I-shaped GFRP profiling node supporting arch frame for underground engineering and construction method of I-shaped GFRP profiling node supporting arch frame
By using the flange connection and contoured liner assembly design of the I-shaped GFRP contoured node support arch frame, the problems of corrosion and welding safety of traditional arch frames in humid environments are solved, achieving efficient and safe underground engineering support.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- POWERCHINA HUADONG ENG CORP LTD
- Filing Date
- 2026-02-06
- Publication Date
- 2026-05-12
AI Technical Summary
Traditional I-beam or H-beam arch frames are prone to corrosion in damp, acidic or alkaline seepage environments underground, and the joints are prone to loosening. Welding construction poses safety hazards, and FRP profiles have poor compressive strength, making it difficult to meet the support requirements of high ground stress areas.
The arch frame is supported by I-shaped GFRP contoured nodes. By setting flange docking structures and contoured liner assemblies at the connection nodes, the contoured liner assemblies are used to wrap and support the I-shaped section, eliminating gaps. Bolt connections and tapered chemical anchors are used for fixation, avoiding welding operations.
It improves the bending and shear stiffness of the joint, prevents flange tearing, achieves corrosion-free operation throughout the entire life cycle, enhances construction safety and efficiency, and meets the support requirements of high ground stress areas.
Smart Images
Figure CN122014290A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of underground engineering support technology, and in particular to an I-shaped GFRP contoured joint support arch frame for underground engineering and its construction method, which is applicable to environments such as water diversion tunnels, drainage corridors and traffic tunnels in water conservancy and hydropower projects. Background Technology
[0002] In the initial support of underground water conservancy and hydropower projects, there has long been a dual challenge of material durability and construction safety. The existing technology has the following defects: (1) Insufficient corrosion resistance: Traditional I-beams or H-beams are prone to corrosion in damp, acidic or alkaline seepage environments underground. The service life of ordinary steel arches in drainage corridor environments is often lower than the design life of the project, requiring frequent maintenance or secondary reinforcement. (2) Significant construction safety hazards: The connection of traditional steel arches mostly relies on underground welding. Hot work in tunnels with narrow spaces, poor ventilation, or even gas can easily cause fires or explosions; and the fumes generated by welding seriously endanger the health of workers.
[0003] To address the corrosion problem, FRP (fiber reinforced plastic) profiles are currently being tested. However, the use of these profiles still suffers from the defects of composite material connection processes. Conventional FRP hollow pipes have poor compressive strength, are prone to crushing at bolted connections, and are difficult to apply high preload. Even with I-beam FRP profiles, existing connection methods typically involve directly clamping the flanges with flat plates. Because the connection between the inner flange and the web of the I-beam has chamfers or complex geometry, ordinary flat plates cannot fit tightly into this area. Under immense pressure from the surrounding rock, nodes where only the flange edge bears the load are prone to loosening, torsion, and even localized buckling and tearing of the flange due to "gaps," failing to meet the support requirements of high-stress zones. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide an I-shaped GFRP contoured joint support arch frame for underground engineering and its construction method, in view of the above-mentioned problems.
[0005] The technical solution adopted in this invention is: an I-shaped GFRP contoured joint support arch frame for underground engineering, comprising: A pair of anchoring bases; I-shaped GFRP columns are vertically and symmetrically positioned on a pair of anchoring bases; The I-shaped GFRP arch beam is detachably connected to the top of the corresponding I-shaped GFRP column via flange butt joint structure at both ends; The contoured liner assembly is respectively disposed on at least a portion of the two ends of the I-shaped GFRP arch beam, at least a portion of the top of the I-shaped GFRP column, and the anchoring base, respectively covering the outer flange, inner flange, and web of the corresponding sections of the two ends of the I-shaped GFRP arch beam, the top of the I-shaped GFRP column, and the bottom of the I-shaped GFRP column, and is used to provide wrapping support for the flange plates and web of the I-shaped GFRP column and the I-shaped GFRP arch beam.
[0006] Using the aforementioned technical means, a flange butt joint structure is set at the connection node between the I-shaped GFRP column and the I-shaped GFRP arch beam, which facilitates the splicing to form an arch frame structure without the need for welding operations on the construction site. Furthermore, a contoured liner assembly is installed within the connection section, which wraps around the outer flange, inner flange, and web sidewall of the supporting flange plate, so that the contoured liner assembly provides wrapping support for the I-shaped section. It also conforms to the chamfer or complex geometric areas at the junction of the flange and the web, eliminating the gap between the traditional flat plate and the profile.
