Vacuum preloading and pumping method for super-soft soil

Abstract

This invention relates to a vacuum preloading and drainage method for ultra-soft soil. The method includes filling a sludge tank with sludge and installing vertical drainage boards within the sludge. The vertical drainage boards are connected to a vacuum pump via drainage pipes, which are also open to the atmosphere. After vacuum preloading for a certain period, the vacuum pump is turned off, and the drainage pipes are opened to the atmosphere, allowing air to enter and creating a pressure difference between the surface of the vertical drainage boards and the sludge, preventing clogging. After vacuum drainage, the sludge near the surface of the drainage boards gradually becomes denser, while the pressure inside the sludge tank is lower than atmospheric pressure. This invention, by opening the drainage boards to the atmosphere after vacuum drainage for a certain period, creates a pressure difference on the surface of the drainage boards, pushing the denser sludge layer on the surface of the drainage boards to disperse or move away, allowing other, more fluid sludge to replace the original denser sludge layer, thereby slowing down or prolonging the clogging process of the drainage boards.

Description

Technical Field

[0001] This invention relates to a vacuum preloading and extraction method for ultra-soft soil. Background Technology

[0002] Typical silt includes dredged silt, backfill silt, and engineering waste mud. This type of silt has a high water content (100%-190%), high compressibility, low strength, and the soil is in a fluid and suspended state. Vacuum preloading consolidation is a widely used soft soil treatment technology.

[0003] The drawback is that during the vacuum pre-compression consolidation process, the permeate membrane of the drainage board will almost always become clogged, which will affect the effectiveness and time of sludge treatment. Summary of the Invention

[0004] The purpose of this invention is to provide a vacuum preloading and drainage method for ultra-soft soil that can reduce or delay the clogging of drainage boards.

[0005] Therefore, the present invention provides a vacuum preloading and drainage method for ultra-soft soil, which includes filling a sludge pool with sludge and setting a vertical drainage board in the sludge, connecting the vertical drainage board to a vacuum pump through a drainage pipe, and the drainage pipe can also be connected to the atmosphere. After the vacuum pump has performed vacuum preloading and drainage for a certain period of time, the vacuum pump is turned off and the drainage pipe is connected to the atmosphere so that the atmosphere enters the drainage pipe and forms a pressure difference between the surface of the vertical drainage board and the sludge to prevent clogging.

[0006] Furthermore, the drain pipe is connected to one end of the vertical drainage plate near the bottom of the sludge pool.

[0007] Furthermore, the drain pipe is connected to a tee connector, which is connected to the drain pipe, the vacuum pump, and the atmospheric extension pipe respectively. The atmospheric extension pipe is provided with an openable and closable sealing cap.

[0008] Furthermore, the vertical drainage plate includes an inner support frame and a membrane cavity. A filter membrane is provided on the outer side of the inner support frame. A portion of the filter membrane is stored in the membrane cavity. The filter membrane is movable relative to the inner support frame, so that the redundant portion of the filter membrane stored in the membrane cavity can be moved to the outer surface of the inner support frame to replace the working portion of the filter membrane.

[0009] Furthermore, the vertical drainage plate has membrane cavities on both sides, and membrane cylinders suitable for connection with motors are provided in the membrane cavities. The two ends of the filter membrane are fixed to the membrane cylinders on both sides of the vertical drainage plate.

[0010] Furthermore, the vertical drainage plate includes a sealed membrane cavity, which includes a sealed outer shell, a sealing layer fixed to the inner support frame, and a sealing gasket disposed between the filter membrane and the sealed outer shell.

[0011] Furthermore, the vertical drainage plate includes a permeable membrane cavity, and the permeable membrane cavity includes a permeable outer shell.

[0012] Furthermore, both ends of the permeable outer shell and the sealed outer shell are provided with mud scraping parts.

[0013] Furthermore, a mud-pushing plate is provided on the outer side of the inner support frame. One end of the mud-pushing plate is movably connected to the middle of the inner support frame, and the other end is fixed to the inner side of the filter membrane.

[0014] The above-mentioned vacuum pre-compression extraction method specifically includes the following steps:

[0015] (1) Silt is blown into the sludge pond and vertical drainage boards are installed. One end of the vertical drainage board near the bottom of the sludge pond is connected to a drainage pipe. The drainage pipe is connected to a T-joint, which is connected to a vacuum pump and an atmospheric extension pipe.

