Vacuum preloading device for underwater soft soil base layer and construction technology of vacuum preloading device

Abstract

The invention provides an underwater soft soil base layer vacuum preloading device and a construction technology thereof.The underwater soft soil base layer vacuum preloading device comprises a drainage body, an underwater vacuum preloading device, a first pipe body and a vacuum pump, a plurality of mounting holes are formed in the bottom of the underwater vacuum preloading device and used for mounting the drainage body, and the drainage body is inserted into a mud surface; a second pipe body is arranged at the top of the underwater vacuum preloading device and connected to a vacuum pump through a first pipe body, and the vacuum pump is arranged on the ship body or the shore base. According to the vacuum preloading device for the underwater soft soil base layer and the construction technology of the vacuum preloading device, the underwater vacuum preloading device is a recyclable device, the construction cost can be reduced, the drainage body is of a prefabricated sleeve structure, people do not need to go down, film laying is not needed, negative pressure is formed on the upper portion of the to-be-treated foundation, pore water in the foundation flows out along a specially-made drainage channel, and the construction efficiency is improved. By adopting the assembly type design, a plurality of underwater vacuum preloading devices can be combined for application, the stability of the system in an underwater environment is improved, and the system is plug-and-play and is convenient to recycle and reuse.

Description

Technical Field

[0001] The invention belongs to the field of underwater soft soil base construction, and in particular relates to a vacuum preloading device for an underwater soft soil base and a construction process thereof. Background Art

[0002] Marine soft soil not only has the general soft soil characteristics of high water content, high compressibility, low strength and poor permeability, but also has the particularity of the marine environment, which makes the soft soil foundation in the offshore area have large settlement, slow consolidation and long settlement duration. At the same time, due to settlement and other reasons, the built buildings or structures will be affected by a series of diseases such as local deformation and cracking, panel damage, and seawater contact scouring, causing a series of safety hazards. Therefore, before the construction of offshore wind power suction pile foundations, offshore airports, industrial artificial islands, etc., it is necessary to treat and reinforce the marine soft soil foundation.

[0003] The vacuum preloading method is to lay a horizontal drainage sand cushion layer and a vertical drainage board set on the soft clay foundation, lay a specific airtight sealing membrane on the upper part of the sand cushion layer, and use the drainage filter pipe and vacuum device at the bottom to reduce the pore water pressure of the lower soil to form a negative pressure, and use atmospheric pressure to achieve the purpose of strengthening the land and increasing the effective stress.

[0004] However, vacuum preloading is currently mostly used in land-based projects, and there are only a handful of cases of vacuum preloading projects that can be used in underwater environments, and most of the projects are located in the intertidal zone. There is still a blank in the application of this technology in a completely underwater environment.

[0005] The biggest problem with the existing underwater vacuum preloading processing technology is how to lay the membrane underwater. The laying of the sealing membrane is the key factor that determines whether the vacuum preloading can work smoothly. If this problem can be solved, underwater vacuum preloading will be widely used in engineering. Summary of the invention

[0006] In view of this, the present invention aims to propose a vacuum preloading device for underwater soft soil base to solve the problem that vacuum preloading projects in underwater environments in the prior art are difficult to carry out and the construction conditions are relatively limited.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] A vacuum preloading device for an underwater soft soil base comprises a drainage body, an underwater vacuum preloading device, a first pipe body and a vacuum pump. A plurality of mounting holes are arranged at the bottom of the underwater vacuum preloading device, and the mounting holes are used to install the drainage body. The drainage body is plugged into the mud surface. A second pipe body is arranged on the top of the underwater vacuum preloading device. The second pipe body is connected to the vacuum pump through the first pipe body. The vacuum pump is arranged on a hull or a shore foundation. Water in the mud surface is discharged through the drainage body, the underwater vacuum preloading device, the second pipe body, the first pipe body and the vacuum pump.

[0009] Furthermore, the underwater vacuum prestressing device includes an upper shell and a lower shell, the bottom of the lower shell is provided with a plurality of mounting holes, the upper end of the lower shell is sealed and connected to the lower end of the upper shell, and the upper end of the upper shell is installed with a first tube body.

[0010] Furthermore, a connecting pipe is provided on the upper shell, and a solenoid valve is installed on the connecting pipe.

[0011] Furthermore, a water-gas separation chamber is installed on the first tube body.

