An arch unit and a supporting arch for a large-section tunnel in soft rock
By designing arch frame units, a composite structure is formed by filling concrete with I-beams, ribs, and grouting pipes, which solves the problem of poor performance of traditional support methods in soft rock strata and achieves effective support and construction safety for large-section tunnels in soft rock.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- POWERCHINA HUADONG ENG CORP LTD
- Filing Date
- 2025-07-11
- Publication Date
- 2026-05-29
AI Technical Summary
Traditional methods for controlling the deformation of surrounding rock in large-section tunnels have limited effectiveness in soft rock formations, resulting in slow construction progress, difficulty in ensuring safety, easy damage to the support system, and inability to effectively control large deformation and cross-sectional convergence in soft rock.
The system employs arch frame units, including pre-fabricated curved I-beams, rib plates to close openings, and grouting pipes to fill concrete, forming a composite structure. Multiple arch frame units are spliced together to form a steel arch frame, which is then fixed with anchor pipes. The number and curvature of the arch frames can be adjusted to adapt to different geological formations.
It improves bending stiffness and load-bearing capacity, suppresses rheological deformation of soft rock, avoids local instability of the support structure, and ensures construction quality and safety.
Smart Images
Figure CN224300901U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of construction technology for excavating large-section tunnels, and in particular to an arch frame unit and an arch frame for supporting large-section tunnels in soft rock. Background Technology
[0002] In the construction of tunnels and underground engineering projects, the construction of large-section tunnels often faces complex geological conditions. In particular, when tunnels encounter weak surrounding rock sections during excavation, soft rock strata are characterized by low strength, large deformation, and easy breakage. This not only leads to slow construction progress but also makes it difficult to guarantee construction safety, posing significant unfavorable factors for tunnel construction and operation.
[0003] Current traditional methods for controlling the deformation of surrounding rock in large-section tunnels often employ shotcrete with steel arch support. While this support structure can provide some support, its effectiveness is often limited under extremely severe soft rock deformation conditions. It cannot effectively control the problem of large deformation in soft rock, leading to severe cross-sectional convergence, uneven damage and crushing of the support system, which in turn causes shrinkage on both sides of the tunnel wall and overall deformation and diameter reduction of the tunnel. Summary of the Invention
[0004] The technical problem to be solved by this utility model is: to provide an arch frame unit and an arch frame for supporting large-section tunnels in soft rock, in view of the above-mentioned problems.
[0005] The technical solution adopted in this utility model is: an arch frame unit, comprising:
[0006] I-beams, pre-processed into an arc-shaped structure;
[0007] Ribs are located on both sides of the web of the I-beam. The top and bottom of the ribs are connected to the flanges at both ends of the I-beam, respectively, which can block the openings on both sides of the I-beam, thus forming an internal cavity.
[0008] Grouting pipes, which are installed through the ribs, are used to inject concrete filler into the cavity;
[0009] Connectors, located at both ends of the I-beam, can seal the end openings of the I-beam and splice adjacent arch frame units to form a steel arch frame.
[0010] In some embodiments, the connector includes a connecting plate, bolt holes, and high-strength bolts. Both ends of the I-beam are provided with connecting plates that can seal their own ends. The connecting plate is provided with multiple bolt holes. The high-strength bolts are threaded into the bolt holes. The high-strength bolts pass through the bolt holes on the connecting plates of adjacent arch frame units, so that adjacent arch frame units can be connected.
[0011] In some embodiments, the thickness of the connecting plate is 10mm, the diameter of the bolt hole is 25mm, and the specification of the high-strength bolt is M20.
[0012] In some embodiments, the concrete filler comprises C40 micro-expansion fine aggregate concrete.
[0013] In some embodiments, the ribs are made of 8mm steel plates.
[0014] In some embodiments, the port of the grouting pipe is threaded.
[0015] Another technical solution adopted in this utility model is: a support arch frame for large-section tunnels in soft rock, comprising:
[0016] Multiple arch frame units are sequentially spliced to form a complete steel arch frame. The steel arch frame is installed inside the excavated tunnel and can provide support for the tunnel wall.