[0016] (2) Start the vacuum pump to pump for a certain period of time, then turn off the vacuum pump and open the sealing cap of the atmospheric extension tube;

[0017] (3) Before restarting the vacuum pump, turn on the micro motor in the vertical drainage plate so that the redundant part of the filter membrane in the sealed membrane cavity replaces the working part of the filter membrane. The working part of the filter membrane drives the mud pusher to remove the sludge layer on both sides of the vertical drainage plate, and the original working part of the filter membrane enters the membrane tube of the permeable membrane cavity.

[0018] (4) Start the vacuum pump to perform vacuum extraction. The filter membrane in the water-permeable membrane cavity is immersed in the water flow, and the sludge in the filter membrane is removed under the action of vacuum extraction.

[0019] (5) Repeat the above process.

[0020] The beneficial technical effects of this invention are as follows:

[0021] (1) The present invention connects the drainage board to the atmosphere after vacuuming for a certain period of time, so that a pressure difference is formed on the surface of the drainage board, which pushes the relatively dense silt layer on the surface of the drainage board to disperse or move away, so that other more fluid silt replaces the original relatively dense silt layer, thereby slowing down or prolonging the clogging of the drainage board.

[0022] (2) In a specific embodiment of the present invention, the vertical drainage plate includes a filter membrane on the outside of the inner support frame. The filter membrane includes a redundant part in the membrane cavity and a working part on the outside of the inner support frame. After vacuum pumping for a period of time, the movable filter membrane allows the redundant part to replace the working part, thereby preventing or slowing down the clogging of the filter membrane. At the same time, the original working part is incorporated into the membrane cavity. The membrane cavity is permeable to water, so that the original working part can remove the sludge on its surface through vacuum pumping and water flow.

[0023] (3) In a specific embodiment of the present invention, a mud-pushing plate is provided on the outer side of the inner support frame of the vertical drainage plate. The mud-pushing plate can push the dense sludge layer on both sides of the vertical drainage plate away under the action of the filter membrane, thereby further reducing the occurrence of sludge blockage. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the present invention;

[0025] Figure 2 This is a schematic diagram of the cross-section of a vertical drainage board;

[0026] Figure 3 This is a schematic diagram of a membrane tube;

[0027] Figure 4 for Figure 2 A magnified view of a portion of the image;

[0028] Figure 5 A schematic diagram of the cross-section of a vertical drainage board with a mud-pushing plate;

[0029] Figure 6 This is a schematic diagram of the working of the mud pusher.

[0030] Explanation of reference numerals in the attached drawings: 1. Sludge tank; 2. Vertical drainage plate; 21. Inner support frame; 22. Outer support frame; 23. Membrane cavity; 231. Sealed membrane cavity; 232. Permeable membrane cavity; 233. Sealing shell; 234. Sealing layer; 235. Sealing gasket; 236. Permeable shell; 24. Filter membrane; 241. Working part; 242. Redundant part; 25. Membrane tube; 3. Drainage pipe; 4. T-joint; 5. Atmospheric extension pipe; 6. Sealing cap; 7. Motor; 8. Sealing partition; 9. Sealing ring; 10. Sludge scraper; 11. Vacuum pump; 12. Sealing membrane; 13. Sealing trench; 14. Sludge pusher. Detailed Implementation

