Vacuum prepressing well-point dewatering system and working method

Abstract

The invention relates to the technical field of civil engineering foundation treatment, in particular to a vacuum prepressing well point dewatering system and a working method.The vacuum prepressing well point dewatering system comprises a backfill layer, an original soil layer and vacuum well point pipes, the vacuum well point pipes are embedded into the backfill layer and the original soil layer, dewatering pipes are inserted into the original soil layer, and horizontal pipes are arranged between the vacuum well point pipes and the dewatering pipes; a partition connecting sleeve is arranged between the horizontal pipe and the downcast pipe, a steel wire braided flexible rubber hose is arranged on the inner side of the horizontal pipe, one end of the steel wire braided flexible rubber hose extends into the downcast pipe, and the other end of the steel wire braided flexible rubber hose extends into the vacuum well point pipe. The water pumping pipe is arranged in the vacuum well point pipe, the cushion layer is arranged on the upper side of the backfilling layer, and the water pumping assembly and the vacuum assembly are arranged on the upper side of the cushion layer. The vacuum well point pipe and the downcast pipe are connected through the steel wire woven flexible rubber hose, the steel wire woven flexible rubber hose pumps accumulated water and air in the downcast pipe, and if blockage occurs, the steel wire woven flexible rubber hose is directly cleaned or replaced; maintenance is convenient and fast, and use cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering foundation treatment, and in particular to a vacuum preloading well point dewatering system and a working method. Background Art

[0002] Before building construction on the foundation, it is necessary to dewater the foundation to lower the groundwater level. For dewatering of soft soil foundation, vacuum preloading method is generally used to lower the groundwater level.

[0003] Vacuum preloading well point dewatering is to bury a certain number of well point pipes around the foundation pit or in the foundation, and use the negative pressure generated by the vacuum pump to extract groundwater from the well point pipes, thereby lowering the groundwater level. This method combines the advantages of vacuum preloading and well point dewatering, and can effectively improve foundation conditions.

[0004] The vacuum pump is connected to the precipitation well point pipe (precipitation pipe) through the water collection main pipe (vacuum well point pipe). After the vacuum pump is turned on, the groundwater enters the precipitation pipe under the action of vacuum suction, and then is discharged through the water collection main pipe, thereby lowering the groundwater level. At the same time, the vacuum effect can also increase the effective stress and shear strength of the soil, and improve the physical properties of the soil.

[0005] In the prior art, if there is a problem with the precipitation well point pipe, it is necessary to pull out the precipitation well point pipe for maintenance. The operation is cumbersome, the maintenance cycle is long, the maintenance cost is high, and it is not conducive to the progress of the project. In addition, the pumping pipe generally adopts fixed-point pumping. If the accumulated water level is too low, the pumping pipe is exposed to the water surface, and the pump runs dry, which can easily damage the life of the pump. If the mouth of the pumping pipe is set too low, it is easy to stir up the sediment, causing the sediment to enter the drainage system and cause blockage. Summary of the invention

[0006] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a vacuum preloading well point dewatering system and a working method.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: A vacuum preloading wellpoint dewatering system, comprising a backfill layer, an original soil layer and a vacuum wellpoint pipe, wherein the vacuum wellpoint pipe is embedded in the backfill layer and the original soil layer, a dewatering pipe is inserted in the original soil layer, a horizontal pipe is provided between the vacuum wellpoint pipe and the dewatering pipe, a partition connecting sleeve is provided between the horizontal pipe and the dewatering pipe, a steel wire braided soft rubber hose is provided inside the horizontal pipe, one end of the steel wire braided soft rubber hose extends into the dewatering pipe, and the other end of the steel wire braided soft rubber hose extends into the vacuum wellpoint pipe, a blind hole cavity adapted to the dewatering pipe is provided in the original soil layer, and the blind hole cavity is communicated with the vacuum wellpoint pipe through the steel wire braided soft rubber hose; A pumping pipe is provided in the vacuum well point pipe, and the vacuum well point pipe is used to accumulate groundwater and separate water and gas at the same time. A cushion layer is provided on the upper side of the backfill layer, and a pumping assembly and a vacuum assembly are provided on the upper side of the cushion layer. The vacuum assembly is used to evacuate the vacuum well point pipe, pre-compress the original soil layer, lower the underground water level of the foundation, and increase the effective stress of the foundation. The pumping assembly is used to extract the accumulated water in the vacuum well point pipe and discharge it in time.

