Device and method for detecting air pressure dewatering effect of residual foam soil pressure shield mud

Abstract

This invention proposes a device and method for detecting the dewatering effect of pneumatic pressure slurry containing residual foam in tunnel boring machine (TBM) slurry, relating to the field of slurry dewatering treatment and detection technology. It includes a support frame, a lower pressure chamber, and an upper pressure chamber. The upper pressure chamber is equipped with an air inlet, an exhaust valve, and a feed pipe; the air inlet is connected to an air compressor via the air inlet pipe. The lower pressure chamber is equipped with a drain outlet and a second exhaust valve. A filter structure is installed between the upper and lower pressure chambers. Below the drain outlet, a liquid receiving container and a mass measuring device are installed, which is connected to a data acquisition and processing device. This invention integrates the entire process of defoaming, flocculation, and pressure filtration of TBM slurry. It is convenient to operate, provides precise pressure control, and allows for real-time monitoring. It is suitable for complex slurry systems containing residual foaming agents, achieving rapid dewatering, convenient sample loading, and real-time accurate monitoring of the dewatering process. It provides reliable data for reagent selection and process optimization under different working conditions and a reliable detection platform for the resource utilization of TBM slurry.

Description

Technical Field

[0001] This invention relates to the field of mud dewatering treatment and testing technology, specifically to a pneumatic testing device and method for rapidly detecting the dewatering effect of complex mud systems containing residual foaming agents under different working conditions. Background Technology

[0002] During the excavation of earth pressure balance shield tunneling machines, a modified material mainly composed of foaming agents needs to be injected into the tunnel face and soil chamber. Residual foaming agents will undergo secondary foaming during the in-situ treatment of the shield excavated soil, leading to the formation of a foam-soil mixture. This foam-soil mixture not only hinders the effective contact between flocculants and soil particles, resulting in a significant reduction in flocculation and sedimentation efficiency and subsequent filter press dewatering, but also causes overflow of the flocculation tank, causing environmental pollution. Currently, there is a lack of systematic research methods and reliable testing platforms for rapidly screening efficient flocculants under different working conditions (such as residual foaming agent content and defoamer dosage) for shield excavated soil containing residual foaming agents. Therefore, there is an urgent need to develop a rapid testing device that can simulate the working principle of a plate and frame filter press, is suitable for high-foam content excavated soil slurry, has convenient sample loading operation, and can accurately monitor the dewatering process in real time, providing technical support for the optimization of defoaming and flocculation processes. Summary of the Invention

[0003] To address the aforementioned problems, this invention aims to provide a device and method for detecting the air pressure dewatering effect of earth pressure shield tunneling mud containing residual foam. This device can simulate the working principle of a plate and frame filter press, is suitable for complex mud systems containing residual foaming agents, and enables rapid dewatering, convenient sample loading, and real-time accurate monitoring of the dewatering process. It provides reliable data for reagent selection and process optimization under different working conditions.

[0004] The specific technical solution of the present invention is as follows: This invention first proposes a device for testing the air pressure dewatering effect of earth pressure shield tunneling slurry containing residual foam. The device includes a support frame, a lower pressure chamber fixedly mounted on the support frame, and an upper pressure chamber detachably and sealed to the upper end of the lower pressure chamber. The upper pressure chamber has an air inlet at its top connected to an exhaust valve. The air inlet is connected to an air compressor via an air inlet pipe, and a pressure regulating valve is connected to the air inlet pipe to control the air pressure inside the upper pressure chamber. A feed inlet is located on the side wall of the upper pressure chamber, and an upwardly inclined feed pipe is fixed to the feed inlet. A sealing cap is detachably mounted on the feed pipe to close the feed pipe after slurry filling. A drain outlet is located at the bottom of the lower pressure chamber, and a drain valve is installed at the drain outlet. The lower pressure chamber is equipped with a valve; a second exhaust valve for discharging gas from the chamber is also connected to the side wall of the lower pressure chamber; a filter structure is provided between the upper and lower pressure chambers, the filter structure includes a filter cloth and a sealing ring, the mating flanges of the upper and lower pressure chambers are fixedly connected by bolts, and the filter cloth and sealing ring are pressed between the two mating flanges; a liquid receiving container is provided below the drain outlet, and a mass measuring device for measuring the mass of the liquid discharged from the drain outlet is provided below the liquid receiving container. The mass measuring device is connected to a data acquisition and processing device, which receives the data transmitted by the mass measuring device and processes the data into a curve showing the change of drainage mass over time.

