Vacuum combined with surcharge preloading system for soft ground reinforcement

Abstract

This application discloses a soft soil foundation reinforcement system using vacuum combined with surcharge preloading, relating to the field of building foundations. It includes, from bottom to top, a soft soil foundation, a medium-coarse sand cushion layer, a vacuum sealing layer, a surcharge preloading earth layer, and a drainage device. A sealing gap is formed between the vacuum sealing layer and the medium-coarse sand cushion layer. The drainage device includes a drainage filter pipe, a plastic drainage strip, and a vacuum pump. The drainage filter pipe is laid inside the sealing gap, and the vacuum pump is located outside the sealing gap and connected to the drainage filter pipe. The main body of the plastic drainage strip is inserted into the soft soil foundation, and its upper end extends out of the soft soil foundation and is connected to the drainage filter pipe. The drainage filter pipe is fitted with a spiral steel wire skeleton, the spiral spacing of which is greater than the width of the plastic drainage strip. The outer end of the plastic drainage strip covers the outer circumference of the drainage filter pipe and is located between the spiral coils of the spiral steel wire skeleton. This application enables the filter holes of the drainage filter pipe to fully function as air passages during the vacuuming process.

Description

Technical Field

[0001] This application relates to the field of building foundations, and in particular to soft foundation systems reinforced by vacuum combined surcharge preloading. Background Technology

[0002] Vacuum-combined surcharge preloading is a foundation treatment method that combines surcharge preloading and vacuum preloading, creating a superposition of two load effects. It mainly consists of a drainage system, a sealing system, and a pressurization system. Plastic drainage strips are inserted into the soft soil layer using a plate inserter, connected to horizontal drainage filter pipes to form vertical and horizontal drainage systems. The pressure created by the vacuum in the pressurization system accelerates the upward discharge of pore water, thereby accelerating the settlement process of the soft soil foundation, compacting and reinforcing the foundation, and improving its bearing capacity. This has become a widely used foundation treatment technology for reinforcing soft foundations in coastal areas in recent years.

[0003] During vacuum preloading, the vacuum pump applies negative pressure to the soft soil foundation through the drainage filter pipe and plastic drainage belt. The drainage filter pipe is laid between the medium-coarse sand cushion layer and the vacuum sealing layer. The upward-facing part of the drainage filter pipe contacts the vacuum sealing layer, while the downward-facing part contacts the medium-coarse sand cushion layer. This prevents the filter holes on the surface of the drainage filter pipe from fully facilitating airflow during the vacuuming process, thus limiting the effectiveness of the vacuuming. Summary of the Invention

[0004] In order to enable the drainage filter pipe's filter holes to fully function as aeration holes during the vacuuming process, this application provides a soft foundation system for vacuum combined surcharge preloading reinforcement.

[0005] The vacuum combined surcharge preloading reinforcement soft soil foundation system provided in this application adopts the following technical solution:

[0006] A soft soil foundation reinforcement system using vacuum combined surcharge preloading includes, from bottom to top, a soft soil foundation, a medium-coarse sand cushion layer, a drainage device, a vacuum sealing layer, and a surcharge preloading earthwork layer. A sealing gap is formed between the vacuum sealing layer and the medium-coarse sand cushion layer. The drainage device includes a drainage filter pipe, a plastic drainage strip, and a vacuum pump. The drainage filter pipe is laid inside the sealing gap, and the vacuum pump is located outside the sealing gap and connected to the drainage filter pipe. The main body of the plastic drainage strip is inserted into the soft soil foundation, and its upper end extends out of the soft soil foundation and is connected to the drainage filter pipe. The drainage filter pipe is fitted with a spiral steel wire skeleton, the spiral spacing of which is greater than the width of the plastic drainage strip. The outer end of the plastic drainage strip covers the outer circumference of the drainage filter pipe and is located between the spiral coils of the spiral steel wire skeleton.

