A deep foundation pit concrete steel support composite structure and construction method thereof

Abstract

A deep foundation pit concrete steel support composite structure and construction method, the concrete steel support composite structure includes a column, a concrete support and a steel support, the column is vertically fixed in the foundation pit, and a corbel is fixedly installed on the top of the column; the end of the concrete support is fixed to the top of the enclosure structure, and the concrete support falls on the corbel; both ends of the steel support support the enclosure structure on the corresponding side through the installed prestressed mechanism, the steel support is fixedly connected to a support rod, and the support rod is vertically fixedly connected to the concrete support; the construction method includes steps S10 to S90. In the embodiment of the present invention, the corbel is arranged at the top of the column to support the concrete support structure, so that it further supports the steel support so that there is a larger space under the support structure, which is convenient for the construction of the basement project, and the corbel is also kept away from the basement floor. When the corbel is disassembled, the basement has completed the construction of multiple floor slabs, and will not collide with the basement floor to cause leakage.

Description

Technical Field

[0001] The invention belongs to the technical field of building foundation pit support, and in particular relates to a deep foundation pit concrete steel support composite structure and a construction method thereof. Background Art

[0002] In the existing foundation pit support structure, a concrete steel support combined structure system is usually adopted, in which a corbel is welded on the column, the support beam is erected on the corbel, and the steel support is placed on the support beam. The support beam usually acts as a support beam to support the steel support. This traditional structural system has the following problems in actual construction:

[0003] First of all, in order to weld the corbels to the columns, space for manual welding needs to be reserved. Therefore, during construction, the foundation pit must be dug to a certain depth so that the section of the column where the corbels need to be installed is exposed. Only then can the welding of the corbels on the columns be completed, and then the support beams can be erected on the corbels and steel supports can be placed. However, since the foundation pit has been dug, the installation of the support beams and steel supports needs to be carried out in the space above the bottom of the foundation pit, resulting in high-altitude operations. This type of high-altitude operation brings a series of construction problems, including difficult installation and positioning, high risk factors for operations, and reliance on auxiliary safety measures such as aerial vehicles, operating platforms and safety belts, which increases the difficulty and complexity of operations and reduces work efficiency.

[0004] Secondly, when the foundation pit is dug to the designed elevation, the basement floor needs to be poured on the bottom of the foundation pit, and the brackets are welded at the adjacent positions on the columns to continue installing the support beams and steel supports. At this time, the brackets are close to the basement floor, which can easily hinder the pouring of the floor and reduce the efficiency of the floor construction.

[0005] In addition, when the corbel is removed, there is a risk of collision with the basement floor due to its location close to the basement floor, which can easily damage the basement floor and cause water leakage. Even if the basement floor is filled with concrete after the collision, it is still difficult to completely avoid the hidden danger of water leakage, and it may increase the construction time and affect the overall project progress.

[0006] Therefore, the existing foundation pit support system has problems such as low construction efficiency, high risk of high-altitude operations, easy obstruction of bottom plate construction, and easy leakage after the removal of the corbels, which urgently need to be improved. Summary of the invention

[0007] In view of the shortcomings existing in the related technologies, the present invention provides a deep foundation pit concrete steel support composite structure and a construction method thereof, so as to solve the problems existing in the current foundation pit support structure system, such as low construction efficiency, high risk of high-altitude operations, obstructed bottom plate pouring construction and easy leakage.

[0008] The present invention provides a deep foundation pit concrete steel support composite structure for supporting a foundation pit, comprising:

[0009] The column is fixed vertically in the foundation pit, and a corbel is fixedly installed on the top thereof;

[0010] Concrete supports, whose ends are fixed to the top of the enclosure structure, and the concrete supports rest on the corbels;

[0011] The steel support has two ends that support the enclosure structure on the corresponding side through installed prestressed mechanisms. The steel support is fixedly connected with a support rod, and the support rod is vertically fixedly connected to the concrete support.

[0012] In some of the embodiments, the concrete support has a transverse support beam and a longitudinal support beam, which are cross-connected and the connection point falls on the column. There are four corbel rings installed on the column, and the four corbels are all supported on the corresponding transverse support beam and longitudinal support beam above.

[0013] In some of the embodiments, the retaining structure includes retaining piles and cap beams integrally cast on top of the retaining piles, and the concrete support is integrally cast and connected to the cap beam.

[0014] In some of the embodiments, the steel support includes an I-beam and a channel steel, a plurality of I-beams are arranged side by side, and the channel steels are arranged in pairs up and down, and the channel steels are connected to the plurality of I-beams in sequence by bolts or welding;

[0015] The prestressed mechanism includes a support seat, a jack and a support top plate. The ends of the I-beams are welded to the support seats. The jacks are fixedly installed on the support seats and multiple jacks are arranged side by side. Each jack is aligned with a corresponding I-beam. The piston rods of the multiple jacks are hingedly connected to the support top plate. Under the push of the jacks, the support top plate is pressed against the enclosure structure.