[0012] Furthermore, a plurality of alignment heads are circumferentially arranged at the lower end of the upper shell body, and a plurality of alignment grooves are axially arranged at the upper end of the lower shell body. The alignment heads and the alignment grooves correspond one to one, and each alignment head is correspondingly inserted into an alignment groove for positioning the relative positions of the lower shell body and the upper shell body. The cross-section of the inner ring contour of the alignment groove is a trapezoidal structure, and the outer contour of the alignment head is adapted to the inner ring contour of the alignment groove.

[0013] Furthermore, an abutment groove is circumferentially provided at the upper end of the lower shell, and an abutment platform is circumferentially provided at the lower end of the upper shell. The cross section of the outer contour of the abutment platform is a triangular structure, and the inner circle contour of the abutment groove is adapted to the abutment platform.

[0014] Furthermore, a rubber water stop strip is arranged in the abutment groove.

[0015] Furthermore, a flow channel is provided on the abutment platform, a slurry delivery hose is installed at the inlet end of the flow channel, and the outlet end of the flow channel is located at the tip of the abutment platform and is connected to the abutment groove.

[0016] Furthermore, the drainage body comprises bamboo, and a drainage board is sleeved on the outer periphery of the bamboo, and a sheath is arranged on the outer periphery of the drainage board, a conical head is installed on the bottom end of the bamboo, and the lower end of the sheath abuts against the upper end of the conical head.

[0017] Compared with the prior art, the vacuum preloading device for an underwater soft soil base described in the present invention has the following beneficial effects: the underwater vacuum preloading device is a recyclable device, which can reduce construction costs; the drainage body adopts a prefabricated sleeve structure, and no personnel are required, and no membrane is required. Negative pressure is formed on the upper part of the foundation to be treated, so that the pore water in the foundation flows out along a special drainage channel; and an assembled design is adopted, so multiple underwater vacuum preloading devices can be used in combination, thereby improving the stability of the system in the underwater environment; it is plug-and-play, and is easy to recycle and reuse.

[0018] Another object of the present invention is to propose a vacuum preloading construction process for underwater soft soil base to solve the problem that there are only a few vacuum preloading engineering cases in underwater environments in the prior art, and most of the applied projects are located in the intertidal zone, which is difficult to apply in a completely underwater environment.

[0019] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0020] A construction process for vacuum preloading of an underwater soft soil base comprises the following steps:

[0021] S1. Move the lower shell down to the area to be constructed;

[0022] S2. Pass one end of the drainage body through the installation hole and press it down into the mud surface;

[0023] S3, buckle the upper shell to the upper end of the lower shell, and completely sink the upper shell under the water;

[0024] S4, start the vacuum pump to form a vacuum negative pressure and extract the pore water below the mud surface;

[0025] S5. After pre-pressing is completed, the vacuum pre-pressing device is unloaded and recovered.

[0026] Compared with the prior art, the vacuum preloading construction process of an underwater soft soil base described in the present invention has the following advantages: the construction method can be fully applied to underwater environments, and the water body is adsorbed by vacuum negative pressure below the underwater mud surface to make the marine soft body locally hardened to meet the construction requirements, and the construction method is simple, low-cost and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0028] Figure 1 It is a construction schematic diagram of a vacuum preloading device for an underwater soft soil base according to an embodiment of the present invention;

[0029] Figure 2It is a schematic structural diagram of the upper housing according to an embodiment of the present invention;

[0030] Figure 3 It is a top view schematic diagram of the lower housing according to an embodiment of the present invention;

[0031] Figure 4 It is a cross-sectional schematic diagram of the cooperation between the alignment head and the alignment groove according to an embodiment of the present invention;

[0032] Figure 5 It is a cross-sectional schematic diagram of an upper shell and a lower shell according to an embodiment of the present invention being sealed and connected by a rubber water stop strip;

[0033] Figure 6 It is a cross-sectional schematic diagram of the upper shell and the lower shell connected by grouting sealing according to an embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of the structure of the bamboo and the drainage board according to the embodiment of the present invention;

[0035] Figure 8 It is a schematic structural diagram of the drainage body described in an embodiment of the present invention.

