump operating frequency. At the same time, according to the formula Q=vA (Q is the water flow rate, A is the cross-sectional area of ​​the water flow, and v is the corresponding dynamic water flow velocity), and the cross-section of the test chamber 1 with an inner diameter of 200mm, the water inlet pump 7 and the slurry inlet pump 6 can achieve water flow velocities of 300m / d~1300m / d and 150m / d~450m / d respectively in the chamber.

[0069] See Figure 1 , Figure 2 and Figure 6 In an optional embodiment of the present invention, the data acquisition module may include a storage box 8 and a weighing platform 9. The storage box 8 is located at the drain end of the test chamber 1, and a drain outlet and a slurry outlet are provided on one side of the storage box 8. The drain outlet is connected to a pre-drainage hole 34 via a drain pipe 21, and the slurry outlet is connected to a pre-drainage hole 35 via a slurry discharge pipe 26. The weighing platform 9 is located at the bottom of the storage box 8.

[0070] In this embodiment, the collection box 8 is placed on the weighing platform 9, with a weighing range of 0 kg to 100 kg and an accuracy of 0.01 kg. It is used to collect the clean water discharged from the test chamber 1 during the test or the mixture after the test. Here, the dimensions of the collection box 8 can be 500 mm × 400 mm × 420 mm. Preferably, a graduated transparent scale is provided on the side of the collection box 8 away from the test chamber 1, with a measuring range of 0 mm to 410 mm and an accuracy of 5 mm, to facilitate real-time observation of the collected mixture.

[0071] The weighing platform 9 integrates a weighing module at its bottom to monitor the mass of the mixture collected in the collection box 8. The weighing module is connected to the central control module via PLC communication to record the changes in the mass of the suspension in real time during the test. This allows for accurate calculation of the mud loss and provides quantitative data support for evaluating mud performance.

[0072] See Figure 6 In an optional embodiment of the present invention, a drainage valve 22 and a drainage flow meter 23 are provided on the drainage pipe 21, and a slurry discharge valve 27 is provided on the slurry discharge pipe 26.

[0073] Preferably, the drain valve 22 is located at the drain reserved hole 34, the slurry discharge valve 27 is located at the slurry discharge reserved hole 35, and the drainage flow meter 23 is located on the drain valve 22 to monitor the drainage flow rate. Preferably, both the drain valve 22 and the slurry discharge valve 27 can be electric valves, and the drainage flow meter 23 can be an electronic flow meter. Here, the drain valve 22, the slurry discharge valve 27, and the drainage flow meter 23 are respectively connected to the central control module via PLC communication to monitor the flow rate of the liquid discharged from the test chamber 1.

[0074] In an optional embodiment of the present invention, the pressure relief assembly may include a first pressure relief assembly and a second pressure relief assembly. The first pressure relief assembly is disposed at the liquid inlet end of the test chamber 1 and communicates with the test chamber 1 through a pressure relief reserved hole 32. The second pressure relief assembly is disposed at the liquid outlet end of the test chamber 1 and communicates with the test chamber 1 through a drainage reserved hole 34.

[0075] Because test chamber 1 has a certain length, the permeation path is relatively long and the hydraulic gradient changes significantly during the test, resulting in a pressure difference between the inlet and outlet ends (e.g., when the pressure at the outlet reaches 1.15 MPa, the pressure at the inlet end may already be above 1.25 MPa). By adding pressure relief components to both the inlet and outlet ends of test chamber 1, when the test pressure exceeds 1.2 MPa, the pressure relief components on both sides are activated simultaneously to automatically relieve pressure in test chamber 1. This ensures the safety of the bentonite slurry throughout the high-pressure anti-dispersion performance test and also ensures the balance of the pressure relief process, guaranteeing the safety and accuracy of the test. In addition, the pressure relief components at both ends can prevent the acrylic glass chamber from shattering due to excessive pressure caused by misoperation or pipeline blockage, and also avoids the problem of untimely response of the safety valve caused by the pressure difference between the inlet and outlet ends, ensuring the safety of the experimental personnel.

[0076] See Figure 4 In an optional embodiment of the present invention, the first pressure relief assembly may include an inlet valve 17, an inlet safety valve 18, and a second inlet pressure gauge 19. The inlet valve 17 is fixedly connected to the pressure relief reserved hole 32 to adjust the opening degree of the pressure relief reserved hole 32; the inlet safety valve 18 is disposed on the other side of the inlet valve 17, and the second inlet pressure gauge 19 is disposed between the inlet safety valve 18 and the inlet valve 17 and communicates with the pressure relief reserved hole 32 through the inlet valve 17.