[0005] Furthermore, the upper pressure chamber includes a first tube body, an end cap fixed to the upper end of the first tube body, and corresponding fixing flanges fixed to both the first tube body and the end cap, which are fixedly connected by a second bolt; the feed pipe is a steel pipe, and the feed pipe is inclined at an angle of 30° to 60° to the side wall of the upper pressure chamber; the lower pressure chamber includes a second tube body and a conical tube body, with the conical tube body fixedly connected to the lower end of the second tube body.

[0006] Furthermore, both the upper and lower pressure chambers are made of stainless steel or high-transparency acrylic glass.

[0007] Furthermore, the bracket is a stainless steel bracket, which is welded and fixed to the outer wall of the lower pressure chamber.

[0008] Furthermore, a pressure gauge is installed on the top of the upper pressure chamber to monitor the pressure inside the upper pressure chamber.

[0009] Furthermore, the pressure regulating valve is a precision pressure reducing valve, which is used in conjunction with the pressure gauge to achieve precise pressure setting and stable maintenance.

[0010] Furthermore, the filter cloth is an industrial filter cloth, and its pore size is selected according to the particle size distribution of the mud to be tested.

[0011] Furthermore, the sealing ring is a corrosion-resistant rubber sealing ring, which is embedded in the end face sealing groove of the mating flange.

[0012] This invention also proposes a method for detecting the air pressure dewatering effect of earth pressure shield tunneling slurry containing residual foam. The method utilizes the aforementioned air pressure dewatering effect detection device for earth pressure shield tunneling slurry containing residual foam, and includes the following steps: S1. Equipment preparation: Select a filter cloth with a suitable pore size according to the working conditions to be tested, place the sealing ring and filter cloth between the mating flanges, cover the upper pressure chamber, and fasten the upper and lower pressure chambers with bolts; close the drain valve of the lower pressure chamber and the second exhaust valve on the side wall, and close the exhaust valve of the upper pressure chamber. S2. Prepare mud samples: Use an acrylic plate to make a scale model based on the on-site flocculation tank. Use a high-speed mixer to simulate the secondary foaming process of the foaming agent remaining on the slag due to the on-site circulating water flushing. Prepare mud containing different residual foaming agent concentrations, different defoamer concentrations, and flocculant types and dosages. Record the initial water mass, defoamer mass, and flocculant mass added to prepare the mud, and measure the volume and mass of the prepared mud. S3. Filling the mud: Open the sealing cap of the feed pipe and slowly pour the prepared mud to be tested into the pressure chamber through the feed pipe. Use the inclined angle of the feed pipe to make the mud flow smoothly. After filling, immediately fix the sealing cap to ensure that the feed pipe is well sealed. S4. Apply air pressure and monitor in real time: Open the drain outlet, the air compressor starts working, slowly adjust the pressure regulating valve to make the pressure in the upper pressure chamber reach the preset value and keep the pressure constant; at the same time, clear the mass measurement device, turn on the data acquisition and processing device, and start recording the change data of the drainage quality over time in real time. S5. Dehydration process determination: Continuous monitoring until the drainage volume per unit time is less than the set threshold, or the preset dehydration time is reached, then the dehydration process is considered to be over. S6. Data calculation and processing: Based on the recorded drainage quality-time curve, the amount of mud dewatering is obtained; the upper pressure chamber (3) is disassembled, the dewatered mud cake is taken out, and its final moisture content is measured; by comparing the final moisture content under different working conditions, the influence of defoamer and flocculant on the dewatering process and the optimal dosage are evaluated.

[0013] The beneficial effects of this invention are as follows: This invention connects the entire process of shield tunneling slag defoaming-flocculation-pressure filtration, is easy to operate, has precise pressure control, and allows for real-time monitoring. It is suitable for complex mud systems containing residual foaming agents, enabling rapid dewatering, convenient sample loading, and real-time and accurate monitoring of the dewatering process. It provides reliable data for agent selection and process optimization under different working conditions, and provides a reliable testing platform for the resource utilization of shield tunneling slag. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the air pressure dewatering effect testing device for earth pressure shield slurry containing residual foam in the present invention; Figure 2 This is a schematic diagram of the sealing ring and filter cloth in this invention; Figure 3 This is a schematic diagram of the structure of the mud sample preparation device in this invention.