[0016] In some of the embodiments, a connecting plate is fixedly mounted on the top of the support rod, and the connecting plate is welded to the embedded parts embedded in the bottom surface of the concrete support;

[0017] Two support clamps are fixedly installed at the bottom end of the support rod, the top of the I-beam is located between the two support clamps, and the wing plates on both sides are inserted into the clamping grooves provided in the corresponding support clamps;

[0018] The I-beams are connected to the concrete supports through corresponding support rods.

[0019] In some embodiments, the steel support is arranged transversely, and the concrete support has transverse support beams and longitudinal support beams arranged in a cross-shaped manner;

[0020] The steel supports are fixedly connected to the longitudinal support beams of the concrete support arrangement through support rods, and are both located below the spaces between adjacent transverse support beams.

[0021] In some of the embodiments, the steel supports are distributed in multiple layers from top to bottom, and each layer supports the corresponding waist beams of the enclosure structure, and the waist beams are vertically aligned from top to bottom;

[0022] The steel supports of two adjacent layers are arranged in a vertical staggered manner, and the spacing between adjacent steel supports of each layer below the space between two adjacent transverse support beams is the same.

[0023] The present invention also provides a deep foundation pit construction method, which adopts the deep foundation pit concrete steel support composite structure, and the specific steps are as follows:

[0024] S10: Carry out the construction of retaining piles and columns of the retaining structure;

[0025] S20: excavate to the first support construction working surface, pour concrete to form a cushion layer, tie steel bars on the cushion layer, tie the crown beam and the steel cage of the concrete support to connect the two as one, fix the embedded parts on the lower side of the steel cage of the concrete support, pour concrete on the steel cage, and pour the crown beam and concrete support;

[0026] S30: excavate to the second support construction working surface, pour concrete to form a cushion layer, tie steel bars on the cushion layer to form a steel cage of the waist beam, pour concrete on the steel cage to form the waist beam;

[0027] S40: hoisting each support section of the steel support and placing it on the second support construction work surface, installing a support rod on each support section, and welding the top of the support rod to the corresponding embedded part on the concrete support;

[0028] S50: connecting adjacent support sections through connecting seats, and installing prestressing mechanisms at the ends of steel supports;

[0029] S60: The piston rod of the jack in the prestressing mechanism extends and presses against the waist beam, applying prestress to the steel support;

[0030] S70: According to steps S30 to S60, multiple steel supports are installed in sequence until the excavation reaches the base elevation;

[0031] S80: Carry out the reinforcement binding and concrete pouring construction of the basement floor;

[0032] S90: Carry out support replacement construction and remove each steel support in sequence from bottom to top.

[0033] In some of the embodiments, in step S40, an inclined iron is knocked in between the support section and the second support construction working surface, the support sections are adjusted to be horizontal and aligned on the same horizontal plane, and after the support section is installed with the support rod, a connecting plate is welded and installed on the top of the support rod, so that the connecting plate is attached to the corresponding embedded part surface, and the connecting plate is welded to the embedded part.

[0034] In some embodiments, two support clamps are fixedly mounted on the bottom end of the support rod, the top of the I-beam of the support section is located between the two support clamps, and the wing plates on both sides thereof are inserted into the clamp grooves provided in the corresponding support clamps for sliding installation;

[0035] In step S50, the supporting section is slid, the connecting seat is placed between adjacent supporting sections, and is fixedly connected to the supporting sections on both sides by bolts.

[0036] Compared with the prior art, the beneficial effects of the present application are: in the embodiment of the present invention, the corbel is arranged at the top of the column to support the concrete support structure, the steel support is connected to the concrete support through the support rod, and the column vertically supports it through the concrete support and the support rod to keep it vertically stable, the support and connection structures of the steel support are located above it, and the corbel is also arranged at the top, so that there is a larger space under the support structure, which is convenient for the construction of the basement project and also keeps the corbel away from the basement floor. When the corbel is removed, the basement has completed the construction of multiple floor slabs and will not collide with the basement floor to cause water leakage. In addition, during the construction process, the steel support can be directly placed on the construction work surface for leveling and connection with the concrete support, eliminating the cumbersome steps and safety hazards brought by high-altitude operations, improving construction efficiency, and solving the problems of low construction efficiency, high risk of high-altitude operations, obstructed bottom slab pouring construction and easy leakage in the current foundation pit support structure system. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. 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 drawings:

[0038] Figure 1 The structure diagram of the deep foundation pit concrete steel support composite structure of the present invention is shown in FIG. Figure 1 ;