[0077] See Figure 6 The second pressure relief assembly may include a drain end safety valve 24 and a second drain end pressure gauge 25. The drain end safety valve 24 is located at the drain reserved hole 34, and one end of the drain end safety valve 24 is connected to one end of the drain pipe 21; the second drain end pressure gauge 25 is located on the drain end safety valve 24 and is connected to the drain reserved hole 34.

[0078] In this embodiment, the inlet valve 17 is installed on the pressure relief reserved hole 32 and one side is connected to the inlet safety valve 18. During the test, the inlet valve 17 is normally open so as to monitor the pressure in the test chamber 1.

[0079] Here, both the inlet safety valve 18 and the outlet safety valve 24 can be spring-loaded safety valves. When the pressure inside the test chamber 1 exceeds 1.2 MPa (the safety limit of the safety valves), both safety valves will automatically and quickly open. At this time, the liquid inside the test chamber 1 will flow out through the pipes on the inlet safety valve 18 and the outlet safety valve 24 to relieve pressure and ensure the safety of the test process. When the pressure inside the test chamber 1 returns to the normal range, the inlet safety valve 18 and the outlet safety valve 24 will automatically close to maintain the sealing of the test chamber 1.

[0080] Here, both the second inlet pressure gauge 19 and the second outlet pressure gauge 25 can be mechanical pressure gauges. The second inlet pressure gauge 19 is installed on the inlet pipe section of the inlet safety valve 18 and may be close to the inlet safety valve 18. The second outlet pressure gauge 25 is installed on the inlet pipe section of the outlet safety valve 24 and may be close to the outlet safety valve 24, in order to monitor the pressure inside the test chamber 1 in real time. Here, the current safety status of the test chamber 1 can also be determined by comparing the pressure gauge readings with the safety limit value of the safety valve.

[0081] Preferably, see Figure 2 , Figure 4 as well as Figure 6 The sealing test module may also include a positioning block 20 and an end support seat; the end support seat is set at both ends of the test chamber 1 and is attached to and fixedly connected to the ends of the test chamber 1 (here, the slurry inlet reserved hole 29, water inlet reserved hole 30, liquid inlet end center reserved hole 31, pressure relief reserved hole 32, liquid outlet end center reserved hole 33, drainage reserved hole 34 and slurry discharge reserved hole 35 can be respectively opened on the end support seats at both ends of the test chamber 1 and communicate with the inside of the test chamber 1. At this time, the end support seat serves as the sealing component at both ends of the test chamber 1); the positioning block 20 is set on one side of the end support seat, and one end of the positioning block 20 is screwed to the end support seat and the other end is screwed to the bracket 36, so as to play a positioning role when installing the test chamber 1.

[0082] The testing system provided in the above embodiments of the present invention specifically includes the following steps when performing hydrostatic high-pressure anti-dispersion performance testing:

[0083] Step 11: Add water, bentonite, and additives to bentonite slurry tank 4 in the correct proportions to prepare the bentonite slurry required for testing.

[0084] Step 12: Open the inlet valve 14 and the drain valve 22, and close the remaining valves. Adjust the inlet pump 7 to a low-frequency operating state and start operation to fill and pressurize the test chamber 1 with water;

[0085] Step 13: When the drainage pipe 21 starts to drain, immediately close the drainage valve 22; after pressurization to the set pressure, turn off the operation switch of the water inlet pump 7; then close the water inlet valve 14 to form a pressure holding system in the test chamber 1.

[0086] Step 14: Turn on the power to the grout pump 6 and adjust its operating frequency to a suitable grouting speed; open the grout inlet valve 11 and the operating switch of the grout pump 6. After observing the operating frequency increase from 0, adjust the opening of the drain valve 22 to ensure that the pressure inside the pipe remains stable within the current operating range during the grout injection process.

[0087] Step 15: After the pressure gauge 25 at the second drain end stabilizes and there is no obvious slurry remaining in the bentonite slurry tank 4, turn off the operation switch of the slurry pump 6, and then close the drain valve 22 and the slurry inlet valve 11 to ensure that the test chamber 1 forms a pressure holding system.

[0088] The testing system provided in the above embodiments of the present invention specifically includes the following steps when performing dynamic high-pressure erosion resistance testing:

[0089] Step 21: Weigh out the water, bentonite, and additives in sufficient quantities according to the ratio and add them to the bentonite slurry tank 4 to prepare the bentonite slurry required for the test.

[0090] Step 22: Fully open the inlet valve 14 and the outlet valve 22, and close the remaining valves. Adjust the frequency of the inlet pump 7 to meet the required flow rate of the water under the current operating conditions, and then start the pump to fill and pressurize the test chamber 1 with water.

[0091] Step 23: After the drainage pipe 21 starts to drain water, the opening of the drainage valve 22 is dynamically adjusted based on the real-time reading of the drainage flow meter 23, so as to ensure that the dynamic water flow rate reaches the current working condition requirement under the premise that the working pressure in the test chamber 1 rises slowly.