[0016] The reference numerals in the diagram are as follows: 1-Bracket, 2-Lower pressure chamber, 3-Upper pressure chamber, 4-Exhaust valve, 5-Air inlet, 6-Pressure gauge, 7-Pressure regulating valve, 8-Feed pipe, 9-Bolt, 10-Sealing ring, 11-Filter cloth, 12-Mass measuring device, 13-Data acquisition and processing device, 14-Second exhaust valve, 15-Drain outlet, 16-Air compressor, 17-High-speed mixer, 18-Scale model, 19-Air inlet pipe, 20-Connecting flange. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1

[0019] Reference Figure 1 and 2A device for testing the air pressure dewatering effect of earth pressure shield tunneling slurry containing residual foam includes a support 1, a lower pressure chamber 2 fixedly mounted on the support 1, and an upper pressure chamber 3 detachably and sealed to the upper end of the lower pressure chamber 2. The upper pressure chamber 3 has an air inlet 5 at its top connected to an exhaust valve 4 for controlling drainage. The air inlet 5 is connected to an air compressor 16 via an air inlet pipe 19, and a pressure regulating valve 7 is connected to the air inlet pipe 19 to control the air pressure inside the upper pressure chamber 3. The upper pressure chamber 3 has a feed inlet on its side wall, with an upwardly inclined feed pipe 8 fixed to the feed inlet. A sealing cap is detachably mounted on the feed pipe 8 to close the feed pipe 8 after slurry filling. The lower pressure chamber 2 has a drain outlet 15 at its bottom, with a drain valve mounted on the drain outlet 15. The lower pressure chamber 2 is also connected to a second exhaust valve 14 for discharging gas from the chamber. A filter structure is provided between the upper pressure chamber 3 and the lower pressure chamber 2. The filter structure includes a filter cloth 11 and a sealing ring 10. The mating flanges 20 of the upper pressure chamber 3 and the lower pressure chamber 2 are fixedly connected by bolts 9. The filter cloth 11 and the sealing ring 10 are pressed between the two mating flanges 20. A liquid receiving container is provided below the drain outlet 15. A mass measuring device 12 for measuring the mass of the liquid discharged from the drain outlet 15 is provided below the liquid receiving container. The mass measuring device 12 is connected to a data acquisition and processing device 13. The data acquisition and processing device 13 receives the data transmitted by the mass measuring device 12 and processes the data into a curve showing the change of drainage mass over time.

[0020] The upper pressure chamber 3 includes a first pipe body with an end cap fixed to its upper end. Corresponding fixing flanges are fixed to both the first pipe body and the end cap, and the fixing flanges are connected by a second bolt. The feed pipe 8 is a steel pipe, inclined at a 30°–60° angle to the side wall of the upper pressure chamber 3 to facilitate the smooth flow of slurry into the chamber by gravity. The sealing cap preferably uses a quick-connect fitting and is equipped with a sealing gasket to ensure sealing performance under high pressure. The lower pressure chamber 2 includes a second pipe body and a conical pipe body. The conical pipe body is fixedly connected to the lower end of the second pipe body, allowing for convenient and rapid liquid drainage and preventing liquid accumulation. Both the upper pressure chamber 3 and the lower pressure chamber 2 are made of stainless steel or high-transparency acrylic glass. The support 1 is a stainless steel support 1, welded and fixed to the outer wall of the lower pressure chamber 2.

[0021] An air compressor (16) is used to inject compressed air into the upper pressure chamber 3. A pressure gauge 6 is also installed on the top of the upper pressure chamber 3 to monitor the pressure inside the upper pressure chamber 3. The pressure regulating valve 7 is a precision pressure reducing valve, which works in conjunction with the pressure gauge 6 to achieve precise pressure setting and stable maintenance. The function of the second exhaust valve 14 is to discharge any gas that may accumulate in the chamber after the test is completed or before it begins, to prevent air blockage from affecting drainage, or to release pressure before disassembly.

[0022] Both the lower end of the upper pressure chamber 3 and the upper end of the lower pressure chamber 2 are fixed with mating flanges 20, and at least one mating flange 20 has an end face sealing groove on its opposite surface. The filter cloth 11 is an industrial filter cloth, and its pore size is selected according to the particle size distribution of the slurry to be tested. The sealing ring 10 is a corrosion-resistant rubber sealing ring, which is embedded in the end face sealing groove of the mating flange 20. During installation, the filter cloth 11 is first laid flat on the mating flange 20 of the lower pressure chamber 2, the sealing ring 10 is placed, then the upper pressure chamber is covered, and finally the mating flange 20 is fastened with multiple bolts 9, thereby firmly pressing the filter cloth 11 and the sealing ring 10 together to ensure that neither slurry nor gas leaks under high pressure.

[0023] The mass measuring device 12 may be an electronic scale or other device with a weight sensor, and the data acquisition and processing device 13 may be a computer.

