Composite drainage system and method capable of achieving dual effects of pressurization and range extension
The composite drainage system, which combines pressurization and range extension, solves the problems of vacuum attenuation and siltation in the treatment of soft soil foundations using the vacuum preloading method, enabling effective treatment of deep soil and improving project quality and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 江苏盐城港港湾开发建设集团有限公司
- Filing Date
- 2026-02-13
- Publication Date
- 2026-05-12
AI Technical Summary
When treating soft soil foundations, the vacuum degree of traditional vacuum preloading method is severely reduced along the depth direction, which cannot be effectively transferred to the deep soil. This results in poor treatment effect of deep soil and problems such as vacuum degree loss and siltation, which affect project safety and schedule.
The composite drainage system employs both pressurization and range extension functions. By setting up a pressurization system and a range extension system, and using a vacuum pump and an air compressor connected to the composite drainage board respectively, the system is switched by valve control to achieve deep vacuum transmission and accelerated drainage by air pressure difference. Combined with high-pressure gas backwashing, the risk of clogging is reduced.
It effectively improved the treatment effect of deep soil, reduced the amount of materials used, shortened the construction period, reduced construction costs, and improved the treatment quality and safety of soft soil foundations.
Smart Images
Figure CN122013748A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of soft soil foundation treatment technology, and in particular to a composite drainage system and method that can achieve both pressurization and range extension. Background Technology
[0002] Soft soil is widely distributed in coastal areas, inland lakes, and river deltas in my country, and these areas are often key areas for economic development and infrastructure construction. Meanwhile, with the continuous improvement of my country's comprehensive national strength and economic development, the demand for port throughput is increasing. On the one hand, coastal cities face a shortage of land resources; on the other hand, there is the issue of secondary utilization of dredged soil. Therefore, some port expansion projects in coastal areas have gradually expanded to the development and utilization of new port land areas formed by reclaiming nearshore waters with dredged soil. However, dredged soft soil has characteristics such as high water content, low strength, high compressibility, poor permeability, and thick soil layers. If buildings or structures are directly constructed on it without corresponding engineering measures, it will lead to excessive settlement and insufficient stability, seriously affecting the safety and performance of the project.
[0003] With increasing environmental awareness, engineering construction demands higher environmental protection standards, and vacuum preloading technology, as a green and environmentally friendly foundation treatment method, has received growing attention. After years of research and engineering application, vacuum preloading has become a major method for soft soil foundation treatment in my country. However, in the process of treating deep, reclaimed silty soft soil foundations in port areas, the traditional vacuum preloading process has gradually revealed some limitations: (1) The vacuum degree in the drainage board is severely reduced along the depth direction of the drainage board insertion. The vacuum degree reduction in the recently filled silt is as high as -10 kPa / m or more, which makes it impossible for the vacuum degree to be transmitted to the deep soil.
[0004] (2) During the vacuuming process, the drainage board will bend and become clogged as the soil is drained and consolidated, resulting in a large loss of vacuum along the way. The vacuum cannot be transmitted to the deep soil, and only a shallow hard shell layer is formed on the surface of the soil. The deep soil is still soft silt, resulting in poor treatment effect of deep soil and large post-construction settlement.
[0005] To address the issues of insufficient treatment depth and poor treatment effect on deep soil using traditional vacuum preloading methods, and to shorten the construction period to some extent, it is necessary to improve the traditional vacuum preloading process. Summary of the Invention
[0006] In view of this, the purpose of this invention is to propose a composite drainage system and method that can achieve both pressurization and range extension, so as to solve the problem of poor treatment effect on deep soil.
