A novel roof support device and installation method thereof

Abstract

The present invention relates to the technical field of underground mining safety, and provides a novel roof support device and an installation method thereof. The device comprises: a threaded welding nail rubber combination connecting rod, a steel-concrete combined pressure-bearing body, a triangular frame and a welding nail rubber pillar arranged in sequence from top to bottom; the upper end of the threaded welding nail rubber combination connecting rod is installed at the fixing hole of the roof; the steel-concrete combined pressure-bearing body is a box without side walls formed by connecting two rectangular steel plates and connecting welding nails; the lower end of the threaded welding nail rubber combination connecting rod is fixedly connected to the upper rectangular steel plate of the steel-concrete combined pressure-bearing body; the lower rectangular steel plate of the steel-concrete combined pressure-bearing body is fixedly connected to the upper part of the triangular frame, and the lower part of the triangular frame is connected to the welding nail rubber pillar. The beneficial effect of the present invention is that the device uses a large number of welding nail rubber combination connecting rods, which, on the one hand, utilizes the high compressive resistance of the welding nails to enhance the support effect on the mine roof, and on the other hand, reduces the shear stiffness due to the presence of the rubber sleeve.

Description

Technical Field

[0001] The invention relates to the technical field of underground mining safety, and in particular to a novel roof support device and an installation method thereof. Background Art

[0002] In recent years, with the rapid development of social economy, the amount of coal resources required has increased, the mining depth has gradually deepened, and the mining area has also been increasing. At present, the mining methods include open-pit mining, underground mining and in-situ modified mining. my country's coal production is mainly based on underground mining.

[0003] In my country, underground mining method occupies a dominant position in coal mining. However, underground safety accidents occur frequently, which seriously threaten the personal safety of construction workers. People are gradually paying attention to the safety of the roof and construction safety during underground tunnel excavation. At present, the roof support control technology in my country is mainly studied from two aspects: deep hole pre-splitting blasting and optimization of support equipment technology. The most important of these is the roof support equipment technology. The research on roof support has never stopped, and the support form has developed from wood support, stone support, scaffolding support, etc. to the current hydraulic support and anchor bolt net support.

[0004] Traditional hydraulic support and anchor bolt support have certain advantages in certain aspects and degrees. However, in some tunnels with complex geological conditions, the application of traditional hydraulic support and anchor bolt support has certain limitations, including the following disadvantages:

[0005] 1. When there is a goaf above the drift, the traditional hydraulic support has high requirements on the hardness of the coal or soil below, otherwise the stability of the support cannot be guaranteed.

[0006] 2. The hydraulic support occupies a large area, is not easy to install and disassemble, and has high requirements and restrictions on the width of the working surface.

[0007] 3. Anchor support is an invisible support, and it is not easy to monitor and detect the quality and reliability of the support. Sometimes roof falls may occur without obvious signs.

[0008] 4. For soft rock tunnels, anchor support cannot effectively control roof collapse, and collapse occurs frequently.

[0009] 5. When mining thick coal seams, the top coal tunnel used in the mining working face has very strict requirements on the compression resistance, shear resistance, bending resistance and torsion resistance of the support device, which are difficult for traditional anchor support and hydraulic support to meet. Summary of the invention

[0010] The purpose of the present invention is to provide a novel roof support device and an installation method thereof to solve the technical problems existing in the prior art.

[0011] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a new type of roof support device, comprising: a threaded welded rubber combination connecting rod, a steel-concrete combined pressure-bearing body, a triangular frame and a welded rubber pillar arranged in sequence from top to bottom; the upper end of the threaded welded rubber combination connecting rod is installed at the fixing hole of the roof; wherein the outer threaded weld in the threaded welded rubber combination connecting rod is wrapped in the inner threaded rubber sleeve, and the threaded welded rubber combination connecting rod is used in conjunction with the filling expansion agent around it; the steel-concrete combined pressure-bearing body is a side wall-free box formed by two rectangular steel plates connected with connecting welds; the lower end of the threaded welded rubber combination connecting rod is fixedly connected to the rectangular steel plate on the upper side of the steel-concrete combined pressure-bearing body; the rectangular steel plate on the lower side of the steel-concrete combined pressure-bearing body is fixedly connected to the upper part of the triangular frame, and the lower part of the triangular frame is connected to the welded rubber pillar.