[0007] By adopting the above technical solution, the soft soil foundation reinforcement system using vacuum combined with surcharge preloading accelerates the drainage of pore water in the soil through the combined action of vacuum preloading and surcharge preloading, enabling rapid drainage and consolidation of the soft soil foundation. A vacuum pump evacuates the sealing gap between the medium-coarse sand cushion layer and the vacuum sealing layer via drainage filter pipes and plastic drainage belts. By installing a spiral steel wire skeleton on the drainage filter pipe, a certain gap is maintained between the drainage filter pipe and the medium-coarse sand cushion layer, and the vacuum sealing layer cannot easily obstruct the upper part of the drainage filter pipe, ensuring that the upward and downward filter holes of the drainage filter pipe remain connected to the sealing gap. Given a fixed density of filter holes in the drainage filter pipe, the utilization rate of the filter holes is increased, allowing the vacuum pump to perform vacuuming operations more smoothly. Furthermore, the spiral steel wire skeleton on the drainage filter pipe can replace the surcharge preloading portion of the drainage filter pipe, protecting it and reducing the risk of deformation under pressure. Furthermore, when the upper end of the plastic drainage strip is wrapped with a drainage filter pipe, the upper part of the plastic drainage strip is positioned between adjacent spiral coils of the spiral steel wire skeleton, which can protect the upper part of the plastic drainage strip and reduce the possibility of internal voids in the upper part of the plastic drainage strip being compressed and collapsed.

[0008] Optionally, the drainage filter pipe is provided with an elongated limiting spring. The limiting spring is located on the side of the plastic drainage strip away from the drainage filter pipe. The length of the limiting spring is greater than the spiral spacing of the spiral steel wire skeleton. The two ends of the limiting spring are respectively inserted into the gap between the spiral steel wire skeleton and the drainage filter pipe. The middle part of the limiting spring abuts against the surface of the plastic drainage strip away from the drainage filter pipe. The limiting spring forces the plastic drainage strip to press against the surface of the drainage filter pipe.

[0009] By adopting the above technical solution, the plastic drainage tape covering the surface of the drainage filter pipe enhances the continuity between the internal voids of the plastic drainage tape and the inner cavity of the drainage filter pipe, making it easier for the vacuum pump to apply negative pressure to the soft soil foundation. When the plastic drainage tape is connected to the drainage filter pipe, the axial position of the upper end of the plastic drainage tape along the drainage filter pipe is restricted by the spiral steel wire skeleton. The contact state between the upper end of the plastic drainage tape and the outer circumference of the drainage filter plate is maintained by limiting springs, ensuring that the plastic drainage tape stably wraps around the drainage filter pipe. The connection between the plastic drainage tape and the drainage filter pipe is stable, reliable, convenient, and quick.

[0010] Optionally, the two ends of the limiting spring are respectively provided with arc-shaped portions, the concave side of the arc-shaped portion is away from the drain filter pipe, and the concave side of the arc-shaped portion abuts against the steel wire of the spiral steel wire skeleton.

[0011] By adopting the above technical solution, the arc-shaped parts at both ends of the limiting spring are inserted between the spiral steel wire skeleton and the drainage filter pipe, and the concave side of the arc-shaped part abuts against the spiral steel wire skeleton, which can restrict the relative position between the limiting spring and the spiral steel wire skeleton and reduce the possibility of the limiting spring falling off.

[0012] Optionally, one side of the limiting spring has a serrated edge, with the tips of the serrated edge forming an obtuse angle with the surface of the limiting spring, and the tips of the serrated edge abutting the surface of the plastic drainage strip.

[0013] By adopting the above technical solution, the outer layer of the plastic drainage strip is a non-woven geotextile, and the serrated edge of the limiting spring abuts against the surface of the plastic drainage strip, so that the serrated edge of the limiting spring hooks the geotextile of the plastic drainage strip, which helps to keep the relative position between the plastic drainage strip and the limiting spring stable.

[0014] Optionally, the drainage filter pipe is provided with a long strip-shaped limiting spring, which is located on the side of the plastic drainage strip away from the drainage filter pipe; both ends of the limiting spring are respectively provided with snap hooks, which face the drainage filter pipe and snap into the steel wire of the spiral steel wire skeleton.

[0015] By adopting the above technical solution, the limiting spring sheet forces the plastic drainage strip to remain in contact with the outer circumference of the drainage filter pipe. The limiting spring sheet is connected to the spiral steel wire skeleton by a snap hook, with the snap hook facing the drainage filter pipe, making the connection between the limiting spring sheet and the spiral steel wire skeleton more convenient.

[0016] Optionally, the drainage filter pipe is provided with a positioning rod, the positioning rod including a plug section and a hook section, the hook section holding the drainage filter pipe, and the plug section inserting into the soft soil foundation.