[0031] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0032] Reference Figure 1As shown, a vacuum preloading and drainage method for ultra-soft soil according to the present invention includes filling a sludge tank 1 with sludge and setting a vertical drainage plate 2 in the sludge. The vertical drainage plate 2 is connected to a vacuum pump 11 through a drainage pipe 3. The drainage pipe 3 can also be connected to the atmosphere. After the vacuum pump 11 is started and vacuum preloading is performed for a certain period of time, the vacuum pump 11 is turned off and the drainage pipe 3 is connected to the atmosphere so that the atmosphere enters the drainage pipe 3 and forms a pressure difference between the surface of the vertical drainage plate 2 and the sludge to prevent the vertical drainage plate 2 from being blocked. The surface of the sludge tank 1 also includes a sealing membrane 12 that isolates the sludge from the atmosphere. Sealing trenches 13 can also be provided on both sides of the sludge tank 1. The drain pipe 3 can be connected to the end of the vertical drainage plate 2 near the bottom of the sludge tank to improve the transmission effect of the vacuum degree of the vertical drainage plate 2 during vacuum pre-pressurization and pumping. The drain pipe 3 is connected to a three-way connector 4, which is connected to the drain pipe 3, the vacuum pump 11 and the atmospheric extension pipe 5 respectively. The atmospheric extension pipe 5 is provided with an openable and closable sealing cap 6, which can be equipped with an electric actuator for remote control opening and closing. After vacuum pre-compression and pumping for a certain period of time, due to the decreasing vacuum level during vacuum pumping, the sludge near the vertical drainage plate 2 dewaters faster than the sludge in other parts. A relatively dense sludge layer with a lower water content and a denser surface than the sludge in other parts is formed on the surface of the vertical drainage plate 2. The vacuum pump 11 is stopped and the sealing cap 6 is opened to allow the vertical drainage plate 2 to communicate with the atmosphere. After vacuum pumping, the sludge in the sludge tank 1 is under negative pressure compared to atmospheric pressure. A positive pressure difference is generated between the surface of the vertical drainage plate 2 and the sludge in the sludge tank 1, which pushes the dense sludge layer on the surface of the vertical drainage plate 2 to disperse and move away from the surface of the vertical drainage plate 2. Other sludge with higher fluidity and water content flows and replaces and mixes with the dense sludge layer. Then the sealing cap 6 is closed and the vacuum pump 11 is restarted. The above process is repeated to reduce the clogging of the vertical drainage plate 2.

[0033] In the above embodiments, reference is made to Figures 2 to 4As shown, the vertical drainage plate 2 includes an inner support frame 21 and a membrane cavity 23. A filter membrane 24 is provided on the outer side of the inner support frame 21. A portion of the filter membrane 24 is stored in the membrane cavity 23. The filter membrane 24 can move relative to the inner support frame 21, so that the redundant portion 242 of the filter membrane stored in the membrane cavity 23 can move to the outer surface of the inner support frame 21 to replace the working portion 241 of the filter membrane. Since this portion of the filter membrane 24 stored in the membrane cavity 23 does not participate in the initial stage of filtration, it is referred to as the redundant portion 242 of the filter membrane. The portion of the filter membrane located on the outer side of the inner support frame 21 is referred to as the working portion 241. In the initial stage, vacuum pump 11 is turned on to perform vacuum pumping. When vacuum pumping has been performed for a certain period of time or when the drainage volume is abnormal, vacuum pump 11 is turned off and the vertical drainage plate 2 is connected to the atmosphere to process it. After the dense sludge layer on the surface of the vertical drainage plate 2 is separated from the vertical drainage plate 2, the redundant part 242 of the filter membrane 24 is used to replace the working part 241. Since the filter membrane 24 will accumulate particles in the sludge on the surface of the working part 241 after working for a period of time, these accumulated fine particles will affect the filtration channel of the filter membrane 24 and affect filtration and drainage to a certain extent. By replacing the filter membrane, the filtration capacity of the drainage plate is restored.

[0034] In the above embodiments, reference is made to Figures 2 to 4 As shown, membrane cavities 23 are provided on both sides of the vertical drainage plate 2. Membrane cylinders 25 suitable for connection to the motor 7 are provided within the membrane cavities 23. The two ends of the filter membrane 24 are fixed to the membrane cylinders 25 on both sides of the vertical drainage plate 2. A sealed motor cavity may also be provided in the vertical drainage plate 2, containing a micro motor 7. A sealing partition 8 is provided between the motor cavity and the membrane cavity 23. The motor shaft is connected to the membrane cylinder 25, and a sealing ring 9 is provided between the motor shaft and the sealing partition 8. The filter membranes 24 on both sides of the vertical drainage plate 2 can be fixed to a set of the aforementioned membrane cylinders 25 for movement of the filter membranes 24. The two sets of membrane cylinders 25 on the same side can be connected by a belt, allowing one set of motor 7 to simultaneously move the filter membranes 24 on both sides of the vertical drainage plate 2 connected to the membrane cylinders 25.