[0012] In an optional embodiment, the diameter d1 of the outer threaded welding nail, the thickness d2 of the inner threaded rubber sleeve, and the width d s and the filling expansion agent thickness d3 should meet d s =d1+2d2+2d3.

[0013] In an optional embodiment, the length L1 of the outer threaded welding nail, the length L2 of the inner threaded rubber sleeve, the depth L of the fixing hole and the height L3 of the filling expansion agent should satisfy L=L2, L1=L3 <L。

[0014] In an optional embodiment, the threaded weld stud rubber combination connecting rod is riveted to the fixing hole port of the steel-concrete combination pressure-bearing body through a damping nut I, and one or more threaded weld stud rubber combination connecting rods are riveted to each of the steel-concrete combination pressure-bearing bodies; the two rectangular steel plates of the steel-concrete combination pressure-bearing body are welded to the connecting weld studs, and the connecting weld studs are wrapped with rubber sleeves I.

[0015] In an optional embodiment, the weld nail rubber pillar is formed by wrapping a pressure-bearing weld nail and a rubber sleeve II, and the lower end of the weld nail rubber pillar is riveted to the rectangular tray through a damping nut III.

[0016] In an optional embodiment, the upper parts of the two-part brackets of the triangular frame are riveted to the lower center positions of two adjacent steel-concrete composite pressure-bearing bodies through damping nuts; the intersection vertices of the two-part brackets of the triangular frame are riveted to the upper ends of the welded rubber pillars through damping nuts II.

[0017] In an optional embodiment, the rectangular steel plate in the steel-concrete composite pressure-bearing body has a thickness of 20 mm, the connecting weld nail has a length of 200 mm and a diameter of 22 mm, and the rubber sleeve I has a thickness of 4 mm and a height of 16.5 mm.

[0018] In an optional embodiment, cement concrete needs to be poured inside the steel-concrete composite pressure-bearing body, and the cement concrete is made of C60 high-strength cement, coarse aggregate, fine aggregate, fly ash, steel fiber, and water reducing agent.

[0019] On the other hand, the present invention also provides a method for installing the novel roof support device as described above, comprising the following steps:

[0020] Step 1: Install each of the threaded welded nail rubber combination connecting rods into a fixing hole drilled by a drilling machine on the top plate, and use a mud pump to fill the expansion agent, so that the threaded welded nail rubber combination connecting rod is firmly embedded in the interior of the top plate rock layer by relying on its expansion mechanism;

[0021] Step 2: Assemble the steel-concrete composite pressure-bearing body and the welded rubber pillars separately;

[0022] Step 3: Rivet the threaded rivet rubber composite connecting rod to the steel-concrete composite pressure-bearing body, use nuts to rivet the triangular frame to the centers of the two adjacent steel-concrete composite pressure-bearing bodies, then rivet the rivet rubber pillar to the rectangular tray, and then rivet the rivet rubber pillar to the triangular frame;

[0023] Step 4: Use baffles to surround the steel-concrete composite pressure-bearing body, use an instrument to prepare high-strength cement concrete in a predetermined proportion, pour the cement concrete in the middle of the steel-concrete composite pressure-bearing body, and remove the baffles around it after the cement concrete solidifies.

[0024] The beneficial effects of the present invention are:

[0025] (1) The novel roof support device of the present invention uses a large number of welded nail rubber combination connecting rods. On the one hand, the high compressive resistance of the welded nails is used to enhance the support effect on the mine roof. On the other hand, the presence of the rubber sleeve reduces the shear stiffness, thereby improving the defect that the traditional support method cannot take into account multiple mechanical requirements when the roof is broken and a large area is under pressure. A threaded welded nail rubber combination connecting rod is arranged at the upper center point of each steel-concrete composite pressure-bearing body. The main mechanism is to enhance the bite force between the threaded welded nail rubber combination connecting rod and the outer expansion agent, thereby generating a strong pulling force on the steel-concrete composite pressure-bearing body, so that the steel-concrete composite pressure-bearing body can tightly support the roof to achieve a supporting effect.