[0017] By adopting the above technical solution, the positioning rod can locate the position of the drainage filter pipe, which helps to keep the drainage filter pipe straight during installation and helps to reduce the energy loss of the vacuum pump during the vacuuming process through the drainage filter pipe.

[0018] Optionally, the arc angle of the hook section is greater than 180 degrees, the hook section has a clamping force on the outer circumferential surface of the drain filter pipe, and a guide section is provided at the end of the hook section away from the plug section.

[0019] By adopting the above technical solution, the positioning rod clamps the drainage filter pipe through the hook section. The arc angle of the hook section is greater than 180 degrees, which helps to keep the drainage filter pipe inside the hook section. As the drainage filter pipe enters the inside of the hook section, the guide section can guide the drainage filter pipe, making the connection between the hook section and the drainage filter pipe more convenient.

[0020] Optionally, the insertion section of the positioning rod is surrounded by multiple reinforcing rods in the circumferential direction, the reinforcing rods abutting against each other in pairs, and the reinforcing rods and the insertion section of the positioning rod together form a rod bundle; several water-guiding gaps are formed between the multiple reinforcing rods and the insertion section of the positioning rod.

[0021] By adopting the above technical solution, the insertion section of the reinforcing rod and the positioning rod forms a rod bundle. The rod bundle has strong axial stiffness, making it less prone to bending deformation when the rod bundle is inserted into the soft soil foundation, thus making it easier for the positioning rod to be inserted. On the other hand, the reinforcing rod surrounds the insertion section of the positioning rod, creating a water-conducting gap between the two sections, which helps to increase the path for the vacuum pump to evacuate the soft soil foundation.

[0022] Optionally, a guide sleeve is fitted at the lower end of the rod bundle. The guide sleeve has a water filter hole and a bottom wall. The bottom wall of the guide sleeve is inclined relative to the center line of the guide sleeve.

[0023] By adopting the above technical solution, the guide sleeve is fitted onto the lower end of the rod bundle, allowing the guide sleeve to replace the lower end of the rod bundle in inserting into the soft soil foundation. This helps reduce the amount of sand entering the water-conducting gap in the soft soil foundation and also reduces the resistance of the lower end of the rod bundle inserting into the soft soil foundation. The bottom wall of the guide sleeve is inclined, forming a pointed tip between the bottom wall and the peripheral wall, which further reduces the resistance of the rod bundle inserting into the soft soil foundation.

[0024] Optionally, the drainage filter pipe is fitted with a positioning plate through the filter hole. The positioning plate is elongated and its two sides simultaneously abut against the edge of the filter hole of the drainage filter pipe. One end of the positioning plate is provided with a positioning hook, which hooks onto the wire of the spiral steel wire skeleton.

[0025] By adopting the above technical solution, the positioning plate can position the spiral coil of the spiral steel wire skeleton. When the gravity load of the surcharge preloaded earth layer is applied to the spiral steel wire skeleton, the spiral coil of the spiral steel wire skeleton is not prone to deformation and movement along the circumference, so that the spiral coil of the spiral steel wire skeleton can effectively support the surcharge preloaded earth layer, thereby enabling the spiral coil of the spiral steel wire skeleton to fully play its role in protecting the drainage filter pipe.

[0026] In summary, this application includes at least one of the following beneficial technical effects:

[0027] By incorporating a spiral steel wire skeleton into the drainage filter pipe, a certain gap is maintained between the drainage filter pipe and the medium-coarse sand pad, preventing the vacuum sealing layer from obstructing the upper part of the drainage filter pipe. This ensures that the upward-facing and downward-facing filter holes of the drainage filter pipe remain connected to the sealing gap. Given a fixed density of filter holes in the drainage filter pipe, the utilization rate of the filter holes is increased, allowing the vacuum pump to perform vacuuming operations more smoothly.

[0028] The joint between the reinforcing rod and the positioning rod forms a rod bundle. This rod bundle has high axial stiffness, making it less prone to bending and deformation when inserted into soft soil foundations, thus facilitating insertion. Furthermore, the reinforcing rod surrounds the joint of the positioning rod, creating a water-conducting gap between them, which helps increase the pathway for the vacuum pump to evacuate the soft soil foundation. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of Example 1.

