A soft foundation reinforcement construction device and method combining vacuum preloading and air pressure splitting

Abstract

The application discloses a soft foundation reinforcement construction device and method combining vacuum preloading and air pressure splitting, which comprises a pressurizing unit, a vacuum unit and a soft foundation reinforcement construction method combining air pressure splitting, wherein the pressurizing unit comprises a pressurizing tank, an air injection pipe, an air injection pipe and a nozzle component; the vacuum unit comprises a drainage plate, a corrugated hose, a vacuum pump and a drain pipe; the first installation component is connected with the second installation component, the convenient connection of the nozzle and the air injection pipe is completed, the sealing piece is arranged, the problem that the air outlet hole is blocked by the soil when the air injection pipe penetrates into the soil is effectively solved, the combined construction mode of the hydraulic fill sand heaped load vacuum preloading and air pressure splitting technology is adopted, the hydraulic fill sand is blown on the sealed vacuum drainage plate area to perform heaped loading, high-pressure gas is injected into the soft soil between the drainage plates, the air pressure splitting is generated, the flow channel of the underground water is expanded, the soil settlement is accelerated, the precipitation consolidation efficiency is improved, the construction period can be greatly shortened, and the construction cost is saved.

Description

Technical Field

[0001] This invention relates to the field of soft soil foundation reinforcement, and in particular to a soft soil foundation reinforcement construction device and method that combines vacuum preloading with pneumatic fracturing. Background Technology

[0002] Soft soil is widely distributed in coastal and riverine areas of my country. In addition to its high water content, high compressibility, low shear strength, and low permeability coefficient, this type of soil is usually buried deep, and the bottom strata are hydraulically connected with the surrounding waters, making the engineering geological conditions extremely complex.

[0003] Soft soil consolidation is a crucial step in modern engineering construction, primarily used to improve soil engineering properties and enhance the bearing capacity and stability of engineering foundations. Traditional soil consolidation methods mainly employ techniques such as prestressed reinforcement, drilling and grouting, and static compaction. However, these methods suffer from drawbacks such as low efficiency, high cost, long construction periods, and significant destructiveness, making it difficult to meet the demands of modern engineering construction for speed, quality, and environmental protection.

[0004] Vacuum preloading is one of the most commonly used methods for treating soft clay and dredged silt in coastal and riverside areas. However, vacuum preloading has a long processing time, and because the sealing membrane is easily damaged, it is difficult to maintain the vacuum level in the sealed area, which gradually decreases with the depth of treatment, thus limiting its treatment depth.

[0005] Patent No. ZL202110946194.4, entitled "A Reinforcement Device and Reinforcement Process for Large-Area Silt Foundations in Coastal Areas", mainly introduces a two-stage vacuum surcharge combined preloading method for reinforcing silt foundations. This device and process are mainly used for reinforcing dredged silt with particularly high water content. It is not suitable for treating deep soft soil foundations in tidal flat areas, does not propose measures to maintain vacuum, and requires a certain extension of the treatment time for phased construction.

[0006] The installation of the jet nozzles in existing soft soil reinforcement construction devices is cumbersome, and the air outlets are not protected against clogging. As the jet nozzles penetrate the soil, the soil can easily clog the air outlets, hindering the subsequent air pressure fracturing process. Summary of the Invention

[0007] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0008] In view of the problems existing in the prior art, the present invention is proposed.

[0009] Therefore, the technical problem to be solved by the present invention is that the existing soft soil reinforcement technology takes a long time to carry out in stages and is not suitable for the treatment of deep soft soil foundations in tidal flat areas. At the same time, the air jet nozzles in the existing soft soil reinforcement construction devices are cumbersome to install, and the air outlets are not protected against clogging.

[0010] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a soft soil foundation reinforcement construction device combining vacuum preloading and pneumatic splitting, which includes a pressurization unit, wherein the pressurization unit includes a pressurization tank, a jet pipe, an injection pipe and a nozzle component, the jet pipe is connected to the injection pipe, the injection pipe is connected to the pressurization tank and the nozzle component is connected to the jet pipe; The nozzle component includes a first mounting component and a second mounting component. The first mounting component is connected to the air outlet end of the jet pipe, and the second mounting component is connected to the first mounting component. The first mounting component includes a mounting housing, a locking component, and a limiting component. The locking component is disposed in the internal cavity of the mounting housing, and the limiting component is disposed on one side of the mounting housing and connected to the locking component. The second installation component includes an air outlet and a sealing component, wherein the sealing component is disposed in the internal cavity of the air outlet.