[0036] Description of reference numerals:

[0037] 1-drainage body; 11-bamboo; 12-drainage board; 13-conical head; 14-sheath; 2-underwater vacuum preloading device; 21-upper shell; 22-lower shell; 23-second tube body; 24-installation hole; 25-connecting pipe; 26-solenoid valve; 27-alignment head; 28-alignment groove; 29-abutment groove; 210-abutment platform; 211-rubber water stop strip; 212-flow channel; 213-slurry delivery hose; 3-first tube body; 4-vacuum pump; 5-mud surface; 6-hull; 7-water-gas separation chamber. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0039] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0041] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0042] like Figure 1-Figure 8 As shown, a vacuum preloading device for an underwater soft soil base comprises a drainage body 1, an underwater vacuum preloading device 2, a first pipe body 3 and a vacuum pump 4. The bottom of the underwater vacuum preloading device 2 is provided with a plurality of mounting holes 24, and the mounting holes 24 are used to install the drainage body 1. The drainage body 1 is plugged into the mud surface 5. A second pipe body 23 is arranged on the top of the underwater vacuum preloading device 2. The second pipe body 23 is connected to the vacuum pump 4 through the first pipe body 3. The vacuum pump 4 is arranged on a hull 6 or a shore. The water in the mud surface 5 passes through the drainage body 1. , underwater vacuum preloading device 2, second pipe body 23, first pipe body 3 and vacuum pump 4 are discharged. The underwater vacuum preloading device 2 is a recyclable device, which can reduce construction costs. The drainage body 1 adopts a prefabricated sleeve structure, which does not require people to go down and does not require membrane laying. Negative pressure is formed on the upper part of the foundation to be treated, so that the pore water in the foundation flows out with the special drainage channel. In addition, it adopts an assembled design, and multiple underwater vacuum preloading devices 2 can be used in combination to improve the stability of the system in the underwater environment. It is plug-and-play and easy to recycle and reuse.

[0043] The underwater vacuum prestressing device 2 includes an upper shell 21 and a lower shell 22. A plurality of mounting holes 24 are provided at the bottom of the lower shell 22. The upper end of the lower shell 22 is sealed and connected to the lower end of the upper shell 21. A first tube body 3 is installed at the upper end of the upper shell 21. A connecting pipe 25 is provided on the upper shell 21. A solenoid valve 26 is installed on the connecting pipe 25. A water-gas separation chamber 7 is installed on the first tube body 3. The solenoid valve 26, the water-gas separation chamber 7 and the vacuum pump 4 are prior arts and will not be described in detail here.

[0044] The lower end of the upper shell 21 is provided with a plurality of alignment heads 27 along the circumferential direction, and the upper end of the lower shell 22 is provided with a plurality of alignment grooves 28 along the axial direction. The alignment heads 27 and the alignment grooves 28 correspond to each other one by one. Each alignment head 27 is correspondingly inserted into an alignment groove 28 for positioning the relative position of the lower shell 22 and the upper shell 21, and the cross-section of the inner circle contour of the alignment groove 28 is a trapezoidal structure. The outer contour of the alignment head 27 is adapted to the inner circle contour of the alignment groove 28. In this embodiment, the upper shell 21 is a cubic box-shaped bottomless steel structure. The side length of the "steel box" is 10 to 20 meters, the height is 0.5 to 1 meter, and the thickness of the steel plate is 30 to 50 mm. The second tube body 23 and the solenoid valve 26 are connected to the top of the "steel box", and there are reinforced ribs at the connection. A pointed alignment head 27 is provided at the edge of the side wall of the steel box. The lower shell 22 is a cubic box-shaped bottomless steel structure, the side length of the "steel box" is 10-20m, the height is 2-4m, and the thickness of the steel plate is 30-50mm. The upper shell 21 is provided with a tip every 2m, and the lower shell 22 is provided with a positioning groove 28 at the corresponding position.

[0045] The upper end of the lower shell 22 is provided with an abutment groove 29 along the circumferential direction, and the lower end of the upper shell 21 is provided with an abutment platform 210 along the circumferential direction. The cross section of the outer contour of the abutment platform 210 is a triangular structure. The inner circle contour of the abutment groove 29 is adapted to the abutment platform 210. In order to achieve a sealed connection between the upper shell 21 and the lower shell 22, two embodiments are provided as follows:

[0046] Embodiment 1:

[0047] A rubber water stop strip 211 is arranged in the abutting groove 29 , and a sealing connection between the upper shell 21 and the lower shell 22 is achieved through the rubber water stop strip 211 . The rubber water stop strip 211 is pre-arranged.