[0039] Figure 2 The structure diagram of the deep foundation pit concrete steel support composite structure of the present invention is shown in FIG. Figure 2 ;

[0040] Figure 3 This is a structural schematic diagram of the top of a column in the deep foundation pit concrete steel support composite structure of the present invention;

[0041] Figure 4 It is a structural schematic diagram of a neutral pole of a deep foundation pit concrete steel support composite structure of the present invention;

[0042] Figure 5 It is a structural schematic diagram of the steel support in the deep foundation pit concrete steel support composite structure of the present invention;

[0043] Figure 6 It is a structural schematic diagram of the support sections of the steel supports in the deep foundation pit concrete steel support composite structure of the present invention being connected in series through the connecting seats;

[0044] Figure 7 It is a flowchart of the deep foundation pit construction method of the present invention.

[0045] In the figure:

[0046] 1. Column; 2. Concrete support; 21. Horizontal support beam; 22. Longitudinal support beam; 23. Embedded parts;

[0047] 3. Steel support; 31. I-beam; 32. Channel steel; 33. Wing plate; 34. Support section; 35. Connecting seat;

[0048] 4. Enclosure structure; 41. Enclosure piles; 42. Crown beam; 43. Waist beam;

[0049] 5. Corbel; 6. Prestressed mechanism; 61. Jack; 62. Support seat; 63. Support top plate; 64. Mounting slot;

[0050] 7. Support rod; 71. Connecting plate; 72. Support clamp seat; 73. Clamp groove. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0052] In the description of the present invention, it should be understood that the terms "center", "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations 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 should not be understood as a limitation on the present invention.

[0053] The terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Thus, a feature defined as "first", "second", and "third" may explicitly or implicitly include one or more of the features.

[0054] 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 direct connection, or an indirect connection 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 according to specific circumstances.

[0055] like Figure 1 to Figure 2 As shown, in an illustrative embodiment of the deep foundation pit concrete steel support composite structure of the present invention, the deep foundation pit concrete steel support composite structure includes a column 1, a concrete support 2 and a steel support 3.

[0056] The inner wall of the foundation pit is directly supported by the retaining structure 4, which has retaining piles 41, a crown beam 42 and a waist beam 43. There are a number of retaining piles 41, which are arranged in a row and surround the inner wall of the foundation pit. The crown beam 42 is integrally connected to the top of the retaining pile 41, and is surrounded by the top of the foundation pit along the arrangement direction of the retaining piles 41. The waist beam 43 is integrally connected to the retaining pile 41 connected to the crown beam 42, and is connected to the inner side wall of the retaining pile 41. The foundation pit can also be provided with a circle of continuously arranged retaining piles 41 on the inner side of the retaining pile 41 connected to the crown beam 42, and the waist beam 43 is integrally connected to the top of the retaining pile 41 at the inner position.

[0057] The continuously arranged retaining piles 41 form a retaining wall structure to support the inner wall of the foundation pit. The crown beam 42 connects all the retaining piles 41 together to prevent the top edge of the foundation pit from collapsing. The waist beam 43 is set with a horizontal beam at the middle height of the retaining wall. When the foundation pit is supported by diagonal braces, one end of the diagonal brace is fixed on the waist beam 43, so that the support of the diagonal brace on the retaining wall can be changed from a point to a line, thereby improving the stability of the retaining wall; when the supporting structure adopts steel support 3, the steel support 3 is prestressed and fixed on the waist beam 43, which can also achieve the effect of changing a point support into a line.

[0058] The column 1 is a steel pipe pile, which is vertically fixed in the foundation pit, and its bottom end is inserted into a deeper position below the base elevation. The top of the column 1 is fixedly installed with a corbel 5 by welding. The column 1 can also adopt a reinforced concrete structure.

[0059] The concrete support 2 is a reinforced concrete structure, which has a plurality of beam structures arranged in a grid shape, and the ends of the beam structures are fixedly connected to the top of the maintenance structure, and serve as an inner support inside the enclosure structure 4. When the foundation pit is large, the concrete support 2 generally has a large span, and the concrete support 2 falls on the corbel 5 at the top of the column 1, so that it is supported vertically and stably, avoiding deformation, keeping the structure in a horizontal plane, and stably supporting the top edge of the foundation pit.