[0011] As a soft soil reinforcement construction device combining vacuum preloading and pneumatic splitting according to the present invention, the positioning component includes a positioning block, a positioning sleeve and a first spring. The positioning block passes through the positioning hole in the side wall of the mounting housing and is connected to the positioning groove provided in the side wall of the jet pipe. The positioning block is connected to the positioning sleeve through the first spring. The positioning sleeve is connected to the inner side wall of the mounting housing.

[0012] As a preferred embodiment of the soft soil reinforcement construction device combining vacuum preloading and pneumatic splitting described in this invention, the limiting component includes a limiting ring, a manual ring, and a limiting rod. The limiting ring is connected to the limiting rod, and the limiting rod is connected to the locking block through a limiting hole provided on the side wall of the locking sleeve. The limiting ring passes through a limiting opening on the side wall of the mounting housing and is connected to the manual ring. A resistance rod is provided on the side wall of the limiting opening. The resistance rod is connected to the limiting ring, and a resistance block is provided on the side wall of the resistance rod. The resistance block is connected to the resistance rod through a second spring.

[0013] As a preferred embodiment of the soft soil reinforcement construction device combining vacuum preloading and pneumatic splitting described in this invention, the air outlet component includes an air outlet nozzle and a snap-fit ​​post. The side wall of the air outlet nozzle is provided with an air outlet hole. One end of the snap-fit ​​post is connected to the air outlet nozzle, and the other end is connected to the snap-fit ​​groove on the side wall of the mounting housing.

[0014] As a preferred embodiment of the soft soil reinforcement construction device combining vacuum preloading and pneumatic splitting described in this invention, the sealing component includes a first sealing plate, a second sealing plate, and a pressure plate. The first sealing plate and the second sealing plate are disposed in the cavity of the side wall of the air outlet nozzle, and the side walls of the first sealing plate and the second sealing plate are provided with air outlet holes. The pressure plate is connected to the inner side walls of the first sealing plate and the second sealing plate, and the outer side walls of the first sealing plate and the second sealing plate are provided with a first push block and a second push block.

[0015] As a preferred embodiment of the soft soil reinforcement construction device combining vacuum preloading and pneumatic splitting described in this invention, wherein: the first sealing plate is connected to the inner wall of the air outlet nozzle cavity via a third spring; the first push block is connected to the manual ring via a connecting rod, a connecting rod sleeve, and a fourth spring; the connecting rod sleeve is connected to one side of the manual ring; and the fourth spring is disposed inside the connecting rod sleeve.

[0016] As a preferred embodiment of the soft soil foundation reinforcement construction device combining vacuum preloading and pneumatic splitting described in this invention, it further includes a vacuum unit, which is disposed on one side of the pressurization unit and includes a drainage plate, a filter pipe, and a vacuum pump. The vacuum pump is connected to the pressurization tank, the drain pipe is connected to the drainage plate, and the filter pipe is connected to the drainage plate.

[0017] A method for soft soil foundation reinforcement using vacuum preloading combined with pneumatic fracturing, comprising: The construction area was vacuum-sealed. The vacuum-sealed area is filled with sand to increase the negative pressure. High-pressure gas splits the soil, creating an internal and external gas circulation.

[0018] As a preferred embodiment of the soft soil reinforcement construction method combining vacuum preloading and pneumatic splitting described in this invention, the internal and external gas circulation involves the gas extracted by the vacuum pump being transported to the pressurization tank, and the pressurization tank then injecting high-pressure air into the soft soil between the drainage boards.

[0019] As a preferred embodiment of the soft soil reinforcement construction device combining vacuum preloading and pneumatic splitting described in this invention, the pneumatic splitting method utilizes high-pressure gas to split the soil at different depths in the soft soil, thereby expanding the water flow channels in the soft soil and accelerating the flow and discharge of water.

