Foundation pit gas film foundation and construction method thereof

Abstract

The invention discloses a foundation pit gas film foundation and a construction method thereof.The foundation pit gas film foundation comprises H-shaped steel which is sequentially connected end to end, the H-shaped steel is composed of an upper flange plate, a lower flange plate and a web, one end of the web is connected with the upper flange plate, the other end of the web is connected with the lower flange plate making contact with the ground, and the lower flange plate is provided with an open hole and a fixing mechanism; the foundation pit air film foundation further comprises spiral ground piles penetrating through the open holes and extending into the ground. The fixing mechanism is used for limiting the spiral ground pile; a connecting mechanism connected with a gas film material is arranged on the upper flange plate; the spiral ground pile is of a hollow structure, and a buffering mechanism and a reinforcing mechanism are arranged in the spiral ground pile. When the H-shaped steel is subjected to drawing force, the fixing mechanism is driven to trigger the buffering mechanism to counteract the drawing force, and meanwhile the reinforcing mechanism is triggered to increase the underground shearing force of the spiral ground pile. The problems that when an existing foundation pit air film foundation is used in coastal areas, the foundation is unstable and an air film is turned over due to low soil bearing capacity and strong wind cannot be handled are solved.

Description

Technical Field

[0001] The invention relates to the technical field of air film buildings, and in particular to a foundation pit air film foundation and a construction method thereof. Background Art

[0002] The foundation pit air film foundation is a temporary structural system used for foundation pit support and closure. It is mainly composed of supporting structures and fixing devices. It is used to protect the foundation pit construction environment and play the role of dust prevention, noise reduction, thermal insulation and rain erosion prevention. The supporting structure is used to bear the load of the air film and transfer it to the foundation. The design and construction of the foundation pit air film foundation directly affects the overall stability and safety of the air film structure and is an indispensable part of the foundation pit project.

[0003] Traditional air film foundations usually use concrete foundations or simple ground anchors, which mainly rely on soil friction or their own weight to provide support. However, in coastal areas, sedimentary soil is usually relatively soft and has a high water content, which significantly reduces the soil bearing capacity. Concrete foundations are prone to settlement or tilting under such geological conditions and cannot provide sufficient support, resulting in unstable air film structures. In addition, coastal areas often encounter strong winds, and traditional air film foundations are susceptible to huge pull-out forces under strong winds. Traditional fixing methods, such as simple bolt connections or ground anchors, may not provide sufficient pull-out resistance under strong wind conditions, causing the air film to be overturned or torn, posing serious safety hazards.

[0004] CN 106401269 A discloses an air film reinforcement cable and an air film building. The patent mainly controls the compression force of the air film by adjusting the cable length, but does not provide an effective wind-resistant design for strong wind weather along the coast, and cannot effectively resist the huge pulling force caused by strong winds. The cable length adjustment requires manual operation, lacks an automated linkage mechanism, and cannot be dynamically adjusted to offset the pulling force under strong wind conditions.

[0005] CN 110847208 A discloses an air film foundation structure suitable for plateau frozen soil and its construction method. The patent mainly relies on the interference between the tooth structure and the stratum to provide pull-out resistance. However, in the case of low bearing capacity of coastal sedimentary soil, the pull-out resistance of the tooth structure may be insufficient and cannot effectively resist the pull-out force caused by strong winds. The patent requires on-site pouring of the foundation body and installation of prefabricated tooth structures. The construction process is complicated and the cycle is long, which cannot meet the needs of rapid construction. Summary of the invention

[0006] The purpose of the present invention is to provide a foundation pit air film foundation and a construction method thereof, so as to solve the problem that the existing foundation pit air film foundation cannot cope with the low soil bearing capacity and strong wind that causes the foundation to become unstable and the air film to be overturned when used in coastal areas.

[0007] The present invention is achieved through the following technical solutions:

[0008] According to one aspect of the present invention, there is provided an air film foundation for a foundation pit, comprising an H-shaped steel arranged around the foundation pit and connected end to end in sequence, wherein the H-shaped steel is composed of an upper flange plate, a lower flange plate and a web plate, one end of the web plate is connected to the upper flange plate, and the other end of the web plate is connected to the lower flange plate in contact with the ground, and the lower flange plate is provided with an opening and a fixing mechanism; the foundation pit air film foundation also includes a spiral ground pile passing through the opening and extending into the ground; the fixing mechanism is used to limit the spiral ground pile; a connecting mechanism for connecting the air film material is provided on the upper flange plate; the spiral ground pile is a hollow structure, and a buffer mechanism and a reinforcing mechanism are provided inside it; when the H-shaped steel is subjected to a pulling force, the fixing mechanism is driven to trigger the buffer mechanism to offset the pulling force, and at the same time the reinforcing mechanism is triggered to increase the shear force of the spiral ground pile underground, thereby further offsetting the pulling force.

