Asymmetric special-shaped foundation pit support structure and construction method thereof

Abstract

The invention relates to an asymmetric special-shaped foundation pit enclosure structure and a construction method thereof.The asymmetric special-shaped foundation pit enclosure structure is arranged on the outer side of an inner foundation pit and comprises an enclosure pile structure, an extrusion soil body layer and a flange plate enclosure structure, and the enclosure pile structure comprises a plurality of enclosure piles; the fender piles are sequentially arranged and pre-embedded along the periphery of the inner foundation pit, the outer side of the fender pile structure is filled with an extrusion soil body layer, a flange plate enclosure structure is arranged on the periphery of the outer side of the extrusion soil body layer, the flange plate enclosure structure comprises a plurality of flange plates connected through buckles, and each flange plate comprises an embedded plate, a plate pile and a plate end buckle. The embedded plate is welded to the head end of the plate pile, the tail end of the plate pile is welded to the plate end buckle, and the embedded plate is clamped in a cavity of the plate end buckle; the invention aims to solve the problems that a large-scale horizontal inner supporting structure is used in an inner foundation pit, local plasticity of an enclosure structure of the inner foundation pit and a soil body on the inner side of the inner foundation pit is easily caused, and the stability and safety of the inner foundation pit are influenced.

Description

Technical Field

[0001] The invention relates to the technical field of civil engineering, and in particular to an asymmetric special-shaped foundation pit retaining structure and a construction method thereof. Background Art

[0002] With the expansion of urbanization, the forms of buildings have become more and more complex, and the area and depth of foundation pits have also changed accordingly, including the pit-in-pit structure of deep and large foundation pits. Such special-shaped foundation pits often face the problem of asymmetric excavation of the outer and inner foundation pits, which increases the safety risks of construction.

[0003] In order to solve the problem of excavation of asymmetric and special-shaped foundation pits, the current projects mainly use retaining piles in the inner and outer foundation pits in combination with retaining structures with different levels of internal support to prevent the soil around the foundation pit from deforming inward due to the pressure of the outer soil. However, since the horizontal internal support structure is generally made of reinforced concrete or large-diameter steel pipes, and the inner foundation pit is often smaller than the outer foundation pit, the horizontal internal support structure using reinforced concrete or large-diameter steel pipes will cause the retaining piles in the inner foundation pit to become partially plastic and unable to be disassembled and reused, and even cause the soil around the inner foundation pit to become partially plastic, thus affecting the self-stability of the foundation pit and posing a hidden danger to the stability of the foundation pit structure.

[0004] Therefore, it is hoped that an asymmetric special-shaped foundation pit retaining structure and a construction method thereof can solve the problems existing in the prior art. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides an asymmetric and special-shaped foundation pit retaining structure and a construction method thereof. The retaining structure of the asymmetric and special-shaped foundation pit is formed by arranging flange plate structures and retaining piles around the inner foundation pit, aiming to solve the problem that the use of a large-scale horizontal internal support structure in the inner foundation pit easily causes local plasticity of the retaining structure of the inner foundation pit and the soil inside the inner foundation pit, thereby affecting the stability and safety of the inner foundation pit.

[0007] (II) Technical solution

[0008] In order to achieve the above-mentioned object, the main technical scheme adopted by the present invention includes: providing an asymmetric special-shaped foundation pit retaining structure, the asymmetric special-shaped foundation pit retaining structure is arranged on the outside of the inner foundation pit, and the asymmetric special-shaped foundation pit retaining structure includes a retaining pile structure, an extruded soil layer and a flange plate retaining structure;

[0009] The retaining pile structure comprises a plurality of retaining piles, which are pre-buried in sequence along the periphery of the inner foundation pit, an extruded soil layer is filled on the outside of the retaining pile structure, and a flange plate retaining structure is arranged around the outside of the extruded soil layer;

[0010] The flange plate enclosure structure includes a plurality of flange plates connected by snaps, and the flange plates include: an embedded plate, a sheet pile and a plate end snap. The embedded plate is welded to the head end of the sheet pile, and the tail end of the sheet pile is welded to the plate end snap. The embedded plate is clamped in the cavity of the plate end snap, so that the flange plates are connected to each other.

