Section steel and grating combined hole pile method underground excavation primary support structure

Abstract

The utility model belongs to the technical field of tunnel construction, and particularly discloses a profile steel and grating combined hole pile method underground excavation primary support structure which comprises a bearing mechanism and a connecting mechanism. All parts in the bearing mechanism are connected through a connecting mechanism and are arranged at the upper end of the pilot tunnel excavation working face; the grid component and the profile steel component in the bearing mechanism are connected through the connecting mechanism to form the primary supporting structure, so that the characteristics of the two materials are ingeniously fused, and firm supporting force is provided for the top and the two sides of the primary supporting structure through the profile steel component; deformation of the whole structure can be effectively controlled through the high strength and rigidity characteristics of the primary support structure, stability of the primary support structure is ensured, meanwhile, the grating component is adopted at the bottom of the primary support structure, stability of the primary support structure in the pilot tunnel excavation period is ensured, the bottom cutting difficulty of the primary support structure is lowered, the follow-up tunnel pile method construction difficulty is further lowered, and construction efficiency is improved. And the defects existing when a single material is adopted are effectively avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field of tunnel construction, and more specifically relates to a hole pile method concealed excavation primary support structure composed of section steel and grid. Background Art

[0002] In current urban tunnel construction, faced with the complexity of the surrounding environment, the dense impact of surface and underground buildings, and the strict requirements for controlling surface settlement, the hole pile method, as an efficient construction technology, is being increasingly applied in engineering practice. The hole pile method, also known as the Pile-Beam-Arch approach (PBA), is a type of shallow buried tunneling method. During construction, a pilot tunnel is first excavated. Then, strip (pile) foundations, bottom longitudinal beams, side piles, center columns, crown beams, and top longitudinal beams are constructed within the pilot tunnel. Then, a buckle arch is excavated and constructed. Finally, within the support system formed by the pile-beam-arch, the soil is excavated layer by layer and the internal structure is constructed. When using the hole pile method for tunneling, in order to stabilize the surrounding rock or soil to ensure construction safety and tunnel stability, a support skeleton structure, namely the primary support structure, needs to be arranged according to the tunnel excavation contour.

[0003] The primary support structure of the traditional hole pile method for underground excavation generally adopts a grid steel frame or a steel frame. Among them, the grid steel frame is made of welded steel bars, which is easy to obtain and has flexible cross-sectional forms and sizes, and is suitable for the needs of different spans and shapes. For example, the Chinese patent with document number CN111042833A discloses a method for simply backfilling concrete in the guide tunnel of a station using the hole pile method, which includes the following steps: 1) After the side piles and the crown beam are cast, the station primary support grid is erected above the crown beam; 2) After the primary support grid is erected, a sealing plate is used to close the mold on the clear side of the station primary support grid, a concrete feed port is reserved on the arch, and the sealing plate is supported by support rods ; 3) spraying concrete on the outside of the primary support grille of the station to form the main primary support structure of the station; 4) using the concrete feed port to carry out the backfill construction of the concrete on the outside of the primary support grille of the station, and the backfill construction is carried out in two times; the Chinese patent with the document number CN113738377A discloses a rock stratum hole pile method station main structure construction method, including side longitudinal beam construction, middle longitudinal beam construction, middle arch and second side arch construction, middle arch and side arch secondary lining construction, track top air duct and middle plate construction, bottom plate construction and main side wall construction, and, by setting up the side arch grille steel frame as the primary support structure in the first guide tunnel and the fourth guide tunnel, the construction safety is ensured.

[0004] Although grid steel frames are widely used as primary support structures, when deformation control requirements are high due to factors such as engineering risks and extremely shallow overburden, grid steel frames are prone to deformation, which can easily lead to large initial deformation during excavation. In these cases, section steel frames can be used as primary support structures. These frames are characterized by high rigidity, rapid load bearing, and good deformation control. However, when section steel frames are used as primary support structures in underground pile excavation construction, the need to cut the section steel frames during the pile foundation construction phase can increase construction difficulty, prolong the construction period, and thus increase risks. Therefore, a new primary support structure is urgently needed to address these issues. Utility Model Content

