A mud permeation film forming experiment device and a method for measuring mud permeation performance thereof

Abstract

The present application relates to a kind of mud permeation film forming experimental device and the method for measuring mud permeation performance thereof, to solve the problem of low use rate of single adaptation scene in present stage permeation mud film measurement, test cylinder in equipment includes coaxial sleeve internal adjusting cylinder and external observation cylinder, water permeation zone is arranged from bottom to top in internal adjusting cylinder, permeation zone, mud zone and cavity zone, lubricating layer, temperature control device and salt control device are arranged between external observation cylinder and internal adjusting cylinder, and the beneficial effect is that it can be suitable for a variety of construction environment, wide working range, and the degree of automation in adjusting process is high.

Description

Technical Field

[0001] This invention relates to permeability testing equipment for urban subways, cross-river and cross-sea tunnels, and in particular to a mud permeation film-forming experimental device and a method for measuring mud permeability. Background Technology

[0002] In recent years, slurry-balanced shield tunneling machines have been widely used in complex geological environments such as crossing rivers and seas. Slurry-balanced shield tunneling machines balance the water and soil pressure at the excavation face by adjusting the slurry pressure within the pressure chamber. Because the slurry pressure is greater than the pore water pressure of the strata, fine particles in the slurry permeate into the strata under the pressure difference, forming an impermeable mud film, thus stabilizing the strata. Therefore, the permeability and film-forming characteristics of the slurry directly affect the stability of slurry-balanced shield tunneling.

[0003] Currently, domestic testing equipment for mud permeability formations is quite large, and obtaining multiple sets of mud permeability results is time-consuming. Among published Chinese patent documents, patent CN 207470190 U discloses a device for simulating mud film formation at the excavation face of a slurry shield tunnel and measuring the permeability coefficient of the mud film. This device can directly measure the permeability coefficient of the mud film after it has formed using clean water, providing more accurate test results. However, the applicant argues that with the development of shield tunneling technology, the combination of a simple structure and reverse osmosis technology is insufficient to handle various shield tunneling scenarios. For example, the high sodium chloride content in the rock strata of submarine tunnels has a destructive effect on mud film formation. Similarly, the temperature environment of the rock strata in high-altitude permafrost or low-altitude sandy environments differs from normal temperature, also affecting mud film formation. These factors are not considered in current measurement methods, resulting in limited applicability and a narrow measurement scope for the equipment.

[0004] Therefore, how to quickly obtain the permeability of mud under various geological conditions, and how to ensure that the various functions are not mutually exclusive, is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a mud permeation film-forming test device adapted to multiple modes and a method for measuring mud permeability performance.

[0006] This application provides a mud permeation film forming test device adaptable to multiple modes, including a test cylinder, a main system, and a pressurization system. The test cylinder is placed on the main system. The test cylinder is made of transparent material and has horizontal graduations. A drain pipe is installed at the bottom of the test cylinder, and the top of the test cylinder is connected to the output end of the pressurization system. The test cylinder includes an internal adjustment cylinder and an external observation cylinder coaxially mounted. The internal adjustment cylinder has a water permeability zone, a permeation zone, a mud zone, and a cavity zone from bottom to top. A lubrication layer, a temperature control device, and a salt control device are provided between the external observation cylinder and the internal adjustment cylinder.

[0007] The main system includes a gantry frame and a bottom support. A sealing cover that mates with the test cylinder is installed on the gantry frame. The bottom support includes a movable sector plate and a supporting component for the movable sector plate. The movable sector plate is slidably connected to the gantry frame.

[0008] The pressurization system includes an air source and a pressure regulator connected to the air source. The pressure regulator includes a first pressure gauge and a pressure reducer. The first pressure gauge measures the outlet pressure of the pressure reducer. The air outlet of the pressure reducer is connected to the vent of the permeation zone through an air pipe. One end of the air pipe connected to the vent is equipped with a vent valve adapted to a multi-mode mud permeation film forming test device.