[0007] In some embodiments, the conformal liner assembly includes an outer node cover plate, an inner node conformal liner, and bolt fasteners. The outer flange of the top of the I-shaped GFRP column and the corresponding section of the two side flanges at both ends of the I-shaped GFRP arch beam is covered with an outer node cover plate. The inner flange of the top of the I-shaped GFRP column and the corresponding section of the two side flanges at both ends of the I-shaped GFRP arch beam is covered with an inner node conformal liner. The inner node conformal liner is symmetrically arranged on both sides of the web. The inner node conformal liner can abut against at least a portion of the sidewalls on both sides of the web. The bolt fasteners can penetrate the outer node cover plate, the flanges, and the inner node conformal liner and lock them in place.
[0008] In some embodiments, the inner contouring liner of the node has an L-shaped structure or a semi-frame structure. The L-shaped inner contouring liner can abut against the inner flange and at least part of the sidewall of the web of the flange plate. The semi-frame structure inner contouring liner can abut against the inner flange and all the sidewalls of the web of both flange plates. The outer cover plate of the node has a flat plate structure.
[0009] In some embodiments, the contoured liner assembly includes an outer base cover plate, an inner base contoured liner, and bolt fasteners. The anchoring base is provided with an outer base cover plate and an inner base contoured liner. A pair of outer base cover plates are symmetrically arranged, and an inner base contoured liner perpendicular to the outer base cover plates is symmetrically arranged between the pair of outer base cover plates. An insertion space for the I-shaped GFRP column is reserved between the outer base cover plates and the inner base contoured liner. When the bottom of the I-shaped GFRP column is inserted into the insertion space, the pair of outer base cover plates abut against the outer flange of the inner flange plate of the bottom section of the I-shaped GFRP column, and the inner base contoured liner abuts against the inner flange of the inner flange plate of the bottom section of the I-shaped GFRP column and at least part of the sidewalls on both sides of the web. The bolt fasteners can penetrate the outer base cover plate, the flange plate, and the inner base contoured liner and lock them in place.
[0010] In some embodiments, the inner contouring liner of the base has an L-shaped structure or a semi-frame structure. The L-shaped inner contouring liner can abut against the inner flange and at least part of the sidewall of the web of the flange plate. The semi-frame structure inner contouring liner can abut against the inner flange and all the sidewalls of the web of the flange plates at both ends. The outer cover plate of the base has a flat plate structure.
[0011] In some embodiments, the flange docking structure includes node connecting steel plates and node connecting bolts. The top of the I-shaped GFRP column and both ends of the I-shaped GFRP arch beam are provided with node connecting steel plates. The node connecting steel plates at both ends of the I-shaped GFRP arch beam and the node connecting steel plate at the top of the I-shaped GFRP column are connected by node connecting bolts.
[0012] In some embodiments, the anchoring base includes a base connecting steel plate and a tapered chemical anchor. The bottom of the I-shaped GFRP column is connected to the base connecting steel plate, and the base connecting steel plate has bolt holes for inserting the tapered chemical anchor. The tapered chemical anchor passes through the bolt holes to fix the base connecting steel plate to the installation reference surface.
[0013] In some embodiments, both the I-shaped GFRP column and the I-shaped GFRP arch beam are extruded solid structures.
[0014] Another technical solution adopted in this invention is: a construction method for an I-shaped GFRP contoured joint support arch frame for underground engineering, applied to an I-shaped GFRP contoured joint support arch frame, comprising the following steps: S1. Solid I-beam GFRP profiles are prepared in the factory using the pultrusion process, and the I-beam GFRP profiles are cut into I-beam GFRP columns and I-beam GFRP arch beam segments according to the tunnel cross-section design. S2. At the top of the I-shaped GFRP column, the connection sections at both ends of the I-shaped GFRP arch beam, and the top of the base connecting steel plate in the anchor base, a contoured liner assembly is pre-installed. The contoured liner assembly at the node covers the outer flange, inner flange, and web of the node. The contoured liner assembly at the node is fixedly connected to the node connecting steel plate in the flange docking structure. The contoured liner assembly on the base connecting steel plate reserves the insertion space of the I-shaped GFRP column, and bolt holes are reserved in the node connecting steel plate and the base connecting steel plate. S3. Measure and lay out the tunnel floor, drill holes and insert tapered chemical anchors, install the prefabricated base connecting steel plate on the tapered chemical anchors and level and fix it. S4. Install the I-shaped GFRP column into the pre-reserved insertion space on the base connecting steel plate, and lock the I-shaped GFRP column and the conformal liner assembly on the base connecting steel plate with bolt fasteners. S5. Lift the I-shaped GFRP arch beam into position so that the node connection steel plate at the top of the I-shaped GFRP column is aligned with the node connection steel plates at both ends of the I-shaped GFRP arch beam and locked with bolt fasteners to complete the arch frame closure.