[0024] Example 2

[0025] Reference Figure 1-3 A method for detecting the air pressure dewatering effect of earth pressure shield tunneling slurry containing residual foam, using the air pressure dewatering effect detection device for earth pressure shield tunneling slurry containing residual foam described in Example 1, includes the following steps: S1. Equipment preparation: Select a filter cloth 11 with a suitable pore size according to the working conditions to be tested, place the sealing ring 10 and the filter cloth 11 between the mating flange 20, cover the upper pressure chamber 3, and fasten the upper pressure chamber 3 and the lower pressure chamber 2 with bolts 9; close the drain valve of the lower pressure chamber 2 and the second exhaust valve 14 on the side wall, and close the exhaust valve 4 of the upper pressure chamber 3. S2. Prepare mud samples: Use an acrylic plate to make a scale model 18 based on the on-site flocculant tank (e.g., scale ratio of 1:50). Prepare foaming agent according to the foaming agent formula actually used in shield tunneling. Use a high-speed mixer 17 to simulate the secondary foaming of the foaming agent remaining on the slag due to on-site circulating water flushing. Prepare mud containing different residual foaming agent concentrations, different defoamer concentrations, and flocculant types and dosages. Record the initial water mass, defoamer mass, and flocculant mass added to prepare the mud, and measure the volume and mass of the prepared mud. S3. Filling the mud: Open the sealing cap of the feed pipe and slowly pour the prepared mud to be tested into the pressure chamber 3 through the feed pipe 8. Use the inclined angle of the feed pipe to make the mud flow smoothly. After filling, immediately fix the sealing cap to ensure that the feed pipe 8 is well sealed. S4. Apply air pressure and monitor in real time: Open the drain outlet 15, the air compressor 16 starts working, slowly adjust the pressure regulating valve 7 to make the pressure in the upper pressure chamber 3 reach the preset value (such as less than 0.1 g / min, etc.), and keep the pressure constant; at the same time, clear the mass measuring device 12, turn on the data acquisition and processing device 13, and start recording the data of the change of drainage quality over time in real time. S5. Dehydration process determination: Continuous monitoring until the drainage volume per unit time is less than the set threshold, or the preset dehydration time is reached, then the dehydration process is considered to be over. S6. Data Calculation and Processing: Based on the recorded drainage quality-time curve, the amount of mud dewatering is obtained; the upper pressure chamber 3 is disassembled, the dewatered mud cake is taken out, and its final moisture content is measured; by comparing the final moisture content under different working conditions, the influence of defoamer and flocculant on the dewatering process and the optimal dosage are evaluated.

[0026] The formula for calculating soil moisture content is as follows: ; In the formula, ω is the soil moisture content; m is the dry mass of the extracted mud cake; m1 is the initial water mass added when preparing the mud slurry; m2 is the mass of the added defoamer; m3 is the mass of the added flocculant; and m4 is the mass of the liquid collected in the receiving container after the test. For example, when preparing mud slurry with an initial moisture content of 300%, 30g of initial dry soil is used, 90g of water is added, and then defoamer and flocculant are added. In this case, the initial water mass m 1= 90g.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for detecting the air pressure dewatering effect of earth pressure shield tunneling slurry containing residual foam, characterized in that: The device includes a support frame (1), a lower pressure chamber (2) fixedly mounted on the support frame (1), and an upper pressure chamber (3) detachably and sealed to the upper end of the lower pressure chamber (2). The upper pressure chamber (3) has an air inlet (5) at its top and is connected to an exhaust valve (4). The air inlet (5) is connected to an air compressor (16) via an air inlet pipe (19). A pressure regulating valve (7) is connected to the air inlet pipe (19) to control the air pressure inside the upper pressure chamber (3). The upper pressure chamber (3) has a feed inlet on its side wall, with an upwardly inclined feed pipe (8) fixed to the feed inlet. A sealing cap is detachably mounted on the feed pipe (8) to seal the feed pipe (8) after filling with slurry. The lower pressure chamber (2) has a drain outlet (15) at its bottom, with a drain valve mounted on the drain outlet (15). The lower pressure chamber (2) also has a connecting... A second exhaust valve (14) is provided for discharging gas from the chamber; a filter structure is provided between the upper pressure chamber (3) and the lower pressure chamber (2), the filter structure includes a filter cloth (11) and a sealing ring (10), the mating flanges (20) of the upper pressure chamber (3) and the lower pressure chamber (2) are fixedly connected by bolts (9), the filter cloth (11) and the sealing ring (10) are pressed between the two mating flanges (20); a liquid receiving container is provided below the drain outlet (15), and a mass measuring device (12) for measuring the mass of liquid discharged from the drain outlet (15) is provided below the liquid receiving container. The mass measuring device (12) is connected to the data acquisition and processing device (13), the data acquisition and processing device (13) receives the data transmitted by the mass measuring device (12), and the data acquisition and processing device (13) processes the data into a curve of the change of drainage mass over time.