[0009] The pressurization system also includes an air pump and a second pressure gauge. The second pressure gauge measures the outlet pressure of the air pump, and the air outlet of the air pump is connected to the air inlet of the pressure reducer through the air pipe.

[0010] The temperature control device includes heating guide wires coiled in a serpentine pattern on both sides of the inner side of the external observation tube.

[0011] The heating guide wire is replaced by a semiconductor cooling ring inserted on both sides of the outer observation tube.

[0012] The salt control device is installed on the sealing cover. The salt control device includes a pressure-type jog on / off valve. One end of the pressure-type jog on / off valve is connected to a spray outlet, and the other end is connected to a brine storage tank. The spray outlet faces the inside of the test cylinder.

[0013] A protruding observation window is provided in the lower middle part of the external observation tube. The observation window is flat and perpendicular to the horizontal plane.

[0014] A method for measuring mud permeability, using the aforementioned multi-mode mud permeability film-forming test apparatus, includes the following steps:

[0015] S1 equipment preparation:

[0016] (1) The bottom of the test cylinder is sealed to form a pressure circuit. Under normal temperature and pressure, permeable stone, test soil layer and test mud are placed in the test cylinder in sequence.

[0017] (2) Adjust the sealing cap to seal the inner cavity of the test cylinder and then open the vent valve of the pressurization system. As the internal pressure of the pressurization system increases, open the valve of the water pipe of the test cylinder. The permeable zone is composed of a transparent cylinder with scale lines. Permeable stone, test soil layer and test mud are placed in the transparent cylinder in sequence.

[0018] S2 Permeability Test: The mud in the permeable zone seeps down through the test soil layer, and the solidified material remains above the permeable zone (17) to form a mud film. The liquid flows through the permeable zone to the bottom of the test tube and drips into the collection tube. The time is started from the initial dripping liquid. The permeability test ends after 30 minutes, and the mud film thickness is recorded.

[0019] S3 Environment Adjustment:

[0020] (1) The temperature control device includes an electrothermal conversion circuit, which is electrically connected to the mains power to simulate different ambient ground temperatures;

[0021] (2) Prepare a brine solution that matches the salinity of the rock strata being surveyed. The brine solution is placed in the brine storage tank (14). During the filling process in the permeation zone, a cycle is formed by filling 5cm. After installing the sealing cap (3) in each cycle, the pressure-type jog valve of the salt control device is jogged at a frequency of 5 times / minute and 2-5ml / time to achieve intermittent spraying and simulate the conditions of the seabed rock strata.

[0022] The technical solution of the present invention has the following advantages compared with the prior art:

[0023] This multi-mode mud permeation film forming test device has a simple structure and is easy to use. The internal regulating cylinder can be replaced to serve as a sample for comparison in a series of tests, without the need for frequent cleaning and replacement of the internal sand and gravel. In particular, under the simulated conditions of low temperature, it can also promote the freezing of the sand and gravel layer, making it easier to remove the internal regulating cylinder and observe it later.

[0024] The addition of a salt control device enables the simulation of the rock strata environment of the submarine tunnel, expanding the simulation scenarios for the infiltration mud membrane test environment. In the initial simulation process, the rock strata environment of the submarine tunnel can be simulated to the greatest extent.

[0025] Applying petroleum jelly to both the inner and outer casings increases friction and can extend the lifespan of the equipment. The design of the observation window prevents friction from affecting the scale observation after repeated tests. Attached Figure Description

[0026] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof.

[0027] Figure 1 This is a structural schematic diagram of the present invention from the main viewing direction.

[0028] Figure 2 This is a schematic diagram of the structure of the present invention viewed from the right.

[0029] Figure 3 This is a top-view structural diagram of the present invention;

[0030] Figure 4 This is a perspective view of the present invention;

[0031] Figure 5 This is a full sectional view of the structure during use;

[0032] Figure 6 This is a schematic diagram showing the unfolded effect of the external observation tube;

[0033] in, Figures 1 to 5 Support components and pressure regulators are omitted.