[0020] The beneficial effects of this invention are: The nozzle component is installed and connected to the first and second mounting components to facilitate the connection between the nozzle and the air jet pipe. At the same time, a sealing component is installed to effectively solve the problem of the air outlet being blocked by the soil when the air jet pipe penetrates deep into the soil, preventing subsequent pressurization work from being hindered and affecting construction efficiency.

[0021] The construction method employs a combination of dredged sand surcharge vacuum preloading and pneumatic fracturing technology. Sand is surcharged over the sealed vacuum drainage board area, while high-pressure gas is injected into the soft soil between the drainage boards, generating pneumatic fracturing and expanding the flow channels for groundwater. Under the triple action of the upper preloading pressure, vacuum negative pressure, and pneumatic fracturing, the movement of groundwater into the drainage board is accelerated, soil settlement is expedited, and the efficiency of dewatering consolidation is improved. This significantly shortens the construction period, saves construction costs, effectively improves the bearing capacity of the foundation, and reduces post-construction settlement. The dredged sand surcharge preloading effectively protects the sealing membrane during surcharge, ensuring the vacuum degree of the sealed area and accelerating the drainage of groundwater. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of the overall device of the present invention.

[0023] Figure 2 This is a schematic diagram of the nozzle component of the present invention.

[0024] Figure 3 This is an exploded schematic diagram of the nozzle component of the present invention.

[0025] Figure 4 This is a schematic diagram of the first mounting component of the present invention.

[0026] Figure 5 This is a cross-sectional schematic diagram of the locking component of the present invention.

[0027] Figure 6 This is a schematic cross-sectional view of the resistance insert of the present invention.

[0028] Figure 7 This is a schematic cross-sectional view of the first sealing plate of the present invention.

[0029] Figure 8 This is an exploded schematic diagram of the sealing component of the present invention. Detailed Implementation

[0030] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0031] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0032] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0033] Example 1 Reference Figure 1 , Figure 2 This is the first embodiment of the present invention. This embodiment provides a soft soil reinforcement construction device that combines vacuum preloading with pneumatic splitting, including a pressurization unit 100 and a vacuum unit 200.

[0034] Furthermore, the pressurization unit 100 includes a pressurization tank 101, a jet pipe 102, an air injection pipe 103, and a nozzle component 104. The jet pipe 102 is connected to the air injection pipe 103, the air injection pipe 103 is connected to the pressurization tank 101, and the nozzle component 104 is connected to the jet pipe 102.

[0035] Furthermore, the vacuum unit 200 is located on one side of the pressurization unit 100 and includes a drain plate 201, a filter tube 202, and a vacuum pump 203. The vacuum pump 203 is connected to the pressurization tank 101, the drain pipe is connected to the drain plate 201, and the filter tube 202 is connected to the drain plate 201.

[0036] Specifically, through the combined action of the pressurization unit 100 and the vacuum unit 200, vacuum preloading combined with pneumatic fracturing is used to reinforce soft foundations and accelerate soil settlement.

[0037] Furthermore, the nozzle component 104 includes a first mounting component 104a and a second mounting component 104b. The first mounting component 104a is connected to the air outlet end of the jet pipe 102, and the second mounting component 104b is connected to the first mounting component 104a. The first mounting component 104a is first connected to the jet pipe 102, and then the second mounting component 104b is connected to the first mounting component 104a to complete the installation of the nozzle component 104.

[0038] Furthermore, the first mounting component 104a includes a mounting housing 104a-1, a locking member 104a-2, and a limiting member 104a-3. The locking member 104a-2 is disposed in the internal cavity of the side wall of the mounting housing 104a-1. The limiting member 104a-3 is disposed on one side of the mounting housing 104a-1 and connected to the locking member 104a-2, thereby enhancing the function of the locking member 104a-2 and achieving a tight connection between the mounting housing 104a-1 and the jet pipe 102. The limiting member 104a-3 then limits the locking member 104a-2, preventing it from slipping after installation and ensuring the stability of the connection.

