Supporting structure for eliminating unbalanced supporting pressure caused by auxiliary pit excavation

Abstract

The utility model discloses a supporting structure for eliminating unbalanced supporting pressure caused by excavation of an auxiliary pit, and relates to the field of supporting structure design during excavation of a foundation pit, and an upper supporting section, a standard supporting section and a lower supporting section of a steel pipe support are connected through bolts. And the connecting base and the connecting top base are welded to the bottom force transmission plate and the top force transmission plate correspondingly. And sleeving the supporting movable head into the lower supporting section of the steel pipe support, and integrally hoisting with the steel pipe support. The upper supporting section is connected with the welded connecting top base through a bolt, the supporting adjustable head is connected with the welded connecting base through a bolt, and therefore a supporting substructure module is formed. When the auxiliary pit steel support applies prestress, the main pit supporting structure synchronously applies force, and unbalance force counteracting is achieved. According to the utility model, the problems of unbalanced supporting pressure of the underground diaphragm wall caused by excavation of the auxiliary pit in the area adjacent to the existing foundation pit and instability of the foundation pit caused by deviation of the underground diaphragm wall are solved, and the device has the advantages of flexibility in arrangement, easiness in construction, recoverability and low cost.

Description

Technical Field

[0001] The utility model relates to the field of geotechnical engineering, in particular to the technical field of foundation pit excavation and support. Background Art

[0002] As urban construction promotes large-scale development of urban underground space, many ultra-deep and ultra-large underground space development projects that are adjacent to each other and constructed at the same time have emerged, especially the excavation of subway station foundation pits, which are often accompanied by the excavation of passages in and out of the station, underground shopping malls, etc. In order to save costs, such foundation pit projects often have two foundation pits sharing the ground connection wall, and the larger and deeper foundation pit is excavated first (referred to as the main pit), and the smaller and shallower foundation pit is excavated later (referred to as the auxiliary pit). This results in the main pit lacking a corresponding force transmission structure to achieve force transmission when the auxiliary pit supports the shared ground connection wall, resulting in unbalanced force. Therefore, it is very important to set up a suitable force transmission structure.

[0003] The existing support settings mainly consider the support of the excavated foundation pit, which often relies on a common ground-connected wall or main pit structure to resist the unbalanced force. However, the unbalanced support axial force is often large, reaching hundreds of kilonewtons, often causing cracks in the ground-connected wall or the main pit structure. However, there is a lack of a universal, easy-to-install support structure to offset the balance force. Summary of the invention

[0004] In view of the deficiencies in the existing technology and the importance of the project, the utility model provides a support structure for eliminating the unbalanced support pressure caused by the excavation of an auxiliary pit. As a force transmission balance structure, it can eliminate the unbalanced support pressure generated in the original foundation pit (main pit) due to the excavation of a new foundation pit (auxiliary pit) in the adjacent foundation pit, aiming to solve the foundation pit support problems involved in the background technology.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0006] A support structure for eliminating the imbalance of support pressure caused by excavation of adjacent foundation pits, comprising one or more support substructures and a force transmission plate, wherein each support substructure comprises a steel pipe support, a connecting top seat, a connecting base and a support joint head;

[0007] The steel pipe support includes an upper support section, a standard support section, and a lower support section; the upper end of the standard support section is connected to the lower end of the upper support section by bolts; the lower end of the standard support section is connected to the upper end of the lower support section by bolts;

[0008] The force transmission plate comprises a top force transmission plate and a bottom force transmission plate;

[0009] The connecting top seat is connected to the top force transmission plate by welding, and the upper end of the upper support section is connected to the connecting top seat by bolts;

[0010] The connecting base is connected to the bottom force transmission plate by welding, and the supporting flexible head is connected to the connecting base by bolts; the supporting flexible head is connected to the lower end of the lower supporting section, so that the direction of the steel pipe support relative to the plane where the connecting base is located can be adjusted;

[0011] The installation steps of the support structure include:

[0012] Step 1: After the construction of the main pit structure wall and the main pit structure middle plate is completed, the top force transfer plate is installed on the main pit structure wall through shear nails, and the bottom force transfer plate is installed on the main pit structure middle plate through shear nails;

[0013] Step 2: hoist the upper support section, standard support section, and lower support section of the steel pipe support to the middle plate of the main pit structure and lay them flat, and connect the upper support section, standard support section, and lower support section with bolts;