[0026] (2) The height of the inner threaded rubber sleeve in the roof fixing hole of the novel roof support device of the present invention is greater than the height of the outer threaded welding nail, and a threaded connection is used. The other parts are largely riveted, which is convenient for disassembly after mining is completed, is conducive to secondary utilization, and improves economic benefits.

[0027] (3) The novel roof support device of the present invention uses the principle of triangular frame force distribution to reduce the vertical force acting on the welded rubber pillar, improve the safety factor, and improve the stress state of the novel support device. In addition, the support device uses a steel-concrete structure, in which the concrete material uses a mixture of various properties (C60 concrete, water reducer, steel fiber, etc.), which enhances its compression, shear, bending, torsion and other performances, and it is easy to observe the pressure of the roof rock layer through the cracking of the concrete, making the invisible visible. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 It is a schematic diagram of the overall structure of a new roof support device provided in one embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram of the internal structure of a steel-concrete composite pressure-bearing body in a new roof support device provided in one embodiment of the present invention.

[0031] Figure 3 A schematic cross-sectional view of a threaded welded stud-rubber composite connecting rod in a novel roof support device provided in one embodiment of the present invention.

[0032] Among them: 1-threaded welded nail rubber combined connecting rod; 2-inner threaded rubber sleeve; 3-inner wall thread of rubber sleeve; 4-outer threaded welded nail; 5-damping nut I; 6-steel-concrete combined pressure-bearing body; 7-rectangular steel plate; 8-cement concrete; 9-connecting welded nail; 10-rubber sleeve I; 11-triangular frame; 12-damping nut II; 13-welded nail rubber pillar; 14-rubber sleeve II; 15-pressure-bearing welded nail; 16-damping nut III; 17-rectangular pallet. DETAILED DESCRIPTION

[0033] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] It should be noted that when a component is referred to as being "fixed on" or "disposed on" another component, it may be directly or indirectly located on the other component. When a component is referred to as being "connected to" another component, it may be directly or indirectly connected to the other component. The directions or positions indicated by the terms "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions or positions shown in the accompanying drawings and are only for the convenience of description and cannot be understood as limitations on the present technical solution. The terms "first" and "second" are only used for the convenience of description and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features.

[0035] Embodiment 1

[0036] Please see attached Figure 1-2 The purpose of this embodiment is to provide a new type of roof support device, which greatly improves the roof collapse problem during underground mining, greatly improves the comprehensive performance of the support device in terms of bending, compression, torsion, shearing, etc., so as to effectively support the roof. The support device includes: a threaded welded nail rubber combination connecting rod 1, a steel-concrete combined pressure-bearing body 6, a triangular frame 11 and a welded nail rubber support 13 arranged in sequence from top to bottom.

[0037] Specifically, the upper end of the threaded weld stud rubber combination connecting rod 1 is installed at the fixing hole of the top plate, wherein the outer threaded weld stud 4 in the threaded weld stud rubber combination connecting rod 1 is wrapped in the inner threaded rubber sleeve 2 to enhance its shear resistance and plasticity, and the outer threaded weld stud 4 is wrapped and connected with the inner threaded rubber sleeve 2 by a threaded connection for easy disassembly; the threaded weld stud rubber combination connecting rod 1 is used in conjunction with the filling expansion agent around it. It should be clarified that the fixing holes of the top plate are used for fastening the threaded welded rubber combination connecting rod 1, and its specific implementation method is: use a drilling rig to drill holes at appropriate positions of the top plate, embed the threaded welded rubber combination connecting rod 1 into the fixing holes, and use a mud pump to grout and fill the expansion agent around the threaded welded rubber combination connecting rod 1. The function of the threaded welded rubber combination connecting rod 1 is mainly to bear lateral pressure inside the rock layer of the top plate and to fix and withstand the tension of the steel-concrete combination pressure-bearing body 6. The filling of the expansion agent is mainly to fix the threaded welded rubber combination connecting rod 1 through its expansion mechanism, and enable the above-mentioned overall structure to play a role in fixing and connecting other lower structures.