[0005] In response to the above defects or improvement needs of the prior art, the present invention provides a primary support structure for a hole pile method concealed excavation, which is a combination of steel sections and grilles. The grille components and steel section components in the load-bearing mechanism are connected to form the primary support structure by using the connecting mechanism, thereby cleverly integrating the characteristics of the two materials. The steel section components provide a strong supporting force at the top and both sides of the primary support structure. The high strength and rigidity characteristics of the steel section components can effectively control the deformation of the entire structure, ensuring that the primary support structure remains stable during complex pile foundation construction, reducing construction obstacles caused by deformation, and reducing the difficulty of pile foundation construction. At the same time, the grille component is used at the bottom of the primary support structure, which not only ensures the stability of the primary support structure during the pilot hole excavation, but also reduces the difficulty of cutting its bottom, further reducing the difficulty of subsequent hole pile method construction, reducing construction time and cost, and effectively avoiding the defects existing when a single material is used.

[0006] In order to achieve the above-mentioned purpose, the utility model provides a hole pile method concealed excavation primary support structure composed of steel and grid, including: a load-bearing mechanism and a connecting mechanism, wherein:

[0007] The various components in the load-bearing mechanism are connected by a connecting mechanism and are arranged at the upper end of the pilot tunnel excavation working surface, which includes a first steel frame, a second steel frame and a grid steel frame; several first steel frames are connected by the connecting mechanism and are vertically arranged at the upper end of the pilot tunnel excavation working surface; the second steel frame is arranged on the upper ends of several first steel frames and is connected to the first steel frames through the connecting mechanism; the grid steel frame is arranged at the upper end of the pilot tunnel excavation working surface and its two ends are respectively connected to two first steel frames through the connecting mechanism.

[0008] Furthermore, the load-bearing structure includes a third steel frame, and two ends of the third steel frame are respectively connected to the two first steel frames through the connecting mechanism.

[0009] Furthermore, the first steel frame, the second steel frame and the third steel frame are made of steel materials including I-beams or H-beams, and the I-beam model is 25b, and the H-beam size is 300mm×150mm.

[0010] Furthermore, the connecting mechanism includes: a first connecting member and a second connecting member; several first connecting members are arranged between the first steel frame and the first steel frame, the first steel frame and the second steel frame, the first steel frame and the third steel frame, and the first steel frame and the grid steel frame, and are connected to the first steel frame, the second steel frame and the third steel frame by bolts and / or welding; the second connecting member is arranged at both ends of the grid steel frame by welding, and is connected to the first connecting member arranged on one side of the first steel frame.

[0011] Furthermore, the first connecting member is a square steel plate with a thickness of 10 to 12 mm;

[0012] The second connecting piece is an angle steel and at least one second connecting piece is provided at one end of the grid steel frame, and its size is 140mm×90mm or 150mm×90mm.

[0013] Furthermore, stiffening plates are provided at the connections between the first connecting member and the first section steel frame, the second section steel frame, and the third section steel frame.

[0014] Furthermore, the grid steel frame is made of linear skeleton steel bars and stirrups, wherein the linear skeleton steel bars are four third-grade steel bars with a diameter of 25 mm, and the stirrups are welded third-grade steel bars with a diameter of 12 mm.

[0015] Furthermore, the second steel frame is perpendicular to the center line of the line in the guide tunnel.

[0016] Furthermore, the second steel frame is arched.

[0017] Furthermore, the second steel frame is linear.

[0018] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0019] (1) The primary support structure of the present invention cleverly combines the characteristics of two materials by connecting the grille components and steel components in the load-bearing structure with the connecting mechanism. The steel components provide strong support at the top and both sides of the primary support structure. Its high strength and rigidity characteristics can effectively control the deformation of the entire structure, ensuring that the primary support structure remains stable during the complex pile foundation construction process, reducing construction obstacles caused by deformation, and reducing the difficulty of pile foundation construction. At the same time, the grille components are used at the bottom of the primary support structure, which not only ensures the stability of the primary support structure during the pilot hole excavation, but also reduces the difficulty of cutting its bottom, further reducing the difficulty of subsequent hole pile construction, reducing construction time and cost, and effectively avoiding the defects existing when using a single material.