[0007] Based on the above objectives, the present invention provides a composite drainage system that can achieve both pressurization and range extension, comprising: a vacuum system, a sealing system, a water vapor separator, and an air compressor installed on the ground surface; the sealing system includes a sealing trench installed around the ground surface and a sealing layer buried in the sealing trench; the sealing layer is buried around the sealing trench; the vacuum system includes a vacuum pump installed above the ground surface; the vacuum pump is connected to multiple sets of vacuum pipelines; one end of each set of vacuum pipelines can be controlled to open and close and is connected to a drainage board inserted into the soft soil layer; The composite drainage system also includes: a range-extending system, a pressurizing system, and multiple composite drainage boards inserted into the soft soil layer, with the multiple composite drainage boards and multiple drainage boards arranged alternately. The range extender system includes a range extender line connected to a vacuum pump, which is connected to a composite drainage board via a three-way valve installed on a steel wire hose. The pressurization system includes a pressurization line connected to an air compressor, which is connected to the composite drainage board via a three-way valve installed on a steel wire hose. Valves are installed on both the booster pipeline and the range extender pipeline. The opening and closing of the booster system and the range extender system are switched by controlling the opening and closing of each valve.
[0008] Preferably, the steel wire hose includes: a main steel wire hose, a pressurizing steel wire hose, and a range-extending steel wire hose. One end of the main steel wire hose is fixedly installed with a hand-type connector, and the main steel wire hose is connected to the composite drainage board through the hand-type connector. The other end of the main steel wire hose is connected to the pressurizing steel wire hose and the range-extending steel wire hose through a three-way valve. The pressurizing steel wire hose and the range-extending steel wire hose are respectively connected to the pressurizing pipeline and the range-extending pipeline.
[0009] Preferably, the main steel wire hose, the pressurizing steel wire hose, and the range-extending steel wire hose are all composed of a reinforcing layer, an inner tube fixedly installed on the inner side wall of the reinforcing layer, and an outer protective sleeve fixedly installed on the outer side wall of the reinforcing layer. The material of the reinforcing layer is spiral steel wire, the material of the inner tube is polytetrafluoroethylene, and the material of the outer protective sleeve is polyvinyl chloride.
[0010] Preferably, the booster pipeline includes a booster branch pipe and a booster main pipe connected to the booster branch pipe. The opposite ends of the booster branch pipe and the booster main pipe are respectively connected to an air compressor and a composite drainage plate. The valve is fixedly installed on the booster main pipe.
[0011] Preferably, the range extender pipeline includes a range extender branch pipe and a range extender main pipe connected to the range extender branch pipe. The opposite ends of the range extender branch pipe and the range extender main pipe are respectively connected to a vacuum pump and a composite drainage plate. The valve is fixedly installed on the range extender main pipe.
[0012] Preferably, the sealing layer comprises: a sealing membrane and a geotextile laid on the ground surface, wherein the sealing membrane and the geotextile are stacked, and the periphery of the sealing membrane and the periphery of the geotextile are buried in the sealing trench.
[0013] Preferably, a butterfly joint is fixedly installed between the vacuum pipeline and the drainage plate.
[0014] Preferably, the composite drainage board includes an outer sheath, an anti-corrosion sleeve and a reinforcing sleeve fixedly installed inside the outer sheath, with the anti-corrosion sleeve and the reinforcing sleeve spaced apart; a flow channel is formed inside the outer sheath, and multiple sets of spaced protrusions are fixedly arranged on both sides of the inner wall of the flow channel, with branch pipes interspersed between adjacent protrusions, and auxiliary pipes embedded inside the branch pipes.
[0015] A composite drainage method that achieves both pressurization and range extension, applied to a composite drainage system, includes the following steps: S1. Lay woven fabric on the surface of the soft soil layer to be treated to provide bearing capacity, and insert drainage boards and composite drainage boards into the soft soil layer at intervals. S2. Install a vacuum pump, a water vapor separator and an air compressor on the ground. Connect the drainage board to the vacuum pump through a vacuum pipeline. Connect the composite drainage board to the vacuum pump and the air compressor through a range extender system and a pressurization system, respectively. Connect the input end of the water vapor separator to the drainage board and the composite drainage board. S3. Excavate a sealing trench around the ground surface covered by the sealing layer, and bury the edges of the sealing layer into the sealing trench for sealing. Start the vacuum pump to implement vacuuming. S4. In the early stage of vacuuming, turn on the range extender system and turn off the pressurization system. This allows the composite drainage board to eliminate the shallow vacuum loss of the soft soil layer through the steel wire hose, and to transfer the vacuum to the deep soil of the soft soil layer, thereby improving the treatment of deep soft soil foundations. S5. In the middle and later stages, the pressurization system is turned on and the range extension system is turned off. The composite drainage board accelerates the drainage rate of the soft soil layer through the steel wire hose under the pressure difference of the pressurization.