[0038] Further, the steel-concrete composite pressure-bearing body 6 is a box without side walls formed by connecting two rectangular steel plates 7 and connecting rivets 9. Preferably, the two rectangular steel plates 7 of the steel-concrete composite pressure-bearing body 6 are welded to the connecting rivets 9, and the connecting rivets 9 are wrapped with rubber sleeves Ⅰ10. The thickness of the rectangular steel plates 7 in the steel-concrete composite pressure-bearing body 6 is 20 mm, the length of the four middle connecting rivets 9 is 200 mm, and the diameter is 22 mm. The thickness of the rubber sleeves Ⅰ10 on the connecting rivets 9 is 4 mm (about 1 / 8 of the diameter of the connecting rivets 9) and the height is 16.5 mm (3 / 4 of the height of the connecting rivets 9). It is worth mentioning that the lower end of the threaded welded rubber composite connecting rod 1 is fixedly connected to the upper rectangular steel plate 7 of the steel-concrete composite pressure-bearing body 6. Preferably, the threaded welded rubber composite connecting rod 1 is riveted to the fixed hole port of the steel-concrete composite pressure-bearing body 6 through the damping nut Ⅰ5, and a threaded welded rubber composite connecting rod 1 is riveted on each steel-concrete composite pressure-bearing body 6. The main mechanism is to enhance the bite force between the threaded welded rubber composite connecting rod 1 and the outer expansion agent through the use of the threaded welded rubber composite connecting rod 1 and the top plate, thereby generating a strong pulling force on the steel-concrete composite pressure-bearing body 6, so that the steel-concrete composite pressure-bearing body 6 can tightly support the top plate to play a supporting effect, and the two adjacent steel-concrete composite pressure-bearing bodies 6 are squeezed and connected by the force.

[0039] It should be pointed out that cement concrete 8 needs to be poured inside the middle of the box body, which is used to enhance the compression and shear resistance, and observe the internal pressure of the rock layer through the cracking of the water-cast cement concrete 8. The materials for pouring cement concrete 8 are C60 high-strength cement, coarse aggregate, fine aggregate, fly ash, steel fiber, water reducer, etc., which are mixed in a certain proportion. Its function is to use high-strength cement materials, water reducers, etc. to enhance the compression resistance of the device. The addition of steel fiber can improve the shear bearing capacity and fatigue performance of the steel-concrete composite pressure-bearing body. During the specific construction of cement concrete 8, the water-cement ratio, steel fiber content, water reducer content, etc. should all meet the mechanical properties, slump and workability of the components. When pouring concrete, appropriate lubricant should be applied to the inner surface of the component to facilitate the removal of concrete during later disassembly and reduce the burden of manpower.

[0040] Furthermore, the lower rectangular steel plate 7 of the steel-concrete composite pressure-bearing body 6 is fixedly connected to the upper part of the triangular frame 11, and the lower part of the triangular frame 11 is connected to the welded rubber pillar 13. Preferably, the upper parts of the two brackets of the triangular frame 11 are riveted to the lower center positions of the two adjacent steel-concrete composite pressure-bearing bodies 6 through damping nuts, respectively, to reduce the bearing pressure in the form of force distribution. The intersection vertex of the two brackets of the triangular frame 11 is riveted to the upper end of the welded rubber pillar 13 through damping nuts II 12.

[0041] In addition, the stud rubber support 13 is the bottommost part, which is formed by wrapping the bearing stud 15 with the rubber sleeve II 14, further enhancing the compressive resistance, shear resistance and fatigue life of the device. The thickness of the rubber sleeve II 14 is set to about 1 / 8 of the diameter of the bearing stud 15, and the height is set to 3 / 4 of the height of the bearing stud 15. The diameter and height of the bearing stud 15 should be appropriate to meet the height of the specific mining roadway and the roof conditions. The lower end of the stud rubber support 13 is riveted to the rectangular tray 17 through the damping nut III 16, increasing the contact area with the ground, which is beneficial for better fixation and enhancing the safety performance.