[0048] Embodiment 2:

[0049] A flow channel 212 is provided on the abutment platform 210, and a slurry delivery hose 213 is installed at the inlet end of the flow channel 212. The outlet end of the flow channel 212 is located at the tip of the abutment platform 210 and is connected to the abutment groove 29. Through an external grouting device, a sealant such as a water glass gel meter is injected between the abutment platform 210 and the abutment groove 29 to achieve a water-stop seal.

[0050] The drainage body 1 comprises bamboo 11, and a drainage board 12 is sleeved around the bamboo 11, and a sheath 14 is arranged around the drainage board 12. A conical head 13 is installed at the bottom of the bamboo 11, and the lower end of the sheath 14 abuts against the upper end of the conical head 13. In this embodiment, the vertical drainage body 1 is composed of bamboo 11 and an annular drainage board 12. The bamboo 11 is taken as the main body, and the annular drainage board 12 is firmly sleeved along its long axis direction. The large contact area of ​​the annular drainage board 12 can effectively improve the drainage efficiency. The annular drainage board 12 is the prior art. Due to the constraint of the middle bamboo 11, the drainage board 12 is not easy to bend, and the treatment effect is better than that of using the drainage board 12 alone. The inside of the bamboo 11 is hollowed out and filled with crushed construction waste. Using construction waste as the filler inside the bamboo 11 is energy-saving and environmentally friendly, and can improve its rigidity. After the vacuum preloading is completed, cement slurry can be poured into the bamboo 11 to make the vertical drainage body 1 play the role of a micropile.

[0051] A construction process for vacuum preloading of an underwater soft soil base comprises the following steps: S1, lowering the lower shell 22 to the area to be constructed; S2, passing one end of the drainage body 1 through the installation hole 24 and pressing it down into the mud surface 5; S3, buckling the upper shell 21 to the upper end of the lower shell 22, and completely sinking the upper shell 21 under the water body; S4, starting the vacuum pump 4 to form a vacuum negative pressure, and extracting the pore water under the mud surface 5; S5, after completing the preloading, unloading and recovering the vacuum preloading device.

[0052] Specifically, during construction, after the transport ship arrives at the designated location, the lower shell 22 is slowly placed into the water. Because the lower shell 22 has a through mounting hole 24, the lower shell 22 is connected up and down, and the pressure is equal. The lower shell 22 can smoothly reach the area to be treated under the traction of the crane. After arriving at the treatment area, it is necessary to install the vertical drainage body 1. When installing, first insert the vertical drainage body 1 into the iron sheath 14, and then insert the sheath 14 together with the vertical drainage body 1 into the hole reserved in the top plate, and slowly drive it into the soil covered by the steel plate. When installing, first drive it in according to the positioning device of the middle hole and the four corner holes. Then, according to the layout of a hole every 2m, drive in the remaining drainage boards 12 in sequence. After the installation is completed, pull out the sheath 14. At this time, the conical head 13 and the vertical drainage body 1 will remain in the soil.

[0053] After the drainage board 12 is inserted, the signal transmitting device previously attached to the top plate of the lower device will continuously transmit GPS signals on the seabed, and the signal can be received by the corresponding signal receiving device on the ship. After receiving the GPS signal, the crane on the ship slowly puts the upper shell 21 into the water. In order to facilitate the sinking of the upper shell 21, two connecting pipes 25 are set on the top of the upper shell 21. The connectivity of the connecting pipe 25 is controlled by the electromagnetic valve 26. After opening the electromagnetic valve 26, the upper and lower parts of the upper shell 21 are connected and the pressure is equal. The upper shell 21 can sink smoothly under the traction of the crane, and then the electromagnetic valve 26 is closed, and a closed cavity is formed inside the upper shell 21 and the lower shell 22. Start the vacuum pump 4, a negative pressure will be formed inside the cavity, and the pore water inside the soil body to be treated will flow into the cavity along the drainage board 12. When the water fills the cavity, it will flow into the water-gas separation chamber 7 along the first tube body 3. As the vacuum is continuously drawn, the pore water pressure of the soil body to be treated will gradually decrease, thereby increasing the effective stress of the soil body.