[0020] (2) The primary support structure of the present invention connects several of the first-shaped steel frames through the connecting mechanism to form the two side walls of the primary support structure, and supports the second-shaped steel frame arranged at the upper end thereof, so that the rigidity of the primary support structure is guaranteed, which helps to effectively control deformation during construction. At the same time, it ensures that the second-shaped steel frame is in close contact with the soil above or with the bottom end of the pipe curtain, so that the primary support structure can effectively bear the soil pressure or ground load, reducing uncertainty and potential risks in construction. Secondly, by arranging the grid steel frame on the pilot tunnel excavation working surface and connecting it with several of the first-shaped steel frames, the contact area between the primary support structure and the pilot tunnel excavation working surface and the rigidity of the primary support structure are increased at the initial stage of construction, thereby effectively improving the stability of the primary support structure.

[0021] (3) The primary support structure of the present invention is connected by arranging the first connecting member or the second connecting member between the first steel frame, the second steel frame, the grid steel frame and the third steel frame. The connecting mechanism can be used as a connecting medium to increase the contact area of ​​the connection of the load-bearing mechanism, thereby improving the stability and bearing capacity of the connection, improving the overall rigidity of the primary support structure, and facilitating construction and adjustment.

[0022] (4) The primary support structure of the present invention can adapt to the complex and changeable underground space and ground conditions by designing the second steel frame into a straight line. At the same time, since the design and manufacture of the straight steel frame are relatively simple, the construction speed can be accelerated and the construction difficulty can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a structural diagram of the primary support structure of an embodiment of the present utility model;

[0024] Figure 2 This is a schematic diagram of the structure of Example A of the present utility model;

[0025] Figure 3This is a schematic structural diagram of a plurality of primary support structures connected in an embodiment of the present utility model;

[0026] In all the drawings, the same reference numerals represent the same technical features, specifically: 1-first steel frame, 2-second steel frame, 3-grid steel frame, 4-third steel frame, 5-first connecting member, 6-second connecting member, 7-guide hole, 8-earth wall, 9-pile. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0028] like Figures 1 to 3 As shown, an embodiment of the present invention provides a primary support structure for a hole pile method of concealed excavation, which is a combination of steel sections and grids, and includes: a load-bearing mechanism and a connecting mechanism; the various components of the load-bearing mechanism are connected by the connecting mechanism and are arranged at the upper end of the pilot tunnel excavation working surface. In actual operation, the primary support structure is formed by connecting the grid components and steel sections in the load-bearing mechanism using the connecting mechanism, thereby cleverly integrating the characteristics of the two materials. The steel sections provide a strong support force at the top and both sides of the primary support structure. Its high strength and rigidity characteristics can effectively control the deformation of the entire structure, ensuring that the primary support structure remains stable during the complex pile foundation construction process, reducing construction obstacles caused by deformation and reducing the difficulty of pile foundation construction. At the same time, the grid components are used at the bottom of the primary support structure, which not only ensures the stability of the primary support structure during the pilot tunnel excavation, but also reduces the difficulty of cutting its bottom, further reducing the difficulty of subsequent hole pile method construction, reducing construction time and cost, and effectively avoiding the defects that exist when using a single material.

[0029] Preferably, the steel section component is a component made of steel sections; and the grille component is a component made of grilles.

[0030] Specifically, if Figures 1 to 3As shown, the load-bearing mechanism is located at the upper end of the pilot tunnel excavation working surface, and is used to bear loads and control deformation, providing a solid foundation for the smooth progress of the project. The load-bearing mechanism includes: a first steel frame 1, a second steel frame 2, and a grid steel frame 3; a plurality of the first steel frames 1 are connected by the connecting mechanism and are vertically located at the upper end of the pilot tunnel excavation working surface; the second steel frames 2 are located at the upper ends of a plurality of the first steel frames 1 and are connected to the first steel frames 1 through the connecting mechanism; the grid steel frame 3 is located at the upper end of the pilot tunnel excavation working surface, and its two ends are respectively connected to two of the first steel frames 1 through the connecting mechanism. During the actual construction process, several of the first-section steel frames 1 are connected by the connecting mechanism to form the two side walls of the primary support structure, and the second-section steel frame 2 located at the upper end thereof is supported, so that the rigidity of the primary support structure is guaranteed, which helps to effectively control deformation during the construction process. At the same time, it ensures that the second-section steel frame 2 is in close contact with the soil above or the bottom end of the pipe curtain, so that the primary support structure can effectively bear the soil pressure or ground load, reducing uncertainty and potential risks in construction. Secondly, by arranging the grid steel frame 3 on the pilot tunnel excavation working surface and connecting it with several of the first-section steel frames 1, the contact area between the primary support structure and the pilot tunnel excavation working surface and the rigidity of the primary support structure are increased at the initial stage of construction, thereby effectively improving the stability of the primary support structure.

