Underground supporting structure and construction method thereof

Abstract

The invention belongs to the technical field of mineral engineering and underground engineering, and particularly discloses an underground supporting structure and a construction method thereof, and the underground supporting structure comprises a plurality of sections of steel pipes, a plurality of sections of steel sleeves and a concrete layer. The multiple sections of steel pipes are of a rectangular structure, each section of steel pipe comprises two oppositely-arranged flange plates and two oppositely-arranged webs, and the flange plates and the webs are alternately connected to form the rectangular structure with a cavity. The web plate is a corrugated steel plate, and a filling hole is formed in the flange plate or the web plate and communicated with the cavity. The multiple sections of steel sleeves are used for connecting two adjacent sections of steel pipes, and the two ends of each steel sleeve are arranged at the end parts of the two adjacent sections of steel pipes in a one-to-one correspondence manner; the multiple sections of steel pipes are connected into an arch structure with a cavity through the multiple sections of steel sleeves. And the concrete layer is filled in the cavity through the filling hole. The self weight of the supporting structure is obviously reduced, and balance of light weight and high strength of the structure is achieved.

Description

Technical Field

[0001] This invention belongs to the field of mining engineering and underground engineering technology, and specifically relates to an underground support structure and its construction method. Background Technology

[0002] With the continuous advancement of my country's deep-earth space development and deep-earth resource extraction strategies, the support challenges for deep tunnels and other underground engineering projects have become increasingly prominent. As development depths increase, geological conditions become more complex and challenging, and the rock mass stress environment changes significantly. Deep underground engineering projects exhibit characteristics such as high ground stress, soft and fractured surrounding rock, rapid deformation, large deformation amounts, and long durations. The mechanical properties and deformation patterns of deep-earth surrounding rock differ significantly from those of shallow surrounding rock, making conventional surrounding rock control theories and technologies ill-suited to the new working conditions of deep underground engineering. This directly impacts the safe and efficient construction of deep-earth space development and resource extraction.

[0003] Currently, a series of technologies have been developed in the field of deep tunnel surrounding rock control, including mining H-beams, mining U-shaped steel frames, and steel-concrete composite supports. While these support structures have high load-bearing capacity, they suffer from high self-weight and low on-site construction efficiency. Furthermore, deep underground construction faces practical challenges such as limited space for large machinery operations and low levels of mechanization. The traditional method of increasing the load-bearing capacity by increasing the cross-sectional dimensions of support structure components would further exacerbate construction difficulties and reduce efficiency. Therefore, there is an urgent need to develop lightweight, high-strength new underground support structures. Summary of the Invention

[0004] To address the aforementioned problems, the purpose of this invention is to provide an underground support structure and its construction method.

[0005] The technical solution of this invention is: an underground support structure, comprising multiple steel pipe sections, multiple steel sleeve sections, and a concrete layer. The multiple steel pipe sections are rectangular, each section including two oppositely arranged flange plates and two oppositely arranged web plates. The flange plates and web plates are alternately connected to form the rectangular structure with a cavity. Filling holes are provided on the flange plates or web plates, communicating with the cavity. The flange plates are flat steel plates, and the web plates are corrugated steel plates. The multiple steel sleeve sections are used for connecting adjacent steel pipe sections. The two ends of the sleeve are fitted onto the ends of two adjacent steel pipe sections, forming an arched structure for support. The concrete layer fills the cavity through the filling holes.

[0006] Furthermore, prestressed tendons are also installed on the steel pipes located away from the ground.

[0007] Furthermore, the web is either a trapezoidal corrugated steel plate or a sinusoidal corrugated steel plate.

[0008] Furthermore, the flange plate is welded to the web plate, and the welding surface between the flange plate and the web plate is a corrugated mating surface.

[0009] Furthermore, the flange plate is thicker than the web plate.

[0010] Furthermore, an exhaust port is provided on the flange or web, and the exhaust port communicates with the cavity.

[0011] Furthermore, the steel sleeve includes a first steel pipe sleeve and a second steel pipe sleeve. One end of the first steel pipe sleeve is fitted onto the end of one of the steel pipes. One end of the second steel pipe sleeve is fixed to the other end of the first steel pipe sleeve, forming a V-shaped structure with the first steel pipe sleeve. The other end of the second steel pipe sleeve passes through the end of another steel pipe.

[0012] Furthermore, the included angle corresponding to the V-shaped structure of the steel sleeve is 100° to 150°.

[0013] Furthermore, the interior of the first steel pipe sleeve is connected to the interior of the second steel pipe sleeve, forming a connecting channel that connects the cavities of the two steel pipes corresponding to the steel sleeve.