[0042] Finally, the diameter d1 of the outer threaded stud 4, the thickness d2 of the inner threaded rubber sleeve 2, the width d of the fixing hole s and the thickness of the filling expansion agent is d3. The filling expansion agent is carried out around the inner threaded rubber sleeve 2, and the expansion agent d3 should satisfy d s = d1 + 2d2 + 2d3. The length L1 of the outer threaded stud 4, the length L2 of the inner threaded rubber sleeve 2, the depth L of the fixing hole and the height L3 of the filling expansion agent should satisfy L = L2, L1 = L3 < L. The advantage that the inner threaded rubber sleeve 2 is higher than the outer threaded stud 4 is that it will not cause the outer threaded stud 4 to be in direct contact with the coal seam and the expansion agent, resulting in difficult disassembly.

[0043] Embodiment 2

[0044] The purpose of this embodiment is to provide an installation method for a new type of roof support device, including the following steps:

[0045] Step 1: Install each threaded stud rubber combined connecting rod 1 into the fixing hole drilled by the drilling machine on the roof, and use the mud pump to fill the expansion agent. Relying on its expansion mechanism, the threaded stud rubber combined connecting rod 1 is firmly embedded inside the roof rock formation.

[0046] Specifically, use the drilling machine to drill a fixing hole at an appropriate position on the roof. The width d of the fixing hole s should be equal to the sum of the diameter (d1 + 2d2) of the threaded stud rubber combined connecting rod 1 and the total thickness 2d3 of the expansion agent filling. The depth L of the fixing hole should be equal to the length L2 of the inner threaded rubber sleeve 2, and greater than the length L1 of the outer threaded stud 4 and the height L3 of the expansion agent filling. Assemble the threaded stud rubber combined connecting rod 1. The specific implementation method is to connect the inner threaded rubber sleeve 2 and the outer threaded stud 4 in an embedded manner, and then embed the threaded stud rubber combined connecting rod 1 into the fixing hole. Use the mud pump to grout and fill the expansion agent around it, and fix the threaded stud rubber combined connecting rod 1 through its expansion mechanism.

[0047] Step 2: Assemble the steel-concrete composite pressure-bearing body 6 and the welded nail rubber pillar 13 separately; embed the rubber sleeve I 10 (4 mm thick, 16.5 mm high) on the surface of the connecting weld nail 9 (22 mm in diameter, 200 mm in length), and then weld the rectangular steel plate 7 (20 mm thick) to the connecting weld nail 9 to form a steel structure; wrap the rubber sleeve II 14 around the pressure-bearing weld nail 15 to assemble the welded nail rubber pillar 13;

[0048] Step 3: After the assembly is completed, the threaded welded rubber composite connecting rod 1 and the steel-concrete composite pressure-bearing body 6 are riveted in the fixing hole using the damping nut I5, so that the steel-concrete composite pressure-bearing body 6 is closely attached to the surface of the top plate, and the triangular frame 11 and the adjacent two steel-concrete composite pressure-bearing bodies 6 are riveted using nuts; the triangular member 11 is riveted to the respective centers of the two adjacent steel-concrete composite pressure-bearing bodies 6, and then the welded rubber pillar 13 and the rectangular tray 17 are riveted using the damping nut III 16, and the welded rubber pillar 13 and the triangular frame 11 are riveted using the damping nut II 12;