[0031] Preferably, the second steel frame 2 is perpendicular to the center line of the line in the guide tunnel 7, so as to ensure that the primary support structure is evenly stressed, avoid stress concentration or uneven load due to improper installation angle, and reduce the risk of structural deformation or damage.

[0032] Preferably, the second steel frame 2 is arched, so as to reduce the bending moment and shear force in the primary support structure and improve the stability and bearing capacity of the primary support structure.

[0033] In an optional embodiment, due to the constraints of factors such as roadside vegetation, pipelines, traffic diversion, and soil cover thickness above the construction guide tunnel, the second steel frame 2 is linear, so as to adapt to the complex and changeable underground space and ground conditions. At the same time, since the design and manufacture of the linear steel frame are relatively simple, the construction speed can be accelerated and the construction difficulty can be reduced.

[0034] In an optional embodiment, when there are multiple pilot tunnels to be constructed, each pilot tunnel is provided with a primary support structure, and the load-bearing mechanism includes a third steel frame 4, and the two ends of the third steel frame 4 are respectively connected to two of the first steel frames 1 through the connecting mechanism, which is used to stably connect the primary support structures of the two pilot tunnels, thereby improving the stability of the multiple primary support structures during the construction of multiple pilot tunnels, thereby improving construction accuracy and construction safety.

[0035] Preferably, the first steel frame 1, the second steel frame 2 and the third steel frame 4 are made of steel including I-beams or H-beams, and the I-beam model is 25b and the H-beam size is 300mm×150mm, which is used to reduce material costs while ensuring that the stability of the primary support structure meets the design requirements.

[0036] Preferably, the grid steel frame 3 is made of linear skeleton steel bars and stirrups, wherein the linear skeleton steel bars are four third-grade steel bars with a diameter of 25 mm, and the stirrups are welded third-grade steel bars with a diameter of 12 mm, which are used to reduce material costs while ensuring that the stability of the primary support structure meets the design requirements.

[0037] Specifically, if Figures 1 to 3 As shown, the connecting mechanism is provided between the various components of the load-bearing mechanism and is used to stably connect the various components of the load-bearing mechanism. The connecting mechanism includes: a first connecting member 5 and a second connecting member 6; a plurality of the first connecting members 5 are provided between the first section steel frame 1 and the first section steel frame 1, the first section steel frame 1 and the second section steel frame 2, the first section steel frame 1 and the third section steel frame 4, and the first section steel frame 1 and the grid steel frame 3, and are connected to the first section steel frame 1, the second section steel frame 2 and the third section steel frame 4 by bolts and / or welding; the second connecting member 6 is provided at both ends of the grid steel frame 3 by welding and is connected to the first connecting member 5 provided on one side of the first section steel frame 1. During the actual construction process, by arranging the first connecting member 5 or the second connecting member 6 between the first section steel frame 1, the second section steel frame 2, the grid steel frame 3 and the third section steel frame 4 for connection, the connecting mechanism can be used as a connecting medium to increase the contact area of ​​the connection of the load-bearing mechanism, thereby improving the stability and bearing capacity of the connection, improving the overall stiffness of the primary support structure, and facilitating construction and adjustment.

[0038] Preferably, stiffening plates are provided at the connections between the first connecting member 5 and the first section steel frame 1 , the second section steel frame 2 , and the third section steel frame 4 to improve connection stability.

[0039] Preferably, the first connecting member 5 is a square steel plate with a thickness of 10 to 12 mm to ensure connection stability.

[0040] In an optional embodiment, the first connecting member 5 is an L-shaped steel plate with a thickness of 10 to 12 mm to ensure connection stability.

[0041] Preferably, the second connecting member 6 is an angle steel and at least one second connecting member 6 is provided at one end of the grid steel frame 3 , and its size is 140 mm×90 mm or 150 mm×90 mm to ensure connection stability.