[0011] The present invention arranges retaining pile structures and flange plate structures around the internal foundation pit in an asymmetric special-shaped foundation pit, and uses the flange plate structure and the retaining piles as a common load-bearing body for the internal foundation pit to bear the external soil pressure, thereby transmitting the soil pressure outside the internal foundation pit to the soil layer at the embedded end of the retaining piles, and utilizing the soil squeezing effect around the retaining piles to improve the self-stabilizing ability of the soil around the retaining piles, so as to overcome the problem of insufficient stability and safety caused by using a large-scale horizontal internal support structure in the internal foundation pit.

[0012] Preferably, the retaining piles are cylindrical, and the length and diameter of the retaining piles are determined according to the shape, length and depth requirements of the inner foundation pit.

[0013] Preferably, the sheet pile is provided with soil squeezing through holes, the soil squeezing through holes are circular, and the soil squeezing through holes are evenly arranged side by side in the sheet pile.

[0014] Preferably, the sheet pile comprises holes, the holes are arranged on the side of the tail end of the sheet pile, and the holes are arranged at intervals of a first preset distance along the length direction of the sheet pile.

[0015] Preferably, the sheet pile further comprises a water injection pipe, the water injection pipe is arranged in the hole, and water outlets are arranged on the water injection pipe at intervals of a second preset distance.

[0016] Preferably, the embedded plate is arranged perpendicular to the sheet piles, and the welding position between the embedded plate and the head end of the sheet pile is located on the center line of the embedded plate.

[0017] Preferably, the plate end buckle is rectangular as a whole, and a notch is provided at the corresponding side end of the plate end buckle connected to the sheet pile, for inserting the sheet pile welded to the embedded plate into the cavity of the plate end buckle.

[0018] A construction method for an asymmetric special-shaped foundation pit retaining structure comprises the following steps:

[0019] Step S01: selecting the retaining piles according to the shape, length and depth of the inner foundation pit of the asymmetric special-shaped foundation pit, and vertically pressing a plurality of the retaining piles into the soil in sequence around the inner foundation pit to form a retaining pile structure of the inner foundation pit;

[0020] Step S02: setting the thickness of the extruded soil layer according to the area of ​​the asymmetric special-shaped foundation pit;

[0021] Step S03: The outer side of the extruded soil layer is set as the position of the flange plate enclosure structure, and one of the flange plates is vertically statically pressed into the soil by a static pressure method, and after the pile pressing is completed, the embedded plate of another flange plate is clamped in the plate end buckle cavity of the flange plate that has been completed by the pile pressing to achieve mutual connection between the flange plates, and the other connected flange plate is vertically statically pressed into the soil, and multiple flange plates are sequentially pressed into the set position of the flange plate enclosure structure to form the flange plate enclosure structure;

[0022] Step S04: After the excavation of the special-shaped foundation pit is completed, water is injected into the water injection pipe inserted in the flange plate, the water outlet valve of the water injection pipe is opened, and water penetrates into the soil around the flange plate to lubricate the soil around the flange plate and the retaining piles. After the water injection is completed, the flange plates are pulled out one by one.

[0023] (III) Beneficial effects

[0024] The beneficial effects of the present invention are as follows: the flange plate type retaining structure in the asymmetric special-shaped foundation pit retaining structure of the present invention is spliced ​​by single flange plates, and is suitable for various special-shaped internal foundation pits; the flange plate structure can both block water and retain soil, greatly reducing the diameter and length of the retaining piles used in the internal foundation pit; the flange plate structure and the retaining piles serve as common load-bearing bodies for the internal foundation pit to bear the external soil pressure, and transfer the soil pressure outside the internal foundation pit to the soil layer at the embedded end of the retaining piles, and utilize the soil squeezing effect around the retaining piles to improve the self-stabilizing ability of the soil around the retaining piles; the flange plate structure and the retaining pile structure strengthen the stability of the inner foundation pit corner while jointly restraining the overall deformation of the foundation pit, thereby ensuring the stability of the entire pit-in-pit system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a top view of the asymmetric special-shaped foundation pit retaining structure of the present invention;

[0026] Figure 2 is a top view of a single flange plate structure of the present invention;

[0027] Figure 3 is a side view of a sheet pile of the present invention;

[0028] Figure 4 It is a side view of the water injection pipe of the present invention.