[0060] The steel support 3 is a steel beam structure, which extends from the inner wall of one side of the enclosure structure 4 to the inner wall of the other side of the enclosure structure 4. Prestressed mechanisms 6 are installed at both ends of the steel support 3. The prestressed mechanisms 6 have jacks 61. The piston rods of the jacks 61 at both ends extend out and support the enclosure structure 4 on the corresponding side, thereby forming horizontal prestress on the steel support 3, so that it is firmly fixed in the foundation pit. Although the steel support 3 is supported in the foundation pit by horizontal prestress, during the construction of the basement, due to its own weight or when it is impacted by a collision, it may slide down and reduce its height position, thereby failing to effectively support the enclosure structure 4 at a predetermined depth. The steel support 3 is fixedly connected to a support rod 7, and the support rod 7 is vertically fixedly connected to the concrete support 2, so that the concrete support 2 supports the steel support 3 vertically, so that it remains stable in height and stably supports the enclosure structure 4. Since the two ends of the steel support 3 need to support the two sides of the enclosure structure respectively, and the width of the foundation pit is relatively large, such as Figure 6 As shown, the steel support 3 is generally composed of a plurality of support sections 34 assembled in series.

[0061] In the above-mentioned schematic embodiment, in the deep foundation pit concrete steel support composite structure, since the corbel 5 is fixedly installed only on the top of the column 1, when the corbel 5 is installed, the foundation pit has not been excavated to the base elevation, and there is no basement floor at this time. If the corbel 5 falls due to unstable operation of the personnel during the installation process, the corbel 5 falls on the ground that will be excavated from the foundation pit later, and there will be no problem of colliding with the basement floor to cause water leakage; and since the supporting structure will be gradually dismantled from bottom to top, and the multi-story basement is also constructed from bottom to top, at this time the basement floor has been covered by the upper floor slab, when the corbel 5 is dismantled, even if the corbel 5 falls on the floor slab, there will be no problem of colliding with the basement floor to cause water leakage, and even if the corbel 5 damages the floor slab, the floor slab is easier to repair than the basement floor slab.

[0062] Compared with the previous use of corbels 5 and support beams for vertical support of steel supports 3, steel supports 3 are only connected to concrete supports 2 through upward support rods 7, and the lower surface of steel supports 3 does not contact any structure, thereby freeing up space under the steel supports 3, increasing the space under the steel supports 3 that can be used for construction operations, and eliminating the obstacles to basement construction operations caused by corbels 5 and support beams.

[0063] During the construction process, since the steel support 3 is not connected to the column 1, but only rests on the inner wall of the retaining structure 4 and is connected to the concrete support 2, there is no need to dig a deeper depth into the foundation pit to install the corbel 5. The installation of the steel support 3 can be carried out on the support construction work surface, and there will be no hanging during the installation process. The positioning difficulties and complicated steps caused by high-altitude operations are eliminated, as well as the increased safety risks and increased safety measures caused by them, thereby improving construction efficiency.

[0064] Ultimately, the problems of low construction efficiency, high risk of high-altitude operations, obstructed bottom plate pouring construction and easy leakage in the current foundation pit support structure system were solved.

[0065] In some embodiments, the concrete support 2 has a transverse support beam 21 and a longitudinal support beam 22, and the transverse support beam 21 and the longitudinal support beam 22 are cross-connected. There are multiple transverse support beams 21 and longitudinal support beams, thereby forming multiple horizontal and vertical cross connection points. Multiple columns 1 are installed in the foundation pit, so that a column 1 is correspondingly arranged under each connection point, and the connection point falls directly on the column 1, so that the column 1 supports the two crossed concrete support beams 2 at the same time, thereby improving the support coverage of the column 1. The column 1 is also located at the corner below the space framed by the transverse and longitudinal support beams, so that the interval between adjacent columns 1 is the same as the interval between the concrete support beams 2, thereby avoiding the columns 1 being too dense and resulting in a reduction in the construction space below. Figure 3 As shown, there are four corbels 5 installed on the column 1, and the four corbels 5 are all placed on the corresponding transverse support beams 21 and longitudinal support beams 22 above. The corbels 5 and the top of the column 1 form a cross-shaped support structure with a larger support area, ensuring that the concrete support 2 beams can be stably supported in both the horizontal and vertical directions. In order to ensure that the corbels 5 and the top surfaces of the column 1 can completely fit the bottom surface of the concrete support 2, the top surface of the corbel 5 is flush with the top surface of the column 1 in the horizontal plane. Adjacent corbels 5 can also be welded together, so that the four corbels 5 are connected as a whole by welding, which not only further improves the stability of the formed support structure, but also can reinforce the top of the column 1 to increase its own strength, thereby more stably supporting the concrete support 2 structure.

[0066] In some embodiments, the enclosure structure 4 includes enclosure piles 41 and a crown beam 42 integrally cast on the top of the enclosure piles 41, and the concrete support 2 beam is integrally cast and connected with the crown beam 42. During the foundation pit support construction process, generally, a pile hole is firstly set, and then the steel cage of the enclosure pile 41 is placed in the pile hole, and concrete is poured into the pile hole, so that the enclosure pile 41 can be constructed in the unexcavated underground, and then the foundation pit is excavated, and the top of the enclosure pile 41 can be exposed when the excavation depth is small, and then the steel bars can be tied to form the crown beam 42 and the steel cage of the concrete support 2. The tying of the steel cages of the two can be carried out at the same time, which is not only efficient, but also connected together by steel bars. After synchronous casting, a solid structure can be formed, which improves the stability of the crown beam 42 supporting the concrete support 2, and forms a more stable support for the top edge of the foundation pit.