[0009] Preferably, the fixing mechanism includes a first clamping block and a second clamping block, the first clamping block is arranged on one side of the spiral ground pile, and the second clamping block is arranged on the other side of the spiral ground pile, and a nut and a screw are provided between the first clamping block and the second clamping block, and the nut and the screw connect the first clamping block and the second clamping block.

[0010] Preferably, the buffer mechanism includes a rod member arranged inside the spiral ground pile, a circular abutment plate is provided at one end of the rod member away from the ground, the diameter of the abutment plate is larger than the outer diameter of the spiral ground pile, and a first spring is provided at one end of the rod member located underground, the first spring connects the inner wall of the spiral ground pile and the end of the rod member; when the first clamping block and the second clamping block are moved upward by the pulling force of the H-shaped steel, they contact the abutment plate, and the first spring generates a reaction force through the abutment plate.

[0011] Preferably, the reinforcing mechanism includes a flange arranged on the outer wall of the rod and a through hole arranged on the outer wall of the spiral ground pile; the thickness of the flange gradually increases along the extending direction of the spiral ground pile; an extension plate is also provided in the spiral ground pile, and a connecting block is provided on the extension plate, and a second spring connecting the connecting block and the inner wall of the spiral ground pile is provided between them; the extension plate can pass through the through hole and extend into the formation; when the second spring is in an initial state, one end of the extension plate away from the inner wall of the spiral ground pile contacts the non-flange section of the rod; when the rod moves upward, the flange causes the extension plate to gradually extend out of the through hole and be inserted into the formation.

[0012] Preferably, along the insertion direction of the screw pile, the cross-sectional shape of the extension plate is a minor arc shape, and a side of the extension plate close to the rod is provided with an opening matching the non-flange section of the rod.

[0013] Preferably, each flange and the through hole matched with the flange, the rod, the connecting block and the second spring are combined into a reinforcement component, and a plurality of reinforcement components are arranged in the spiral ground pile.

[0014] Preferably, waterproof cotton is provided between the upper flange plate and the lower flange plate, and the waterproof cotton is provided on a side of the H-shaped steel outside the air film membrane material, and the waterproof cotton is used to close the space connecting the upper flange plate and the lower flange plate to the outside world.

[0015] Preferably, the connecting mechanism includes an angle steel, screws and nuts arranged on the upper flange plate, the angle steel is connected by a vertical section and a parallel section, the screw passes through the parallel section and the upper flange plate and is fixed by the nut, and the air film membrane material is clamped between the angle steel and the upper flange plate.

[0016] Preferably, a rubber pad is connected between the parallel section and the upper flange plate, and the rubber pad is connected to the parallel section.

[0017] According to another aspect of the present invention, a construction method of a foundation pit air film foundation is provided. The foundation pit air film foundation is the above-mentioned foundation pit air film foundation. The construction method of the foundation pit air film foundation comprises:

[0018] S1, according to the design drawings, mark the installation positions of the spiral piles around the foundation pit;

[0019] S2, using a screw pile screwing device to screw the screw pile into the ground according to the marked position;

[0020] S3, transport the H-shaped steel to the installation location, align the opening of the lower flange plate of the H-shaped steel with the spiral pile, and then install it on the ground;

[0021] S4, installing the first clamping block and the second clamping block on both sides of the spiral pile respectively, connecting the first clamping block and the second clamping block together using nuts and screws, and preliminarily fixing the H-shaped steel;

[0022] S5, install the angle steel on the upper flange plate of the H-shaped steel, and fix the angle steel on the H-shaped steel using screws and nuts;

[0023] S6, unfold the air film material, cover it above the foundation pit, clamp the edge of the air film material between the angle steel and the upper flange plate, and fix it with screws;

[0024] S7, install waterproof cotton on the side of the H-shaped steel outside the air film membrane, and use sealant to seal the connection part to ensure waterproof performance;