[0029] [Reference Signs]

[0030] 1: sheet pile; 2: soil extrusion hole; 3: channel; 4: water injection pipe; 5: plate end buckle; 6: flange plate; 7: retaining pile structure; 8: flange plate retaining structure; 9: extruded soil layer; 10: embedded plate; 11: water outlet. DETAILED DESCRIPTION

[0031] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below in conjunction with the accompanying drawings through specific embodiments. Figure 1 The orientation is used as a reference.

[0032] The asymmetric and special-shaped foundation pit retaining structure and the construction method thereof proposed in the embodiments of the present invention arrange flange plate structures and retaining piles around the inner foundation pit to form a retaining structure for the asymmetric and special-shaped foundation pit, aiming to solve the problem that the use of a large-scale horizontal internal support structure in the inner foundation pit easily causes local plasticity of the retaining structure of the inner foundation pit and the soil inside the inner foundation pit, thereby affecting the stability and safety of the inner foundation pit.

[0033] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0034] Embodiment 1:

[0035] In the construction of asymmetric and special-shaped foundation pits, it is necessary not only to ensure the stability of the external foundation pit, but also to ensure that the inner foundation pit always maintains the design style during the excavation process and is not filled with the outer soil. Therefore, it is necessary to design a more convenient and effective pit-in-pit retaining structure that can give full play to the retaining performance of the inner and outer foundation pit retaining structures.

[0036] Reference Figure 1-Figure 4 As shown, the asymmetric special-shaped foundation pit retaining structure is arranged on the outside of the inner foundation pit, and the asymmetric special-shaped foundation pit retaining structure includes a retaining pile structure 7, an extruded soil layer 9 and a flange plate retaining structure 8.

[0037] The retaining pile structure 7 includes a plurality of retaining piles, which are pre-buried in sequence along the periphery of the inner foundation pit. The retaining piles are cylindrical, and the length and diameter of the retaining piles are determined according to the shape, length and depth requirements of the inner foundation pit. The length and diameter of the retaining piles are determined by referring to the foundation pit design specifications.

[0038] A 200 mm thick extruded soil layer 9 is filled on the outside of the retaining pile structure 7, and a flange plate retaining structure 8 is arranged around the outside of the extruded soil layer 9. The retaining pile structure 7, the flange plate retaining structure 8 and the extruded soil layer 9 therebetween constitute a three-layer retaining system, all of which can effectively share the soil pressure outside the flange sheet piles and play the role of a retaining wall. In addition, the three-dimensional retaining system formed by the retaining pile structure 7 and the flange plate retaining structure 8 improves the retaining strength, thereby reducing the scale of internal support used in the special-shaped internal foundation pit.

[0039] The flange plate enclosure structure 8 includes a plurality of flange plates 6 connected by snaps, and the flange plates 6 include: an embedded plate 10, a sheet pile 1 and a plate end snap 5. The embedded plate 10 is welded to the head end of the sheet pile 1, and the tail end of the sheet pile 1 is welded to the plate end snap 5. The embedded plate 10 is clamped in the cavity of the plate end snap 5, so that the flange plates 6 are connected to each other to form a flange plate enclosure structure 8, which plays a role in water isolation and soil retaining.

[0040] The sheet pile 1 is provided with a soil squeezing through hole 2 with a diameter of 5 mm. The soil squeezing through hole 2 is circular and is achieved by metal laser drilling. The soil squeezing through holes 2 are evenly arranged side by side in the sheet pile 1. When subjected to the passive earth pressure of the outer pit soil, part of the soil outside the pit is squeezed inwardly through the soil squeezing through hole 2 into between the retaining pile structure 7 and the flange plate retaining structure 8, which plays a role in reinforcing the pile side and improves the self-stabilizing performance of the outer soil. In addition, when the outer layer of the inner foundation pit moves into the pit, the flange plate retaining structure 8 is subjected to the passive earth pressure, and the snap-on connection between the flange plates 6 is gradually tightened to exert the soil retaining performance, thereby sharing part of the outer soil pressure.