[0008] Preferably, an air pressure sensor and a vibration sensor are provided on the partition connecting sleeve, and a sealing plate is provided between the partition connecting sleeve and the horizontal pipe.

[0009] Preferably, the blind hole cavity, downcomer and partition connecting sleeve form an independent cavity through a sealing plate, the outer shell of the steel wire braided soft rubber hose is fixedly connected to the sealing plate, and the vibration sensor is against the steel wire braided soft rubber hose.

[0010] Preferably, the bottom of the vacuum well point pipe is paved with sand and gravel, the top of the vacuum well point pipe is provided with a sealed manhole cover, and the upper end of the pumping pipe passes through the sealed manhole cover; the pumping pipe includes a telescopic tube, a float and a flared tube, the flared tube is communicated with the telescopic tube, and a nylon leakage membrane is provided at the bottom of the flared tube.

[0011] Preferably, the water pumping component includes a water pump and a drainage trough, and the water inlet of the water pump is connected to the telescopic tube; the vacuum component includes a vacuum pump and a water-gas separator, and the water-gas separator is connected to the top of the vacuum well point pipe through a pipeline, and the vacuum pump is connected to the top of the water-gas separator.

[0012] Preferably, the cushion layer includes a masonry seat, a geotextile and a sealing membrane, the sealing membrane is arranged between the backfill layer and the geotextile, and the masonry seat is arranged on the upper side of the geotextile.

[0013] The working method of the vacuum preloading well point dewatering system includes: Step S1, determine the required operation area, level the site, set the downpipe points according to the groundwater distribution, and make targeted arrangements; Step S2, using a special pipe insertion device to perform pipe insertion operations, using hydraulic vibration drilling, making pipe holes at corresponding precipitation points, lowering the downcomer to complete the pipe insertion operation, with the upper end of the downcomer exposed 180 to 210 mm, and the lower end of the downcomer leaving an empty pipe hole to form a blind hole cavity; Step S3, insert a steel wire braided soft rubber hose into the downcomer, seal the top of the downcomer with a partition connecting sleeve, cover the steel wire braided soft rubber hose with a horizontal pipe, and after backfilling, the horizontal pipe protects the steel wire braided soft rubber hose; Step S4, according to the distribution of precipitation points, determine the drilling position, after the drilling construction, bury the vacuum well point pipe, lay sand and gravel at the bottom, and pass one end of the steel wire braided soft rubber hose into the vacuum well point pipe, and make a good seal at the connection; Step S5: Install the pumping pipe, select a suitable float, install the sealing manhole cover, and lay the pipes used by the pumping assembly and the vacuum assembly; Step S6, backfill the soil layer, level it, lay the sealing membrane and geotextile in sequence, cement the joints, lay a masonry base at the location where the pumping component and the vacuum component are set, and use it to carry the equipment to prevent the sealing membrane and geotextile from being damaged by the equipment; Step S7, install the pumping assembly and the vacuum assembly, connect the corresponding pipelines, and conduct a power-on test. The vacuum assembly draws a vacuum in the vacuum well point pipe, and the steel wire braided soft rubber hose draws the air in the downflow pipe. Under the negative pressure environment, the groundwater in the original soil layer is drawn to reduce the excess pore water pressure in the soil body; Step S8: Water accumulates in the downdraft pipe, and the steel wire braided soft rubber hose guides the accumulated water to flow into the vacuum well point pipe. The pumping assembly extracts the accumulated water in the vacuum well point pipe for discharge.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The vacuum well point pipe of the present invention is connected to the downcomer pipe by a steel wire braided soft rubber hose. The vacuum component draws a vacuum in the vacuum well point pipe to form a negative pressure, which prompts the steel wire braided soft rubber hose to extract the accumulated water and air in the downcomer pipe. If blockage occurs, the steel wire braided soft rubber hose is directly cleaned or replaced, which is convenient and quick to maintain and has low use cost. 2. The pumping pipe of the present invention adopts a telescopic pipe with a float at the bottom. The water inlet at the bottom of the telescopic pipe floats up and down under the buoyancy of the float, ensuring that the water inlet is always below the water surface to stabilize water pumping and at the same time stay away from the bottom of the water to ensure sedimentation and reduce sedimentation in the pumping system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the general assembly structure of a vacuum preloading well point dewatering system proposed by the present invention; Figure 2 This is a schematic diagram of the structure of a pumping component and a vacuum component of a vacuum preloading well point dewatering system proposed by the present invention; Figure 3 A schematic diagram of the pumping pipe structure of a vacuum preloading well point dewatering system proposed by the present invention; Figure 4 A schematic diagram of the structure of a downpipe of a vacuum preloading well point dewatering system proposed by the present invention; Figure 5 A schematic diagram of the first type of dewatering well point arrangement structure of a vacuum preloading well point dewatering system proposed by the present invention; Figure 6 This is a schematic diagram of the second dewatering well point arrangement structure of the vacuum preloading well point dewatering system proposed by the present invention.

