Device for sealing bottom of foundation pit by adopting spiral anchor pile

Abstract

A device for sealing the bottom of a foundation pit through spiral anchor piles comprises a foundation pit continuous wall arranged on the side wall of the foundation pit, the spiral anchor piles are vertically driven into the bottom of the foundation pit and tightly attached to the foundation pit continuous wall, a waterproof concrete cushion layer is poured at the bottom of the foundation pit, a bottom beam is arranged on the waterproof concrete cushion layer, and concrete is poured into the bottom beam to form a concrete bottom plate. The upper portion of the spiral anchor and the concrete bottom plate of the foundation pit are poured together, on one hand, the anti-pulling capacity of the spiral anchor disc can be fully exerted, the stability of the foundation pit is greatly improved, and damage of confined water to the bottom of the foundation pit is reduced; on the other hand, on-site wet operation can be greatly reduced, the construction period is effectively shortened, environmental pollution and labor requirements are reduced, and obvious environmental benefits and social benefits are achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of foundation pit support, and specifically relates to a device for sealing the bottom of a foundation pit by using spiral anchor piles. Background Art

[0002] In recent years, with the increase in the development of underground space, the excavation area and depth of foundation pit projects are constantly increasing. Construction sites with favorable terrain conditions are becoming saturated, and the number of complex deep foundation pit projects under adverse hydrogeological conditions is increasing. Moreover, the impact of deep foundation pit confined water on foundation pit projects cannot be ignored. Confined water is generally distributed in loose strata. Due to its deep burial depth, high water head, and large water volume, it poses a great threat to the bottom plate of deep foundation pit projects and deep foundation pit construction. When there is a confined water layer, as the excavation depth increases, the thickness of the impermeable layer under the base becomes thinner and thinner. When the residual soil layer from the bottom of the foundation pit to the top plate of the confined aquifer cannot balance the top support force of the confined aquifer, the confined water may break through the bottom of the pit and surge and bulge, causing the foundation pit retaining structure to become unstable, and eventually causing serious foundation pit engineering accidents. With the increase in the excavation depth of the foundation pit, the problem of confined water hazards in deep foundation pit projects has become increasingly prominent. Therefore, choosing the correct and reasonable confined water control technology under complex hydrogeological conditions is the key to achieving safe foundation pit construction.

[0003] For deep foundation pit projects affected by pressurized water, "bottom sealing" technical means can be used. Bottom sealing reinforcement measures are generally applicable to situations where the weight of the overlying soil is slightly less than the buoyancy of the pressurized water when excavating to the base elevation, and the local elevator shaft and other deep areas that cannot meet the stability requirements of pressurized water, as well as small or narrow long foundation pits with obvious spatial effects. In the past, dense engineering piles were often set inside the foundation pit to achieve the purpose of resisting the pressurized water head. This method is more difficult to construct, less economical, and takes a longer construction period. Summary of the invention

[0004] The technical problem to be solved by the utility model is to overcome the deficiencies of the above-mentioned prior art and provide a device for sealing the bottom of a foundation pit using spiral anchor piles, which has higher strength, good safety and stability, reduces the construction period and has higher construction efficiency.

[0005] The technical solution adopted to solve the above technical problems is: a device for sealing the bottom of a foundation pit using spiral anchor piles, comprising a continuous foundation pit wall arranged on the side wall of the foundation pit, a plurality of spiral anchor piles are vertically driven into the bottom of the foundation pit close to the continuous foundation pit wall, a waterproof concrete cushion layer is poured at the bottom of the foundation pit, a bottom beam is arranged on the waterproof concrete cushion layer, concrete is poured inside the bottom beam to form a concrete bottom plate, and the top of the spiral anchor pile extends into the bottom beam and is poured in the concrete bottom plate.

[0006] The spiral anchor piles of the utility model are arranged in a plurality of rows and columns at the bottom of the foundation pit.