[0025] S8, connect the air supply and pressurization system to inflate the air membrane.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects: The technical solution of the present invention significantly improves the stability and safety of the air film foundation in strong coastal wind environments through the synergistic effect of spiral piles, H-shaped steel and linkage mechanical mechanisms. The spiral piles provide high bearing capacity and pull-out resistance through the mechanical bite of the spiral blades and the soil, and the H-shaped steel withstands the tension and deformation of the air film through its high-strength structure. The linkage mechanism is automatically triggered when the pull-out force increases, the buffer mechanism offsets part of the pull-out force through the spring, and the reinforcement mechanism pushes the extension plate into the stratum, further enhancing the shear force of the spiral piles and offsetting the pull-out force. The solution of the present invention can not only dynamically adapt to pull-out forces of different intensities, but also provide continuous and stable support under extreme wind speeds, effectively preventing the air film from being overturned or torn, and ensuring the overall safety and reliability of the air film structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0028] Figure 1 It is a schematic diagram of the structure of the foundation pit air film foundation of the present invention arranged around the foundation pit;

[0029] Figure 2 It is a cross-sectional view of the foundation pit air film foundation of the present invention;

[0030] Figure 3 It is a schematic diagram of the structure of a single H-shaped steel of the present invention;

[0031] Figure 4 It is a structural schematic diagram of a rod member of the present invention;

[0032] Figure 5 It is a structural schematic diagram of the fixing mechanism of the present invention;

[0033] Figure 6 for Figure 2 A magnified image of point A;

[0034] Figure 7 It is a schematic structural diagram of the extension plate of the present invention;

[0035] Figure 8 It is a schematic diagram of the connection mechanism of the present invention.

[0036] The reference numerals represent:

[0037] 10, H-beam, 11, opening, 12, upper flange plate, 13, lower flange plate, 14, web plate,

[0038] 20. Screw piles,

[0039] 31, first clamping block, 32, second clamping block,

[0040] 41, rod, 42, abutment plate, 43, first spring,

[0041] 51, flange, 52, extension plate, 53, second spring, 54, connection block, 55, insertion portion, 56, opening,

[0042] 60, screws, 61, nuts, 62, angle steel, 63, rubber pads,

[0043] 70, waterproof cotton,

[0044] 80, drip bar,

[0045] 90, air film material. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the embodiment of the present invention clearer, the technical scheme of the embodiment of the present invention will be clearly and completely described in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention. The schematic implementation mode of the present invention and its description are only used to explain the present invention and are not intended to limit the present invention. It should be noted that the present invention is already in the actual research and development stage.

[0047] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. The words "include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0048] Traditional air membrane foundations usually rely on concrete or simple ground anchors, supported by soil friction or its own weight. However, in coastal areas, the sedimentary soil is soft and has a high water content, resulting in a significant drop in bearing capacity. Concrete foundations are prone to settlement or tilt, making it difficult to provide sufficient stability. At the same time, strong winds are frequent in coastal areas, and traditional foundations will be subject to huge pull-out forces under the action of strong winds. Simple bolt connections or ground anchors often cannot provide sufficient pull-out resistance, causing the air membrane to be overturned, posing serious safety hazards.

[0049] Embodiment 1:

[0050] like Figures 1 to 3As shown, a foundation pit air film foundation comprises an H-shaped steel 10 which is arranged around the foundation pit and connected end to end in sequence, the H-shaped steel 10 is composed of an upper flange plate 12, a lower flange plate 13 and a web plate 14, one end of the web plate 14 is connected to the upper flange plate 12, and the other end of the web plate 14 is connected to the lower flange plate 13 in contact with the ground, and the lower flange plate 13 is provided with an opening 11 and a fixing mechanism; the foundation pit air film foundation also comprises a spiral ground pile 20 which passes through the opening 11 and extends into the ground; the fixing mechanism is used to limit the spiral ground pile 20; the upper flange plate 12 is provided with a connecting mechanism for connecting the air film membrane material 90; the spiral ground pile 20 is a hollow structure, and a buffer mechanism and a reinforcement mechanism are provided inside it; when the H-shaped steel 10 is subjected to a pulling force, the fixing mechanism is driven to trigger the buffer mechanism to offset the pulling force, and at the same time the reinforcement mechanism is triggered to increase the shear force of the spiral ground pile 20 underground, thereby further offsetting the pulling force.