[0017] A concrete filling layer is placed inside the cavity of the arch frame unit, so that the concrete filling layer and the steel arch frame work together to form a support structure for the excavated tunnel.
[0018] In some embodiments, during the assembly of the plurality of arch frame units, locking anchor pipes are used to fix the arch frame units located at the waist of the arch.
[0019] In some embodiments, the number and curvature of the arch frame units are adjusted according to the dimensions of the excavation section;
[0020] If the tunnel is excavated using the drill and blast method, multiple arch frame units are spliced together to form an arch structure to adapt to the cross-section of the excavated tunnel.
[0021] If the tunnel is excavated using an open-face TBM, multiple arch frame units are spliced together to form a circular structure to adapt to the cross-section of the excavated tunnel.
[0022] The beneficial effects of this utility model are:
[0023] 1. By sealing the open ends of the I-beams with ribs and connectors, and filling the internal cavities of the I-beams with concrete through grouting pipes to form a concrete filling layer, the resulting composite structure enhances the overall bending stiffness and load-bearing capacity of the arch frame unit. The concrete filling layer, working in tandem with the I-beams, suppresses the rheological deformation of soft rock. Multiple arch frame units can also be modularly spliced to form a box-type steel-concrete support arch frame capable of handling large-section tunnels in weak surrounding rock. The number and curvature of the arch frame units can be adjusted according to the dimensions of the excavated tunnel cross-section to adapt to large cross-sectional profiles and prevent local instability of the support structure. Attached Figure Description
[0024] Figure 1 This is a structural schematic diagram of the arch frame unit in this application.
[0025] Figure 2 This is a cross-sectional schematic diagram of the arch frame unit in this application.
[0026] Figure 3 This is a detailed diagram of the node of the connecting plate in this application.
[0027] Figure 4 This is a schematic diagram of the structure used in this application for drill-and-blast excavation.
[0028] Figure 5 This is a structural schematic diagram of the open-type TBM excavation used in this application.
[0029] Figure 6 yes Figure 4 or Figure 5 Detailed drawing of the node at the connection of the central arch frame unit.
[0030] Explanation of reference numerals in the attached figures:
[0031] 1. I-beam; 2. Rib plate; 3. Connecting plate; 4. Bolt hole; 5. High-strength bolt; 6. Grouting pipe; 7. Concrete filling layer.
[0032] 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.
[0033] The term "comprising" is open-ended. As used in the appended claims, it does not exclude additional structures or steps. Detailed Implementation
[0034] 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.
[0035] Example 1:
[0036] Combination Figures 1 to 3As shown, this embodiment is an arch frame unit, including an I-beam 1, ribs 2, grouting pipes 6, and connectors. The I-beam 1 is pre-processed into an arc-shaped structure. Ribs 2 are welded to both sides of the web of the I-beam 1. The top of the ribs 2 is connected to the top flange of the I-beam 1, and the bottom of the ribs 2 is connected to the bottom flange of the I-beam 1. The ribs 2 can seal the openings on both sides of the I-beam 1, forming a cavity inside the I-beam 1. Grouting pipes 6 are provided through the ribs 2, through which concrete filler can be injected into the cavity inside the I-beam 1. Connectors are provided at both ends of the I-beam 1. The connectors can seal the end openings of the I-beam 1, and the connectors can also splice adjacent arch frame units to form a steel arch frame.
[0037] In some implementations, the connector includes a connecting plate 3, bolt holes 4, and high-strength bolts 5. Both ends of the I-beam 1 are welded with connecting plates 3 capable of sealing their own ends. The connecting plates 3 have multiple bolt holes 4, and the high-strength bolts 5 are threaded into the bolt holes 4. The high-strength bolts 5 pass through the bolt holes 4 on the connecting plates 3 of adjacent arch frame units, allowing adjacent arch frame units to be connected. Specifically, in this embodiment, the connecting plate 3 has dimensions of 250×300×10mm, and each connecting plate 3 has four bolt holes 4 with a diameter of 25mm. The high-strength bolts 5 are M20.