[0092] Step 24: After confirming that the working pressure and dynamic water flow rate in the current test chamber 1 are stable at the state required for the current working condition, turn on the power of the grout pump 6 and adjust its operating frequency to a suitable grouting speed.

[0093] Step 25: Open the operation switch of the slurry inlet valve 11 and the slurry inlet pump 6 in sequence. After observing that the operating frequency of the slurry inlet pump 6 increases from 0, dynamically adjust the opening of the drain valve 22 again to ensure that the working pressure and dynamic water flow rate in the test chamber 1 remain stable within the range required by the current working conditions.

[0094] Step 26: When there is no obvious slurry remaining in the bentonite mud tank 4, turn off the operation switch of the slurry pump 6 and dynamically adjust the opening of the drain valve 22 again to ensure that the working pressure and water flow rate in the pipe meet the requirements of the working conditions.

[0095] Step 27: After confirming that the current pressure and water flow velocity in the pipe are stable, observe the continuous scouring of the bentonite slurry. When the scouring time reaches 30 minutes, turn off the power to the slurry pump 6 and the water pump 7, and close the drain valve 22, the water inlet valve 14 and the slurry inlet valve 11 in sequence to ensure that the test chamber 1 forms a pressure-holding chamber.

[0096] After the test is completed, the test solution is collected and the data is analyzed, which includes the following steps:

[0097] Step 31: After the suspension in test chamber 1 has been allowed to settle for a period of time, open drain valve 22 and collect the suspension through collection box 8. After the upper suspension has been mostly drained, close all valves.

[0098] Step 32 involves testing the collected suspension for parameters such as turbidity, pH, conductivity, and dissolved oxygen. pH, conductivity, and dissolved oxygen can be measured using a three-in-one sensor, with digital signals fed back to the central control module. Turbidity testing utilizes a portable turbidity meter equipped with a display screen for direct data reading.

[0099] Step 33: After the above data measurement is completed, record the liquid level height of the suspension and calculate the volume (V0) using the graduated transparent scale equipped in the storage box 8; weigh the mass (M0) of the suspension in the storage box 8 using the weighing platform 9 and record it.

[0100] Compare the mass of pure water of the same volume, and calculate the impact of bentonite slurry loss on the suspension using the following formula ( ),in Indicating the density of water:

[0101]

[0102] Step 34: After the relevant data for the suspension have been measured, open the slurry discharge valve 27 and collect the slurry to be tested using a measuring cup with a capacity of 3000 mL. Once the measuring cup is almost full, close all valves again.

[0103] Step 35: Test the physical properties of the collected mud, including density, funnel viscosity, and apparent viscosity. The density is measured using a 1002 mud density scale, the funnel viscosity is measured using a Marshall funnel viscometer, and the apparent viscosity is measured using a six-speed rotational viscometer.

[0104] Step 36: After the above measurements are completed, compare the results of each basic performance index of the mud before and after the pressure anti-dispersion test to characterize the degree of loss of bentonite mud during the test; calculate the mud density loss rate according to the following formula ( ), Funnel viscosity loss rate ( ), plastic viscosity loss rate ( ) and yield stress loss rate ( ):

[0105]

[0106]

[0107]

[0108]

[0109] In the formula, , , , These represent the density, funnel viscosity, plastic viscosity, and yield stress of the mud before the pressurized anti-dispersion test was conducted. , , , These represent the density, funnel viscosity, plastic viscosity, and yield stress of the mud after conducting a pressurized anti-dispersion test.

[0110] Step 37: Compare and analyze the test results under different working conditions, such as different pressures, different flow rates, and different mud ratios, summarize the main factors affecting the anti-dispersion performance of bentonite mud, and conclude the optimal anti-dispersion mud ratio.

[0111] The testing system provided in the above embodiments of the present invention uses a high-pressure resistant plexiglass cavity as the testing chamber, with a light transmittance exceeding 92%. Combined with a pumping module and sealing components, it can provide a visual recording platform and a necessary closed pressurized environment for the entire experimental process. By setting pressure relief components at both ends of the testing chamber, on the one hand, when the pressure inside the testing chamber exceeds the safety threshold, the pressure relief components can automatically activate to relieve pressure, preventing the testing chamber from failing under extreme conditions. On the other hand, it can avoid the problem of untimely response of the safety valve due to the pressure difference between the inlet and outlet ends, thus ensuring the accuracy and safety of the test.

[0112] The above-mentioned testing system can realize the dynamic water anti-dispersion performance test with full visualization under high pressure environment, which solves the contradiction between the high transparency of the test chamber and the insufficient pressure resistance, and overcomes the problem caused by the easy failure of the sealing device under pressure environment, thus meeting the research on the anti-dispersion characteristics of bentonite mud under high pressure environment.