[0034] 1. Gantry frame; 2. Handle; 3. Sealing cap; 4. External observation tube; 5. Semiconductor cooling ring; 6. Collection tube; 7. Movable fan-shaped plate; 8. Air pump; 9. Pressure gauge; 10. Pressure reducer; 11. Support component; 12. Spray outlet; 13. Pressure-type jog on / off valve; 14. Brine storage tank; 15. Button; 16. Permeable zone; 17. Infiltration zone; 18. Mud zone; 19. Cavity zone; 20. Heating guide wire; 21. Air pipe mounting hole; 22. Slide groove; 23. Internal adjusting cylinder; 24. Observation window; 25. Second pressure gauge (see attached diagram). Detailed Implementation

[0035] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention. Example 1

[0036] In one specific embodiment, the present invention provides a mud permeation film formation test device adapted to multiple modes, comprising:

[0037] The test cylinder, main system, and pressurization system are arranged together, with the test cylinder situated on top of the main system. The test cylinder is made of transparent material and has horizontal graduations. A drain pipe is installed at the bottom of the test cylinder, and the top of the test cylinder is connected to the output of the pressurization system.

[0038] The test tube includes an internal adjustment tube 23 and an external observation tube 4, which are coaxially mounted. The internal adjustment tube 23 is provided with a water permeable zone 16, an infiltration zone 17, a mud zone 18 and a cavity zone 19 from bottom to top. The external observation tube 4 and the internal adjustment tube 23 are provided with a lubricating layer, a temperature control device and a salt control device.

[0039] The main system includes a gantry frame 1 and a bottom support. A sealing cover 3 that mates with the test cylinder is installed on the gantry frame 1. The bottom support includes a movable sector plate 7 and a support component 11 for the movable sector plate 7. The sector plate is slidably connected to the gantry frame 1.

[0040] The pressurization system includes an air source and a pressure regulator connected to the air source. The pressure regulator includes a first pressure gauge 9 and a pressure reducer 10. The first pressure gauge 9 measures the outlet pressure of the pressure reducer 10. The air outlet of the pressure reducer 10 is connected to the vent of the permeation zone 17 through an air pipe. A vent valve is provided at one end of the air pipe connected to the vent to adapt to the multi-mode mud permeation film forming test device.

[0041] The pressurization system also includes an air pump 8 and a second pressure gauge 25. The second pressure gauge 25 measures the outlet pressure of the air pump 8. The air outlet of the air pump 8 is connected to the air inlet of the pressure reducer 10 through an air pipe.

[0042] The temperature control device includes heating guide wires 20 arranged in a serpentine pattern on both sides of the inner side of the outer observation tube 4.

[0043] The salt control device is installed on the sealing cover 3. The salt control device includes a pressure-type jog on / off valve 13 and a button 15. One end of the pressure-type jog on / off valve 13 is connected to the spray outlet 12, and the other end is connected to the brine storage tank 14. The spray outlet 12 faces the inside of the test cylinder.

[0044] A protruding observation window 24 is provided in the lower middle part of the external observation tube 4. The observation window 24 is flat and perpendicular to the horizontal plane.

[0045] A method for measuring mud permeability, using the aforementioned multi-mode mud permeability film-forming test apparatus, includes the following steps:

[0046] S1 equipment preparation:

[0047] (1) The bottom of the test cylinder is sealed to form a pressure circuit. Under normal temperature and pressure, permeable stone, test soil layer and test mud are placed in the test cylinder in sequence.

[0048] (2) Adjust the sealing cover 3, seal the inner cavity of the test tube, and then open the vent valve of the pressurization system. As the internal pressure of the pressurization system increases, open the valve of the water pipe of the test tube. The permeable zone 17 is composed of a transparent tube with scale lines. In the transparent tube, permeable stone, test soil layer and test mud are placed in sequence.