[0067] In some embodiments, Figure 5As shown, the steel support 3 includes an I-beam 31 and a channel steel 32. Multiple I-beams 31 are arranged side by side, that is, when the steel support 3 is in the horizontal direction, multiple I-beams 31 are all in the horizontal direction and arranged one by one in the longitudinal direction. The channel steels 32 are arranged in pairs up and down, that is, two channel steels 32, one up and one down, form a group, one channel steel 32 is located at the top, and the upper surfaces of multiple I-beams 31 are all attached to the lower surface of the channel steel 32, and are fixedly connected thereto by bolts or welding; the other channel steel 32 is located at the bottom, and the lower surfaces of multiple I-beams 31 are all attached to the upper surface of the channel steel 32, and are fixedly connected thereto by bolts or welding. Multiple groups of channel steels 32 are fixedly installed along the length direction of the I-beam 31, so as to ensure that the connection is fixed and stable at each position along the length of the I-beam 31. The side plates on both sides of the channel steel 32 can serve as reinforcement ribs of the steel support to improve its structural strength.

[0068] The prestressed mechanism 6 includes a support seat 62, a jack 61 and a support top plate 63. The ends of the I-beam 31 are welded to the support seat 62. The jacks 61 are fixedly mounted on the support seat 62, and multiple jacks 61 are arranged side by side. Each jack 61 is aligned with a corresponding I-beam 31, that is, a jack 61 and a corresponding I-beam 31 are located on the same straight line. The piston rods of the multiple jacks 61 are hingedly connected to the support top plate 63. Under the push of the jacks 61, the support top plate 63 is supported on the enclosure structure 4.

[0069] Since the jacks 61 are aligned with the I-beams 31 one by one, the prestress generated by the jacks 61 pushing up the enclosure structure 4 can be accurately applied to the I-beams 31, avoiding the deformation of the I-beams 31 caused by the prestress deviation, and ensuring the stability of the steel support 3. The piston rods of the jacks 61 are all hinged to the same support top plate 63, which not only ensures the synchronization of the actions of multiple jacks 61, but also enables the prestressed mechanism 6 to adapt to the angle error between the steel support 3 and the inner wall of the enclosure structure 4, and the thrust directions of multiple jacks 61 acting on the support top plate 63 are parallel, ensuring that the thrust generated by the jacks 61 fully acts on the support top plate 63, thereby stably supporting the steel support 3.

[0070] The jacks 61 are all installed in the installation grooves 64 provided in the support base 62. The top of the installation grooves 64 is open, which is convenient for construction workers to observe the extension and contraction state of the jacks 61. The support base 62 protects the jacks 61 in other directions except the top measurement, so as to avoid collision with the jacks 61 and damage during the basement construction process. In addition, the inner walls of the installation grooves 64 are in contact with the outer walls of the jacks 61, which improves the stability of the installation of the jacks 61, and the thrust generated by the jacks 61 can accurately react to the I-beam 31.

[0071] In some embodiments, Figure 4As shown, a connecting plate 71 is fixedly installed at the top of the support rod 7, and the connecting plate 71 is welded to the embedded part 23 embedded in the bottom surface of the concrete support 2. Two support clamps 72 are fixedly installed at the bottom end of the support rod 7, and the top of the I-beam 31 is located between the two support clamps 72, and the wing plates 33 on both sides are inserted into the clamping grooves 73 set in the corresponding support clamps 72, so that the I-beam 31 can slide relative to the support rod 7, which is convenient for aligning with the concrete support 2 during installation, thereby improving the convenience of installation. Each I-beam 31 is connected to the concrete support 2 through the corresponding support rod 7 to ensure that the concrete support 2 fully vertically supports the corresponding steel support 3.

[0072] In some embodiments, the steel support 3 is arranged horizontally, and the concrete support 2 has a cross-arranged transverse support beam 21 and a longitudinal support beam 22. The steel support 3 is fixedly connected to the longitudinal support beam 22 of the concrete support 2 through the support rod 7, and both are located below the space between adjacent transverse support beams 21.

[0073] The steel support 3 is located below the space between the concrete support 2 beams, ensuring that the column 1 and the corbel 5 both support the cross-connection point of the concrete support 2. The remaining bottom surface of the concrete support 2 is connected to the steel support 3 through the support rod 7 to avoid interference between the steel support 3 and the column 1. The steel support 3 can go directly down into the foundation pit through the gap between the adjacent concrete support 2 beams and can quickly reach the installation position without horizontal movement, thereby improving the efficiency of the installation of the steel support 3.