[0051] H-beam 10 has high strength and good bending resistance, can withstand large loads and deformation, and is an ideal choice for air membrane foundation. In order to adapt to the strong wind environment along the coast, H-beam 10 needs to be treated with anti-corrosion treatment, such as hot-dip galvanizing or spraying anti-corrosion coating, to enhance its corrosion resistance and extend its service life.

[0052] The spiral ground pile 20 is the core component of the foundation pit air film foundation, and a buffer mechanism and a reinforcement mechanism are arranged inside the spiral ground pile 20. The spiral ground pile 20 forms a mechanical bite with the soil through its spiral blades, providing high bearing capacity and pull-out resistance, and is particularly suitable for geological conditions with low bearing capacity of sedimentary soil in coastal areas. The buffer mechanism includes a rod 41 and a first spring 43 arranged inside the spiral ground pile 20. When the H-shaped steel 10 is subjected to a pull-out force, the rod 41 generates a reaction force by stretching the first spring 43 to offset part of the pull-out force. The reinforcement mechanism includes a flange 51 on the outer wall of the rod 41, a through hole on the outer wall of the spiral ground pile 20, and an extension plate 52. The extension plate 52 can gradually extend out of the through hole under the action of the pull-out force and be inserted into the stratum, further increasing the shear force of the spiral ground pile 20, thereby offsetting the pull-out force.

[0053] In strong wind weather along the coast, the air film will generate a huge pulling force under the action of strong wind, and the H-shaped steel 10 tends to be pulled up. At this time, the H-shaped steel 10 drives the fixing mechanism to move upward, triggering the buffer mechanism inside the spiral pile 20, and the first spring 43 generates a reaction force to offset part of the pulling force. At the same time, the flange 51 on the rod 41 pushes the extension plate 52 to gradually extend out of the through hole and insert into the stratum, increasing the shear force of the spiral pile 20 underground and further offsetting the pulling force.

[0054] In summary, this scheme provides an air membrane foundation for a foundation pit suitable for sedimentary soil in coastal areas with low bearing capacity and susceptible to strong winds. Through the combined design of spiral piles 20 and H-shaped steels 10, and the introduction of a linkage mechanical mechanism, rapid installation, high wind resistance and high construction efficiency are achieved.

[0055] like Figure 2 and Figure 5 As shown, the fixing mechanism includes a first clamping block 31 and a second clamping block 32. The first clamping block 31 is arranged on one side of the spiral pile 20, and the second clamping block 32 is arranged on the other side of the spiral pile 20. A nut 61 and a screw 60 are arranged between the first clamping block 31 and the second clamping block 32, and the nut 61 and the screw 60 connect the first clamping block 31 and the second clamping block 32.

[0056] After the lower flange plate 13 of the H-beam 10 passes through the opening 11 of the spiral pile 20, the first clamping block 31 and the second clamping block 32 are respectively located on both sides of the lower flange plate 13 of the H-beam 10. The construction personnel tighten the nut 61 and the screw 60 so that the first clamping block 31 and the second clamping block 32 apply a clamping force to the H-beam 10, and the H-beam 10 is firmly fixed on the spiral pile 20. It can provide sufficient clamping force to ensure the stability of the H-beam 10 under strong wind conditions, and the fixing strength of the H-beam 10 can be conveniently adjusted by adjusting the tightness of the nut 61 and the screw 60.

[0057] Preferably, the buffer mechanism includes a rod 41 arranged inside the spiral pile 20, a circular abutment plate 42 is provided at the end of the rod 41 away from the ground, the diameter of the abutment plate 42 is larger than the outer diameter of the spiral pile 20, and a first spring 43 is provided at the end of the rod 41 located underground, the first spring 43 connects the inner wall of the spiral pile 20 and the end of the rod 41; when the first clamping block 31 and the second clamping block 32 are moved upward by the pulling force of the H-shaped steel 10, they contact the abutment plate 42, and the first spring 43 generates a reaction force through the abutment plate 42.

[0058] When strong winds cause the air film to generate a pulling force and the H-beam 10 tends to be pulled up or displaced upward, the H-beam 10 drives the fixing mechanism (the first clamping block 31 and the second clamping block 32) to move upward. When the first clamping block 31 and the second clamping block 32 contact the abutment plate 42 at the end of the rod 41, the abutment plate 42 generates a reaction force by stretching the first spring 43 to offset part of the pulling force. Through the setting of the buffer mechanism, this solution can effectively slow down the displacement of the H-beam 10 when the pulling force increases, thereby improving the wind resistance and stability of the air film foundation. At the same time, the elastic force adjustment function of the first spring 43 enables the buffer mechanism to adapt to pulling forces of different intensities, and has good adaptability and reliability.