2. The pneumatic mud dewatering effect rapid detection device according to claim 1, characterized in that: The upper pressure chamber (3) includes a first tube body, an end cap fixed to the upper end of the first tube body, and corresponding fixed flanges fixed to both the first tube body and the end cap. The fixed flanges are fixedly connected by a second bolt. The feed pipe (8) is a steel pipe, and the feed pipe (8) is inclined at an angle of 30° to 60° to the side wall of the upper pressure chamber (3). The lower pressure chamber (2) includes a second tube body and a conical tube body, and the conical tube body is fixedly connected to the lower end of the second tube body.

3. The pneumatic mud dewatering effect rapid detection device according to claim 1, characterized in that: Both the upper pressure chamber (3) and the lower pressure chamber (2) are made of stainless steel or high-transparency organic glass.

4. The pneumatic mud dewatering effect rapid detection device according to claim 1, characterized in that: The bracket (1) is a stainless steel bracket (1) and is welded and fixed to the outer wall of the lower pressure chamber (2).

5. The pneumatic mud dewatering effect rapid detection device according to claim 1, characterized in that: A pressure gauge (6) is also provided on the top of the upper pressure chamber (3), which is used to monitor the pressure inside the upper pressure chamber (3).

6. The pneumatic mud dewatering effect rapid detection device according to claim 5, characterized in that: The pressure regulating valve (7) is a precision pressure reducing valve. The precision pressure reducing valve is used in conjunction with the pressure gauge (6) to achieve precise setting and stable maintenance of pressure.

7. The pneumatic mud dewatering effect rapid detection device according to claim 1, characterized in that: The filter cloth (11) is an industrial filter cloth, and its pore size is selected according to the particle size distribution of the mud to be tested.

8. The pneumatic mud dewatering effect rapid detection device according to claim 1, characterized in that: The sealing ring (10) is a corrosion-resistant rubber sealing ring, which is embedded in the end face sealing groove of the mating flange (20).

9. A method for detecting the air pressure dewatering effect of earth pressure shield tunneling slurry containing residual foam, characterized in that: The air pressure dewatering effect testing device for earth pressure shield tunneling slurry containing residual foam, as described in any one of claims 1-8, includes the following steps: S1. Equipment preparation: Select a filter cloth (11) with a suitable pore size according to the working conditions to be tested, place the sealing ring (10) and the filter cloth (11) between the mating flange (20), cover the upper pressure chamber (3), and fasten the upper pressure chamber (3) and the lower pressure chamber (2) with bolts (9); close the drain valve of the lower pressure chamber (2) and the second exhaust valve (14) on the side wall, and close the exhaust valve (4) of the upper pressure chamber (3); S2. Prepare mud samples: Use acrylic plates to make a scale model (18) based on the on-site flocculation tank. Use a high-speed mixer (17) to simulate the secondary foaming process of the foaming agent remaining on the slag caused by the on-site circulating water flushing. Prepare mud containing different residual foaming agent concentrations, different defoamer concentrations, and flocculant types and dosages. Record the initial water mass, defoamer mass, and flocculant mass added to prepare the mud, and measure the volume and mass of the prepared mud. S3. Filling mud: Open the sealing cover of the feed pipe and slowly pour the prepared mud to be tested into the pressure chamber (3) through the feed pipe (8). Use the inclined angle of the feed pipe to make the mud flow smoothly. After filling, immediately fix the sealing cover to ensure that the feed pipe (8) is well sealed. S4. Apply air pressure and monitor in real time: Open the drain outlet (15), the air compressor (16) works, slowly adjust the pressure regulating valve (7) to make the pressure in the upper pressure chamber (3) reach the preset value and keep the pressure constant; at the same time, clear the mass measuring device (12), turn on the data acquisition and processing device (13), and start recording the data of the change of drainage quality over time in real time. S5. Dehydration process determination: Continuous monitoring until the drainage volume per unit time is less than the set threshold, or the preset dehydration time is reached, then the dehydration process is considered to be over. S6. Data calculation and processing: Based on the recorded drainage quality-time curve, the amount of mud dewatering is obtained; the upper pressure chamber (3) is disassembled, the dewatered mud cake is taken out, and its final moisture content is measured; by comparing the final moisture content under different working conditions, the influence of defoamer and flocculant on the dewatering process and the optimal dosage are evaluated.

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