[0074] In some embodiments, the steel supports 3 are distributed in multiple layers from top to bottom, that is, the deep foundation pit is supported by multiple steel supports 3, and each layer supports the corresponding waist beam 43 of the enclosure structure 4, and the waist beam 43 is vertically aligned from top to bottom. Multiple waist beams 43 can be integrally connected to the enclosure piles 41 connected to the crown beam 42, and enclosure piles 41 can be added between adjacent waist beams 43 for vertical support. The support transmission from multiple steel supports 3 to the waist beam 43 will not increase the waist beam 43's occupation of the internal space of the foundation pit, ensuring that the internal space of the foundation pit is maximized, which is convenient for the construction of the basement structure.

[0075] The steel supports 3 of two adjacent layers are arranged in a vertically staggered manner, and with respect to the space below between two adjacent transverse support beams 21, the spacing between two adjacent steel supports 3 in each layer of steel supports 3 is the same, that is, in the vertical space between the transverse support beams 21, at least two steel supports 3 of each layer of supporting structure are arranged longitudinally, and the longitudinal spacing of the steel supports 3 of each layer is the same, thereby ensuring that the distribution density of the steel supports 3 of each layer of steel support 3 supporting structure is the same, and each depth position of the foundation pit can be fully supported, and the position of the bottom surface of the longitudinal support beam 22 is fully utilized to weld and fix the support rods 7 of each layer of steel supports 3.

[0076] Based on the above-mentioned deep foundation pit concrete steel support composite structure, the present invention also provides a deep foundation pit construction method, the deep foundation pit construction method adopts the above-mentioned deep foundation pit concrete steel support composite structure, such as Figure 7 As shown, the specific steps are as follows:

[0077] S10: Construction of the retaining piles 41 of the retaining structure 4 and the construction of the columns 1. More specifically, pile holes are continuously drilled at the edge of the foundation pit, and the steel cages of the retaining piles 41 are placed, and concrete is poured into the pile holes, thereby constructing the retaining piles 41 underground. Pile holes are drilled in the foundation pit according to the designed positions. When the columns 1 are steel pipe piles, the columns 1 are placed in the pile holes, and the bottom of the columns 1 is driven into the soil with a pile driver; when the columns 1 are reinforced concrete structures, the steel cages can be placed in the pile holes, and the bottom of the steel cages can be driven into the soil with a pile driver, and then concrete is poured into the pile holes, thereby constructing the retaining piles 41 underground.

[0078] S20: Excavate to the first support construction working surface, pour concrete to form a cushion layer, use the cushion layer as a basis, tie steel bars on the cushion layer, tie the crown beam 42 and the steel cage of the concrete support 2 to connect the two as one, and fix the embedded parts 23 on the lower side of the steel cage of the concrete support 2, pour concrete on the steel cage, and cast the crown beam 42 and the concrete support 2.

[0079] S30: Excavate to the second support construction working surface, pour concrete to form a cushion layer, tie steel bars on the cushion layer to form a steel cage of the waist beam 43, pour concrete on the steel cage to form the waist beam 43, and the cast waist beam 43 is integrally connected to the side wall of the retaining pile 41.

[0080] S40: hoisting and placing each support section 34 of the steel support 3 on the second support construction work surface, installing a support rod 7 on each support section 34 , and welding the top of the support rod 7 to the corresponding embedded part 23 on the concrete support 2 .

[0081] S50: Connect adjacent support sections 34 through the connecting seat 35, and install the prestressed mechanism 6 at the end of the steel support 3. The structure of the connecting seat 35 is similar to that of the support section 34, and has a plurality of I-beams arranged side by side. Both ends of the connecting seat 35 have fixing plates, and both ends of the I-beams are vertically welded to the corresponding fixing plates. Except for one end of two support sections 34 that need to be connected to the prestressed mechanism 6, the ends of the remaining support sections 34 are welded to docking plates, which are in contact with the fixing plates of the corresponding connecting seats 35 and fixedly connected by bolts. The number of I-beams set in the connecting seat 35 is the same as that of the support section 34, and when the connecting seat 35 and the support section 34 are connected, the I-beams are aligned one by one in the same straight line.

[0082] S60: The piston rod of the jack 61 in the prestressing mechanism 6 extends out and presses against the waist beam 43, applying prestress to the steel support 3, thereby fixing the steel support 3 and enabling it to horizontally support the enclosure structure 4.

[0083] S70: According to steps S30 to S60, the installation of multiple steel supports 3 is completed in sequence until the excavation reaches the base elevation.