[0039] The second installation component 104b includes an air outlet 104b-1 and a sealing component 104b-2. The sealing component 104b-2 is disposed in the cavity inside the side wall of the air outlet 104b-1. By setting the sealing component 104b-2, the soil will not block the air outlet before the pressurized gas comes out of the air outlet 104b-1 and when the jet pipe 102 penetrates into the soil. Moreover, when the pressurized gas enters, the sealing component 104b-2 can move to allow the gas to flow smoothly into the soil.

[0040] In summary, the first installation component 104a and the second installation component 104b solve the problem of inconvenient installation of the nozzle and air jet pipe 102, and at the same time, solve the problem of the nozzle's air outlet being blocked by the soil during the process of penetrating the soil, thus effectively improving the construction efficiency.

[0041] Example 2 Reference Figures 3-8 This is the second embodiment of the present invention, which is based on the previous embodiment.

[0042] Specifically, the locking component 104a-2 includes a locking block 104a-2a, a locking sleeve 104a-2b, and a first spring 104a-2c. The locking block 104a-2a passes through a locking opening in the side wall of the mounting housing 104a-1 and connects to a locking groove 102a in the side wall of the jet pipe 102. The locking block 104a-2a is connected to the locking sleeve 104a-2b via the first spring 104a-2c. The locking sleeve 104a-2b is connected to the mounting housing. The inner walls of 104a-1 are connected. During installation, the mounting housing 104a-1 is inserted into the jet end of the jet pipe 102. At this time, the locking block 104a-2a will compress the first spring 104a-2c and partially retract into the locking sleeve 104a-2b, so that the mounting housing 104a-1 can slide smoothly on the jet pipe 102 to the installation position. When the locking block 104a-2a enters the locking groove 102a, the first spring 104a-2c returns to its original position, and the initial installation is completed.

[0043] As a preferred option, multiple slots 102a can be provided to meet different installation requirements.

[0044] Furthermore, the limiting component 104a-3 includes a limiting ring 104a-3a, a manual ring 104a-3b, and a limiting rod 104a-3c. The limiting ring 104a-3a is connected to the limiting rod 104a-3c. The limiting rod 104a-3c is connected to the locking block 104a-2a through a limiting hole 104a-2d provided on the side wall of the locking sleeve 104a-2b, thereby limiting the locking block 104a-2a. The movement of 04a-2a involves the limiting ring 104a-3a passing through the limiting opening 104a-1b on the side wall of the mounting housing 104a-1 and connecting with the manual ring 104a-3b. When the mounting housing 104a-2a reaches the installation position, the manual ring 104a-3b is pushed upward, causing the limiting rod 104a-3c to be inserted into the locking sleeve 104a-2b, thus preventing the locking block 104a-2a from moving.

[0045] Preferably, a resistance rod 104a-1c is provided on the side wall of the limiting opening 104a-1b. The resistance rod 104a-1c is connected to the limiting ring 104a-3a, and a resistance block 104a-1d is provided on the side wall of the resistance rod 104a-1c. The resistance block 104a-1d is connected to the resistance rod 104a-1c through a second spring 104a-1e. The limiting ring 104a-3a has an opening, which, when it moves upward, drives the limiting ring. When the ring 104a-3a is in motion, the resistance rod 104a-1c will be inserted into the hole. Since it is a manual action, it will squeeze the resistance block 104a-1d when moving upward, causing it to compress the second spring 104a-1e, so that the limiting ring 104a-3a can move upward smoothly. After it is released, the manual action is lost, and the limiting ring 104a-3a cannot fall freely to squeeze the resistance block 104a-1d. Therefore, it also restricts the limiting ring 104a-3a.