[0015] The beneficial effects of this invention are: 1. By introducing a contoured liner assembly into the arch frame structure, the outer cover plate and the inner L-shaped / semi-frame contoured liner in the contoured liner assembly provide three-dimensional wrapping support for the junction area between the I-shaped GFRP flange and the web. The outer cover plate provides the external bearing surface of the flange plate, and the inner contoured liner fits the inner flange and the side wall of the web, filling the geometric gaps that traditional flat plate clamps cannot cover. The "outer cover plate-flange-inner liner" structure forms a multi-layer composite bearing system. With bolt fastening, "contour wrapping + interlocking" is achieved, which effectively prevents the composite flange from tearing and buckling under heavy loads. The bending load capacity of the joint is significantly better than that of ordinary flat plate connections.
[0016] 2. By using solid extrusion-molded I-beam GFRP profiles (glass fiber reinforced composite materials), they have excellent resistance to acids and alkalis, water seepage, and electrochemical corrosion. They hardly deteriorate in humid underground environments containing corrosive ions, completely replacing easily corroded steel and achieving full life-cycle maintenance-free corrosion protection.
[0017] 3. All components in this structure are prefabricated and drilled in the factory. The main node connections are all bolted or flanged. No welding work is required in the well during the assembly operation. The anchor base is mechanically anchored with tapered chemical bolts. The arch frame segments are assembled on site with pre-installed flanges and bolt fasteners, realizing the construction mode of factory prefabrication and on-site bolt assembly. This eliminates hot work and significantly improves the construction safety in complex environments such as high humidity and confined spaces. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the planar structure of this application.
[0019] Figure 2 This is a schematic diagram of the connection node structure between the arch beam segment and the column segment in this application.
[0020] Figure 3 This is a schematic diagram of the connection node structure between the column segment and the anchor base in this application.
[0021] Figure 4 This is a schematic diagram of the cross-sectional structure of the I-shaped GFRP column in this application.
[0022] Explanation of reference numerals in the attached figures: 1. I-shaped GFRP column; 2. I-shaped GFRP arch beam; 3. Contouring liner assembly; 4. Anchor base; 31. Outer cover plate of node; 32. Inner contour liner of node; 33. Node connecting steel plate; 34. Bolt fastener; 35. Node connecting bolt; 41. Outer cover plate of base; 42. Inner contour liner of base; 43. Base connecting steel plate; 45. Conical chemical anchor; 5. Bolt hole.
[0023] This specification includes references to "one embodiment" or "implementation". The use of the phrase "in one embodiment" or "in an embodiment" does not necessarily refer to the same embodiment. Specific features, structures, or characteristics may be combined in any suitable manner consistent with this disclosure.
[0024] The term "comprising" is open-ended. As used in the appended claims, it does not exclude additional structures or steps.
[0025] "First," "second," etc. As used in this article, these terms serve as labels for the nouns preceding them and do not imply any type of ordering (e.g., spatial, temporal, logical, etc.).
[0026] The term "based on," as used herein, describes one or more factors that influence the determination. This term does not exclude additional factors influencing the determination. That is, the determination may be based solely on these factors or at least partially on them. Consider the phrase "A is determined based on B." In this case, B is the factor influencing the determination of A, and such phrases do not exclude the possibility that the determination of A may also be based on C. In other instances, A may be determined solely on B. Detailed Implementation
[0027] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be further described below with reference to specific embodiments.
[0028] Example 1: Combination Figures 1 to 4 As shown, this embodiment is an I-shaped GFRP contoured node support arch frame for underground engineering, including a pair of anchor bases 4, I-shaped GFRP columns 1, I-shaped GFRP arch top beams 2, and contoured lining plate assemblies 3. The I-shaped GFRP columns 1 are vertically and symmetrically arranged on a pair of anchor bases 4. The top of the pair of I-shaped GFRP columns 1 is connected to the I-shaped GFRP arch top beams 2. The I-shaped GFRP arch top beams 2 and the top of the I-shaped GFRP columns 1 are detachably connected via a flange docking structure. At least some sections at both ends of the I-shaped GFRP arch beam 2 and at least some sections at the top and bottom of the I-shaped GFRP column 1 are provided with contoured liner assemblies 3. The contoured liner assemblies 3 cover the outer flange, inner flange and web of the corresponding sections of the I-shaped GFRP column 1 and the I-shaped GFRP arch beam 2. The contoured liner assemblies 3 are used to provide wrapping support for the flange plates of the I-shaped GFRP column 1 and the I-shaped GFRP arch beam 2.
[0029] In some embodiments, the conformal liner assembly 3 includes an outer node cover plate 31, an inner node conformal liner plate 32, and bolt fasteners 34. The outer flanges of the corresponding sections of the top of the I-shaped GFRP column 1 and the two side flanges at both ends of the I-shaped GFRP arch beam 2 are covered with the outer node cover plate 31. The inner flanges of the corresponding sections of the top of the I-shaped GFRP column 1 and the two side flanges at both ends of the I-shaped GFRP arch beam 2 are covered with the inner node conformal liner plates 32. The inner node conformal liner plates 32 are symmetrically arranged on both sides of the web. The inner node conformal liner plates 32 can abut against at least a portion of the sidewalls on both sides of the web. The bolt fasteners 34 can penetrate and lock the outer node cover plate 31, the flanges, and the inner node conformal liner plates 32. Specifically, the outer cover plate is a flat plate structure that fits tightly against the outer surface of the profile flange.