[0016] Preferably, in step S5, when the soil consolidation rate of the soft soil layer decreases, intermittent pressurization is performed daily for 30 minutes each time, with a pressurization pressure of 20 kPa. The high-pressure gas during pressurization backwashes the composite drainage board to reduce clogging of the composite drainage board.
[0017] The beneficial effects of this invention are as follows: A composite drainage board is arranged in the center of the area between adjacent drainage boards, and the pressure boosting system and the range-extending system can be flexibly switched through valve control. When the range-extending system is activated, the steel wire hose in the composite drainage board can compensate for shallow vacuum loss, so that the vacuum degree can be effectively transferred to the deep soil, enhancing the treatment effect of deep soft soil foundation. When switching to the pressure boosting system, the soil drainage is accelerated by the air pressure difference, and the high-pressure gas backwashes the composite drainage board, significantly reducing the risk of clogging. At the same time, by switching between the pressure boosting and range-extending systems, the composite drainage board can be used for multiple purposes, which not only expands its functional range but also reduces the amount of materials used, thereby saving construction costs, improving the treatment effect of soft soil foundation and shortening the construction period. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in this 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 for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 This is a schematic diagram of the overall layout and structure of the present invention; Figure 2 This is a schematic diagram of the connection structure between the composite drainage board and the steel wire hose of the present invention; Figure 3 This is a schematic diagram showing the distribution of the drainage board and composite drainage board of the present invention; Figure 4 This is a schematic diagram of a half-section of the composite drainage board of the present invention; Figure 5 This is a partial structural diagram of the composite drainage board of the present invention.
[0020] The diagram is marked as follows: 1. Sealing trench; 2. Ground surface; 3. Soft soil layer; 4. Vacuum pump; 5. Water vapor separator; 6. Air compressor; 7. Sealing membrane; 8. Geotextile; 9. Booster pipeline; 91. Booster branch pipe; 92. Booster main pipe; 10. Extended range pipeline; 101. Extended range branch pipe; 102. Extended range main pipe; 11. Vacuum pipeline; 12. Butterfly joint; 13. Drainage board; 14. Composite drainage board; 141. Outer sheath; 142. Corrosion-resistant sleeve; 143. Reinforced sleeve; 144. Flow channel; 145. Protrusion; 146. Branch pipe; 147. Auxiliary pipe; 15. Steel wire hose; 151. Main steel wire hose; 152. Booster steel wire hose; 153. Extended range steel wire hose; 16. Hand-type joint; 17. Valve; 18. Three-way valve. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. Example
[0022] like Figure 1 , Figure 2 and Figure 3 As shown, a composite drainage system capable of both pressurization and range extension includes: a vacuum system, a sealing system, a water vapor separator 5, and an air compressor 6 installed on the ground surface 2. The sealing system includes a sealing trench 1 surrounding the ground surface 2 and a sealing layer buried within the sealing trench 1. The sealing layer includes a sealing membrane 7 and geotextile 8 laid on the ground surface 2, stacked together, with the perimeter of both the sealing membrane 7 and the geotextile 8 buried in the sealing trench 1. The perimeter of the sealing layer is also buried within the sealing trench 1. The vacuum system includes a vacuum pump 4 installed above the ground surface 2, connected to multiple sets of vacuum pipelines 11 and multiple sets of vacuum... One end of the vacuum pipeline 11 is connected to a drainage board 13 inserted into the soft soil layer 3, which can be controlled to open and close. Preferably, a butterfly joint 12 is fixedly installed between the vacuum pipeline 11 and the drainage board 13. The butterfly joint 12 can connect the vacuum pipeline 11 and the drainage board 13 and achieve on / off control at the same time. The sealing layer buried in the sealing trench 1 can provide a sealing cover for the soft soil layer 3 below the ground surface 