[0030] Figure 2 yes Figure 1 A magnified view of a portion of point A in the middle.

[0031] Figure 3 This is a schematic diagram of Example 1 illustrating the connection between the plastic drainage belt and the drainage filter pipe.

[0032] Figure 4 This is a schematic diagram of Example 1 illustrating the connection between the plastic drainage belt and the limiting spring.

[0033] Figure 5 This is a schematic diagram of the limiting spring in Example 1.

[0034] Figure 6 This is a schematic diagram of the positioning piece in Example 1.

[0035] Figure 7 This is a schematic diagram of the positioning rod in Example 1.

[0036] Figure 8 This is a schematic diagram of Example 2 illustrating the connection between the plastic drainage belt and the limiting spring.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Soft soil foundation; 2. Medium-coarse sand cushion layer; 3. Surcharge preloading earthwork layer; 4. Vacuum sealing layer; 41. Geotextile; 42. Sealing membrane; 5. Drainage device; 51. Drainage filter pipe; 52. Plastic drainage belt; 53. Vacuum pump; 531. Connecting pipe; 54. Spiral steel wire skeleton; 55. Limiting spring; 551. Arc-shaped part; 552. Serrated edge; 553. Snap-fit ​​hook; 56. Positioning plate; 561. Positioning hook; 562. Chamfer; 563. Barb; 57. Positioning rod; 571. Insertion section; 572. Hook section; 573. Guide section; 574. Reinforcing rod; 575. Guide sleeve. Detailed Implementation

[0039] The following is in conjunction with the appendix Figure 1-8 This application will be described in further detail.

[0040] Example 1

[0041] This application discloses a soft soil foundation reinforcement system using vacuum combined with surcharge preloading. (Refer to...) Figure 1 and Figure 2 The soft soil foundation system reinforced by vacuum combined surcharge preloading includes, from bottom to top, a soft soil foundation 1, a medium-coarse sand cushion layer 2, a drainage device 5, a vacuum sealing layer 4, and a surcharge preloading earthwork layer 3. The vacuum sealing layer 4 includes two layers of geotextile 41 and two layers of sealing membrane 42, with the two layers of sealing membrane 42 located between the two layers of geotextile 41. A sealing gap is formed between the vacuum sealing layer 4 and the medium-coarse sand cushion layer 2. The drainage device 5 includes a drainage filter pipe 51, a plastic drainage strip 52, and a vacuum pump 53. The drainage filter pipe 51 is laid inside the sealing gap and is a crisscrossing network of pipes. The surface of the drainage filter pipe 51 is evenly distributed with filter holes. The vacuum pump 53 is located outside the sealing gap and is connected to the drainage filter pipe 51 through a connecting pipe 531. The main body of the plastic drainage strip 52 is inserted into the soft soil foundation 1, and the upper end of the plastic drainage strip 52 extends out of the soft soil foundation 1 and is connected to the drainage filter pipe 51.

[0042] The main construction process of the soft soil foundation reinforcement system using vacuum combined surcharge preloading is as follows: First, the site within the preloading treatment area is cleaned and leveled, and a 30-40cm thick medium-coarse sand cushion layer 2 is laid. Then, plastic drainage tape 52 is driven in using a sluice box inserter. Next, drainage filter pipe 51 is laid and connected to the plastic drainage tape 52. Connecting pipe 531 is connected to drainage filter pipe 51 and extends beyond the preloading treatment area of ​​the site. A sealing trench is excavated around the site, and a layer of geotextile 41 and two layers of sealing membrane 42 are laid. The sealing membrane 42 is buried in clay layer through the sealing trench. The sealing trench is backfilled with silt and clay and compacted. Then, a cofferdam is built upwards. Connect the connecting pipe 531 to the vacuum pump 53, turn on the vacuum pump 53 to evacuate and pressurize, check the sealing degree of the vacuum sealing membrane 42, and enter the vacuum constant load when the vacuum reaches 80 kPa. After the vacuum degree under the membrane stabilizes, lay another layer of geotextile 41 to protect the sealing membrane 42, and start filling and piling up crushed sand and soil. The relevant compaction degree requirements are rolled and filled layer by layer to the design elevation, and surcharge preloading is carried out. After the settlement reaches the design requirements, stop the air extraction and clean up the site. The two loads of vacuum preloading and surcharge preloading work together.