[0014] A construction method for an underground support structure, comprising the following steps: Position the first steel pipe section and fit the end of the first steel sleeve section onto one end of the first steel pipe section. Insert one end of the second steel pipe section into the other end of the first steel sleeve section, and then fit the end of the second steel sleeve section onto the other end of the second steel pipe section. Complete the assembly of all steel pipes and sleeves in this alternating connection method to form an arched structure.

[0015] Filling holes are drilled in the flanges or webs, and concrete is filled into the cavity through the filling holes. After the concrete in the cavity has cured to the design strength, an underground support structure is formed.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention adopts a rectangular steel tube structure with flat steel plates for the flanges and corrugated steel plates for the web. While ensuring a bending load capacity similar to that of traditional flat steel plate steel tubes, the corrugated web significantly reduces the cross-sectional area and the self-weight of the support structure. This effectively solves the pain points of limited large-scale mechanical operations and high difficulty of manual construction in deep underground engineering, and achieves a balance between lightweight structure and high strength.

[0017] Adjacent steel pipes are connected by steel sleeves, making the assembly process simple and eliminating the need for complex on-site welding. They can be quickly assembled into an arched structure, which is suitable for narrow underground working spaces, significantly improving construction efficiency. The angle can also be flexibly adjusted to adapt to different tunnel cross sections.

[0018] The arched structure has a reasonable stress distribution and can disperse the high stress load in the deep part. The concrete filling the cavity and the steel pipe form a synergistic load-bearing system. The steel pipe constrains the concrete and the concrete enhances the stability of the steel pipe, which greatly improves the compressive and deformation resistance of the support structure and is suitable for complex working conditions with soft and broken surrounding rock and large deformation.

[0019] This invention features a simple structure, allowing concrete filling to be completed through grouting holes. Compared to traditional support technologies, it achieves key breakthroughs in lightweighting, construction efficiency, and load-bearing reliability, providing a safe and efficient support solution for deep-earth development. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the structure of the steel pipe after being filled with a concrete layer according to the present invention; Figure 3 This is a cross-sectional view of the steel pipe of the present invention after being filled with a concrete layer; Figure 4 This is a schematic diagram of the steel sleeve structure of Embodiment 1 of the present invention; Figure 5 A schematic diagram of the structure of Embodiment 3 of the present invention.

[0021] Among them, 1-steel pipe, 101-filling hole, 102-vent hole, 11-flange plate, 12-web plate, 13-prestressed tendon, 2-steel sleeve, 3-arch structure. Detailed Implementation

[0022] The following is combined Figures 1 to 5 The specific embodiments of the present invention will be described in detail below. In the description of the present invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships, are 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, and are not intended to indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0023] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more sections of that feature; in the description of this invention, unless otherwise stated, "multiple sections" means two or more sections.

[0024] Example 1 like Figure 1The diagram illustrates an underground support structure comprising multiple steel pipe sections 1, multiple steel sleeve sections 2, and a concrete layer. The multiple steel pipe sections 1 are rectangular in structure, as shown below. Figure 1 , Figure 2 As shown, each section of steel pipe 1 includes two oppositely arranged flange plates 11 and two oppositely arranged web plates 12. The flange plates 11 and web plates 12 are alternately connected to form a rectangular structure with a cavity. A filling hole 101 is provided on the flange plate 11 or web plate 12, and the filling hole 101 communicates with the cavity. The concrete layer is filled into the cavity through the filling hole 101.

[0025] Flange plate 11 is a flat steel plate, and web plate 12 is a corrugated steel plate. It should be noted that flange plate 11 is made of alloy steel with a standard yield strength of not less than 300 MPa. In this embodiment, flange plate 11 is made of Q355B alloy steel with a standard yield strength of 355 MPa. The width and thickness of the two flange plates 11 can be designed to be the same or different specifications according to the actual stress conditions of the support structure to ensure the rationality of the structural stress. The thickness of web plate 12 is not less than 1.2 mm.

[0026] The multi-section steel sleeve 2 is used to connect two adjacent steel pipe sections 1. The two ends of the steel sleeve 2 are fitted onto the ends of the two adjacent steel pipe sections 1 in a one-to-one correspondence. The multi-section steel sleeve 2 and the multi-section steel pipe 1 form an arch structure 3, which is used for support.

[0027] It should be noted that: the arched structure 3 in this embodiment is a non-closed structure; the steel pipe 1 has three sections, and the sleeve 2 has two sections, as shown below. Figure 1 The three steel pipe sections 1 shown are of different lengths. The end of the steel pipe 1 in contact with the ground is also fixed with an end plate. The end plate is used to seal the end of the steel pipe 1 and increase the grounding area. The thickness of the end plate is not less than 10mm. The length of the steel pipe 1 and the angle of the V-shaped structure of the sleeve 2 need to be adjusted according to the actual environment in practical applications, which will not be elaborated here.