[0007] The spiral anchor piles of the utility model are arranged in a staggered manner between adjacent columns or adjacent rows.

[0008] The spiral anchor pile of the utility model has the following characteristics: the anchor rod is a hollow structure, a pressure plate is arranged on the top of the anchor rod, the prestressed steel bar passes through the pressure plate and extends into the bottom of the anchor rod and is welded to the bottom, the upper end of the prestressed steel bar is fastened to the pressure plate by a nut, and a plurality of groups of spiral anchor plates are arranged at intervals outside the anchor rod.

[0009] The spiral anchor plates of the utility model are arranged outside the anchor rod at equal intervals.

[0010] The pressure plate of the utility model is a circular or rectangular structure.

[0011] The lower end of the anchor rod of the utility model is a conical structure.

[0012] Compared with the prior art, the utility model has the following advantages:

[0013] (1) Compared with the traditional base treatment method, the foundation pit bottom sealing device of the utility model saves more materials, has higher strength, and is safer and more stable; it adopts a spiral anchor structure, which is simple to process and manufacture, has low construction difficulty, can save labor, shorten the construction period, and has higher construction efficiency.

[0014] (2) The prestressed spiral anchor structure adopted by the utility model combines the prestressed steel bar with the spiral anchor plate to make the stress form of the structure more diversified. The joint stress of the two improves the strength of the structure, making the structure safer and more reliable.

[0015] (3) The utility model casts the upper part of the spiral anchor together with the concrete bottom plate of the foundation pit. On the one hand, it can give full play to the pull-out resistance of the spiral anchor plate, greatly improve the stability of the foundation pit, and reduce the harm of pressurized water to the bottom of the foundation pit. On the other hand, it can greatly reduce on-site wet operations, effectively shorten the construction period, reduce environmental pollution and labor demand, and has obvious environmental and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a front cross-sectional view of the foundation pit of the utility model.

[0017] Figure 2 It is a side sectional view of the foundation pit of the utility model.

[0018] Figure 3 It is a foundation pit plan of the utility model.

[0019] Figure 4 yes Figure 1 Schematic diagram of the structure of the middle spiral anchor pile 4.

[0020] In the figure: 1. continuous wall of foundation pit; 2. bottom beam; 3. concrete bottom plate; 4. spiral anchor pile; 5. spiral anchor plate; 4-1. prestressed steel bar; 4-2. nut; 4-3. pressure plate; 4-4. anchor rod; 4-5. spiral anchor plate. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited to these embodiments.