[0030] In some embodiments, the contoured liner assembly 3 includes an outer base cover plate 41, an inner base contoured liner plate 42, and bolt fasteners 34. The anchor base 4 is provided with an outer base cover plate 41 and an inner base contoured liner plate 42. A pair of outer base cover plates 41 are symmetrically arranged, and an inner base contoured liner plate 42 perpendicular to the outer base cover plates 41 is symmetrically arranged between the pair of outer base cover plates 41. An insertion space for an I-shaped GFRP column 1 is reserved between the outer base cover plate 41 and the inner base contoured liner plate 42. When the bottom of the I-shaped GFRP column 1 is inserted into the insertion space, a pair of outer base cover plates 41 abut against the outer flange of the inner flange plate of the bottom section of the I-shaped GFRP column 1, and the inner base contour liner 42 abuts against the inner flange of the inner flange plate of the bottom section of the I-shaped GFRP column 1 and at least part of the sidewalls on both sides of the web plate. The bolt fastener 34 can penetrate the outer base cover plate 41, the flange plate and the inner base contour liner 42 and lock them.
[0031] A multi-layered composite pressure-bearing path is constructed through the outer cover plate, inner contoured liner, flange plate, and bolts. Bolt fasteners 34 sequentially penetrate the outer cover plate, solid flange plate, and inner contoured liner. At this point, the inner contoured liner not only acts as a gasket to distribute pressure but also as a stiffening rib, limiting the warping deformation of the I-beam flange. Simultaneously, the bolt preload is evenly transmitted through the multiple layers of plates, reducing the risk of localized crushing of the I-beam GFRP to some extent.
[0032] In some implementations, the inner contouring liner 32 of the node and the inner contouring liner 42 of the base have an L-shaped or semi-frame structure. The L-shaped inner contouring liner 32 of the node and the inner contouring liner 42 of the base can abut against the inner flange and at least part of the sidewall of the web of the flange plate. The semi-frame structure inner contouring liner 32 of the node and the inner contouring liner 42 of the base can abut against the inner flange and all the sidewall of the web of the flange plates at both ends. The outer cover plate 31 of the node and the outer cover plate 41 of the base have a flat plate structure. Specifically, the inner contouring liner 32 of the node and the inner contouring liner 42 of the base have a bending structure that matches the height of the inner contour of the I-shaped profile. The bending structure is L-shaped or semi-frame-shaped, which not only fits the surface of the inner flange, but also extends and closely fits part or all of the web surface, forming a wrapping and support for the root of the I-shaped flange. The L-shaped structure features an inner contoured liner that fits against one side flange and part of the web sidewall. The L-shape is suitable for low to medium stress zones, balancing economy and ease of construction. The semi-frame structure has an inner contoured liner that wraps around both side flanges and the entire web sidewall. The semi-frame provides higher constraint stiffness and is suitable for high ground stress zones. Both forms can be flexibly selected according to the working conditions to achieve graded support design.
[0033] To address the geometric characteristics of the flange-web chamfered area in an I-shaped GFRP section, an inner contoured liner with an L-shaped or semi-frame structure is installed to form a full circumferential constraint on the I-shaped section, eliminating geometric gaps, improving the bending and shear stiffness of the joint, and preventing torsional loosening. By achieving a tight fit and full-section support between the inner flange and the web sidewall, the limitation of traditional FRP connections relying solely on the flange edge for stress is overcome.
[0034] In this embodiment, a contoured embedded clamping structure is constructed on the base using the contoured liner assembly 3. The outer cover plate 41 of the base is perpendicular to the base connecting steel plate 43 and fits the outer surface of the outer flange of the GFRP column. The inner contoured liner 42 of the base is symmetrically arranged on both sides of the web, in an L-shape or semi-frame shape, and fits the inner surface of the inner flange and the side wall of the web of the GFRP column. The outer cover plate and the inner contoured liner form an insertion space, which is also the contoured clamping space at the bottom of the column. The bolt fasteners 34 penetrate the outer cover plate 41, the flange plate, and the inner contoured liner 42 of the base in sequence to apply preload. This structure forms a closed or semi-closed mechanical enclosure through symmetrical internal and external clamping. Under the lateral pressure of the surrounding rock or uneven settlement, it can effectively resist the bending moment, shear force, and torque at the bottom of the column, and prevent the joint from loosening or overturning.