[0043] Reference Figure 3 The drainage filter pipe 51 is fitted with a spiral steel wire skeleton 54, the surface of which is covered with a rubber outer layer. The spiral spacing of the spiral steel wire skeleton 54 is greater than the width of the plastic drainage strip 52. The outer end of the plastic drainage strip 52 covers the outer circumference of the drainage filter pipe 51 and is located between the spiral coils of the spiral steel wire skeleton 54. The spiral steel wire skeleton 54 can maintain a certain gap between the drainage filter pipe 51 and the medium-coarse sand pad 2, and prevent the vacuum sealing layer 4 from blocking the upper part of the drainage filter pipe 51, so that the upward and downward filter holes of the drainage filter pipe 51 can remain in communication with the sealing gap.

[0044] Reference Figure 4 and Figure 5 The drain filter pipe 51 is equipped with a long strip-shaped limiting spring 55. The limiting spring 55 is made of a metal material with excellent elasticity, such as spring steel or beryllium bronze. The limiting spring 55 is located on the side of the plastic drain strip 52 away from the drain filter pipe 51. Arc-shaped portions 551 extend from both ends of the limiting spring 55. The length of the limiting spring 55 is greater than the spiral spacing of the spiral steel wire skeleton 54. The middle part of the limiting spring 55 abuts against the surface of the plastic drain strip 52 away from the drain filter pipe 51. The arc-shaped portions 551 at both ends of the limiting spring 55 are inserted into the gap between the spiral steel wire skeleton 54 and the drain filter pipe 51. The concave side of the arc-shaped portion 551 abuts against the steel wire of the spiral steel wire skeleton 54. The limiting spring 55 forces the plastic drain strip 52 to press tightly against the surface of the drain filter pipe 51.

[0045] The plastic drainage strip 52 covers the surface of the drainage filter pipe 51. The limiting spring 55 can keep the plastic drainage strip 52 stably covering the drainage filter pipe 51, thereby making the connection between the gap inside the plastic drainage strip 52 and the inner cavity of the drainage filter pipe 51 more continuous, making it easier for the vacuum pump 53 to apply negative pressure to the soft soil foundation 1.

[0046] Reference Figure 5 One edge of the limiting spring 55 is a serrated edge 552, with the tips of the serrated edges forming an obtuse angle with the surface of the limiting spring 55. The tips of the serrated edges 552 abut against the surface of the plastic drainage strip 52. The plastic drainage strip 52 includes a plastic core board and a non-woven geotextile for use as a filter layer. The serrated edge 552 of the limiting spring 55 can hook onto the geotextile on the surface of the plastic drainage strip 52, so that the limiting spring 55 provides a good limiting effect on the plastic drainage strip 52, thereby improving the stability of the connection between the plastic drainage strip 52 and the drainage filter pipe 51.

[0047] Reference Figure 6 A long, rectangular positioning piece 56, made of metal, is inserted into the drain filter pipe 51 through the filter holes. Both sides of the positioning piece 56 abut against the edges of the filter holes in the drain filter pipe 51. One end of the positioning piece 56 has a positioning hook 561 facing the drain filter pipe 51, which hooks onto the wire of the spiral wire skeleton 54. The end of the positioning piece 56 away from the positioning hook 561 has a chamfer 562, making it easier to insert the positioning piece 56 into the filter holes of the drain filter pipe 51. One edge of the positioning piece 56 has a barb 563, which hooks onto the inner edge of the filter holes in the drain filter pipe 51, preventing the positioning piece 56 from easily detaching from the drain filter pipe 51.

[0048] The positioning piece 56 can position the spiral coil of the spiral wire skeleton 54. When the gravity load of the preloaded earthwork layer 3 is applied to the spiral wire skeleton 54, the spiral coil of the spiral wire skeleton 54 is not prone to deformation and movement along the circumference, so that the spiral coil of the spiral wire skeleton 54 can effectively support the preloaded earthwork layer 3, thereby enabling the spiral coil of the spiral wire skeleton 54 to fully play its role in protecting the drainage filter pipe 51.