[0059] During the installation process, since the opening diameter of the H-beam 10 is larger than the diameter of the backing plate 42, the construction sequence needs to be specially adjusted. First, screw the spiral pile 20 into the ground to ensure that its verticality and depth meet the design requirements. Next, align the opening 11 on the lower flange plate 13 of the H-beam 10 with the installed spiral pile 20, so that the spiral pile 20 passes through the opening to achieve preliminary positioning. Then, install the backing plate 4 above the spiral pile 20. This installation sequence ensures that the backing plate 42 can effectively press on the H-beam 10, and provide continuous clamping force through the spring mechanism to prevent the H-beam 10 from being pulled up under strong winds. At the same time, it allows the backing plate 42 to generate a reaction force through the spring mechanism when the pull-out force increases, offsetting part of the pull-out force, thereby improving the stability and wind resistance of the air membrane foundation.

[0060] like Figure 2 , Figure 4 and Figure 6 As shown, the reinforcing mechanism includes a flange 51 arranged on the outer wall of the rod 41 and a through hole arranged on the outer wall of the spiral pile 20; along the extending direction of the spiral pile 20, the thickness of the flange 51 gradually increases; an extension plate 52 is also provided in the spiral pile 20, and a connecting block 54 is provided on the extension plate 52, and a second spring 53 connected to the inner wall of the spiral pile 20 is provided between the connecting block 54 and the inner wall of the spiral pile 20; the extension plate 52 can pass through the through hole and extend into the formation; when the second spring 53 is in the initial state, one end of the extension plate 52 away from the inner wall of the spiral pile 20 contacts the non-flange section of the rod 41; when the rod 41 moves upward, the flange 51 causes the extension plate 52 to gradually extend out of the through hole and insert into the formation.

[0061] After the extension plate 52 is inserted into the ground, the compression and friction with the surrounding soil significantly enhance the pull-out resistance of the spiral pile 20. Under the action of the pull-out force, the extension plate 52 extends and embeds into the soil, forming a larger force-bearing area, dispersing the pull-out force into a larger soil volume, thereby effectively offsetting the pull-out force and stabilizing the spiral pile 20.

[0062] When the extension plate 52 is in the initial state, blocking the through hole can effectively prevent soil, debris or moisture from entering the screw pile 20 and avoid damaging the internal structure. The shape of the through hole matches the extension plate 52, ensuring that the extension plate 52 can be smoothly extended and retracted, while providing good sealing performance in the initial state.

[0063] The mechanism automatically extends the extension plate 52 and inserts it into the ground when the pull-out force increases by means of mechanical linkage, thereby significantly increasing the shear force of the spiral pile 20 and further offsetting the pull-out force. The thickness of the flange 51 gradually increases from the upper end to the lower end of the rod 41, which means that when the rod 41 moves upward, the thickness of the flange 51 will gradually increase, and the force applied to the extension plate 52 will also gradually increase. The extension plate 52 is arranged perpendicular to the axis of the spiral pile 20, is located inside the spiral pile 20, and passes through the through hole on the outer wall of the spiral pile 20. One end of the extension plate 52 contacts the non-flange section of the rod 41, and the other end can extend out of the spiral pile 20 through the through hole and insert into the ground. As the rod 41 continues to rise, the force applied by the flange 51 to the extension plate 52 gradually increases, pushing the extension plate 52 to gradually extend out of the through hole and insert into the ground, thereby significantly increasing the shear force of the spiral pile 20 and offsetting the pull-out force. The extension amount of the extension plate 52 is proportional to the magnitude of the pulling force. The greater the pulling force, the more the extension plate 52 extends, and the greater the shear force, thereby achieving adaptive adjustment of pulling forces of different strengths. The mechanism has a simple structure, few parts, is easy to manufacture and maintain, and realizes automatic adjustment through mechanical linkage, with high reliability and stability.