[0016] In the figure: 1. Pumping assembly; 11. Pumping pump; 12. Drainage trough; 2. Cushion layer; 21. Masonry seat; 22. Geotextile; 23. Sealing membrane; 3. Backfill layer; 4. Horizontal pipe; 41. Steel wire braided soft rubber hose; 5. Downflow pipe; 51. Blind hole cavity; 52. Partition connecting sleeve; 53. Air pressure sensor; 54. Vibration sensor; 55. Sealing plate; 6. Original soil layer; 7. Vacuum well point pipe; 71. Sealing manhole cover; 8. Pumping pipe; 81. Telescopic pipe; 82. Float; 83. Expanding pipe; 84. Nylon leakage membrane; 9. Vacuum assembly; 91. Vacuum pump; 92. Water vapor separator. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Reference Figure 1-6 A vacuum preloading wellpoint dewatering system comprises a backfill layer 3, an original soil layer 6 and a vacuum wellpoint pipe 7. The vacuum wellpoint pipe 7 is embedded in the backfill layer 3 and the original soil layer 6. A dewatering pipe 5 is inserted into the original soil layer 6. The dewatering pipe 5 is made of a steel pipe or a PVC pipe. A horizontal pipe 4 is arranged between the vacuum wellpoint pipe 7 and the dewatering pipe 5. A partition connecting sleeve 52 is arranged between the horizontal pipe 4 and the dewatering pipe 5. A sealing plate 55 is arranged between the partition connecting sleeve 52 and the horizontal pipe 4. A plurality of sealing plates 55 can be provided as needed to block different positions respectively and improve the sealing reliability. A steel wire braided soft rubber hose 41 is provided inside the horizontal pipe 4, one end of the steel wire braided soft rubber hose 41 extends into the downcomer pipe 5, and the two are movably connected, so that the steel wire braided soft rubber hose 41 is easy to replace. When a problem occurs, there is no need to pull out the downcomer pipe 5, which reduces maintenance costs. The other end of the steel wire braided soft rubber hose 41 extends into the vacuum well point pipe 7 to achieve connectivity; A blind hole cavity 51 adapted to the downcomer 5 is provided in the original soil layer 6. The blind hole cavity 51 is communicated with the vacuum well point pipe 7 through the steel wire braided soft rubber tube 41. The blind hole cavity 51 in the original soil layer 6 completes the water collection and seepage process, accumulates a certain amount of groundwater, and is extracted through the steel wire braided soft rubber tube 41. The blind hole cavity 51, the downcomer 5 and the partition connection sleeve 52 form an independent cavity through the sealing plate 55. The outer shell of the steel wire braided soft rubber tube 41 is fixedly connected to the sealing plate 55. Through the steel wire braided soft rubber tube 41, the independent cavity can be vacuumed to extract groundwater in the nearby soil; An air pressure sensor 53 and a vibration sensor 54 are provided on the partition connection sleeve 52. The air pressure sensor 53 and the vibration sensor 54 are electrically connected to an industrial computer or other monitoring equipment to provide real-time feedback on the internal working conditions of the precipitation system. The air pressure sensor 53 is used to detect the air pressure in the independent cavity to determine whether there is air leakage at the connection between the precipitation pipe 5, the partition connection sleeve 52 and the sealing plate 55. The vibration sensor 54 is against the steel wire braided soft rubber hose 41. When water flows in the steel wire braided soft rubber hose 41, vibration is generated and collected by the vibration sensor 54, so that it is convenient for detection personnel to determine the working conditions of the precipitation system. The vacuum well point pipe 7 is used to accumulate groundwater and separate water and gas at the same time. Sand and gravel are laid at the bottom of the vacuum well point pipe 7. A sealed manhole cover 71 is provided on the top of the vacuum well point pipe 7. A pumping pipe 8 is provided in the vacuum well point pipe 7. The upper end of the pumping pipe 8 passes through the sealed manhole cover 71. The pumping pipe 8 includes a telescopic pipe 81, a float 82 and a flared pipe 83. The flared pipe 83 is communicated with the telescopic pipe 81. A nylon leakage membrane 84 is provided at the bottom of the flared pipe 83 to isolate mud and sand to prevent it from entering the pipeline and damaging the equipment.