[0049] S2 Permeability Test: The mud in permeable zone 17 permeates down through the test soil layer, and the solidified material remains above permeable zone 17 to form a mud film. The liquid flows through permeable zone 17 to the bottom of the test cylinder and drips into the collection tube 6. The timing starts from the initial dripping liquid and the permeability test ends after 30 minutes. The thickness of the mud film is recorded.

[0050] S3 Environment Adjustment:

[0051] (1) The temperature control device includes an electrothermal conversion circuit, which is electrically connected to the mains power to simulate different ambient ground temperatures;

[0052] (2) Prepare a brine solution that matches the salinity of the rock strata being surveyed. Place the brine solution in the brine storage tank 14. During the filling process in the permeation zone 17, start a cycle with a filling of 5cm. After installing the sealing cap 3 in each cycle, press the button 15 at a frequency of 5 times / minute and 2-5ml / time to realize the intermittent spraying and simulate the seabed rock strata conditions.

[0053] During the work, the test coatings mostly use sand and gravel to simulate rock strata, and then use mortar with different ratios to conduct experiments to simulate the best mortar comparison. During the test, multiple internal adjustment cylinders 23 can be pre-set to form a comparison of mud film formation under the same sand and gravel conditions.

[0054] When simulating medium-high temperature or variable temperature environments, the heating guide wire 20 is energized to regulate the temperature of the test cylinder. In this embodiment, a temperature detection device can also be added.

[0055] During the measurement process, sand and gravel are first installed in the inner bucket according to the preset conditions, the temperature is adjusted, and the environment is simulated. Then, mortar is injected under the condition of bottom disconnection. After that, the top of the test bucket is sealed to further simulate the air pressure environment of the construction site. Then, the top and bottom are connected, and the mud slowly passes through the sand and gravel to form a mud film, gradually completing the mud penetration film formation test.

[0056] The replacement of the internal adjusting cylinder 23 is achieved by the deformation of the main system. Specifically, the bottom support component 11 is a hydraulic lifting system. Under the guidance of the sliding grooves 22 on both sides, the internal adjusting cylinder is lifted and lowered, while being supported in the test state.

[0057] Furthermore, the external observation tube 4 can also be positioned with the help of the handle 2 on the top of the sealing cover 3. Example 2

[0058] The working principle of this embodiment is the same as that of Embodiment 1, with the specific difference being that the heating guide wire 20 is replaced by semiconductor cooling rings 5 ​​inserted on both sides of the outer side of the external observation cylinder 4. The working principle of the semiconductor cooling rings 5 ​​is equivalent to that of semiconductor cooling chips in the prior art. Utilizing the Peltier effect of semiconductor materials, when direct current passes through a coupler formed by two different semiconductor materials connected in series, heat can be absorbed and released at the two ends of the coupler respectively, achieving the purpose of cooling. By using energized electrodes to achieve a cooling effect on one side and a heating effect on the other, and then changing the direction of the current, the hot and cold surfaces can be switched, thereby controlling the temperature of the external observation cylinder 4. This simulates the temperature of rock strata under different environments and pressures, achieving a more realistic environmental simulation.