[0035] In some implementation schemes, the flange connection structure includes node connecting steel plates 33 and node connecting bolts 35. Node connecting steel plates 33 are provided at the top of the I-shaped GFRP column 1 and at both ends of the I-shaped GFRP arch beam 2. The node connecting steel plates 33 at both ends of the I-shaped GFRP arch beam 2 are connected to the node connecting steel plate 33 at the top of the I-shaped GFRP column 1 via node connecting bolts 35. Specifically, bolt holes 5 are pre-drilled on the node connecting steel plates 33. The node connecting bolts 35 pass through the node connecting steel plates 33 at the ends of the I-shaped GFRP arch beam 2 and the node connecting steel plates 33 at the top of the I-shaped GFRP column 1, enabling rapid assembly between segments.
[0036] By connecting the node steel plate 33 and the node connecting bolt 35, the weak connection between GFRP segments is transformed into a steel-to-steel bolt connection, making full use of the high strength advantage of steel.
[0037] In some implementations, the anchoring base 4 includes a base connecting steel plate 43 and a tapered chemical anchor 45. The bottom of the I-shaped GFRP column 1 is connected to the base connecting steel plate 43. The base connecting steel plate 43 has bolt holes 5 for the tapered chemical anchor 45 to pass through. The tapered chemical anchor 45 passes through the bolt holes 5 to fix the base connecting steel plate 43 to the installation reference surface.
[0038] High pull-out resistance is provided by chemical bolts to ensure the stability of the base, and the steel plate serves as a transition component to achieve effective force transfer in the non-metallic geotechnical structure.
[0039] In some implementation schemes, both the I-shaped GFRP column 1 and the I-shaped GFRP arch beam 2 are solid structures formed by extrusion molding.
[0040] Because solid structures are characterized by no cavities, continuous fibers, and dense cross-sections, they significantly improve the compressive and bending resistance compared to hollow tubes. This avoids local buckling of hollow structures under bolt pressure, provides high compressive strength to withstand the high preload of connecting bolts, and the extrusion process ensures material uniformity and consistent mechanical properties.
[0041] In some implementations, the connectors in this embodiment are all made of stainless steel, and the connectors include node connecting steel plate 33, node connecting bolt 35, base connecting steel plate 43, and bolt fastener 34.
[0042] The implementation principle of the I-shaped GFRP contoured joint support arch frame for underground engineering in this embodiment is as follows: Firstly, the solid extruded I-beam GFRP (glass fiber reinforced polymer) profiles possess excellent resistance to acids and alkalis, water seepage, and electrochemical corrosion. They exhibit virtually no degradation in humid underground environments containing corrosive ions, completely replacing easily corroded steel. By using solid GFRP in conjunction with stainless steel connectors, the corrosion problem in drainage corridor environments is completely solved, resulting in low life-cycle costs.
[0043] To address the weaknesses of GFRP, such as its lower compressive strength compared to its tensile strength and its susceptibility to failure under localized pressure, a contoured liner assembly 3 is introduced in the node and base areas. This assembly, comprising an outer cover plate 41 and an inner contoured liner 42, provides three-dimensional support to the junction of the I-shaped GFRP flange and web. The outer cover plate 41 provides an external bearing surface, while the inner contoured liner 42 conforms to the inner flange and web sidewalls, filling geometric gaps that traditional flat plate clamps cannot cover. This effectively prevents tearing and buckling of the composite flange under heavy loads, resulting in significantly better bending resistance at the node compared to ordinary flat plate connections. A multi-layered composite bearing system is formed by bolts penetrating the outer cover plate, flange, and inner liner, significantly improving local compressive strength and shear capacity. This prevents the GFRP material around the bolt holes from collapsing due to stress concentration, allowing for effective application of high-preload bolts and ensuring the overall stiffness and load-bearing capacity of the node. By using the outer cover plate 41 of the node / base and the inner contour liner plate 42 of the node / base to perform geometric matching and mechanical reinforcement on the flange-web corner of the key stress area, the original weak connection is transformed into a reliable connection with surface contact and multi-layer pressure bearing, thereby achieving stress homogenization and load-bearing path optimization.
[0044] This structure breaks down complex underground support structures into standardized prefabricated components such as columns and arch beams. High-precision processing and pre-assembly are completed in the factory, and only fire-free operations such as positioning, bolting, and fastening are performed on site, achieving safe, fast, and high-quality support construction. The installation efficiency is more than 30% higher than that of traditional steel arch frames.
[0045] Example 2: This embodiment describes a construction method for an I-shaped GFRP contoured joint support arch frame used in underground engineering. Applied to the I-shaped GFRP contoured joint support arch frame described in Embodiment 1, the method includes the following steps: S1. Solid I-shaped GFRP profiles are prepared in the factory using the pultrusion process, and the I-shaped GFRP profiles are cut into I-shaped GFRP column 1 and I-shaped GFRP arch beam 2 segments according to the tunnel cross-section design.
[0046] S1.1 Solid I-shaped GFRP profiles are prepared using the pultrusion process and cut into column and arch beam segments according to the design length.