[0035] In the above embodiments, reference is made to Figure 2 and Figure 4 As shown, a sealed membrane cavity 231 is provided on one side of the vertical drainage plate 2. The sealed membrane cavity 231 includes a sealed outer shell 233, a sealing layer 234 fixed to the inner support frame 21, and a sealing gasket 235 disposed between the filter membrane 24 and the sealed outer shell 233. The sealed outer shell 233 can be made of plastic, and the sealing layer 234 and the sealing gasket 235 can be made of rubber. In the initial stage, the redundant portion 242 of the filter membrane 24 is stored in the sealed membrane cavity 231. As mentioned above, in the initial stage, the redundant portion 242 of the filter membrane 24 does not participate in the operation. The sealed membrane cavity 231 can prevent water from the drainage channel of the vertical drainage plate 2 from entering the sealed membrane cavity 231 and prevent small particles that penetrate the filter membrane from entering the redundant portion 242 of the filter membrane and affecting the filtration capacity of the redundant portion 242 of the filter membrane.

[0036] In the above embodiments, reference is made to Figure 2 As shown, the vertical drainage plate 2 has a permeable membrane cavity 232 and a sealed membrane cavity 231 on both sides. The permeable membrane cavity 232 includes a permeable outer shell 236. The permeable outer shell 236 is equipped with a filter membrane 24. Under the action of vacuum pre-pressure pumping, water in the sludge enters the permeable membrane cavity 232 through the permeable outer shell 236. When the working part 241 of the filter membrane 24 enters the permeable membrane cavity 232, a large number of sludge particles are adhered to the surface of the working part 241 of the filter membrane 24. The water filtered by the filter membrane 24 enters the permeable membrane cavity 232. This part of the water contains only a small number of fine particles. The original working part 241 of the filter membrane containing a large number of sludge particles is immersed in the drainage channel. After being washed by vacuum pressure and water flow, some or all of the fine particles on the working part 241 of the filter membrane 24 are removed, thereby partially restoring its filtration capacity and enabling repeated replacement. Since the filtered water contains only fine particles, and the contamination of the redundant part 242 of the filter membrane 24 in the initial stage is not considered, the sealed membrane cavity 231 of the vertical drainage plate 2 can also be replaced by the permeable membrane cavity 232.

[0037] In the above embodiments, reference is made to Figure 2 and Figure 3 As shown, the permeable outer shell 236 and the sealed outer shell 233 are provided with sludge scraping parts 10 at both ends. The shape of the sludge scraping parts 10 can be triangular. When the filter membrane 24 moves into the membrane cavity 23, it removes the attached sludge particles on the surface of the filter membrane 24 and prevents the drainage channel of the vertical drainage plate 2 from being blocked.

[0038] In the above embodiments, reference is made to Figure 5 and Figure 6 As shown, a pusher plate 14 is provided on the outer side of the inner support frame 21. One end of the pusher plate 14 is movably connected to the middle of the inner support frame 21, and the other end is fixed to the inner side of the filter membrane 24. When the filter membrane 24 moves, the filter membrane 24 drives the pusher plate 14, which is fixed to the filter membrane 24 at one end, to flip outward. This causes the filter membrane 24 and the pusher plate 14 to push the dense sludge layer accumulated around the vertical drainage plate 2 away from both sides of the vertical drainage plate 2, allowing other highly fluid sludge with high water content to enter the surface of the vertical drainage plate 2, thereby alleviating or delaying the clogging time of the vertical drainage plate 2. In this embodiment, the scraper part 10 adopts a blunt shape, such as an arc or semi-circular shape, to prevent damage to the filter membrane 24.

[0039] In the above embodiments, reference is made to Figure 2 As shown, the vertical drainage plate 2 also includes an outer support frame 22, which is fixed around the outside of the sealing shell 233 and the permeable shell 236 to fix the sealing shell 233 and the permeable shell 236 to the vertical drainage plate 2.

[0040] In the above embodiments, the vacuum pre-compression extraction method includes the following steps:

[0041] (1) Excavate sludge pond 1, blow sludge into sludge pond 1, and install vertical drainage board 2. Connect the end of vertical drainage board 2 near the bottom of sludge pond to drainage pipe 3. Drainage pipe 3 is connected to tee connector 4. Tee connector 4 is connected to vacuum pump 11 and atmospheric extension pipe 5.

[0042] (2) Start the vacuum pump 11 to pump for a certain period of time, turn off the vacuum pump 11, and open the sealing cap 6 of the atmospheric extension pipe 5; disperse and move away the relatively dense silt layer on the surface of the vertical drainage plate 2, and mix it with the silt with strong fluidity and high water content;

[0043] (3) Before restarting the vacuum pump 11, turn on the motor 7 so that the redundant part 242 of the filter membrane in the sealed membrane cavity 231 replaces the working part 241 of the filter membrane. The working part 241 of the filter membrane 24 drives the pusher plate 14 to remove the silt layer on both sides of the vertical drainage plate 2. The original working part 241 of the filter membrane 24 enters the membrane tube 25 of the permeable membrane cavity 232.