[0113] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A testing system for the anti-dispersion performance of bentonite slurry under high pressure, characterized in that, include: A sealing test module includes a base and a test chamber, wherein the base is disposed below the test chamber and is engaged with the bottom of the test chamber; The test chamber is an acrylic glass chamber, and both ends of the test chamber are equipped with sealing components and pressure relief components. The test chamber, together with the sealing components, provides a closed pressurized environment for testing the anti-dispersion performance of bentonite slurry; the test chamber, together with the pressure relief components, maintains the pressure environment within the test chamber. A pumping module is located at the inlet end of the test chamber and communicates with the test chamber, and is used to transport bentonite slurry and clean water; A collection module is located at the drain end of the test chamber and is connected to the test chamber, used to collect and weigh the mass of the mixture after testing; as well as The central control module is connected to the pumping module, the components in the test chamber, and the acquisition module via PLC communication. It is used to control the pumping frequency during the test, observe the pressure in the test chamber, and read the mass of the mixture after the test.

2. The anti-dispersion performance testing system for bentonite slurry under high pressure environment according to claim 1, characterized in that, The base includes: Support blocks are symmetrically arranged below the test chamber, with the top of the support blocks engaging with the bottom of the test chamber; and A bracket is disposed below the support block and detachably connected to the bottom of the support block.

3. The anti-dispersion performance testing system for bentonite slurry under high pressure environment according to claim 1, characterized in that, The liquid inlet end is provided with a slurry inlet hole, a water inlet hole, and a center reserved hole. A first liquid inlet end pressure gauge is installed on the center reserved hole. The drain end is provided with a slurry discharge reserved hole, a drainage reserved hole and a center reserved hole of the drain end, and a first drain end pressure gauge is installed on the center reserved hole of the drain end.

4. The anti-dispersion performance testing system for bentonite slurry under high pressure environment according to claim 3, characterized in that, The pumping module includes: The slurry pump has one end connected to the bentonite slurry tank via a slurry inlet pipe, and the other end connected to the slurry inlet pre-drilled hole via a slurry inlet pipe; and The water pump has one end connected to the clean water tank via an inlet pipe, and the other end connected to the water inlet pre-reserved hole via an inlet pipe.

5. The anti-dispersion performance testing system for bentonite slurry under high pressure environment according to claim 4, characterized in that, The pumpable flow rate range of the slurry pump is 0.18 m³ / s. 3 / h~0.9m 3 The pump's flow rate is 0.4 m³ / h, with a variable frequency range of 10Hz to 50Hz. 3 / h~1.8m 3 / h, with a variable frequency range of 10Hz~50Hz.

6. The anti-dispersion performance testing system for bentonite slurry under high pressure environment according to claim 4, characterized in that, The slurry inlet pipeline is equipped with a slurry inlet valve and a slurry inlet flow meter, and the water inlet pipeline is equipped with a water inlet valve and a water inlet flow meter.

7. The anti-dispersion performance testing system for bentonite slurry under high pressure environment according to claim 3, characterized in that, The acquisition module includes: A storage box is located at the drain end of the test chamber. A drain outlet and a slurry outlet are provided on one side of the storage box. The drain outlet is connected to a pre-drainage hole via a drain pipe, and the slurry outlet is connected to a pre-drainage hole via a slurry outlet pipe. A weighing platform is installed at the bottom of the storage box.

8. The anti-dispersion performance testing system for bentonite slurry under high pressure environment according to claim 7, characterized in that, The drainage pipeline is equipped with a drainage valve and a drainage flow meter, and the slurry discharge pipeline is equipped with a slurry discharge valve.

9. The anti-dispersion performance testing system for bentonite slurry under high pressure environment according to claim 1, characterized in that, The pressure relief assembly includes: A first pressure relief assembly is disposed at the liquid inlet end of the test chamber and communicates with the test chamber through a pressure relief pre-drilled hole on the liquid inlet end; and The second pressure relief component is located at the drain end of the test chamber and communicates with the test chamber through a pre-drainage hole on the drain end.

10. The anti-dispersion performance testing system for bentonite slurry under high pressure environment according to claim 9, characterized in that, The first pressure relief component includes: The inlet valve is fixedly connected to the pressure relief reserved hole to adjust the opening degree of the pressure relief reserved hole; A safety valve at the inlet end is located on the other side of the valve at the inlet end; and A second inlet pressure gauge is installed between the inlet valve and the inlet safety valve, and is connected to the pressure relief port through the inlet valve; and / or The second pressure relief assembly includes: A drain safety valve is installed at the pre-drained hole, and one end of the drain safety valve is connected to one end of the drain pipe; and The second drain end pressure gauge is installed on the drain end safety valve and is connected to the drain reserved hole.

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