[0046] The air outlet component 104b-1 includes an air outlet nozzle 104b-1a and a snap-fit ​​post 104b-1b. The air outlet nozzle 104b-1a has an air outlet hole on its side wall. One end of the snap-fit ​​post 104b-1b is connected to the air outlet nozzle 104b-1a, and the other end is connected to a snap-fit ​​groove on the side wall of the mounting housing 104a-1. The snap-fit ​​post 104b-1b is divided into two sections, with the upper section having a larger diameter. The snap-fit ​​groove is divided into upper and lower layers, with the outer layer being narrower. The inner width is relatively large, and one end of the snap-fit ​​groove has a large opening that matches the diameter of the top of the snap-fit ​​post 104b-1b. During installation, the snap-fit ​​post 104b-1b is snapped into the larger opening, so that the larger diameter section is completely inserted into the snap-fit ​​groove. Then, the air outlet nozzle 104b-1a is rotated so that the larger section of the snap-fit ​​post 104b-1b is at the end of the larger opening, thus realizing the installation of the air outlet nozzle 104b-1a and the mounting housing 104a-1.

[0047] Furthermore, the sealing component 104b-2 includes a first sealing plate 104b-2a, a second sealing plate 104b-2b, and a pressure plate 104b-2c. The first sealing plate 104b-2a and the second sealing plate 104b-2b are disposed within the cavity of the side wall of the air outlet nozzle 104b-1a, and both the first sealing plate 104b-2a and the second sealing plate 104b-2b have air outlet holes on their side walls. The size of the air outlet holes matches the air outlet holes of the air outlet nozzle 104b-1a. The pressure plate 104b-2c is connected to the inner side wall of the first sealing plate 104b-2a and the second sealing plate 104b-2b, and the outer side wall of the first sealing plate 104b-2a and the second sealing plate 104b-2b is provided with a first push block 104b-2d and a second push block 104b-2c. Block 104b-2e, the first sealing plate 104b-2a is connected to the top of the inner wall of the air nozzle 104b-1a through the third spring 104b-2f. The first sealing plate 104b-2a can move upward under force to compress the third spring 104b-2f. The first pushed block 104b-2d is connected to the manual ring 104a-3b through the connecting rod 104b-2g, the connecting rod sleeve 104b-2h and the fourth spring 104b-2i. The connecting rod sleeve 104b-2h is connected to one side of the manual ring 104a-3b. The fourth spring 104b-2i is located inside the connecting rod sleeve 104b-2h. The connecting rod 104b-2g is not fixedly connected to the fourth spring 104b-2i and the connecting rod sleeve 104b-2h.

[0048] Preferably, the connection between the connecting rod 104b-2g, the connecting rod sleeve 104b-2h, and the fourth spring 104b-2i and the manual ring 104a-3b can be configured such that after the air nozzle 104b-1a is rotated and installed, the connecting rod 104b-2g just reaches the open end of the connecting rod sleeve 104b-2h.

[0049] During implementation, the first sealing plate 104b-2a and the second sealing plate 104b-2b are initially in a state where they do not block the vent, and pressurized gas can flow normally. However, when the jet pipe 102 penetrates the soil, the soil will act on the first push block 104b-2d and the second push block 104b-2e, causing them to move upward. At this time, it will drive the first sealing plate 104b-2a and the second sealing plate 104b-2b to move upward, thereby causing the vent to close actively, preventing soil from entering the vent and causing blockage. At this time, the connecting rod 104b-2g, under the action of the first push block 104b-2d, squeezes the fourth spring 104b-2i, thereby squeezing the manual ring 104a-3b, making the installation of the upper first mounting component 104a more stable.

[0050] When pressurized gas is introduced into the jet pipe 102, the pressurized gas acts on the pressure plate 104b-2c, causing it to move the first sealing plate 104b-2a and the second sealing plate 104b-2b downwards, opening the vent hole and allowing the pressurized gas to enter and exit normally. At the same time, the force of the third spring 104b-2f restoring its deformation also causes the first sealing plate 104b-2a to move downwards and open the vent hole.

[0051] In summary, the combined effect of the locking component 104a-2, the limiting component 104a-3, the air outlet component 104b-1, and the sealing component 104b-2 solves the problem of blockage at the air outlet end of the air jet pipe 102 when penetrating deep into the soil, and further stabilizes the installation of the first installation component 104a, making the installation more stable.

[0052] Example 3 Reference Figure 1 This is the third embodiment of the present invention, which is based on the previous embodiment, but differs in that it provides a soft soil foundation reinforcement construction method combining vacuum preloading and pneumatic fracturing, including... The construction area was vacuum-sealed. The vacuum-sealed area is filled with sand to increase the negative pressure. High-pressure gas splits the soil, creating an internal and external gas circulation.