Claims

1. A mud permeation film-forming test device adaptable to multiple modes, comprising a test cylinder, a main system, and a pressurization system, wherein the test cylinder is placed on the main system; the test cylinder is made of transparent material and has horizontal graduations on it; a drain pipe is installed at the bottom of the test cylinder, and the top of the test cylinder is connected to the output end of the pressurization system, characterized in that: The test tube includes an internal adjustment tube (23) and an external observation tube (4) coaxially mounted. The internal adjustment tube (23) is provided with a water permeable zone (16), an infiltration zone (17), a mud zone (18), and a cavity zone (19) from bottom to top. The external observation tube (4) and the internal adjustment tube (23) are provided with a lubricating layer, a temperature control device, and a salt control device. The main system includes a gantry frame (1) and a bottom support. A sealing cover (3) that cooperates with the test tube is installed on the gantry frame (1). The bottom support includes a movable sector plate (7) and a support component for the movable sector plate (7). (11) The movable fan-shaped plate (7) is slidably connected to the gantry frame (1); the salt control device is installed on the sealing cover (3), the salt control device includes a pressure-type jog on / off valve (13), one end of the pressure-type jog on / off valve (13) is connected to the spray outlet (12), and the other end is connected to the brine storage tank (14), the spray outlet (12) faces the inside of the test cylinder; the bottom support component (11) is a hydraulic lifting system, which, under the restriction and guidance of the sliding grooves (22) on both sides, drives the internal regulating cylinder to rise and fall, and supports it in the test state.

2. The adaptable multi-mode mud permeation film formation test device as described in claim 1, characterized in that: The pressurization system includes an air source and a pressure regulator connected to the air source. The pressure regulator includes a first pressure gauge (9) and a pressure reducer (10). The first pressure gauge (9) measures the outlet pressure of the pressure reducer (10). The air outlet of the pressure reducer (10) is connected to the air vent of the permeation zone (17) through an air pipe. One end of the air pipe connected to the air vent is provided with an air valve adapted to a multi-mode mud permeation film forming test device. The pressurization system also includes an air pump (8) and a second pressure gauge (25), the second pressure gauge (25) measuring the outlet pressure of the air pump (8), and the air outlet of the air pump (8) being connected to the air inlet of the pressure reducer (10) through the air pipe.

3. The adaptable multi-mode mud permeation film formation test device as described in claim 1, characterized in that: The temperature control device includes heating guide wires (20) coiled in a serpentine pattern on both sides of the inner side of the outer observation tube (4).

4. The adaptable multi-mode mud permeation film formation test device as described in claim 3, characterized in that: The heating guide wire (20) is replaced by a semiconductor cooling ring (5) inserted on both sides of the outer side of the external observation tube (4).

5. The adaptable multi-mode mud permeation film formation test device as described in claim 1, characterized in that: The outer observation tube (4) has a protruding observation window (24) at its lower center. The observation window (24) is flat and perpendicular to the horizontal plane.

6. A method for measuring the permeability of mud, characterized in that, The method of using the adaptable multi-mode mud permeation film formation test apparatus according to claim 1 includes the following steps: S1 equipment preparation: (1) The bottom of the test cylinder is sealed to form a pressure circuit. Under normal temperature and pressure, permeable stone, test soil layer and test mud are placed in the test cylinder in sequence. (2) Adjust the sealing cap (3) to seal the inner cavity of the test tube and then open the vent valve of the pressurization system. As the internal pressure of the pressurization system increases, open the valve of the test tube drain pipe. The permeable zone (17) is composed of a transparent tube with graduation lines. Permeable stone, test soil layer and test mud are placed in the transparent tube in sequence. S2 Permeability Test: The mud in the permeability zone (17) permeates down through the test soil layer, and the solidified material remains above the permeability zone (17) to form a mud film. The liquid flows through the permeability zone (17) to the bottom of the test tube and drips into the collection tube (6). The time is started from the initial dripping liquid. The permeability test ends after 30 minutes, and the mud film thickness is recorded. S3 Environment Adjustment: (1) The temperature control device includes an electrothermal conversion circuit, which is electrically connected to the mains power to simulate different ambient ground temperatures; (2) Prepare a brine solution that matches the salinity of the rock strata being surveyed. The brine solution is placed in a brine storage tank (14). During the filling process in the permeation zone (17), the filling is done in cycles of 5cm. After installing the sealing cap (3) in each cycle, the pressure-type jog valve (13) of the salt control device is jogged at a frequency of 5 times / minute and 2-5ml / time to achieve intermittent spraying and simulate the conditions of the seabed rock strata.

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