[0041] The sheet pile 1 includes a channel 3, which is arranged on the side of the tail end of the sheet pile 1. The channels 3 are arranged at intervals of 1 m along the length direction of the sheet pile 1. A water injection pipe 4 is arranged in the channel 3, and a water outlet 11 is arranged on the water injection pipe 4.

[0042] The embedded plate 10 is arranged perpendicular to the sheet pile 1 , and the welding position between the embedded plate 10 and the head end of the sheet pile 1 is located at the center line of the embedded plate 10 .

[0043] The plate end buckle 5 is rectangular in shape as a whole, and a notch is provided at the corresponding side end of the plate end buckle 5 connected to the sheet pile 1 for inserting the sheet pile 1 welded with the embedded plate 10 into the cavity of the plate end buckle 5 .

[0044] A construction method for an asymmetric special-shaped foundation pit retaining structure comprises the following steps:

[0045] Step S01: selecting the retaining piles according to the shape, length and depth of the inner foundation pit of the asymmetric special-shaped foundation pit, and vertically pressing a plurality of the retaining piles into the soil in sequence around the inner foundation pit to form a retaining pile structure 7 of the inner foundation pit;

[0046] Step S02: Determine the pile diameter of the retaining pile according to the area of ​​the asymmetric special-shaped foundation pit, and the thickness of the extruded soil layer 9 is equal to the pile diameter of the retaining pile;

[0047] Step S03: The outer side of the extruded soil layer 9 is set as the position of the flange plate enclosure structure 8, and one of the flange plates 6 is vertically statically pressed into the soil by a static pressure method, and after the pile pressing is completed, the embedded plate 10 of the other flange plate 6 is clamped in the plate end buckle 5 cavity of the flange plate 6 that has been completed with pile pressing to achieve mutual connection between the flange plates 6, and the other connected flange plate 6 is vertically statically pressed into the soil, and multiple flange plates 6 are pressed in sequence along the set position of the flange plate enclosure structure 8 to form the flange plate enclosure structure 8;

[0048] When the outer soil of the inner foundation pit moves into the pit, the flange plate retaining structure 8 is subjected to the passive earth pressure, and the buckles between the flange plates 6 are gradually tightened, exerting their soil retaining performance and sharing the outer soil pressure of the inner foundation pit. The special-shaped foundation pit will cause the soil pressure of the inner foundation pit to be unevenly distributed. The soil at the position with higher pressure is squeezed into the squeezed soil layer 9 between the retaining pile structure 7 and the flange plate retaining structure 8 through the soil squeezing through hole 2, thereby releasing part of the pressure; as the buckles between the flange plates 6 are gradually tightened, the soil with uneven pressure distribution on the outer side of the inner foundation pit is secondary distributed through the flange plate retaining structure 8, so that it acts evenly on the squeezed soil layer 9 which can be regarded as an elastic body. The squeezed soil layer 9 can disperse part of the soil pressure, and finally the retaining pile structure 7 on the inner side of the inner foundation pit is subjected to uniform soil pressure, reducing the danger of the retaining pile structure 7 caused by the bias pressure of the special-shaped pit;

[0049] Step S04: After the excavation of the special-shaped foundation pit is completed, water is injected into the water injection pipe 4 inserted in the flange plate 6, the valve of the water outlet 11 of the water injection pipe 4 is opened, and water penetrates into the soil around the flange plate 6, lubricates and softens the soil around the flange plate 6 and the retaining piles, and reduces the pulling resistance of the flange plate 6. After the water injection is completed, the flange plates 6 are pulled out one by one.

[0050] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0051] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] In the present invention, unless otherwise clearly specified and limited, when a first feature is “on” or “below” a second feature, it may be that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, when a first feature is “above”, “above” or “above” a second feature, it may be that the first feature is directly above or obliquely above the second feature, or it may simply mean that the first feature is higher in level than the second feature. When a first feature is “below”, “below” or “below” a second feature, it may be that the first feature is directly below or obliquely below the second feature, or it may simply mean that the first feature is lower in level than the second feature.