[0053] Furthermore, the internal and external gas circulation involves pumping gas from the vacuum pump to a pressurizing tank, which then injects high-pressure air into the soft soil between the drainage boards. The air pressure splits the soil at different depths in the soft foundation, expanding the water flow channels and accelerating the flow and discharge of water.

[0054] The construction steps are illustrated using a specific project as an example: The project site has a relatively flat terrain, but it is low-lying, requiring an average backfill depth of about 1.5 meters to reach the ±0 elevation. According to the engineering geological survey data, the soft soil in the upper part of the site contains many layers of silty sand and silt, resembling a thousand-layer cake, with obvious horizontal thin-layer stratification. These layers serve as channels for the horizontal movement of groundwater, which helps to lower the groundwater level and reduce pore water pressure. However, due to the thinness of the layers, the groundwater in these layers has a certain viscosity and flows slowly under its own weight. By creating a vacuum in the sealed drainage board area, a negative pressure is formed in the sealed area, which can accelerate the flow of groundwater in the layers through the drainage board. At the same time, by injecting high-pressure air into the soil between the manholes, air pressure fracturing is generated, expanding the flow channels of pore water pressure and accelerating the flow of pore water to the drainage board. In addition, sand surcharges are applied above the sealed area to accelerate the settlement of the soft soil, thereby promoting the dewatering consolidation settlement of the soft foundation, improving efficiency and saving construction time.

[0055] A highly efficient combined construction method of vacuum preloading and pneumatic fracturing with dredged sand is adopted for the treatment of soft soil foundations covering large areas and deep soft soil foundations. The main steps include: Step 1: Ascertain the engineering and hydrogeological conditions of the treatment site, including the permeability coefficient, hydraulic conductivity, radius of influence of the soil layers, and the depth of unconfined and confined aquifers.

[0056] Geological surveys revealed that the groundwater types within the site are primarily unconfined pore water and slightly confined water contained in the Quaternary loose layers. The unconfined aquifers are located within the silty soft soil layer, while the layers of fine sand interbedded with silty clay within the site exhibit slightly confined characteristics and are classified as confined aquifers. Simple pumping tests determined the hydraulic parameters of each soil layer, including permeability, conductivity, and radius of influence, as shown in Table 1.

[0057] Table 1 Hydraulic parameters of aquifers

[0058] Step 2: Leveling the site. Use machinery to remove topsoil such as brick rubble, weeds, and tree roots from the construction area, and then level and compact the entire construction area.

[0059] Step 3: Construction of drainage board 201 and air jet pipe 102. The plastic drainage boards are vertically inserted into the soft soil base using a drainage board insertion machine. The drainage boards 201 are arranged in a square with a horizontal and vertical spacing of 1.0m, and a 70cm joint is reserved at the top for connection with the filter pipe. The air jet pipe 102 is installed between four adjacent drainage boards at a spacing of 3.0m and at different depths.

[0060] Step 4: Vacuum Piping Installation. Filter pipe 202 uses Φ40 PVC corrugated flexible hose, and the main pipe uses Φ63 PVC corrugated flexible hose. Drainage board 201 is tied to filter pipe 202, with at least two turns. Filter pipe 202 is connected to the main pipe via a four-way or three-way connector. Filter pipe 202 is installed along the shorter side, every 2 meters; the main pipe is installed along the longer side, every 30 meters. Both filter pipe 202 and the main pipe must be buried in the topsoil and connected to the vacuum pump 203.

[0061] Step 5: Geotextile laying. To protect the sealing membrane, lay 200g / m2 non-woven geotextile and 200g / m2 woven geotextile under the membrane, and lay 250g / m2 non-woven geotextile on top of the membrane. The overlap width of the seams should be greater than or equal to 10cm.

[0062] Step Six: Sealing Film Laying. The sealing film should be 0.12–0.16 mm thick, with two layers laid. Polyethylene or polyvinyl chloride film should be used, and the film should be pressed into the sealing trench at least 50 cm below the bottom. The sealing film should be laid in layers and overlapped according to the order of the areas. The overlap width should be no less than 2 meters. After each layer is laid, a designated person should inspect the film for damage. If any tears are found, they should be cleaned with water and repaired with adhesive.