[0084] S80: Carry out reinforcement binding and concrete pouring construction of basement floor.

[0085] S90: Replace the support and dismantle each steel support 3 from bottom to top. More specifically, since the basement floor has reached the design strength, the adjacent steel support 3 above is dismantled at this time, and the basement floor can replace the dismantled steel support 3 to support the enclosure structure 4, and the support structure is changed; the basement is further built upwards and the upper floor is constructed. After the concrete of the floor reaches the design strength, the adjacent steel support 3 above the floor can be dismantled, and the upper floor can replace the newly dismantled steel support 3 to support the enclosure structure 4, and the support structure is changed again. By analogy, as the basement structure is constructed layer by layer from bottom to top, each steel support 3 is gradually dismantled.

[0086] Each support section 34 of the steel support 3 is directly placed on the second support construction work surface before installation and fixation. By moving on the second support construction work surface, each support section 34 can be connected in a straight line, and the steel support 3 can be fixed on the set elevation of the foundation pit through prestressing; by moving on the second support construction work surface, the installed vertical pole can be aligned with the embedded part 23 on the upper concrete support 2, so that the column 1 and the embedded part 23 are welded and connected, and the connection between the steel support 3 and the concrete support 2 is completed. The steel support 3 is easy to move and install, which improves the construction efficiency.

[0087] Compared with the original construction method which requires digging first to install the corbel 5, in the current construction process, the steel support 3 always falls on the support construction work surface during installation and fixing, and the steel support 3 will not be suspended in the air, eliminating the problems of difficult installation and positioning, high construction risks, and complex risk prevention and control measures caused by high-altitude operations.

[0088] Furthermore, in step S40, an inclined iron is knocked in between the support section 34 and the second support construction working surface, the support sections 34 are adjusted to be horizontal and aligned on the same horizontal plane, and after the support section 34 is installed with the support rod 7, a connecting plate 71 is welded and installed on the top of the support rod 7, so that the connecting plate 71 is attached to the surface of the corresponding embedded part 23, and the connecting plate 71 is welded and connected to the embedded part 23.

[0089] Since the steel support 3 is placed on the construction work surface before being assembled and connected to the concrete support 2, it can be directly used as a support. The inclined iron is driven into the support section 34 to lift and adjust it to a horizontal state. At this time, after the support section 34 is installed with the support rod 7, there is still a gap between the top of the support rod 7 and the bottom surface of the concrete. A connecting plate 71 of appropriate thickness is selected and welded to the top of the vertical rod. At the same time, the connecting plate 71 can be just attached to the embedded part 23 of the concrete support 2 and welded to it. At this time, the support section 34 can be positioned and fixed by the vertical rod to keep it in a horizontally aligned state. Therefore, after the various support sections 34 are assembled together, the steel support 3 as a whole remains horizontal, and the prestressed supporting enclosure structure 4 is more stably supported, thereby avoiding the formation of an angle between the prestressed and the inner wall of the enclosure structure 4 due to the inclination of the steel support 3, which in turn causes the prestressed force to cause the end of the steel support 3 to slide upward or downward, thereby affecting the stability of the steel support 3 fixation.

[0090] Furthermore, two support clamps 72 are fixedly installed at the bottom end of the support rod 7, the top of the I-beam 31 of the support section 34 is located between the two support clamps 72, and the wing plates 33 on both sides thereof are inserted into the clamping grooves 73 provided in the corresponding support clamps 72, so that the support section 34 can slide relative to the vertical rod.

[0091] Before step S50, the vertical pole has been welded to the embedded part 23, and the height of the support section 34 has been fixed, ensuring that each support section 34 is at the same height position. In step S50, each support section 34 needs to be connected in series through the connecting seat 35. At this time, the spacing between the support sections 34 does not necessarily ensure that the connecting seat 35 can be placed therein. Since the support sections 34 can slide, the spacing between the support sections 34 can be adjusted so that the connecting seat 35 can be placed between adjacent support sections 34 and fixedly connected to the support sections 34 on both sides by bolts. At this time, since the support section 34 is allowed to partially fall on the construction work surface or is lifted relatively less relative to the construction work surface, the inclined iron can still be driven in at this time. When the support section 34 is not horizontal after moving, the support section 34 is adjusted to be horizontal again, so that the support section 34 remains horizontal for series connection, and the installation accuracy of the steel support 3 is ensured.