2 when vacuuming under negative pressure, ensuring the effect of negative pressure extraction. This allows the vacuum pump 4 and the air compressor 6 to perform negative pressure extraction in the soft soil layer 3 through multiple sets of vacuum pipelines 11 with the help of the drainage board 13, and the extracted mixed gas and liquid are separated through the water vapor separator 5. The composite drainage system further includes: a range extender system, a pressurization system, and multiple composite drainage boards 14 inserted into the soft soil layer 3, with the composite drainage boards 14 and multiple drainage boards 13 arranged alternately; the range extender system includes a range extender pipeline 10 connected to a vacuum pump 4, and the range extender pipeline 10 is connected to the composite drainage boards 14 via a three-way valve 18 installed on a steel wire hose 15; the pressurization system includes a pressurization pipeline 9 connected to an air compressor 6, and the pressurization pipeline 9 is connected to the composite drainage boards 14 via a three-way valve 18 installed on a steel wire hose 15; both the pressurization pipeline 9 and the range extender pipeline 10 are equipped with valves 17, and the opening and closing of the pressurization system and the range extender system are switched by controlling the opening and closing of each valve 17; the composite drainage boards are arranged at the center positions of the areas formed between adjacent drainage boards 13. 14. By controlling the opening and closing of valves 17 at different positions, the pressurization system and the range extender system can be switched. When the range extender system is turned on and the pressurization system is turned off, the steel wire hose 15 on the composite drainage board 14 can eliminate the vacuum loss in the shallow part of the soft soil layer 3, thereby transferring the vacuum to the deeper soil and improving the treatment effect of the deep soft soil foundation. When the pressurization system is turned on and the range extender system is turned off, the soil in the soft soil layer 3 can accelerate the drainage rate under the pressure difference of the pressurization. Moreover, the high-pressure gas during pressurization can backwash the composite drainage board 14, thereby effectively reducing the risk of clogging of the composite drainage board 14. By switching the opening and closing of the pressurization system and the range extender system, the composite drainage board 14 can be used for multiple purposes, while also saving material and achieving the goal of saving costs.
[0023] Furthermore, such as Figure 2As shown, the steel wire hose 15 includes: a main steel wire hose 151, a pressurizing steel wire hose 152, and a range-extending steel wire hose 153. Each of the main steel wire hose 151, pressurizing steel wire hose 152, and range-extending steel wire hose 153 consists of a reinforcing layer, an inner tube fixedly installed on the inner wall of the reinforcing layer, and an outer protective sleeve fixedly installed on the outer wall of the reinforcing layer. The reinforcing layer is made of spiral steel wire, the inner tube is made of polytetrafluoroethylene (PTFE), and the outer protective sleeve is made of polyvinyl chloride (PVC). The main steel wire hose 151 is located below the ground surface 2, and its length is determined according to the thickness of the soft soil layer. The pressurizing steel wire hose 152 and the range-extending steel wire hose 153 are located above the ground surface 2. A hand-type connector 16 is fixedly installed at one end of the main steel wire hose 151. The main steel wire hose 151 is connected to the composite drainage board 14 through the hand-type connector 16. The other end of the main steel wire hose 151 is connected to the pressure-boosting steel wire hose 152 and the range-extending steel wire hose 153 through a three-way valve 18. The pressure-boosting steel wire hose 152 and the range-extending steel wire hose 153 are connected to the pressure-boosting pipeline 9 and the range-extending pipeline 10, respectively. When the range-extending system is turned on and the pressure-boosting system is turned off, the main steel wire hose 151 on the composite drainage board 14 can eliminate the loss of shallow vacuum, thereby transferring the vacuum to deeper soil layers and improving the treatment effect of deep soft soil foundations.