[0053] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0054] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An asymmetric special-shaped foundation pit retaining structure, characterized in that: The asymmetric special-shaped foundation pit retaining structure is arranged outside the inner foundation pit, and the asymmetric special-shaped foundation pit retaining structure comprises a retaining pile structure (7), an extruded soil layer (9) and a flange plate retaining structure (8); The retaining pile structure (7) comprises a plurality of retaining piles, which are pre-buried in sequence along the periphery of the inner foundation pit, an extruded soil layer (9) is filled on the outside of the retaining pile structure (7), and a flange plate retaining structure (8) is arranged on the outside of the extruded soil layer (9); The flange plate enclosure structure (8) comprises a plurality of flange plates (6) connected by snap fasteners, wherein the flange plates (6) comprise: an embedded plate (10), a sheet pile (1) and a plate end snap fastener (5), wherein the embedded plate (10) is welded to the head end of the sheet pile (1), and the tail end of the sheet pile (1) is welded to the plate end snap fastener (5), and the embedded plate (10) is clamped in the cavity of the plate end snap fastener (5), so that the flange plates (6) are connected to each other.

2. The asymmetric special-shaped foundation pit retaining structure according to claim 1 is characterized in that: The retaining piles are cylindrical, and the length and diameter of the retaining piles are determined according to the shape, length and depth requirements of the inner foundation pit.

3. The asymmetric special-shaped foundation pit retaining structure according to claim 2 is characterized in that: The sheet pile (1) is provided with soil squeezing through holes (2), the soil squeezing through holes (2) are circular, and the soil squeezing through holes (2) are evenly arranged side by side in the sheet pile (1).

4. The asymmetric special-shaped foundation pit retaining structure according to claim 3 is characterized in that: The sheet pile (1) comprises a hole (3), wherein the hole (3) is arranged on the side of the tail end of the sheet pile (1), and the hole (3) is arranged at intervals of a first preset distance along the length direction of the sheet pile (1).

5. The asymmetric special-shaped foundation pit retaining structure according to claim 4 is characterized in that: The sheet pile (1) further comprises a water injection pipe (4), wherein the water injection pipe (4) is arranged in the hole (3), and water outlets (11) are arranged on the water injection pipe (4) at intervals of a second preset distance.

6. The asymmetric special-shaped foundation pit retaining structure according to claim 1 is characterized in that: The embedded plate (10) is arranged perpendicular to the sheet pile (1), and the welding position between the embedded plate (10) and the head end of the sheet pile (1) is located on the center line of the embedded plate (10).

7. The asymmetric special-shaped foundation pit retaining structure according to claim 1 is characterized in that: The plate end buckle (5) is rectangular in shape as a whole, and a notch is provided at the corresponding side end of the plate end buckle (5) connected to the sheet pile (1), so as to insert the sheet pile (1) welded to the embedded plate (10) into the cavity of the plate end buckle (5).

8. A construction method for an asymmetric special-shaped foundation pit retaining structure as claimed in any one of claims 1 to 7, characterized in that: The following steps are involved: Step S01: selecting the retaining piles according to the shape, length and depth of the inner foundation pit of the asymmetric special-shaped foundation pit, and vertically pressing a plurality of the retaining piles into the soil in sequence around the inner foundation pit to form a retaining pile structure of the inner foundation pit (7); Step S02: setting the thickness of the extruded soil layer (9) according to the area of ​​the asymmetric special-shaped foundation pit; Step S03: The outer side of the extruded soil layer (9) is set as the position of the flange plate enclosure structure (8), and one of the flange plates (6) is vertically statically pressed into the soil by a static pressure method. After the pile pressing is completed, the embedded plate (10) of the other flange plate (6) is clamped in the plate end buckle (5) cavity of the flange plate (6) that has been completed with pile pressing, so as to realize the mutual connection between the flange plates (6), and the other connected flange plate (6) is vertically statically pressed into the soil, and a plurality of flange plates (6) are sequentially pressed along the set position of the flange plate enclosure structure (8) to form the flange plate enclosure structure (8); Step S04: After the excavation of the special-shaped foundation pit is completed, water is injected into the water injection pipe (4) inserted in the flange plate (6), the valve of the water outlet (11) of the water injection pipe (4) is opened, and water penetrates into the soil around the flange plate (6) to lubricate the flange plate (6) and the soil around the retaining piles. After the water injection is completed, the flange plates (6) are pulled out one by one.

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