[0047] S2. At the top of the I-shaped GFRP column 1, the connecting sections at both ends of the I-shaped GFRP arch beam 2, and the top of the base connecting steel plate 43 in the anchor base 4, a contoured liner assembly 3 is pre-installed. The contoured liner assembly 3 at the node covers the outer flange, inner flange, and web of the node. The contoured liner assembly 3 at the node is fixedly connected to the node connecting steel plate 33 in the flange docking structure. The contoured liner assembly 3 on the base connecting steel plate 43 reserves the insertion space of the I-shaped GFRP column 1, and bolt holes 5 are reserved in the node connecting steel plate 33 and the base connecting steel plate 43.
[0048] S2.1. At the connection section between the top and bottom of the I-shaped GFRP column 1 and both ends of the I-shaped GFRP arch beam 2, a contoured liner assembly 3 is pre-installed. The outer cover plate 31 and the inner contoured liner 32 of the node in the contoured liner assembly 3 are used to cover the outer flange, inner flange and web of the node.
[0049] S2.2. Fix the node connection steel plate 33, which serves as the flange, to the conformal liner assembly 3, and make pre-drilled bolt holes 5 on the node connection steel plate 33.
[0050] S2.3 In the factory, the outer cover plate 41 of the base, the inner contour liner plate 42 of the base and the base connecting steel plate 43 of the contour liner plate assembly 3 are integrated. The outer cover plate 41 of the base and the inner contour liner plate 42 of the base form a contour clamping space on the base connecting steel plate 43, and the mounting bolt holes 5 matching the chemical anchors are reserved on the base connecting steel plate 43.
[0051] S3. Measure and lay out the tunnel floor, drill holes and insert tapered chemical anchors 45, install the prefabricated base connecting steel plate 43 on the chemical anchors and level and fix it.
[0052] S3.1. Measure and lay out the tunnel at the designed location at the bottom of the tunnel.
[0053] S3.2 Drill holes for mounting the base connecting steel plate 43, clean the holes and inject water-resistant chemical adhesive.
[0054] S3.3 Insert a conical chemical anchor 45 to solidify it and form a high-strength, durable rock mass anchor point.
[0055] S3.4 Place the 43 sets of prefabricated mounting base connecting steel plates onto the cured chemical anchors.
[0056] S3.5 Adjust the elevation and level of the mounting base connecting steel plate 43, and tighten the nuts to complete the positioning.
[0057] S4. Install the I-shaped GFRP column 1 into the pre-reserved insertion space on the base connecting steel plate 43, and lock the I-shaped GFRP column 1 and the contour liner assembly 3 on the base connecting steel plate 43 with bolt fasteners 34.
[0058] S4.1 Insert the lower end of the I-shaped GFRP column 1 into the contour clamping space of the base connecting steel plate 43.
[0059] S4.2 Insert connecting bolts, which sequentially pass through the outer cover plate 41 of the base, the flange plate of the I-shaped GFRP column 1, and the inner contour liner plate 42 of the base.
[0060] S4.3 Apply the designed preload using a torque wrench to make the contour liner assembly 3 rigidly wrap and constrain the flange root.
[0061] S5. Lift the I-shaped GFRP arch beam 2 into position so that the node connecting steel plate 33 at the top of the I-shaped GFRP column 1 is aligned with the node connecting steel plates 33 at both ends of the I-shaped GFRP arch beam 2 and locked by bolt fasteners 34 to complete the arch frame closure.
[0062] S5.1. The prefabricated I-shaped GFRP arch beam 2 is hoisted to the installation position as a whole or in sections.
[0063] S5.2 Adjust both ends to precisely align the node connecting steel plate 33 at the end of the I-shaped GFRP arch beam 2 with the node connecting steel plate 33 at the top of the I-shaped GFRP column 1.
[0064] S5.3 Ensure that the contoured liner assembly 3 completely covers the junction of the flange and the web in the mating area.
[0065] S5.4 Insert the node connecting bolt 35 into the pre-drilled bolt hole 5 in the aligned node connecting steel plate 33. In this embodiment, high-strength connecting bolts are used.
[0066] Example 3: This embodiment describes an I-shaped GFRP contoured support arch for underground engineering, applied to the support project of a deep-buried drainage gallery in a hydropower station, where the surrounding rock environment is humid.
[0067] (1) Preparation of main materials Solid glass fiber reinforced polymer (GFRP) I-beams with a cross-sectional height of 150mm-200mm were selected as the columns and arch beam segments. The solid structure ensures that the hole wall will not collapse like that of hollow tubes when drilling and bolting, and can withstand the huge torque of high-strength bolts of M20 and above.
[0068] (2) Design of contour node structure The connection between the column and the arch beam adopts a contour-following embedded clamping node.
[0069] 1) The outer cover plate 31 of the node and the outer cover plate 41 of the base are made of 304 stainless steel plate with a thickness of 15mm and cover the outer side of the flange of the I-beam.