[0024] Furthermore, such as Figure 2 As shown, the booster line 9 includes a booster branch pipe 91 and a booster main pipe 92 connected to the booster branch pipe 91. The separate ends of the booster branch pipe 91 and the booster main pipe 92 are respectively connected to the air compressor 6 and the composite drainage plate 14. The valve 17 is fixedly installed on the booster main pipe 92. The range extender line 10 includes a range extender branch pipe 101 and a range extender main pipe 102 connected to the range extender branch pipe 101. The separate ends of the range extender branch pipe 101 and the range extender main pipe 102 are respectively connected to the vacuum pump 4 and the composite drainage plate 14. The valve 17 is fixedly installed on the range extender main pipe 102.
[0025] Furthermore, such as Figure 4 and Figure 5As shown, the composite drainage board 14 includes an outer sheath 141, and an anti-corrosion sleeve 142 and a reinforcing sleeve 143 fixedly installed inside the outer sheath 141, with the anti-corrosion sleeve 142 and the reinforcing sleeve 143 spaced apart. A flow channel 144 is formed inside the outer sheath 141, and multiple sets of spaced protrusions 145 are fixedly arranged on both sides of the inner wall of the flow channel 144. Branch pipes 146 are interspersed between adjacent protrusions 145, and auxiliary pipes 147 are embedded inside the branch pipes 146. The outer sheath 141 provides direct protection for the composite drainage board 14 inserted into the soft soil layer 3, and the anti-corrosion sleeve 142 and the reinforcing sleeve 143 further improve the durability of the composite drainage board 14 during underground operations, thereby reducing... The frequency of replacing the composite drainage board 14 improves the sustainability of the operation. At the same time, the spaced protrusions 145 provided in the flow channel 144 can provide an internal channel formed by the gaps formed by the arrangement of the protrusions 145 when the composite drainage board 14 is subjected to external pressure. This prevents the composite drainage board 14 from losing its transport function due to soil pressure, thus ensuring the treatment effect of deep soft soil foundation. Furthermore, the auxiliary pipe 147 provided between the protrusions 145 by means of the branch pipe 146 can provide a backup auxiliary channel when the internal channel formed by the gaps formed by the arrangement of the protrusions 145 loses its transport function, thereby continuing to meet the transport needs and further ensuring the treatment effect of deep soft soil foundation. Example
[0026] like Figure 1 , Figure 2 and Figure 3 As shown, a composite drainage method that can achieve both pressurization and range extension is applied to the composite drainage system in Example 1, and includes the following steps: S1. Lay woven fabric on the surface 2 of the soft soil layer 3 to be treated to provide a certain bearing capacity, and insert the drainage board 13 and the composite drainage board 14 into the soft soil layer 3 in a spaced manner using a board inserter. S2. Install a vacuum pump 4, a water vapor separator 5, and an air compressor 6 on the ground surface 2. Connect the drainage board 13 to the vacuum pump 4 through the vacuum pipeline 11. Connect the composite drainage board 14 to the vacuum pump 4 and the air compressor 6 through the range extender system and the pressurization system, respectively. Connect the input end of the water vapor separator 5 to the drainage board 13 and the composite drainage board 14 so that the air compressor 6 and the vacuum pump 4 can smoothly perform vacuum preloading treatment on the deep soft soil layer 3 through the drainage board 13 and the composite drainage board 14 during operation. S3. Excavate sealing trench 1 around the ground surface 2 covered by sealing layer, and bury the edges of sealing layer into sealing trench 1 for sealing. Then start vacuum pump 4 to perform vacuuming. S4. In the early stage of vacuuming, due to the rapid settlement rate of the soil, the range extension system can be turned on and the pressurization system can be turned off. At this time, the composite drainage board 14 is equivalent to realizing the function of range extension drainage, so that the composite drainage board 14 eliminates the shallow vacuum loss of the soft soil layer 3 through the steel wire hose 15, and transfers the vacuum to the deep soil of the soft soil layer 3, thereby improving the treatment effect of the deep soft soil foundation of the soft soil layer 3. S5. In the middle and late stages, the soil consolidation rate will decrease significantly. When the soil settlement rate drops below 5 mm / d, the pressurization system can be turned on and the range extension system can be turned off. At this time, the composite drainage board 14 is equivalent to realizing the function of pressurized drainage. The composite drainage board 14 accelerates the drainage rate of the soft soil layer 3 under the pressure difference of the pressurized pressure through the steel wire hose 15. When the soil consolidation rate of the soft soil layer 3 decreases, intermittent pressurization can be carried out every day, each pressurization for 30 minutes, with a pressurization pressure of 20 kPa. The high-pressure gas during pressurization can backwash the composite drainage board 14, thereby reducing the risk of clogging of the composite drainage board 14.