[0014] Step 3, welding steel plates to form a connecting base and a connecting top seat of the wedge-shaped body;

[0015] Step 4, welding the connection base to the bottom force transmission plate, and welding the connection top seat to the top force transmission plate;

[0016] Step 5, insert the support joint into the lower support section of the steel pipe support, and hoist the support joint and the steel pipe support as a whole; after hoisting, the upper support section is connected to the welded connection top seat by bolts, and the support joint is connected to the welded connection base by bolts, thereby forming a support substructure;

[0017] Step 6, repeat steps 2 to 5 to complete the installation of all support substructures;

[0018] Step 7, after the auxiliary pit is excavated, when the auxiliary pit support applies prestress to the common ground-connected wall, a hydraulic device is simultaneously used to apply pressure to the main pit support movable head at the corresponding position of the auxiliary pit support, thereby offsetting the unbalanced force transmitted by the auxiliary pit support.

[0019] Preferably, in the plurality of supporting substructures, the connecting top seat of each supporting substructure is connected to the same top force transmission plate; and the connecting base of each supporting substructure is connected to the same bottom force transmission plate.

[0020] Preferably, there are multiple top force transmission plates, the number of connecting bases connected to a bottom force transmission plate with a length of L is M, the number of connecting top seats connected to a top force transmission plate with a length of L is N, M is greater than N, and L represents a length greater than 0.

[0021] Preferably, M is an integer multiple of N.

[0022] Preferably, the positional relationship between the multiple top force transmission plates includes vertically parallel arrangement.

[0023] Preferably, the connecting top seat and the connecting base are both wedge-shaped bodies welded from steel plates, and the inclined surface angle of the wedge-shaped body cooperates with the pressure applied by the hydraulic device to offset the unbalanced force transmitted by the auxiliary pit support.

[0024] Preferably, the top force transmission plate is installed on the main pit structure wall through shear nails, and the bottom force transmission plate is installed on the main pit structure middle plate through shear nails. The top force transmission plate and the bottom force transmission plate jointly play the role of sharing force transmission.

[0025] Preferably, the number of supporting substructures in step 6 is determined according to the size of the unbalanced force to be offset.

[0026] Preferably, the diameter, wall thickness and other specifications of the steel pipe support are determined according to the magnitude of the engineering force and meet the market standard steel pipe specification requirements.

[0027] Preferably, the standard support section has a hydraulic telescopic device capable of adjusting the length of the standard support section.

[0028] The utility model has the following beneficial effects:

[0029] 1. The support structure of the utility model forms a module, and can flexibly set supports of different angles and different numbers according to engineering requirements to meet the offset of unbalanced forces of different sizes.

[0030] 2. The utility model adopts the steel pipe support with the market standard steel pipe specification, which can be conveniently purchased or rented in the market, reducing the cost of special production.

[0031] 3. The structural material used is mainly steel structure, which has high strength and quality compared with existing concrete, light support, and is convenient for construction and lifting.

[0032] 4. The utility model can be recycled and reused, which greatly reduces industrial costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall situation of the main and auxiliary foundation pit support structures in a specific embodiment of the utility model.

[0034] Figure 2 It is a schematic diagram of the support structure in a specific embodiment of the utility model.

[0035] Figure 3 It is a schematic diagram of the top connection in a specific embodiment of the utility model.

[0036] Figure 4 It is a schematic diagram of the bottom connection in a specific embodiment of the utility model.

[0037] The reference signs in the figure are: 1-concrete support for auxiliary pit; 2-the first steel support for auxiliary pit; 3-the second steel support for auxiliary pit; 4-ground connecting wall for auxiliary pit; 5-common ground connecting wall for main and auxiliary pits; 6-top plate of main pit structure; 7-the first supporting substructure; 8-the second supporting substructure; 9-middle plate of main pit structure; 10-ground connecting wall for main pit; 11-structural wall of main pit; 12-bottom plate of main pit structure; 13-top force transmission plate; 14-connecting top seat; 15-upper support section; 16-connecting bolts; 17-standard support section; 18-lower support section; 19-supporting flexible head; 20-connecting base; 21-bottom force transmission plate; 22-connecting head; 23-base bottom plate; 24-base inclined plate. DETAILED DESCRIPTION

[0038] The following will be combined with the accompanying drawings in the implementation of the utility model to provide a detailed and complete description of the technical solutions in the embodiments of the utility model. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings need not be drawn to scale unless otherwise specified.