[0019] A cushion layer 2 is provided on the upper side of the backfill layer 3, and the cushion layer 2 includes a masonry seat 21, a geotextile 22 and a sealing membrane 23. The sealing membrane 23 is arranged between the backfill layer 3 and the geotextile 22, and the masonry seat 21 is arranged on the upper side of the geotextile 22; A pumping assembly 1 and a vacuum assembly 9 are provided on the upper side of the cushion layer 2. The vacuum assembly 9 is used to draw a vacuum in the vacuum well point pipe 7 to improve the water collection effect, pre-press the original soil layer 6, reduce the underground water level of the foundation, and increase the effective stress of the foundation. The pumping assembly 1 is used to extract the accumulated water in the vacuum well point pipe 7 and discharge it in time; The pumping assembly 1 includes a pump 11 and a drain trough 12. The water inlet of the pump 11 is connected to the telescopic pipe 81. A signal sensor can be arranged in the vacuum well point pipe 7 to detect the amount of accumulated water and automatically control the operation of the pump 11 to realize intelligent automatic management. The vacuum assembly 9 includes a vacuum pump 91 and a water-gas separator 92. The water-gas separator 92 is connected to the top of the vacuum well point pipe 7 through a pipeline. The vacuum pump 91 is connected to the top of the water-gas separator 92. The vacuum pump 91 evacuates the air to create a negative pressure, sucks the air in the vacuum well point pipe 7, and the air enters the water-gas separator 92 to separate the water-gas.

[0020] The working method of the vacuum preloading well point dewatering system includes: Step S1, select the land area, set the vacuum preloading range, determine the required operation area, level the site, remove the uneven surface soil of the land area, the humus containing many plant roots and construction waste, determine the groundwater distribution of the foundation according to the on-site pumping test, set 5 points of the downpipe, and arrange the downpipe well points in a targeted manner; The traditional precipitation well points are arranged in a square, with 5 enclosed precipitation pipes at a spacing of 2m and a burial depth of 6m. The 5 precipitation pipes in the construction area are 2m apart, and a combination of long and short pipes is used, with the long pipe buried at a depth of 6m and the short pipe buried at a depth of 3m. This makes the construction simple and convenient for workers to operate. Furthermore, a ring arrangement may be adopted, such as Figure 6 As shown, with the vacuum well point pipe 7 as the center, the downpipe 5 is arranged around the vacuum well point pipe 7, and targeted downpipes are carried out according to the pumping test results, and multiple groups can also cooperate to carry out regional downpipes; Alternatively, a staggered form of 4 long and short horizontal pipes may be used, such as Figure 5 As shown, two dewatering pipes 5, one far and one near, are used on both sides of the vacuum well point pipe 7, which is suitable for dewatering operations in strip-shaped or long-strip construction areas; Step S2, using a special pipe insertion device to perform pipe insertion operation, using hydraulic vibration to make holes, making pipe holes at corresponding precipitation points, lowering the downcomer 5 to complete the pipe insertion operation, the upper end of the downcomer 5 is exposed 180-210mm, generally 200mm, the insertion depth is controlled, the pipe hole depth is greater than the length of the downcomer 5, and the vacant pipe hole at the lower end of the downcomer 5 forms a blind hole cavity 51 for water seepage; Step S3, insert the steel wire braided soft rubber hose 41 into the downcomer 5, seal the top of the downcomer 5 through the sealing plate 55 on the partition connecting sleeve 52, cover the steel wire braided soft rubber hose 41 with the horizontal pipe 4, and after backfilling, during the strong tamping construction, the horizontal pipe 4 protects the steel wire braided soft rubber hose 41; Step S4, according to the distribution of precipitation points, determine the drilling position, after the drilling construction, bury the vacuum well point pipe 7, lay sand and gravel at the bottom to prevent the bottom mud and sand from surging and affecting the pumping, one end of the steel wire braided soft rubber hose 41 is passed into the vacuum well point pipe 7, the connection is well sealed for vacuuming, and at the same time guides the accumulated water in the precipitation pipe 5 into the vacuum well point pipe 7; Step S5, install the water pumping pipe 8, select a suitable float 82, ensure that the buoyancy of the float 82 in the water is greater than the sum of the gravity of the movable part of the telescopic tube 81 and the sliding resistance of the telescopic tube 81, when the water level in the vacuum well point pipe 7 changes, the float 82 moves with the liquid level, ensure that the expanded pipe 83 can stably extract the accumulated water, and prevent the expanded pipe 83 from sinking to the bottom and sucking up mud and sand; Install the sealing manhole cover 71, seal the vacuum well point pipe 7, and lay the pipes used by the pumping assembly 1 and the vacuum assembly 9; Step S6, backfill the soil layer, level it, lay the sealing membrane 23 and the geotextile 22 in sequence, cement the joints to improve the sealing effect, lay the masonry seat 21 at the location where the pumping component 1 and the vacuum component 9 are set, and use it to carry the equipment to prevent the sealing membrane 23 and the geotextile 22 from being damaged by the equipment; Step S7, install the pumping component 1 and the vacuum component 9, connect the corresponding pipelines, and power on for testing. The vacuum component 9 evacuates the vacuum well point pipe 7. When evacuating, the negative pressure level is maintained at -80 to -95 kPa. The vacuum well point pipe 7 can be provided with an air pressure sensor to detect the internal air pressure to ensure that the system works reliably. The steel wire braided soft rubber hose 41 extracts the air in the downcomer 5. Under the negative pressure environment, the groundwater in the original soil layer 6 is drawn, and the water in the upper soil layer infiltrates. Under the vacuum environment, the water is collected and gathered in the downcomer 5 to reduce the excess pore water pressure in the soil body. Step S8: Water accumulates in the downcomer 5, the steel wire braided soft rubber hose 41 guides the accumulated water to flow into the vacuum well point pipe 7, and the pumping assembly 1 extracts the accumulated water in the vacuum well point pipe 7 for discharge; The pumping assembly 1 and the vacuum assembly 9 are equipped with dual power supplies to ensure the normal operation of the system. When the vacuum assembly 9 is in operation, continuous pumping should be ensured. The normal water discharge pattern is first large and then small, and first muddy and then clear. During operation, it should be observed frequently. If there is any abnormal situation such as no water flow, check whether the pipeline is leaking or blocked immediately. If any problem is found, correct it in time. When the well point needs maintenance, remove the sealing film 23 and the geotextile 22, open the sealing manhole cover 71 for well point maintenance. If the situation is serious, directly pull out the steel wire braided soft rubber hose 41, repair or replace it. The blocked part can be directly cut open and connected with a joint for temporary use. It is easy to maintain and low cost. After the problem is solved, it can be re-buried and put into use.