[0044] (4) Start the vacuum pump 11 to perform vacuum pumping. The filter membrane 24 in the permeable membrane cavity 232 is immersed in the water flow and the sludge particles on the surface of the filter membrane 24 in the permeable membrane cavity 232 are removed under the flushing action of vacuum pumping and water flow in the drainage channel.

[0045] (5) Repeat the above process.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for vacuum preloading and dewatering of ultra-soft soil, comprising filling a sludge tank with sludge and installing vertical drainage boards in the sludge, connecting the vertical drainage boards to a vacuum pump via drainage pipes, characterized in that: The drain pipe can also be connected to the atmosphere. After the vacuum pump has been pre-pressurized for a certain period of time, the vacuum pump is turned off and the drain pipe is connected to the atmosphere, so that the atmosphere enters the drain pipe and forms a pressure difference between the surface of the vertical drain plate and the silt to prevent clogging. The vertical drain plate includes an inner support frame and a membrane cavity. A filter membrane is provided on the outside of the inner support frame. A portion of the filter membrane is stored in the membrane cavity. The filter membrane can move relative to the inner support frame, so that the redundant part of the filter membrane stored in the membrane cavity can be moved to the outer surface of the inner support frame to replace the working part of the filter membrane.

2. The vacuum preloading and extraction method for ultra-soft soil according to claim 1, characterized in that: The drainage pipe is connected to the end of the vertical drainage board near the bottom of the sludge pool.

3. The vacuum preloading and extraction method for ultra-soft soil according to claim 1, characterized in that: The drain pipe is connected to a tee connector, which is connected to the drain pipe, the vacuum pump and the atmospheric extension pipe respectively. The atmospheric extension pipe is equipped with an openable and closable sealing cap.

4. A vacuum preloading and extraction method for ultra-soft soil according to claim 1, 2, or 3, characterized in that: The vertical drainage plate has membrane cavities on both sides, and membrane cylinders suitable for connection with motors are provided in the membrane cavities. The two ends of the filter membrane are fixed to the membrane cylinders on both sides of the vertical drainage plate.

5. The vacuum preloading and extraction method for ultra-soft soil according to claim 4, characterized in that: The vertical drainage plate includes a sealed membrane cavity, which includes a sealed outer shell, a sealing layer fixed to the inner support frame, and a sealing gasket disposed between the filter membrane and the sealed outer shell.

6. The vacuum preloading and extraction method for ultra-soft soil according to claim 5, characterized in that: The vertical drainage board includes a permeable membrane cavity, and the permeable membrane cavity includes a permeable outer shell.

7. The vacuum preloading and extraction method for ultra-soft soil according to claim 6, characterized in that: Both ends of the permeable outer shell and the sealed outer shell are equipped with mud scraping parts.

8. The vacuum preloading and pumping method for ultra-soft soil according to claim 6, characterized in that: The inner support frame is provided with a mud-pushing plate on the outside. One end of the mud-pushing plate is movably connected to the middle of the inner support frame, and the other end is fixed to the inner side of the filter membrane.

9. A vacuum preloading and extraction method for ultra-soft soil according to claim 8, characterized in that: Includes the following steps: (1) Silt is blown into the sludge pool and vertical drainage boards are installed. The end of the vertical drainage board near the bottom of the sludge pool is connected to the drainage pipe. The drainage pipe is connected to a T-joint and the T-joint is connected to the vacuum pump and the atmospheric extension pipe. (2) Start the vacuum pump to pump for a certain period of time, then turn off the vacuum pump and open the sealing cap of the atmospheric extension tube; (3) Before restarting the vacuum pump, turn on the motor connected to the vertical drainage plate so that the redundant part of the filter membrane in the sealed membrane cavity replaces the working part of the filter membrane. The working part of the filter membrane drives the mud pusher to remove the sludge layer on both sides of the vertical drainage plate, and the original working part of the filter membrane enters the membrane tube of the permeable membrane cavity. (4) Start the vacuum pump to perform vacuum extraction. The filter membrane in the water-permeable membrane cavity is immersed in the water flow and the fine particles of silt in the filter membrane are removed under the action of vacuum extraction. (5) Repeat the above process.

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