[0049] Reference Figure 7The drainage filter pipe 51 is equipped with a positioning rod 57, which is made of steel. The positioning rod 57 includes an insertion section 571 and a hook section 572. The hook section 572 holds the drainage filter pipe 51, and the arc angle of the hook section 572 is greater than 180 degrees. The hook section 572 has a clamping force on the outer circumference of the drainage filter pipe 51. A guide section 573 is provided at the end of the hook section 572 away from the insertion section 571. Multiple reinforcing rods 574 are arranged circumferentially around the insertion section 571 of the positioning rod 57. The reinforcing rods 574 are made of steel and abut against each other in pairs and are connected and fixed by spot welding. The reinforcing rods 574 and the insertion section 571 of the positioning rod 57 together form a rod bundle, which is inserted into the soft soil foundation 1. Several water-guiding gaps are formed between the insertion sections 571 of the multiple reinforcing rods 574 and the positioning rods 57.

[0050] The positioning rod 57 can position the drainage filter pipe 51, which helps to keep the drainage filter pipe 51 straight during installation and reduces energy loss during the vacuum pump 53's vacuuming process through the drainage filter pipe 51. The reinforcing rod 574 and the insertion section 571 of the positioning rod 57 form a rod bundle, which is less prone to bending and deformation during insertion into the soft soil foundation 1. On the other hand, the reinforcing rod 574 surrounds the insertion section 571 of the positioning rod 57, forming a water-conducting gap between the reinforcing rod 574 and the insertion section 571 of the positioning rod 57, which helps to increase the path for the vacuum pump 53 to vacuum the soft soil foundation 1.

[0051] A guide sleeve 575, made of steel, is fitted onto the lower end of the rod bundle. The guide sleeve 575 is welded to one or more of the reinforcing rods 574. The guide sleeve 575 has a water filter hole and a bottom wall, which is inclined relative to the centerline of the guide sleeve 575. This inclined bottom wall creates a pointed tip between the bottom wall and the peripheral wall, reducing the resistance when the rod bundle is inserted into the soft soil foundation 1.

[0052] The implementation principle of the vacuum combined surcharge preloading reinforcement soft soil foundation system in this application embodiment is as follows: The vacuum combined surcharge preloading reinforcement soft soil foundation system promotes the rapid drainage of pore water in the soil through the combined action of vacuum preloading and surcharge preloading, enabling the soft soil foundation 1 to quickly drain and consolidate. The vacuum pump 53 evacuates the sealing gap between the medium-coarse sand cushion layer 2 and the vacuum sealing layer 4 through the drainage filter pipe 51 and the plastic drainage belt 52. By installing a spiral steel wire skeleton 54 on the drainage filter pipe 51, the upward and downward filter holes of the drainage filter pipe 51 can be kept in communication with the sealing gap. Under the premise of a certain distribution density of filter holes in the drainage filter pipe 51, the utilization rate of the filter holes in the drainage filter pipe 51 can be increased, thereby enabling the vacuum pump 53 to perform vacuuming operations more smoothly.

[0053] On the other hand, the spiral steel wire skeleton 54 is sleeved on the drainage filter pipe 51, so that the spiral steel wire skeleton can replace the preload of the load-bearing part of the drainage filter pipe 51, thus protecting the drainage filter pipe 51 and reducing the occurrence of pressure deformation of the drainage filter pipe 51.

[0054] Example 2

[0055] The difference between this embodiment and embodiment 1 is that the limiting spring 55 in this embodiment has a different structure than the limiting spring 55 in embodiment 1. In this embodiment, the two ends of the limiting spring 55 do not have arc-shaped portions 551.

[0056] Reference Figure 8 In this embodiment, the limiting spring 55 is located on the side of the plastic drainage belt 52 away from the drainage filter pipe 51. The two ends of the limiting spring 55 are respectively provided with snap hooks 553, which face the drainage filter pipe 51 and snap hooks 553 snap onto the steel wire of the spiral steel wire skeleton 54.

[0057] During the connection of the limiting spring 55 and the spiral wire skeleton 54, pressure is only required to be applied to the snap hook 553 of the limiting spring 55 to clamp the wire of the spiral wire skeleton 54. The connection of the limiting spring 55 is more convenient.