[0021] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0022] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0023] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0024] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

Claims

1. A vacuum preloading well point dewatering system, comprising a backfill layer (3), an original soil layer (6) and a vacuum well point pipe (7), characterized in that: The vacuum well point pipe (7) is embedded in the backfill layer (3) and the original soil layer (6); a downcomer pipe (5) is inserted into the original soil layer (6); a horizontal pipe (4) is provided between the vacuum well point pipe (7) and the downcomer pipe (5); a partition connecting sleeve (52) is provided between the horizontal pipe (4) and the downcomer pipe (5); a steel wire braided soft rubber hose (41) is provided inside the horizontal pipe (4); one end of the steel wire braided soft rubber hose (41) extends into the downcomer pipe (5); the other end of the steel wire braided soft rubber hose (41) extends into the vacuum well point pipe (7); a blind hole cavity (51) adapted to the downcomer pipe (5) is provided in the original soil layer (6); the blind hole cavity (51) is communicated with the vacuum well point pipe (7) through the steel wire braided soft rubber hose (41); A pumping pipe (8) is provided in the vacuum well point pipe (7), and the vacuum well point pipe (7) is used to accumulate groundwater and simultaneously separate water and gas. A cushion layer (2) is provided on the upper side of the backfill layer (3), and a pumping assembly (1) and a vacuum assembly (9) are provided on the upper side of the cushion layer (2). The vacuum assembly (9) is used to draw a vacuum in the vacuum well point pipe (7), pre-press the original soil layer (6), lower the groundwater level of the foundation, and increase the effective stress of the foundation. The pumping assembly (1) is used to extract the water accumulated in the vacuum well point pipe (7) and discharge it in a timely manner.

2. A vacuum preloading well point dewatering system according to claim 1, characterized in that: An air pressure sensor (53) and a vibration sensor (54) are provided on the partition connection sleeve (52), and a sealing plate (55) is provided between the partition connection sleeve (52) and the horizontal pipe (4).