[0063] Step 7: Excavation and Sealing of the Membrane-Coating Trench. The membrane-coating trench is 0.5m wide at the bottom and 2m deep, with a slope of 1:0.75. The excavation depth reaches 1-2 layers of clay. If the surface sandy soil is encountered, the bottom of the membrane-coating trench should penetrate at least 0.5m into the silt layer. If a highly permeable interlayer is encountered, the interlayer should be excavated and backfilled with 30cm-50cm thick clay. Then, the sealing membrane is spread on the sides and bottom of the membrane-coating trench, and then backfilled to the top of the trench, compacting and sealing the membrane.

[0064] Step 8: Vacuum pump 203 installation and vacuuming. Install one 7.5KW vacuum pump for every 1000m2. Gradually increase the pump operating rate before the pump pressure stabilizes at 80Kpa. After the pressure stabilizes, ensure that the pump operating rate is not less than 85%.

[0065] Step 9: Connect the vacuum-pressure splitting system. Connect an air injection pipe to the outlet of the vacuum pump and connect it to the pressurization tank 101 to compress the air. Then connect the other end of the air injection pipe to the jet pipe 102. The jet pipes 102 are evenly distributed at various depths within the treatment area and are connected in parallel.

[0066] Step 10: Sand Filling. First, construct an earthen cofferdam along the outside of the membrane trench. Bury a drainage pipe 0.3 meters below the bottom of the cofferdam. The drainage pipe is connected to the drainage ditch outside the cofferdam to drain water from the sand filling. Then, use a sand dredger to blow sand onto the sealing membrane through the pipeline for preloading. The sand filling can also effectively protect the sealing membrane, thus ensuring the vacuum degree of the sealing area.

[0067] Step 11: Dewatering, Settlement, and Consolidation. Vacuum pump 203 and pressurization tank 101 are activated. Under the combined effects of shovel filling, air pressure fracturing, and sealed vacuum, the pore water in the soft soil foundation moves towards the drainage board and collects. Passing through the drainage board, filter pipe, and drainage pipe, it is then pumped by the vacuum pump to the drainage tank. This reduces the pore water pressure in the soft soil foundation and increases the effective stress, thereby achieving settlement and consolidation.

[0068] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A soft soil foundation reinforcement construction device combining vacuum preloading and pneumatic fracturing, characterized in that: include, A pressurization unit (100) includes a pressurization tank (101), a jet pipe (102), an air injection pipe (103), and a nozzle component (104). The jet pipe (102) is connected to the air injection pipe (103), the air injection pipe (103) is connected to the pressurization tank (101), and the nozzle component (104) is connected to the jet pipe (102). The nozzle component (104) includes a first mounting component (104a) and a second mounting component (104b). The first mounting component (104a) is connected to the air outlet end of the jet pipe (102), and the second mounting component (104b) is connected to the first mounting component (104a). The first mounting assembly (104a) includes a mounting housing (104a-1), a locking member (104a-2), and a limiting member (104a-3). The locking member (104a-2) is disposed in the internal cavity of the mounting housing (104a-1), and the limiting member (104a-3) is disposed on one side of the mounting housing (104a-1) and connected to the locking member (104a-2). The second mounting assembly (104b) includes an air outlet (104b-1) and a sealing element (104b-2), wherein the sealing element (104b-2) is disposed in the cavity inside the air outlet (104b-1); The locking component (104a-2) includes a locking block (104a-2a), a locking sleeve (104a-2b), and a first spring (104a-2c). The locking block (104a-2a) passes through the locking opening in the side wall of the mounting housing (104a-1) and is connected to the locking groove (102a) provided in the side wall of the jet pipe (102). The locking block (104a-2a) is connected to the locking sleeve (104a-2b) through the first spring (104a-2c). The locking sleeve (104a-2b) is connected to the inner side wall of the mounting housing (104a-1). The limiting component (104a-3) includes a limiting ring (104a-3a), a manual ring (104a-3b), and a limiting rod (104a-3c). The limiting ring (104a-3a) is connected to the limiting rod (104a-3c). The limiting rod (104a-3c) is connected to the locking block (104a-2a) through a limiting hole (104a-2d) provided on the side wall of the locking sleeve (104a-2b). The limiting ring (104a-3a) passes through a limiting opening (104a-1b) on the side wall of the mounting housing (104a-1) and is connected to the manual ring (104a-3b). A resistance rod (104a-1c) is provided on the side wall of the limiting opening (104a-1b). The resistance rod (104a-1c) is connected to the limiting ring (104a-3a). A resistance block (104a-1d) is provided on the side wall of the resistance rod (104a-1c). The resistance block (104a-1d) is connected to the resistance rod (104a-1c) through a second spring (104a-1e). The air outlet component (104b-1) includes an air outlet nozzle (104b-1a) and a snap-fit ​​post (104b-1b). The air outlet nozzle (104b-1a) has an air outlet hole on its side wall. One end of the snap-fit ​​post (104b-1b) is connected to the air outlet nozzle (104b-1a), and the other end is connected to the snap-fit ​​groove on the side wall of the mounting housing (104a-1).