[0054] The number of vertical drainage bodies 1 to be installed is determined according to the specific conditions of the project. In order to reduce the soil squeezing effect of the vertical drainage bodies 1 when vacuuming, it is necessary to stipulate the layout of the vertical drainage bodies 1: when installing the vertical drainage bodies 1, starting from the center of the area, a drainage body 1 is installed every 2m in the horizontal and vertical directions. When installing the vertical drainage bodies 1, the vertical drainage bodies 1 are required to exceed the mud surface by about 530cm to facilitate horizontal drainage.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A vacuum preloading device for underwater soft soil base, characterized in that: The invention comprises a drainage body (1), an underwater vacuum preloading device (2), a first pipe body (3) and a vacuum pump (4); a plurality of mounting holes (24) are provided at the bottom of the underwater vacuum preloading device (2); and the mounting holes (24) are used to install the drainage body (1); the drainage body (1) is plugged into a mud surface (5); a second pipe body (23) is provided on the top of the underwater vacuum preloading device (2); the second pipe body (23) is connected to the vacuum pump (4) through the first pipe body (3); the vacuum pump (4) is provided on a hull (6) or a shore base; and water in the mud surface (5) is discharged through the drainage body (1), the underwater vacuum preloading device (2), the second pipe body (23), the first pipe body (3) and the vacuum pump (4).

2. The vacuum preloading device for underwater soft soil base according to claim 1, characterized in that: The underwater vacuum preloading device (2) comprises an upper shell (21) and a lower shell (22); a plurality of mounting holes (24) are provided at the bottom of the lower shell (22); the upper end of the lower shell (22) is sealedly connected to the lower end of the upper shell (21); and a first tube (3) is installed at the upper end of the upper shell (21).

3. The vacuum preloading device for underwater soft soil base according to claim 2, characterized in that: A connecting pipe (25) is provided on the upper shell (21), and a solenoid valve (26) is installed on the connecting pipe (25).

4. The vacuum preloading device for underwater soft soil base according to claim 2, characterized in that: A water-gas separation chamber (7) is installed on the first tube body (3).

5. The vacuum preloading device for underwater soft soil base according to claim 2, characterized in that: A plurality of alignment heads (27) are arranged along the circumferential direction at the lower end of the upper shell (21), and a plurality of alignment grooves (28) are arranged along the axial direction at the upper end of the lower shell (22). The alignment heads (27) and the alignment grooves (28) correspond to each other one by one, and each alignment head (27) is correspondingly inserted into an alignment groove (28) for locating the relative position of the lower shell (22) and the upper shell (21). The cross-section of the inner ring profile of the alignment groove (28) is a trapezoidal structure, and the outer contour of the alignment head (27) is adapted to the inner ring profile of the alignment groove (28).

6. The vacuum preloading device for underwater soft soil base according to claim 5, characterized in that: An abutment groove (29) is circumferentially provided at the upper end of the lower shell (22), and an abutment platform (210) is circumferentially provided at the lower end of the upper shell (21). The cross section of the outer contour of the abutment platform (210) is a triangular structure, and the inner circle contour of the abutment groove (29) is adapted to the abutment platform (210).

7. The vacuum preloading device for underwater soft soil base according to claim 6, characterized in that: A rubber water stop strip (211) is arranged in the abutment groove (29).

8. The vacuum preloading device for underwater soft soil base according to claim 6, characterized in that: A flow channel (212) is provided on the abutment platform (210), a slurry delivery hose (213) is installed at the inlet end of the flow channel (212), and the outlet end of the flow channel (212) is located at the tip of the abutment platform (210) and is connected to the abutment groove (29).

9. The vacuum preloading device for underwater soft soil base according to claim 1, characterized in that: The drainage body (1) comprises a bamboo (11), a drainage board (12) is sleeved on the outer periphery of the bamboo (11), and a protective sleeve (14) is arranged on the outer periphery of the drainage board (12); a conical head (13) is installed at the bottom end of the bamboo (11), and the lower end of the protective sleeve (14) abuts against the upper end of the conical head (13).

10. A construction process implemented by using a vacuum preloading device for underwater soft soil base according to any one of claims 1 to 9, characterized in that: The steps include: S1. Move the lower shell down to the area to be constructed; S2. Pass one end of the drainage body through the installation hole and press it down into the mud surface; S3, buckle the upper shell to the upper end of the lower shell, and completely sink the upper shell under the water; S4, start the vacuum pump to form a vacuum negative pressure and extract the pore water below the mud surface; S5. After pre-pressing is completed, the vacuum pre-pressing device is unloaded and recovered.

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