[0027] This invention is intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.
Claims
1. A composite drainage system capable of achieving both pressurization and range extension, comprising: The vacuum system, sealing system, water vapor separator (5) and air compressor (6) installed on the ground surface (2) are characterized in that the sealing system includes a sealing trench (1) installed around the ground surface (2) and a sealing layer buried in the sealing trench (1), the sealing layer is buried around the sealing trench (1), and the vacuum system includes a vacuum pump (4) installed above the ground surface (2), the vacuum pump (4) is connected to multiple sets of vacuum pipelines (11), and one end of each set of vacuum pipelines (11) can be controlled to be connected to a drainage board (13) inserted into the soft soil layer (3). The composite drainage system also includes: a range-extending system, a pressurizing system, and multiple composite drainage boards (14) inserted into the soft soil layer (3), with the multiple composite drainage boards (14) and multiple drainage boards (13) arranged alternately; The range extender system includes a range extender line (10) connected to a vacuum pump (4), the range extender line (10) being connected to a composite drainage board (14) via a three-way valve (18) installed on a steel wire hose (15), and the pressurization system includes a pressurization line (9) connected to an air compressor (6), the pressurization line (9) being connected to the composite drainage board (14) via a three-way valve (18) installed on a steel wire hose (15); Both the booster line (9) and the range extender line (10) are equipped with valves (17), and the opening and closing of the booster system and the range extender system are switched by controlling the opening and closing of each valve (17).
2. The composite drainage system according to claim 1, which can achieve both pressurization and range extension, is characterized in that, The steel wire hose (15) includes: a main steel wire hose (151), a pressurizing steel wire hose (152), and a range-extending steel wire hose (153). One end of the main steel wire hose (151) is fixedly installed with a hand-type connector (16). The main steel wire hose (151) is connected to the composite drainage board (14) through the hand-type connector (16). The other end of the main steel wire hose (151) is connected to the pressurizing steel wire hose (152) and the range-extending steel wire hose (153) through a three-way valve (18). The pressurizing steel wire hose (152) and the range-extending steel wire hose (153) are connected to the pressurizing pipeline (9) and the range-extending pipeline (10) respectively.
3. A composite drainage system capable of achieving both pressurization and range extension according to claim 2, characterized in that, The main steel wire hose (151), the pressurizing steel wire hose (152), and the range-extending steel wire hose (153) are all composed of a reinforcing layer, an inner tube fixedly installed on the inner side wall of the reinforcing layer, and an outer protective sleeve fixedly installed on the outer side wall of the reinforcing layer. The material of the reinforcing layer is spiral steel wire, the material of the inner tube is polytetrafluoroethylene, and the material of the outer protective sleeve is polyvinyl chloride.