[0022] Example 1

[0023] exist Figures 1 to 4 In the present invention, a device for sealing the bottom of a foundation pit using spiral anchor piles is involved, comprising a continuous foundation pit wall 1 arranged on the side wall of the foundation pit, and a plurality of spiral anchor piles 4 are vertically driven into the bottom of the foundation pit close to the continuous foundation pit wall 1. In the present embodiment, the spiral anchor piles 4 are arranged in a plurality of rows and columns at the bottom of the foundation pit. In order to balance the buoyancy of the pressurized aquifer, the spiral anchor piles 4 are staggered between adjacent columns or rows. The distance between adjacent spiral anchor piles 4 and the number of spiral anchor piles 4 are determined according to actual working conditions. Specifically, the spiral anchor pile 4 is composed of prestressed steel bars 4-1, nuts 4-2, pressure plates 4-3, anchor rods 4-4, and spiral anchor plates 4-5. The anchor rod 4-4 is a hollow structure. A pressure plate 4-3 is fixedly installed on the top of the anchor rod 4-4. The pressure plate 4-3 is a rectangular structure or a circular structure, which mainly increases the contact area between the upper part of the spiral anchor pile 4 and the concrete base plate 3. The prestressed steel bars 4-1 pass through the pressure plate 4-3 and extend into the bottom of the anchor rod 4-4 and are welded to the bottom. The upper end of the prestressed steel bars 4-1 is fastened to the pressure plate 4-3 by nuts 4-2. Several groups of spiral anchor plates 4-5 are arranged at intervals outside the anchor rod 4-4. In this embodiment, the spiral anchor plates 4-5 are arranged at equal intervals outside the anchor rod 4-4. In order to facilitate driving into the bottom of the foundation pit, the lower end of the anchor rod 4-4 is a conical structure. A waterproof concrete cushion layer 5 is poured at the bottom of the foundation pit, a bottom beam 2 is arranged on the waterproof concrete cushion layer 5, concrete is poured inside the bottom beam 2 to form a concrete bottom plate 3, the top of the spiral anchor pile 4 extends into the bottom beam 2 and is poured in the concrete bottom plate 3, and it is necessary to ensure that the prestressed steel bar 4-1 and the pressure plate 4-3 are poured in the concrete bottom plate 3. The device sets a corresponding number of spiral anchor plates 4-5 according to the actual working conditions. The diameter of the spiral anchor plate 4-5 and the prestressed steel bar 4-1 are used to balance the buoyancy of the pressure-bearing aquifer. The top of the spiral anchor pile 4 is integrally cast with the foundation pit concrete bottom plate 3 to improve the integrity of the structure. The buoyancy of the pressure-bearing aquifer first acts on the foundation pit concrete bottom plate 3. Because the foundation pit concrete bottom plate 3 and the spiral anchor pile 4 are integrally cast, the buoyancy is transmitted to the spiral anchor pile 4. The spiral anchor pile 4 relies on the pull-out resistance of the prestressed steel bar 4-1 and the spiral anchor plate 4-5 to balance the structure under the action of the buoyancy of the pressure-bearing aquifer.

Claims

1. A device for sealing the bottom of a foundation pit using spiral anchor piles, characterized in that: The invention comprises a continuous foundation pit wall (1) arranged on the side wall of a foundation pit, a plurality of spiral anchor piles (4) are vertically driven into the bottom of the foundation pit close to the continuous foundation pit wall (1), a waterproof concrete cushion layer (5) is poured at the bottom of the foundation pit, a bottom beam (2) is arranged on the waterproof concrete cushion layer (5), concrete is poured inside the bottom beam (2) to form a concrete bottom plate (3), and the tops of the spiral anchor piles (4) extend into the bottom beam (2) and are poured into the concrete bottom plate (3).

2. The device for sealing the bottom of a foundation pit using spiral anchor piles according to claim 1, characterized in that: The spiral anchor piles (4) are arranged in a plurality of rows and columns at the bottom of the foundation pit.

3. The device for sealing the bottom of a foundation pit using spiral anchor piles according to claim 2, characterized in that: The spiral anchor piles (4) are arranged alternately between adjacent columns or rows.

4. The device for sealing the bottom of a foundation pit using spiral anchor piles according to claim 1, characterized in that The spiral anchor pile (4) is as follows: the anchor rod (4-4) is a hollow structure, a pressure plate (4-3) is arranged on the top of the anchor rod (4-4), a prestressed steel bar (4-1) passes through the pressure plate (4-3) and extends into the bottom of the anchor rod (4-4) and is welded to the bottom, the upper end of the prestressed steel bar (4-1) is fastened to the pressure plate (4-3) through a nut (4-2), and a plurality of groups of spiral anchor plates (4-5) are arranged at intervals outside the anchor rod (4-4).

5. The device for sealing the bottom of a foundation pit using spiral anchor piles according to claim 4 is characterized in that: The spiral anchor plates (4-5) are arranged outside the anchor rod (4-4) at equal intervals.

6. The device for sealing the bottom of a foundation pit using spiral anchor piles according to claim 4, characterized in that: The pressure plate (4-3) is a circular or rectangular structure.

7. The device for sealing the bottom of a foundation pit using spiral anchor piles according to claim 4, characterized in that: The lower end of the anchor rod (4-4) is a conical structure.

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