[0070] 2) Inner contour liner 32 of the node and inner contour liner 42 of the base: L-shaped or channel-shaped steel components formed by stamping or welding with special molds. This component is precisely embedded in the angle between the web and flange of the I-beam, completely filling the inner space. It not only increases the contact area of the bolt connection, but also acts as a stiffening rib to prevent the flange from rolling inward.
[0071] 3) Bolt fastener 34: M12 / M16, made of 304 stainless steel. Bolt fastener 34 penetrates sequentially from the outside to the inside through the outer cover plate, solid flange, and inner contoured liner. After tightening, the high compressive strength of the solid GFRP is utilized to apply a high preload force, forming a friction-type joint.
[0072] 4) Flange prefabrication: The inner contour liner 32 and the outer cover plate 31 of the node are welded to the node connection steel plate 33 with a thickness of 20mm to serve as a flange. The node connection steel plate 33 is provided with reserved bolt holes 5.
[0073] (3) Arch foot anchorage design The anchoring base 4 at the bottom of the column adopts the same contour clamping principle as the node. A contour liner 42 is also provided on the top of the base connecting steel plate 43, which, together with the outer cover plate 41, securely locks the column. The base connecting steel plate 43 is deeply embedded into the bedrock through pre-drilled bolt holes 5 and tapered chemical anchors 45. The tapered chemical anchors 45 are M20, grade 8.8. The chemical anchors utilize chemical adhesives to bond with the rock mass, exhibiting strong water resistance and anchoring force that does not decrease over time.
[0074] (4) Construction method 1) Factory prefabrication: Based on the tunnel cross-section design, solid GFRP I-beams are cut to the designed length in the factory, and installation holes are pre-drilled at the connection end using CNC machine tools.
[0075] 2) Base treatment and anchoring: Measure and lay out the tunnel floor, drill holes and insert tapered chemical anchors 45.
[0076] 3) Base installation: Install the base connecting steel plate 43 onto the chemical anchor and level and fix it.
[0077] 4) Column erection: Insert the solid I-shaped GFRP column 1 into the base, insert the bolts and tighten them. Use the conformal liner assembly 3 on the base connecting steel plate 43 to achieve rigid constraint on the root of the column.
[0078] 5) Arch assembly: Lift the I-shaped GFRP arch beam 2 with the pre-installed contour lining plate assembly 3 at the node into place, so that the node connecting steel plate 33 of the I-shaped GFRP arch beam 2 is aligned with the node connecting steel plate 33 at the top of the I-shaped GFRP column 1.
[0079] 6) System closure: Insert connecting steel plate bolts into the reserved bolt holes 5, i.e., insert M22 high-strength bolts, and tighten them with a torque wrench to complete the arch frame closure. The entire process is without welding or on-site cutting.
[0080] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.
Claims
1. An I-shaped GFRP contoured joint support arch frame for underground engineering, characterized in that, include: A pair of anchor bases (4); I-shaped GFRP columns (1) are vertically and symmetrically arranged on a pair of anchor bases (4); The I-shaped GFRP arch beam (2) is detachably connected to the top of the corresponding I-shaped GFRP column (1) at both ends via a flange butt joint structure; The contoured liner assembly (3) is respectively installed on at least a portion of the two ends of the I-shaped GFRP arch beam (2), at least a portion of the top of the I-shaped GFRP column (1), and the anchor base (4), respectively covering the outer flange, inner flange, and web of the two ends of the I-shaped GFRP arch beam (2), the top of the I-shaped GFRP column (1), and the bottom of the I-shaped GFRP column (1), and is used to provide wrapping support for the flange plates and web of the I-shaped GFRP column (1) and the I-shaped GFRP arch beam (2).
2. The I-shaped GFRP contoured joint support arch frame for underground engineering according to claim 1, characterized in that: The conformal liner assembly (3) includes an outer node cover plate (31), an inner node conformal liner plate (32), and bolt fasteners (34). The outer flange of the top of the I-shaped GFRP column (1) and the corresponding section of the two side flange plates at both ends of the I-shaped GFRP arch beam (2) is covered with an outer node cover plate (31). The inner flange of the top of the I-shaped GFRP column (1) and the corresponding section of the two side flange plates at both ends of the I-shaped GFRP arch beam (2) is covered with an inner node conformal liner plate (32). The inner node conformal liner plates (32) are symmetrically arranged on both sides of the web. The inner node conformal liner plates (32) can abut against at least part of the sidewalls on both sides of the web. The bolt fasteners (34) can penetrate the outer node cover plate (31), the flange plate, and the inner node conformal liner plate (32) and lock them.
3. The I-shaped GFRP contoured joint support arch frame for underground engineering according to claim 2, characterized in that: The inner contoured liner (32) of the node has an L-shaped structure or a semi-frame structure. The L-shaped inner contoured liner (32) of the node can abut against the inner flange and at least part of the sidewall of the web of the flange plate. The semi-frame structure inner contoured liner (32) of the node can abut against the inner flange and all the sidewalls of the web of the flange plates at both ends. The outer cover plate (31) of the node has a flat plate structure.