[0058] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A soft soil foundation reinforcement system using vacuum combined with surcharge preloading, characterized in that, The structure includes, from bottom to top, a soft soil foundation (1), a medium-coarse sand cushion layer (2), a drainage device (5), a vacuum sealing layer (4), and a surcharge preloading earthwork layer (3). A sealing gap is formed between the vacuum sealing layer (4) and the medium-coarse sand cushion layer (2). The drainage device (5) includes a drainage filter pipe (51), a plastic drainage strip (52), and a vacuum pump (53). The drainage filter pipe (51) is laid inside the sealing gap, and the vacuum pump (53) is located outside the sealing gap and connected to the drainage filter pipe (51). The main body of the plastic drainage strip (52) is inserted into the soft soil foundation (1). The upper end of the drainage strip (52) extends out of the soft soil foundation (1) and is connected to the drainage filter pipe (51); the drainage filter pipe (51) is fitted with a spiral steel wire skeleton (54), the spiral spacing of the spiral steel wire skeleton (54) is greater than the width of the plastic drainage strip (52), the outer end of the plastic drainage strip (52) covers the outer circumferential surface of the drainage filter pipe (51) and is located between the spiral coils of the spiral steel wire skeleton (54); the drainage filter pipe (51) is provided with a long strip-shaped limiting spring (55), the limiting spring (55) is located on the side of the plastic drainage strip (52) away from the drainage filter pipe (51); The drainage filter pipe (51) is provided with a positioning rod (57), the positioning rod (57) includes a plug section (571) and a hook section (572), the hook section (572) holds the drainage filter pipe (51), and the plug section (571) is inserted into the soft soil foundation (1); The arc angle of the hook section (572) is greater than 180 degrees. The hook section (572) has a clamping force on the outer peripheral surface of the drain filter pipe (51). A guide section (573) is provided at the end of the hook section (572) away from the plug section (571). The insertion section (571) of the positioning rod (57) is surrounded by a plurality of reinforcing rods (574) in the circumferential direction. The reinforcing rods (574) abut against each other in pairs. The reinforcing rods (574) and the insertion section (571) of the positioning rod (57) together form a rod bundle. Several water-guiding gaps are formed between the plurality of reinforcing rods (574) and the insertion section (571) of the positioning rod (57). The drainage filter pipe (51) is fitted with a positioning piece (56) through the filter hole. The positioning piece (56) is long and narrow. Both sides of the positioning piece (56) abut against the edge of the filter hole of the drainage filter pipe (51). One end of the positioning piece (56) is provided with a positioning hook (561), which hooks the wire of the spiral wire skeleton (54).

2. The soft soil foundation reinforcement system using vacuum combined loading preloading as described in claim 1, characterized in that: The length of the limiting spring (55) is greater than the spiral spacing of the spiral steel wire skeleton (54). The two ends of the limiting spring (55) are respectively inserted into the gap between the spiral steel wire skeleton (54) and the drainage filter pipe (51). The middle part of the limiting spring (55) abuts against the surface of the plastic drainage strip (52) away from the drainage filter pipe (51). The limiting spring (55) forces the plastic drainage strip (52) to press against the surface of the drainage filter pipe (51).

3. The soft soil foundation reinforcement system using vacuum combined loading preloading as described in claim 2, characterized in that: The limiting spring (55) has arc-shaped portions (551) extending from both ends. The concave side of the arc-shaped portion (551) is away from the drain filter pipe (51), and the concave side of the arc-shaped portion (551) abuts against the wire of the spiral wire skeleton (54).

4. The soft soil foundation reinforcement system using vacuum combined loading preloading as described in claim 2, characterized in that: One side of the limiting spring (55) has a serrated edge (552), and the tooth tips of the serrated edge (552) form an obtuse angle with the surface of the limiting spring (55). The tooth tips of the serrated edge (552) abut against the surface of the plastic drainage strip (52).

5. The soft soil foundation reinforcement system using vacuum combined loading preloading as described in claim 1, characterized in that: The limiting spring (55) is provided with snap hooks (553) at both ends, the snap hooks (553) face the drain filter pipe (51), and the snap hooks (553) snap into the steel wire of the spiral steel wire skeleton (54).

6. The soft soil foundation reinforcement system using vacuum combined loading preloading as described in claim 1, characterized in that: The lower end of the rod bundle is fitted with a guide sleeve (575), the guide sleeve (575) has a water filter hole, the guide sleeve (575) has a bottom wall, and the bottom wall of the guide sleeve (575) is inclined relative to the center line of the guide sleeve (575).

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