[0028] Preferably, prestressing tendons 13 are also provided on the steel pipe 1 away from the ground. In practical applications, the prestressing tendons 13 can be any of high-strength steel strands, ordinary anchor cables, and constant-resistance anchor cables. In this embodiment, the prestressing tendons 13 are high-strength steel strands.

[0029] Preferably, the web 12 is either a trapezoidal corrugated steel plate or a sinusoidal corrugated steel plate. In this embodiment, a trapezoidal corrugated steel plate is used, but in practical applications, the web 12 can also be replaced with a sinusoidal corrugated steel plate.

[0030] Preferably, the flange plate 11 and the web plate 12 are welded together, and the welding surfaces of the flange plate 11 and the web plate 12 are corrugated mating surfaces. The weld between the flange plate 11 and the web plate 12 is preferably a single-sided fillet weld.

[0031] Preferably, the flange 11 is thicker than the web 12. Reducing the thickness of the web 12 to make it thinner allows for greater structural lightweighting.

[0032] It should be noted that in practical applications, the thickness of the two flange plates 11 can be adjusted to be different. Specifically, the thickness of the inner flange plate 11 of the arch structure 3 is thicker than that of the inner flange plate 11 of the arch structure 3. This is because in the arch structure 3, the inner flange plate 11 is under tension and the outer flange plate 11 is under compression. The concrete has high compressive strength but low tensile strength. Making the inner flange plate 11 thicker can compensate for the low tensile strength of the concrete, resulting in better economic efficiency.

[0033] Preferably, an vent 102 is provided on the flange 11 or the web 12, and the vent 102 communicates with the cavity. The height of the vent 102 is higher than the height of the filling hole 101. In addition, it should be noted that if the end of the steel pipe 1 is inserted deep into the steel sleeve 2, and if the position of the vent 102 is affected by the steel sleeve 2, then a hole is drilled in the steel sleeve 2 until it penetrates the end of the steel pipe 1. This hole can serve as either the filling hole 101 or the vent 102.

[0034] Preferably, the steel sleeve 2 includes a first steel sleeve 21 and a second steel sleeve 22. One end of the first steel sleeve 21 is fitted onto the end of one of the steel pipes 1; one end of the second steel sleeve 22 is fixed to the other end of the first steel sleeve 21, forming a V-shape with the first steel sleeve 21, and the other end of the second steel sleeve 22 passes through the end of the other steel pipe 1. In this embodiment, the interior of the first steel sleeve 21 and the second steel sleeve 22 are not connected. In practical applications, using a non-through sleeve is more convenient for welding. In this embodiment, both the first steel sleeve 21 and the second steel sleeve 22 are rectangular steel pipes, and the steel sleeve 22 is formed by obliquely welding the first steel sleeve 21 and the second steel sleeve 22.

[0035] Preferably, the included angle corresponding to the 2V-shaped structure of the steel sleeve is 100° to 150°.

[0036] It should be noted that: such as Figure 3 As shown, if the flange plate 11 of the steel pipe 1 is 150mm × 6mm and the corrugated web is 300mm × 1.5mm, considering that the ratio of the bending length to the projected length of the corrugated web steel plate is 1.2, then its cross-sectional area is 2880mm². 2 If a conventional flat steel plate rectangular tube is used to obtain a steel pipe with a cross-section of 150mm × 312mm and a flange thickness of 6mm, its cross-sectional area is 5400mm². 2 A comparison shows that the corrugated steel pipe has a cross-sectional area of ​​53% that of the flat steel pipe. Therefore, the corrugated steel pipe proposed in this invention significantly reduces the weight of the steel pipe while maintaining a similar bending load-bearing capacity to the flat steel pipe, thereby greatly reducing the difficulty of steel pipe scaffolding construction without mechanized assistance.

[0037] A construction method for an underground support structure, comprising the following steps, for constructing the underground support structure proposed in Example 1: Position the first section of steel pipe 1 and fit the end of the first section of steel sleeve 2 onto one end of the first section of steel pipe 1. Insert one end of the second section of steel pipe 1 into the other end of the first section of steel sleeve 2, and then fit the end of the second section of steel sleeve 2 onto the other end of the second section of steel pipe 1. Complete the assembly of all steel pipes 1 and sleeves 2 in this alternating connection method to form an arch structure 3.

[0038] Filling holes 101 and venting holes 102 are drilled on the flange plate 11 or the web plate 12.

[0039] Connect the grouting pipe of the pressure pump to the grouting hole 101, and fill the cavity with concrete through the grouting hole 101. When concrete flows out continuously and evenly from the vent hole 102, it indicates that the concrete in the pipe has been poured and compacted. Stop the grouting and remove the grouting pipe.

[0040] After the concrete inside the cavity has cured to the design strength, it forms an underground support structure.