[0064] like Figure 2 and Figure 8 As shown, the connecting mechanism includes an angle steel 62, a screw 60 and a nut 61 arranged on the upper flange plate 12. The angle steel 62 is connected by a vertical section and a parallel section. The screw 60 passes through the parallel section and the upper flange plate 12 and is fixed by the nut 61. The air film membrane material 90 is clamped between the angle steel 62 and the upper flange plate 12.

[0065] The angle steel 62 is connected by a vertical section and a parallel section to form an "L" shaped structure. The vertical section is vertically connected to the upper flange plate 12 of the H-shaped steel 10, and the parallel section is in contact with the air film material 90. The specifications of the screw 60 and the nut 61 should be selected according to the thickness and stress of the air film material 90 to ensure the connection strength.

[0066] Embodiment 2:

[0067] like Figure 2 As shown, each flange 51 and the through hole matched with the flange 51, the rod 41, the connecting block 54, and the second spring 53 are combined into a reinforcement component, and multiple reinforcement components are arranged in the spiral pile 20. The combination of multiple reinforcement components realizes a multi-level reinforcement function, which can automatically adjust the extension amount of the extension plate 52 according to the size of the pulling force, adapt to the pulling forces of different strengths, and improve the wind resistance of the air film foundation.

[0068] Preferably, waterproof cotton 70 is provided between the upper flange plate 12 and the lower flange plate 13. The waterproof cotton 70 is provided on the side of the H-shaped steel 10 outside the air film membrane 90. The waterproof cotton 70 is used to close the space where the upper flange plate 12 and the lower flange plate 13 are connected to the outside world. The function of the waterproof cotton 70 is to close the space where the H-shaped steel 10 is connected to the outside world, and prevent rainwater and moisture from penetrating into the inside of the H-shaped steel 10 from the connection part. When the air film membrane 90 is fixed on the upper flange plate 12 of the H-shaped steel 10, the waterproof cotton 70 is clamped between the angle steel 62, the rubber pad 63 and the H-shaped steel 10 to form a sealing structure, which effectively blocks the intrusion of external moisture. The waterproof cotton 70 not only protects the H-shaped steel 10 from corrosion and prolongs its service life, but also enhances the durability and reliability of the entire air film foundation. Especially in the humid coastal environment, its waterproof and moisture-proof effect is particularly significant.

[0069] Embodiment 3:

[0070] like Figure 7 As shown, along the insertion direction of the screw pile 20 , the cross-section of the extension plate 52 is a minor arc shape, and an opening 56 matching the non-flange section of the rod 41 is provided on one side of the extension plate 52 close to the rod 41 .

[0071] The design of the inferior arc section and the opening 56 effectively reduces the friction and stagnation between the extension plate 52 and the rod 41, ensures the smooth operation and rapid response of the linkage mechanism, and improves the wind resistance and stability of the air film foundation. The arc design can increase the contact area between the extension plate 52 and the soil, improve the pull-out resistance, reduce stress concentration, and extend the service life of the extension plate 52.

[0072] An insertion portion 55 is provided at one end of the extension section extending into the ground, and the thickness of the insertion portion 55 gradually decreases. The gradually decreasing thickness of the insertion portion 55 can reduce the resistance when inserted into the ground, so that the extension plate 52 can be inserted into the soil more easily. At the same time, the tip design of the insertion portion 55 can reduce the disturbance to the soil, avoid damaging the soil structure, and affect the bearing capacity of the spiral pile 20. In addition, the gradual thickness design can improve the strength and stability of the insertion portion 55, and prevent the insertion portion 55 from breaking or deforming during the force application process.

[0073] like Figure 8 As shown, a rubber pad 63 is connected between the parallel section and the upper flange plate 12, and the rubber pad 63 is connected to the parallel section.

[0074] The rubber pad 63 is sandwiched between the parallel section of the angle steel 62 and the upper flange plate 12 of the H-shaped steel 10, playing a role in buffering and vibration reduction, and also enhancing the sealing of the connection. The rubber pad 63 can effectively buffer the vibration and impact of the air film membrane 90 under the action of strong wind, reduce the stress concentration on the connection part, and extend the service life of the connection. At the same time, the sealing performance of the rubber pad 63 can prevent rainwater and the like from penetrating from the connection part, protect the H-shaped steel 10 and the air film membrane 90 from corrosion, and extend their service life.