4. A composite drainage system capable of achieving both pressurization and range extension as described in claim 1, characterized in that, The booster pipeline (9) includes a booster branch pipe (91) and a booster main pipe (92) connected to the booster branch pipe (91). The opposite ends of the booster branch pipe (91) and the booster main pipe (92) are respectively connected to the air compressor (6) and the composite drainage plate (14). The valve (17) is fixedly installed on the booster main pipe (92).
5. A composite drainage system capable of achieving both pressurization and range extension according to claim 1, characterized in that, The range extender pipeline (10) includes a range extender branch pipe (101) and a range extender main pipe (102) connected to the range extender branch pipe (101). The ends of the range extender branch pipe (101) and the range extender main pipe (102) are respectively connected to a vacuum pump (4) and a composite drainage plate (14). The valve (17) is fixedly installed on the range extender main pipe (102).
6. A composite drainage system capable of achieving both pressurization and range extension according to claim 1, characterized in that, The sealing layer includes a sealing membrane (7) and a geotextile (8) laid on the ground surface (2), the sealing membrane (7) and the geotextile (8) being stacked, and the sealing membrane (7) and the geotextile (8) being buried in the sealing trench (1) around their perimeters.
7. A composite drainage system capable of achieving both pressurization and range extension according to claim 1, characterized in that, A butterfly connector (12) is fixedly installed between the vacuum line (11) and the drainage plate (13).
8. A composite drainage system capable of achieving both pressurization and range extension according to claim 1, characterized in that, The composite drainage board (14) includes an outer sheath (141), an anti-corrosion sleeve (142) and a reinforcing sleeve (143) fixedly installed inside the outer sheath (141), with the anti-corrosion sleeve (142) and the reinforcing sleeve (143) spaced apart; a flow channel (144) is formed inside the outer sheath (141), and multiple sets of spaced protrusions (145) are fixedly arranged on both sides of the inner wall of the flow channel (144), with branch pipes (146) interspersed between adjacent protrusions (145), and an auxiliary pipe (147) is embedded inside the branch pipe (146).
9. A composite drainage method capable of achieving both pressurization and range extension, applied to the composite drainage system as described in claim 1, characterized in that, Includes the following steps: S1. Lay woven fabric on the surface (2) of the soft soil layer (3) to be treated to provide bearing capacity, and insert drainage boards (13) and composite drainage boards (14) into the soft soil layer (3) in a spaced manner. S2. Install a vacuum pump (4), a water vapor separator (5) and an air compressor (6) on the ground surface (2). Connect the drainage board (13) to the vacuum pump (4) through the vacuum pipeline (11), and connect the composite drainage board (14) to the vacuum pump (4) and the air compressor (6) through the range extender system and the pressurization system respectively. Connect the input end of the water vapor separator (5) to the drainage board (13) and the composite drainage board (14). S3. Excavate a sealing trench (1) around the ground surface (2) covered by the sealing layer, and bury the edges of the sealing layer into the sealing trench (1) for sealing. Start the vacuum pump (4) to perform vacuuming. S4. In the early stage of vacuuming, turn on the range extension system and turn off the pressurization system so that the composite drainage board (14) eliminates the shallow vacuum loss of the soft soil layer (3) through the steel wire hose (15) and transfers the vacuum to the deep soil of the soft soil layer (3) to improve the treatment of the deep soft soil foundation of the soft soil layer (3). S5. In the middle and late stages, the pressurization system is turned on and the range extension system is turned off. The composite drainage board (14) accelerates the drainage rate of the soft soil layer (3) through the steel wire hose (15) under the pressure difference of the pressurization.
10. A composite drainage method according to claim 9 that can achieve both pressurization and range extension, characterized in that, In step S5, when the soil consolidation rate of the soft soil layer (3) decreases, intermittent pressurization is carried out every day for 30 minutes each time, with a pressurization pressure of 20 kPa. The high-pressure gas during pressurization backwashes the composite drainage board (14) to reduce the blockage of the composite drainage board.