[0049] Step 4: Use baffles to surround the steel-concrete composite pressure-bearing body 6, and apply lubricant on the inside, use instruments to prepare high-strength cement concrete 8 according to a predetermined ratio, pour cement concrete 8 in the middle of the steel-concrete composite pressure-bearing body 6, and remove the baffles around it after the cement concrete 8 solidifies.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A novel roof support device, comprising: A threaded welded stud rubber composite connecting rod (1), a steel-concrete composite pressure-bearing body (6), a triangular frame (11) and a welded stud rubber support column (13) are arranged in sequence from top to bottom; The invention is characterized in that the upper end of the threaded welding stud rubber combined connecting rod (1) is installed at the fixing hole of the top plate; wherein the outer threaded welding stud (4) in the threaded welding stud rubber combined connecting rod (1) is wrapped in the inner threaded rubber sleeve (2), and the threaded welding stud rubber combined connecting rod (1) is used in conjunction with the filling expansion agent around it; The steel-concrete composite pressure-bearing body (6) is a box without side walls formed by connecting two rectangular steel plates (7) with connecting welding nails (9); the lower end of the threaded welding nail rubber composite connecting rod (1) is fixedly connected to the rectangular steel plate (7) on the upper side of the steel-concrete composite pressure-bearing body (6); The rectangular steel plate (7) on the lower side of the steel-concrete composite pressure-bearing body (6) is fixedly connected to the upper part of the triangular frame (11), and the lower part of the triangular frame (11) is connected to the welded rubber support (13); The diameter d1 of the outer threaded welding stud (4), the thickness d2 of the inner threaded rubber sleeve (2), and the width d s and the filling expansion agent thickness d3 should meet d s =d1+2d2+2d3; The length L1 of the outer threaded welding nail (4), the length L2 of the inner threaded rubber sleeve (2), the depth L of the fixing hole and the height L3 of the filling expansion agent should satisfy L=L2, L1=L3<L.

2. The novel roof support device according to claim 1, characterized in that: The threaded welded stud rubber composite connecting rod (1) is riveted to the fixed hole port of the steel-concrete composite pressure-bearing body (6) through a damping nut I (5), and one threaded welded stud rubber composite connecting rod (1) is riveted to each of the steel-concrete composite pressure-bearing bodies (6); the two rectangular steel plates (7) of the steel-concrete composite pressure-bearing body (6) are welded to the connecting welded studs (9), and the connecting welded studs (9) are wrapped with rubber sleeves I (10).

3. The novel roof support device according to claim 2, characterized in that: The welding nail rubber pillar (13) is formed by wrapping a pressure-bearing welding nail (15) and a rubber sleeve II (14), and the lower end of the welding nail rubber pillar (13) is riveted to a rectangular tray (17) through a damping nut III (16).

4. The novel roof support device according to claim 3 is characterized in that: The upper parts of the two brackets of the triangular frame (11) are riveted to the lower center positions of the two adjacent steel-concrete composite pressure-bearing bodies (6) through damping nuts; the intersection vertices of the two brackets of the triangular frame (11) are riveted to the upper ends of the welded rubber pillars (13) through damping nuts II (12).

5. The novel roof support device according to claim 2, characterized in that: The rectangular steel plate (7) in the steel-concrete composite pressure-bearing body (6) has a thickness of 20 mm, the connecting welding nail (9) has a length of 200 mm and a diameter of 22 mm, and the rubber sleeve I (10) has a thickness of 4 mm and a height of 16.5 mm.

6. The novel roof support device according to claim 4, characterized in that: Cement concrete (8) needs to be poured inside the steel-concrete composite pressure-bearing body (6), and the cement concrete (8) is made of C60 high-strength cement, coarse aggregate, fine aggregate, fly ash, steel fiber, and water reducing agent.

7. The method for installing the novel roof support device according to any one of claims 1 to 6 comprises the following steps: Step 1: Install each of the threaded welded nail rubber combined connecting rods (1) into a fixing hole drilled on the top plate by a drilling machine, and use a mud pump to fill the expansion agent, so that the threaded welded nail rubber combined connecting rod (1) is firmly embedded in the interior of the top plate rock layer by relying on its expansion mechanism; Step 2: Assemble the steel-concrete composite pressure-bearing body (6) and the welded rubber support pillar (13) separately; Step 3: Rivet the threaded welded rubber composite connecting rod (1) to the steel-concrete composite pressure-bearing body (6), use nuts to rivet the centers of the triangular frame (11) and the two adjacent steel-concrete composite pressure-bearing bodies (6), then rivet the welded rubber pillar (13) to the rectangular tray (17), and then rivet the welded rubber pillar (13) to the triangular frame (11); Step 4: Use baffles to surround the steel-concrete composite pressure-bearing body (6), use an instrument to prepare high-strength cement concrete (8) according to a predetermined ratio, pour the cement concrete (8) in the middle of the steel-concrete composite pressure-bearing body (6), and remove the baffles around the periphery after the cement concrete (8) solidifies.

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