[0041] It should be noted that the filling concrete should be high-flowability ordinary concrete, high-strength concrete or coal gangue solid waste concrete, and the concrete strength grade should not be lower than C30.

[0042] Example 2 Unlike Embodiment 1, preferably, the interior of the first steel pipe sleeve 21 is connected to the interior of the second steel pipe sleeve 22, forming a connecting channel that connects the cavities of the two steel pipes 1 corresponding to the steel sleeve 2.

[0043] In this embodiment, both the first steel pipe sleeve 21 and the second steel pipe sleeve 22 are rectangular steel pipes. The steel sleeve 2 is formed by chamfering and butt-welding the first steel pipe sleeve 21 and the second steel pipe sleeve 22. In practical applications, since the interior of the first steel pipe sleeve 21 is connected to the interior of the second steel pipe sleeve 22, the number of filling holes 101 and vent holes 102 on the steel pipe 1 can be reduced. Concrete filling can be achieved with at least one filling hole 101 and at least one vent hole 102, thus reducing the number of openings on the steel pipe 1. However, compared to the scheme in Embodiment 1, the welding position at the corner of the first steel pipe sleeve 21 and the second steel pipe sleeve 22 in this embodiment has stress concentration. If there is a defect in the welding, it is prone to tearing and brittle fracture in the later stages. Therefore, the stability is weaker than that of the scheme in Embodiment 1.

[0044] Example 3: Unlike Example 2, as follows: Figure 5 As shown, arched structure 3 is a closed ring structure. One section of steel pipe 1 is laid on the ground as a ground beam. In this embodiment, steel pipe 1 has 6 sections, and sleeve 2 has 6 sections, as shown below. Figure 5 The six steel pipe sections 1 shown are of different lengths, and the V-shaped structures of the six sleeve sections 2 are of different angles. In practical applications, they need to be adapted to the actual environment, which will not be elaborated here.

[0045] In this embodiment, the flange plate 11 is made of alloy steel of type Q460B, with a standard yield strength of 460MPa; the prestressing tendon 13 is made of ordinary anchor cable.

[0046] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and do not limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the protection scope of the present invention.

Claims

1. An underground support structure, characterized in that, include: The steel pipe consists of multiple sections, each with a rectangular structure. Each section includes two opposing flanges and two opposing webs. The flanges and webs are alternately connected to form the rectangular structure with a cavity. Filling holes are provided on the flanges or webs, and the filling holes communicate with the cavities. The flanges are flat steel plates, and the webs are corrugated steel plates. Multi-section steel sleeves are used to connect two adjacent steel pipe sections. The two ends of the steel sleeves are fitted onto the ends of the two adjacent steel pipe sections one by one. The multi-section steel sleeves and the multi-section steel pipes form an arch structure, which is used for support. A concrete layer is filled into the cavity through a grouting hole.

2. The underground support structure as described in claim 1, characterized in that, Prestressed tendons are also installed on the steel pipes that are far from the ground.

3. The underground support structure as described in claim 1, characterized in that, The web is either a trapezoidal corrugated steel plate or a sinusoidal corrugated steel plate.

4. The underground support structure as described in claim 3, characterized in that, The flange plate is welded to the web plate, and the welding surface between the flange plate and the web plate is a corrugated mating surface.

5. The underground support structure as described in claim 1, characterized in that, The flange is thicker than the web.

6. The underground support structure as described in claim 1, characterized in that, The flange or web is provided with an exhaust hole, which is connected to the cavity.

7. The underground support structure as described in claim 1, characterized in that, The steel casing includes: The first steel pipe sleeve has one end connected to the end of one of the steel pipes; The second steel pipe sleeve has one end fixed to the other end of the first steel pipe sleeve, forming a V-shaped structure with the first steel pipe sleeve. The other end of the second steel pipe sleeve passes through the end of another steel pipe.

8. The underground support structure as described in claim 7, characterized in that, The included angle corresponding to the V-shaped structure of the steel sleeve is 100° to 150°.

9. An underground support structure as described in claim 7, characterized in that, The interior of the first steel pipe sleeve is connected to the interior of the second steel pipe sleeve, forming a connecting channel that connects the cavities of the two steel pipes corresponding to the steel sleeve.

10. A construction method for an underground support structure, characterized in that, The construction of any of the underground support structures described in claims 1-9 includes the following steps: Position the first steel pipe section and fit the end of the first steel sleeve section onto one end of the first steel pipe section. Insert one end of the second steel pipe section into the other end of the first steel sleeve section, and then fit the end of the second steel sleeve section onto the other end of the second steel pipe section. Complete the assembly of all steel pipes and sleeves in this alternating connection method. Filling holes are drilled in the flanges or webs, and concrete is filled into the cavity through the filling holes. After the concrete in the cavity has cured to the design strength, an underground support structure is formed.

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