[0042] The working principle of the present invention is as follows: the size and shape of the primary support structure are determined according to the construction area environment and project construction requirements, and the design and processing of the first steel frame 1, the second steel frame 2, the grid steel frame 3, the third steel frame 4, the first connecting member 5 and the second connecting member 6 can be carried out simultaneously during the initial dark excavation stage; after trial assembly, the various components are transported to the working surface, the lines are laid out, and the primary support structure is first erected at the designed position by bolts, and after checking the bolting effect, subsequent reinforcement is carried out by welding to ensure that the second steel frame 2 is tightly attached to the soil above or the bottom of the pipe curtain, and the primary support structure is perpendicular to the center line of the line in the pilot tunnel 7, so that the elevation deviation of the primary support structure is within ±15mm and the verticality deviation is within 5‰. At this time, the upper end and two side walls of the primary support structure formed by the first steel frame 1 and the second steel frame 2 effectively support the upper load and avoid structural deformation. At the same time, the grid steel frame 3 provided at the lower end is easy to cut, so that the subsequent pile foundation construction can be carried out smoothly, significantly improving construction efficiency and safety.

[0043] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), such directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0044] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features specified as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0045] In this patent, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Those skilled in the art will readily understand that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A hole pile method concealed excavation primary support structure composed of steel and grid, characterized in that: include: Load-bearing mechanism and connecting mechanism, including: The components of the load-bearing mechanism are connected by a connecting mechanism and are arranged at the upper end of the pilot tunnel excavation working surface, and include a first steel frame (1), a second steel frame (2) and a grid steel frame (3); a plurality of the first steel frames (1) are connected by the connecting mechanism and are vertically arranged at the upper end of the pilot tunnel excavation working surface; the second steel frame (2) is arranged at the upper ends of a plurality of the first steel frames (1) and is connected to the first steel frames (1) through the connecting mechanism; the grid steel frame (3) is arranged at the upper end of the pilot tunnel excavation working surface and its two ends are respectively connected to the two first steel frames (1) through the connecting mechanism.

2. The primary support structure according to claim 1, characterized in that: The load-bearing structure comprises a third steel frame (4), and both ends of the third steel frame (4) are respectively connected to the two first steel frames (1) via the connecting mechanism.

3. The primary support structure according to claim 2, characterized in that: The first steel frame (1), the second steel frame (2) and the third steel frame (4) are made of steel materials including I-beams or H-beams, wherein the I-beam model is 25b and the H-beam size is 300mm×150mm.

4. The primary support structure according to claim 2, characterized in that: The connecting mechanism comprises: a first connecting member (5) and a second connecting member (6); a plurality of the first connecting members (5) are arranged between the first section steel frame (1) and the first section steel frame (1), the first section steel frame (1) and the second section steel frame (2), the first section steel frame (1) and the third section steel frame (4), and the first section steel frame (1) and the grid steel frame (3), and are connected to the first section steel frame (1), the second section steel frame (2) and the third section steel frame (4) by bolts and / or welding; the second connecting member (6) is arranged at both ends of the grid steel frame (3) by welding, and is connected to the first connecting member (5) arranged on one side of the first section steel frame (1).

5. The primary support structure according to claim 4, characterized in that: The first connecting member (5) is a square steel plate with a thickness of 10 to 12 mm; The second connecting member (6) is an angle steel and at least one second connecting member (6) is provided at one end of the grid steel frame (3), and its size is 140mm×90mm or 150mm×90mm.

6. The primary support structure according to claim 5, characterized in that: A stiffening plate is provided at the connection between the first connecting member (5) and the first section steel frame (1), the second section steel frame (2), and the third section steel frame (4).

7. The primary support structure according to any one of claims 1 to 6, characterized in that: The grid steel frame (3) is made of linear skeleton steel bars and stirrups, wherein the linear skeleton steel bars are four third-grade steel bars with a diameter of 25 mm, and the stirrups are welded third-grade steel bars with a diameter of 12 mm.

8. The primary support structure according to any one of claims 1 to 6, characterized in that: The second steel frame (2) is perpendicular to the center line of the line in the guide tunnel (7).

9. The primary support structure according to any one of claims 1 to 6, characterized in that: The second steel frame (2) is arched.

10. The primary support structure according to any one of claims 1 to 6, characterized in that: The second steel frame (2) is linear.

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