[0039] Example:

[0040] This implementation case is the excavation of a subway station foundation pit. The main pit is the main train station, and the auxiliary pit is the external entrance and exit station hall and commercial building. Figure 1 As shown, the main pit has been excavated to a depth of 17m. In addition to the excavated retaining structure main pit ground connection wall (including the main and auxiliary pits common ground connection wall) and the main pit structure bottom plate 12, the internal structure construction has been completed, including the main pit structure top plate 6, the main pit structure middle plate 9, and the main pit structure wall 11. The auxiliary pit ground connection wall 4 and the auxiliary pit concrete support 1 have been constructed, and the auxiliary pit has been further excavated to a depth of 9m.

[0041] like Figure 1-3 As shown, a support structure for eliminating the imbalance of support pressure caused by adjacent foundation pit excavation is shown, including one or more support substructures and a force transmission plate, each of the support substructures includes a steel pipe support, a connecting top seat 14, a connecting base 20 and a support movable head 19;

[0042] The steel pipe support includes an upper support section 15, a standard support section 17, and a lower support section 18; the upper end of the standard support section 17 is connected to the lower end of the upper support section 15 by a connecting bolt 16; the lower end of the standard support section 17 is connected to the upper end of the lower support section 18 by a connecting bolt 16;

[0043] The force transmission plate comprises a top force transmission plate 13 and a bottom force transmission plate 21;

[0044] The connecting top seat 14 is connected to the top force transmission plate 13 by welding, and the upper end of the upper support section 15 is connected to the connecting top seat 14 by connecting bolts 16;

[0045] The connecting base 20 is connected to the bottom force transmission plate 21 by welding, and the supporting movable head 19 is connected to the connecting base 20 by connecting bolts 16; the supporting movable head 19 is connected to the lower end of the lower supporting section 18; the connecting base 20 includes a base bottom plate 23 and a base inclined plate 24.

[0046] Before excavating the auxiliary pit, the structural support of the utility model is hoisted onto the middle plate 9 of the main pit structure. Since it is necessary to resist the unbalanced force transmitted by the two steel supports of the auxiliary pit, it is necessary to install two supporting substructures, namely, multiple first supporting substructures 7 and multiple second supporting substructures 8. The connecting bases 20 of the two supporting substructures are located on the same straight line, the connecting top seats 14 of the multiple first supporting substructures 7 are located on the same top force transmission plate 13, the connecting top seats 14 of the multiple second supporting substructures 8 are located on the same top force transmission plate 13, and the connecting top seats 14 of the multiple first supporting substructures 7 and the connecting top seats 14 of the multiple second supporting substructures 8 are not located on the same top force transmission plate 13. The top force transmission plate 13 where the connecting top seats 14 of the two rows of supporting structures are located approximately forms two parallel lines above and below. The diameter of the steel pipe support described in this embodiment is 609 mm and the wall thickness is 16 mm. The unbalanced force transmitted by the steel pipe support of the auxiliary pit is offset by the following steps:

[0047] Step 1, after the construction of the main pit structure wall 11 and the main pit structure middle plate 9 is completed, the top force transfer plate 13 is installed on the main pit structure wall 11 through shear nails, and the bottom force transfer plate 21 is installed on the main pit structure middle plate 9 through shear nails. The top force transfer plate 13 and the bottom force transfer plate 21 are both 40#b type channel steel. The shear nails on the main pit structure wall 11 are arranged vertically in a row with an interval of 40cm, and 2 in each row. The shear nails on the main pit structure middle plate 9 are arranged horizontally in a row with an interval of 40cm, and 2 in each row. Arranging two shear nails in each row can better fix the force transfer plate and transmit force.

[0048] Step 2: hoist the upper support section 15, standard support section 17, and lower support section 18 of the steel pipe support to the main pit structure middle plate 9 and lay them flat, and connect the upper support section 15, standard support section 17, and lower support section 18 in sequence through bolts. The first support substructure 7 is 8.0m, and the second support substructure 8 is 5.4m.

[0049] Step 3, using 16 mm thick steel plates to weld the connecting base 20 and the connecting top 14 of the wedge-shaped body.