2. The soft soil foundation reinforcement construction device combining vacuum preloading and pneumatic fracturing as described in claim 1, characterized in that: The sealing component (104b-2) includes a first sealing plate (104b-2a), a second sealing plate (104b-2b), and a pressure plate (104b-2c). The first sealing plate (104b-2a) and the second sealing plate (104b-2b) are disposed in the cavity of the side wall of the air outlet nozzle (104b-1a), and the side walls of the first sealing plate (104b-2a) and the second sealing plate (104b-2b) are provided with air outlet holes. The pressure plate (104b-2c) is connected to the inner side walls of the first sealing plate (104b-2a) and the second sealing plate (104b-2b), and the outer side walls of the first sealing plate (104b-2a) and the second sealing plate (104b-2b) are provided with a first push block (104b-2d) and a second push block (104b-2e).

3. The soft soil foundation reinforcement construction device combining vacuum preloading and pneumatic fracturing as described in claim 2, characterized in that: The first sealing plate (104b-2a) is connected to the inner wall of the air nozzle (104b-1a) via the third spring (104b-2f). The first push block (104b-2d) is connected to the manual ring (104a-3b) via the connecting rod (104b-2g), the connecting rod sleeve (104b-2h), and the fourth spring (104b-2i). The connecting rod sleeve (104b-2h) is connected to one side of the manual ring (104a-3b). The fourth spring (104b-2i) is located inside the connecting rod sleeve (104b-2h).

4. The soft soil foundation reinforcement construction device combining vacuum preloading and pneumatic fracturing as described in claim 3, characterized in that: It also includes, A vacuum unit (200) is disposed on one side of a pressurizing unit (100) and includes a drain plate (201), a filter tube (202), and a vacuum pump (203). The vacuum pump (203) is connected to the pressurizing tank (101), the vacuum pump (203) is connected to the drain plate (201), and the filter tube (202) is connected to the drain plate (201).

5. A method for reinforcing soft soil foundations using vacuum preloading combined with pneumatic fracturing, characterized in that: Includes a soft soil foundation reinforcement construction device combining vacuum preloading and pneumatic fracturing as described in any one of claims 1 to 4; and, The construction area was vacuum-sealed. The vacuum-sealed area is filled with sand to increase the negative pressure. High-pressure gas splits the soil, creating an internal and external gas circulation.

6. The soft soil foundation reinforcement construction method combining vacuum preloading and pneumatic fracturing as described in claim 5, characterized in that: The gas drawn by the vacuum pump (203) is transported to the pressurization tank (101) through the internal and external gas circulation. The pressurization tank (101) then injects high-pressure air into the soft soil between the drainage boards.

7. The soft soil foundation reinforcement construction method combining vacuum preloading and pneumatic fracturing as described in claim 6, characterized in that: Pneumatic splitting of soil utilizes high-pressure gas to split the soil at different depths in soft soil, thereby expanding the water flow channels in the soft soil and accelerating the flow and discharge of water.

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