4. The I-shaped GFRP contoured joint support arch frame for underground engineering according to claim 1, characterized in that: The contouring liner assembly (3) includes an outer base cover plate (41), an inner base contouring liner plate (42), and bolt fasteners (34). The anchoring base (4) is provided with an outer base cover plate (41) and an inner base contouring liner plate (42). A pair of outer base cover plates (41) are arranged symmetrically, and an inner base contouring liner plate (42) perpendicular to the outer base cover plate (41) is symmetrically arranged between the pair of outer base cover plates (41). The I-beam is reserved between the outer base cover plate (41) and the inner base contouring liner plate (42). The insertion space of the I-shaped GFRP column (1); when the bottom of the I-shaped GFRP column (1) is inserted into the insertion space, a pair of outer base cover plates (41) abut against the outer flange of the inner flange plate of the bottom section of the I-shaped GFRP column (1), and the inner base contour plate (42) abuts against the inner flange of the inner flange plate of the bottom section of the I-shaped GFRP column (1) and at least part of the sidewalls on both sides of the web plate. The bolt fasteners (34) can penetrate the outer base cover plates (41), flange plates and inner base contour plates (42) and lock them.
5. The I-shaped GFRP contoured joint support arch frame for underground engineering according to claim 4, characterized in that: The inner contour liner (42) of the base is in the form of an L-shaped structure or a semi-frame structure. The inner contour liner (42) of the L-shaped structure can abut against the inner flange and at least part of the side wall of the web of the flange plate. The inner contour liner (42) of the semi-frame structure can abut against the inner flange and all the side walls of the web of the flange plates at both ends. The outer cover plate (41) of the base is in the form of a flat plate.
6. The I-shaped GFRP contoured joint support arch frame for underground engineering according to claim 1, characterized in that: The flange connection structure includes node connection steel plates (33) and node connection bolts (35). The top of the I-shaped GFRP column (1) and both ends of the I-shaped GFRP arch beam (2) are provided with node connection steel plates (33). The node connection steel plates (33) at both ends of the I-shaped GFRP arch beam (2) and the node connection steel plates (33) at the top of the I-shaped GFRP column (1) are connected by node connection bolts (35).
7. The I-shaped GFRP contoured joint support arch frame for underground engineering according to claim 1, characterized in that: The anchoring base (4) includes a base connecting steel plate (43) and a tapered chemical anchor (45). The bottom of the I-shaped GFRP column (1) is connected to the base connecting steel plate (43). The base connecting steel plate (43) has a bolt hole (5) for the tapered chemical anchor (45) to be inserted. The tapered chemical anchor (45) passes through the bolt hole (5) to fix the base connecting steel plate (43) to the installation reference surface.
8. The I-shaped GFRP contoured joint support arch frame for underground engineering according to claim 1, characterized in that: Both the I-shaped GFRP column (1) and the I-shaped GFRP arch beam (2) are solid structures formed by extrusion molding.
9. A construction method for an I-shaped GFRP contoured joint support arch frame for underground engineering, applied to the I-shaped GFRP contoured joint support arch frame according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Solid I-shaped GFRP profiles are prepared in the factory using pultrusion process, and the I-shaped GFRP profiles are cut into I-shaped GFRP columns (1) and I-shaped GFRP arch beams (2) segments according to the tunnel cross-section design. S2. At the top of the I-shaped GFRP column (1), the connecting sections at both ends of the I-shaped GFRP arch beam (2), and the top of the base connecting steel plate (43) in the anchor base (4), a contoured liner assembly (3) is pre-installed. The contoured liner assembly (3) at the node covers the outer flange, inner flange, and web at the node. The contoured liner assembly (3) at the node is fixedly connected to the node connecting steel plate (33) in the flange docking structure. The contoured liner assembly (3) on the base connecting steel plate (43) reserves the insertion space of the I-shaped GFRP column (1) and reserves bolt holes (5) in the node connecting steel plate (33) and the base connecting steel plate (43). S3. Measure and lay out the tunnel floor, drill holes and insert tapered chemical anchors (45), install the prefabricated base connecting steel plate (43) on the tapered chemical anchors (45) and level and fix it; S4. Install the I-shaped GFRP column (1) into the reserved insertion space on the base connecting steel plate (43), and lock the I-shaped GFRP column (1) and the contour liner assembly (3) on the base connecting steel plate (43) with bolt fasteners (34). S5. Lift the I-shaped GFRP arch beam (2) into place so that the node connecting steel plate (33) at the top of the I-shaped GFRP column (1) is aligned with the node connecting steel plates (33) at both ends of the I-shaped GFRP arch beam (2) and locked by bolt fasteners (34) to complete the arch frame closure.