[0092] Finally, it should be noted that: the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0093] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A deep foundation pit concrete steel support composite structure, used for supporting the foundation pit, characterized in that: include: A column, which is vertically fixed in the foundation pit and has a corbel fixedly mounted on its top; A concrete support, the end of which is fixed to the top of the enclosure structure, and the concrete support falls on the corbel; A steel support, both ends of which are supported by a prestressed mechanism installed on the corresponding side of the enclosure structure, the steel support is fixedly connected to a support rod, and the support rod is vertically fixedly connected to the concrete support; The steel support includes an I-beam and a channel steel, a plurality of I-beams are arranged side by side, and the channel steels are arranged in pairs up and down, and the channel steels are connected to the plurality of I-beams in sequence by bolts or welding; The prestressed mechanism includes a support seat, a jack and a support top plate. The ends of the I-beams are welded to the support seat. The jacks are fixedly mounted on the support seat and multiple jacks are arranged side by side. Each jack is aligned with a corresponding I-beam. The piston rods of the multiple jacks are hingedly connected to the support top plate. Under the push of the jacks, the support top plate is supported on the enclosure structure. A connecting plate is fixedly installed on the top of the support rod, and the connecting plate is welded and connected to the embedded parts embedded in the bottom surface of the concrete support; Two support clamps are fixedly installed at the bottom end of the support rod, the top of the I-beam is located between the two support clamps, and the wing plates on both sides are inserted into the clamping grooves set corresponding to the support clamps; the I-beams are connected to the concrete support through the corresponding support rods.

2. The deep foundation pit concrete steel support composite structure according to claim 1 is characterized in that: The concrete support has a transverse support beam and a longitudinal support beam, the transverse support beam and the longitudinal support beam are cross-connected, and the connection point falls on the column. There are four corbels installed on the column, and the four corbels are all supported on the corresponding transverse support beam and longitudinal support beam above.

3. The deep foundation pit concrete steel support composite structure according to claim 1 is characterized in that: The enclosure structure comprises enclosure piles and a cap beam integrally cast on the top of the enclosure piles, and the concrete support is integrally cast and connected to the cap beam.

4. The deep foundation pit concrete steel support composite structure according to claim 1 is characterized in that: The steel support is arranged transversely, and the concrete support has transverse support beams and longitudinal support beams arranged in a cross shape; The steel supports are fixedly connected to the longitudinal support beams of the concrete support arrangement through support rods, and are both located below the spaces between adjacent transverse support beams.

5. The deep foundation pit concrete steel support composite structure according to claim 4 is characterized in that: The steel supports are distributed in multiple layers from top to bottom, and each layer supports the corresponding waist beams of the enclosure structure, and the waist beams are vertically aligned from top to bottom; The steel supports of two adjacent layers are arranged in a vertically staggered manner, and the spacing between the adjacent steel supports of each layer below the space between two adjacent transverse support beams is the same.

6. A method for constructing a deep foundation pit, characterized in that: The deep foundation pit concrete steel support composite structure according to any one of claims 1 to 5 is adopted, and the specific steps are as follows; S10: Carry out the construction of retaining piles and columns of the retaining structure; S20: excavate to the first support construction working surface, pour concrete to form a cushion layer, tie steel bars on the cushion layer, tie the crown beam and the steel cage of the concrete support to connect the two as one, fix the embedded parts on the lower side of the steel cage of the concrete support, pour concrete on the steel cage, and pour the crown beam and concrete support; S30: excavate to the second support construction working surface, pour concrete to form a cushion layer, tie steel bars on the cushion layer to form a steel cage of the waist beam, pour concrete on the steel cage to form the waist beam; S40: hoisting each support section of the steel support and placing it on the second support construction work surface, installing a support rod on each support section, and welding the top of the support rod to the corresponding embedded part on the concrete support; S50: connecting adjacent support sections through connecting seats, and installing prestressing mechanisms at the ends of steel supports; S60: The piston rod of the jack in the prestressing mechanism extends and presses against the waist beam, applying prestress to the steel support; S70: According to steps S30 to S60, multiple steel supports are installed in sequence until the excavation reaches the base elevation; S80: Carry out the reinforcement binding and concrete pouring construction of the basement floor; S90: Carry out support replacement construction and remove each steel support in sequence from bottom to top.

7. The deep foundation pit construction method according to claim 6, characterized in that: In step S40, an inclined iron is knocked in between the support section and the second support construction working surface, the support sections are adjusted to be horizontal and aligned on the same horizontal plane. After the support section is installed with the support rod, a connecting plate is welded and installed on the top of the support rod so that the connecting plate is attached to the surface of the corresponding embedded part, and the connecting plate is welded to the embedded part.

8. The deep foundation pit construction method according to claim 7, characterized in that: Two support clamps are fixedly installed at the bottom end of the support rod, the top of the I-beam of the support section is located between the two support clamps, and the wing plates on both sides are inserted into the clamping grooves corresponding to the support clamps for sliding installation; In step S50, the supporting section is slid, the connecting seat is placed between adjacent supporting sections, and is fixedly connected to the supporting sections on both sides by bolts.

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