[0075] like Figure 1 As shown, a drip strip 80 can also be designed on the upper flange plate 12 outside the air film membrane 90 to effectively guide rainwater to flow down along the drip strip 80, and prevent rainwater from penetrating into the interior along the joint between the upper flange plate 12 and the air film membrane 90. The drip strip 80 can effectively prevent rainwater from accumulating on the upper flange plate 12, reduce the erosion of rainwater on the connection parts and the H-shaped steel 10, and thus improve the overall waterproof performance and durability of the air film.

[0076] This scheme also includes a construction method of a foundation pit air film foundation, the foundation pit air film foundation structure is the above-mentioned air film foundation, and the construction method of the foundation pit air film foundation includes:

[0077] S1, clear the debris on the construction site, level the site, and ensure that there are no obstacles in the construction area; according to the design drawings, lay out the lines and determine the size and shape of the foundation pit and the layout of the H-shaped steel 10 and the spiral piles 20.

[0078] S2, mark the installation position of the spiral pile 20 around the foundation pit to ensure the accuracy of the position.

[0079] S3, use the screw pile 20 screwing device to screw the screw pile 20 into the ground according to the marked position; control the verticality of the screw pile 20 to ensure that it is perpendicular to the ground; perform a pull-out force test on the screw pile 20 to ensure that its bearing capacity meets the design requirements.

[0080] S4, move the H-shaped steel 10 to the installation position, align the opening 11 on the lower flange plate 13 of the H-shaped steel 10 with the spiral pile 20 and lower it to the ground; install the first clamping block 31 and the second clamping block 32 on both sides of the spiral pile 20 respectively; use the nut 61 and the screw 60 to connect the first clamping block 31 and the second clamping block 32 together, and preliminarily fix the H-shaped steel 10.

[0081] S5, install the angle steel 62 on the upper flange plate 12 of the H-shaped steel 10; use the screw 60 and the nut 61 to fix the angle steel 62 on the H-shaped steel 10. Install the rubber pad 63 between the parallel section and the upper flange plate 12.

[0082] S6, unfold the air film material 90 to cover the top of the foundation pit; clamp the edge of the air film material 90 between the angle steel 62 and the upper flange plate 12, and fix it with screws 60; ensure that the air film material 90 is tensioned and has no wrinkles.

[0083] S7, installing waterproof cotton 70 on one side of the H-shaped steel 10 outside the air film membrane 90; using sealant to seal the connection part to ensure waterproof performance.

[0084] S8, connect the air supply and pressurization system to inflate the air membrane.

[0085] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them; although the present disclosure has been described in detail with reference to the aforementioned embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present disclosure. The following points need to be explained: In the accompanying drawings of the embodiments of the present invention, only the structures involved in the embodiments of the present invention are involved, and other structures can refer to the general design. In the absence of conflict, the features in the same embodiment and different embodiments of the present invention can be combined with each other. The above is only an exemplary implementation of the present invention, and is not used to limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the attached claims.

Claims

1. A foundation pit air film foundation, comprising H-shaped steel (10) arranged around the foundation pit and connected end to end, the H-shaped steel (10) is composed of an upper flange plate (12), a lower flange plate (13) and a web plate (14), one end of the web plate (14) is connected to the upper flange plate (12), and the other end of the web plate (14) is connected to the lower flange plate (13) in contact with the ground, characterized in that: The lower flange plate (13) is provided with an opening (11) and a fixing mechanism; the foundation pit air film foundation also includes a spiral ground pile (20) passing through the opening (11) and extending into the ground; the fixing mechanism is used to limit the spiral ground pile (20); the upper flange plate (12) is provided with a connecting mechanism for connecting the air film membrane material (90); The spiral ground pile (20) is of a hollow structure, and a buffer mechanism and a reinforcing mechanism are arranged inside the spiral ground pile; when the H-shaped steel (10) is subjected to a pulling force, the fixing mechanism is driven to trigger the buffer mechanism to offset the pulling force, and the reinforcing mechanism is triggered to further offset the pulling force.

2. The foundation pit air film foundation according to claim 1, characterized in that: The fixing mechanism comprises a first clamping block (31) and a second clamping block (32); the first clamping block (31) is arranged on one side of the spiral ground pile (20), and the second clamping block (32) is arranged on the other side of the spiral ground pile (20); a nut (61) and a screw (60) are arranged between the first clamping block (31) and the second clamping block (32); the nut (61) and the screw (60) connect the first clamping block (31) and the second clamping block (32).