[0050] Step 4: weld the connection base 20 to the bottom force transmission plate 21 , and weld the connection top seat 14 to the top force transmission plate 13 .

[0051] Step 5: insert the support joint 19 into the lower support section 18 of the steel pipe support and hoist it together with the steel pipe support. The upper support section 15 is connected to the welded connection top seat 14 by bolts, and the support joint 19 is connected to the welded connection base 20 by bolts. The two support substructures are hoisted and installed in sequence.

[0052] Step 6: Repeat steps 2 to 5 to complete the installation of all support structures.

[0053] Step 7, after the auxiliary pit is excavated to 3.0m, the first steel support 1 of the auxiliary pit is prestressed, and a hydraulic device is simultaneously used to apply pressure to the movable head of the first supporting substructure 7 of the main pit at the corresponding position of the auxiliary pit support, thereby offsetting the unbalanced force transmitted by the first steel support 1 of the auxiliary pit.

[0054] Step 8, after the auxiliary pit is excavated 6.0m, the second steel support 2 of the auxiliary pit is prestressed, and a hydraulic device is simultaneously used to apply pressure to the movable head of the second supporting substructure 8 of the main pit at the corresponding position of the auxiliary pit support, thereby offsetting the unbalanced force transmitted by the second steel support 2 of the auxiliary pit.

[0055] The specific embodiments described herein are merely examples of the present invention, but are not intended to limit the present invention. After reading this specification, the technical personnel in the technical field to which the present invention belongs, and the adaptive modification or supplement or similar substitution made to the present embodiment as needed by the technical personnel in the technical field to which the present invention belongs, all belong to the protection scope of the present invention.

Claims

1. A support structure for eliminating the imbalance of support pressure caused by auxiliary pit excavation, comprising one or more support substructures and a force transfer plate, characterized in that: Each of the supporting substructures comprises a steel pipe support, a connecting top seat, a connecting base and a supporting joint head; The steel pipe support includes an upper support section, a standard support section, and a lower support section; the upper end of the standard support section is connected to the lower end of the upper support section by bolts; the lower end of the standard support section is connected to the upper end of the lower support section by bolts; The force transmission plate comprises a top force transmission plate and a bottom force transmission plate; The connecting top seat is connected to the top force transmission plate by welding, and the upper end of the upper support section is connected to the connecting top seat by bolts; The connecting base is connected to the bottom force transmission plate by welding, and the supporting flexible head is connected to the connecting base by bolts; the supporting flexible head is connected to the lower end of the lower supporting section, so that the direction of the steel pipe support relative to the plane where the connecting base is located can be adjusted.

2. A support structure for eliminating the imbalance of support pressure caused by auxiliary pit excavation according to claim 1, characterized in that: In the plurality of supporting substructures, the connection top seat of each supporting substructure is connected to the same top force transmission plate; and the connection base of each supporting substructure is connected to the same bottom force transmission plate.

3. A support structure for eliminating the imbalance of support pressure caused by auxiliary pit excavation according to claim 2, characterized in that: There are multiple top force transmission plates, the number of connecting bases connected to a bottom force transmission plate with a length of L is M, the number of connecting top seats connected to a top force transmission plate with a length of L is N, M is greater than N, and L represents a length greater than 0.

4. A support structure for eliminating the imbalance of support pressure caused by auxiliary pit excavation according to claim 3, characterized in that: M is an integer multiple of N.

5. A support structure for eliminating the imbalance of support pressure caused by auxiliary pit excavation according to claim 3, characterized in that: The positional relationship between the multiple top force transmission plates includes vertically parallel arrangement.

6. A support structure for eliminating the imbalance of support pressure caused by auxiliary pit excavation according to claim 1, characterized in that: The connecting top seat and the connecting base are both wedge-shaped bodies formed by welding steel plates.

7. A support structure for eliminating the imbalance of support pressure caused by auxiliary pit excavation according to claim 1, characterized in that: The top force transfer plate is installed on the main pit structure wall through shear nails, and the bottom force transfer plate is installed on the main pit structure middle plate through shear nails. The top force transfer plate and the bottom force transfer plate jointly play the role of sharing force transmission.

8. The support structure for eliminating the unbalanced support pressure caused by auxiliary pit excavation according to claim 1, characterized in that: The standard support section has a hydraulic telescopic device capable of adjusting the length of the standard support section.

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