3. A vacuum preloading well point dewatering system according to claim 2, characterized in that: The blind hole cavity (51), the downcomer (5) and the partition connection sleeve (52) form an independent cavity through a sealing plate (55); the outer shell of the steel wire braided soft rubber tube (41) and the sealing plate (55) are fixedly connected; and the vibration sensor (54) abuts against the steel wire braided soft rubber tube (41).

4. The vacuum preloading well point dewatering system according to claim 1, characterized in that: The bottom of the vacuum well point pipe (7) is paved with sand and gravel, the top of the vacuum well point pipe (7) is provided with a sealing well cover (71), and the upper end of the water pumping pipe (8) passes through the sealing well cover (71); The water extraction pipe (8) comprises a telescopic pipe (81), a floating ball (82) and a flared pipe (83); the flared pipe (83) is in communication with the telescopic pipe (81); and a nylon leakage membrane (84) is provided at the bottom of the flared pipe (83).

5. A vacuum preloading well point dewatering system according to claim 4, characterized in that: The water pumping assembly (1) comprises a water pump (11) and a drainage trough (12); the water inlet of the water pump (11) is in communication with the telescopic pipe (81); The vacuum assembly (9) comprises a vacuum pump (91) and a water-gas separator (92); the water-gas separator (92) is connected to the top of the vacuum well point pipe (7) through a pipeline; and the vacuum pump (91) is connected to the top of the water-gas separator (92).

6. The vacuum preloading well point dewatering system according to claim 1, characterized in that: The cushion layer (2) comprises a masonry seat (21), a geotextile (22) and a sealing membrane (23); the sealing membrane (23) is arranged between the backfill layer (3) and the geotextile (22); and the masonry seat (21) is arranged on the upper side of the geotextile (22).

7. A working method of the vacuum preloading well point dewatering system according to any one of claims 1 to 6, characterized in that: include: Step S1, determine the area to be operated, level the site, set the downpipe (5) points according to the groundwater distribution, and make targeted arrangements; Step S2, using a dedicated pipe insertion device to perform pipe insertion operations, using hydraulic vibration drilling to make pipe holes at corresponding precipitation points, lowering the downcomer (5) to complete the pipe insertion operation, with the upper end of the downcomer (5) exposed by 180 to 210 mm, and the lower end of the downcomer (5) leaving the pipe hole vacant to form a blind hole cavity (51); Step S3, inserting the steel wire braided soft rubber hose (41) into the downcomer (5), sealing the top of the downcomer (5) with the partition connecting sleeve (52), and putting the steel wire braided soft rubber hose (41) on the horizontal pipe (4). After backfilling, the horizontal pipe (4) protects the steel wire braided soft rubber hose (41); Step S4, determine the drilling position according to the distribution of precipitation points, bury the vacuum well point pipe (7) after the drilling construction, lay sand and gravel on the bottom, and pass one end of the steel wire braided soft rubber hose (41) into the vacuum well point pipe (7), and make a good seal at the connection; Step S5, installing the water pumping pipe (8), selecting a suitable float (82), installing the sealing manhole cover (71), and laying the pipes used by the water pumping component (1) and the vacuum component (9); Step S6, backfilling the soil layer, leveling it, laying the sealing membrane (23) and the geotextile (22) in sequence, cementing the joints, laying a masonry base (21) at the location where the pumping component (1) and the vacuum component (9) are set, for supporting the equipment, to prevent the sealing membrane (23) and the geotextile (22) from being damaged by the equipment; Step S7, installing the pumping assembly (1) and the vacuum assembly (9), connecting the corresponding pipelines, and powering on for testing. The vacuum assembly (9) draws a vacuum in the vacuum well point pipe (7), and the steel wire braided soft rubber hose (41) draws air from the downcomer pipe (5). Under the negative pressure environment, groundwater in the original soil layer (6) is drawn to reduce the excess pore water pressure in the soil body. Step S8: Water accumulates in the downcomer pipe (5), the steel wire braided soft rubber hose (41) guides the accumulated water to flow into the vacuum well point pipe (7), and the pumping assembly (1) extracts the accumulated water in the vacuum well point pipe (7) for discharge.

8. The working method of the vacuum preloading well point dewatering system according to claim 7 is characterized in that: The pumping assembly (1) and the vacuum assembly (9) are equipped with dual power supplies to ensure the normal operation of the system. When the vacuum assembly (9) is in operation, continuous pumping should be ensured. During operation, it should be observed frequently and any problems should be corrected in a timely manner. If the situation is serious, it is required to pull out the steel wire braided soft rubber hose (41), repair or replace it, and rebury it after the problem is solved.

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