3. The air film foundation for a foundation pit according to claim 2, characterized in that: The buffer mechanism comprises a rod (41) arranged inside the spiral pile (20); a circular abutment plate (42) is arranged at one end of the rod (41) away from the ground, the diameter of the abutment plate (42) is larger than the outer diameter of the spiral pile (20); a first spring (43) is arranged at one end of the rod (41) located underground, the first spring (43) connects the inner wall of the spiral pile (20) and the end of the rod (41); when the first clamping block (31) and the second clamping block (32) are moved upward by the pulling force of the H-shaped steel (10), they contact the abutment plate (42), and the first spring (43) generates a reaction force through the abutment plate (42).

4. The foundation pit air film foundation according to claim 3, characterized in that: The reinforcing mechanism comprises a flange (51) provided on the outer wall of the rod (41) and a through hole provided on the outer wall of the spiral pile (20); along the extending direction of the spiral pile (20), the thickness of the flange (51) gradually increases; The spiral pile (20) is further provided with an extension plate (52), on which a connection block (54) is provided, and between the connection block (54) and the inner wall of the spiral pile (20), a second spring (53) is provided to connect the two. The extension plate (52) can pass through the through hole and extend into the stratum. When the second spring (53) is in an initial state, one end of the extension plate (52) away from the inner wall of the spiral pile (20) contacts the non-flange section of the rod (41). When the rod (41) moves upward, the flange (51) causes the extension plate (52) to gradually extend out of the through hole and be inserted into the stratum.

5. The foundation pit air film foundation according to claim 4, characterized in that: Along the insertion direction of the screw pile (20), the cross-sectional shape of the extension plate (52) is a minor arc shape, and an opening (56) matching the non-flange section of the rod (41) is provided on a side of the extension plate (52) close to the rod (41).

6. The foundation pit air film foundation according to claim 5, characterized in that: Each flange (51) and the through hole matched with the flange (51), the rod (41), the connecting block (54), and the second spring (53) are combined into a reinforcement component, and a plurality of reinforcement components are arranged in the spiral pile (20).

7. The foundation pit air film foundation according to claim 6, characterized in that: A waterproof cotton (70) is provided between the upper flange plate (12) and the lower flange plate (13). The waterproof cotton (70) is provided on a side of the H-shaped steel (10) outside the air film membrane (90). The waterproof cotton (70) is used to seal the space between the upper flange plate (12) and the lower flange plate (13) that is connected to the outside world.

8. The foundation pit air film foundation according to claim 7, characterized in that: The connecting mechanism comprises an angle steel (62), a screw (60) and a nut (61) arranged on the upper flange plate (12); the angle steel (62) is formed by connecting a vertical section and a parallel section; the screw (60) penetrates the parallel section and the upper flange plate (12) and is fixed by the nut (61); the air film material (90) is clamped between the angle steel (62) and the upper flange plate (12).

9. The foundation pit air film foundation according to claim 8, characterized in that: A rubber pad (63) is also connected between the parallel section and the upper flange plate (12), and the rubber pad (63) is connected to the parallel section.

10. A construction method for a foundation pit air film foundation, characterized in that: The foundation pit air film foundation is the foundation pit air film foundation described in claim 9, and the construction method of the foundation pit air film foundation comprises: S1, marking the installation positions of the spiral piles (20) around the foundation pit according to the design drawings; S2, using a screw-in device to screw the screw pile (20) into the ground at the marked position; S3, moving the H-shaped steel (10) to the installation position, aligning the opening (11) of the lower flange plate (13) of the H-shaped steel (10) with the screw pile (20), and then installing it on the ground; S4, installing the first clamping block (31) and the second clamping block (32) on both sides of the spiral pile (20) respectively, and connecting the first clamping block (31) and the second clamping block (32) together using the nut (61) and the screw (60), so as to preliminarily fix the H-shaped steel (10); S5, installing an angle steel (62) on the upper flange plate (12) of the H-shaped steel (10), and fixing the angle steel (62) on the H-shaped steel (10) using the screws (60) and nuts (61); S6, unfold the air film material (90) to cover the top of the foundation pit, clamp the edge of the air film material (90) between the angle steel (62) and the upper flange plate (12), and fix it with the screws (60); S7, installing the waterproof cotton (70) on the side of the H-shaped steel (10) outside the air film material (90); S8, connecting the air supply and pressurization system to inflate the air film material (90).

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