[0038] In some implementations, the concrete filler includes C40 micro-expansion fine aggregate concrete, which has micro-expansion properties that allow the rib plate 2 and the I-beam 1 to fit tightly against the surrounding rock, reduce voids, inhibit continuous deformation of the surrounding rock, and prevent cross-sectional diameter reduction.
[0039] In some implementations, rib 2 is made of 8mm steel plate.
[0040] In some implementation schemes, the ends of the grouting pipe 6 are threaded to prevent grout leakage.
[0041] In some implementation schemes, the arch frame units are mainly made of 20b type I-beams, and the spacing of each arch frame is dynamically designed according to the engineering geological conditions and the size of the tunnel excavation section.
[0042] In some implementation schemes, if relatively self-stabilizing strata are encountered during tunnel excavation and support, concrete filler may not be used to fill the arch frame unit. If extremely soft surrounding rock strata are encountered, C40 micro-expansion fine aggregate concrete can be used to fill and compact the arch frame unit through grouting pipe 6.
[0043] Example 2:
[0044] Combination Figures 4 to 6As shown, this embodiment is a support arch frame for large-section tunnels in soft rock, comprising multiple arch frame units as described in Embodiment 1 and a concrete filling layer 7. The multiple arch frame units are sequentially spliced to form a complete steel arch frame. These steel arch frames are arranged at intervals along the extension direction of the excavated tunnel, providing support for the tunnel walls. Concrete filler is injected into each arch frame unit through grouting pipes 6 to form a concrete filling layer 7 inside the cavity, allowing the concrete filling layer 7 to cooperate with the steel arch frame to form the support structure for the excavated tunnel.
[0045] In some implementation schemes, a single steel arch frame is composed of multiple arch frame units connected sequentially, such as... Figure 6 As shown, each arch frame unit is connected via bolt holes 4 on the corresponding connecting plate 3 and M20 high-strength bolts 5 to form a complete steel arch frame. This connection method using connecting plates 3 and high-strength bolts 5 not only facilitates rapid installation and reduces welding work, but also ensures node strength, avoids the brittle failure of traditional welded nodes, and ensures uniform stress distribution across the entire arch frame. In this embodiment, centralized processing and on-site assembly are primarily employed. During the assembly of multiple arch frame units, anchor pipes are used to fix the arch frame units located at the arch waist, which can prevent the arch frame from sinking or twisting to a certain extent.
[0046] In some implementations, the number and curvature of the arch frame units in this embodiment are adjusted according to the dimensions of the excavation cross-section. For example... Figure 4 As shown, if the tunnel is excavated using the drill-and-blast method, multiple arch frame units are spliced together to form an arch structure to adapt to the cross-section of the excavated tunnel. Figure 5 As shown, if the tunnel is excavated using an open-face TBM, multiple arch frame units are spliced together to form a circular structure to adapt to the cross-section of the excavated tunnel.
[0047] The implementation principle of a support arch frame for large-section tunnels in soft rock, as described in the following embodiment, is as follows:
[0048] Traditional I-beam arch frames are prone to uneven deformation and crushing in soft rock, leading to cross-sectional convergence and support failure. In this embodiment, the support arch frame is mainly applied to weak surrounding rock strata. During the excavation of large-section tunnels, an advanced geological prediction system is used to explore the geology ahead. Based on the data analysis results, the excavation and support parameters are dynamically adjusted for different strata.
[0049] Specifically, in this embodiment, the support arch frame is composed of multiple arch frame units. For a single arch frame unit, an I-beam 1 provides stable skeletal support. Ribs 2 and connecting plates 3 enclose the I-beam 1, and concrete is filled into the enclosed cavity to form a box-type composite beam. The synergistic force distribution between the steel and concrete improves bending stiffness and load-bearing capacity. Traditional I-beams 1 are prone to web buckling, while the concrete-filled box beam avoids local instability. By combining different excavation processes and adjusting the number and curvature of the arch frames according to different excavation sections, multiple arch frame units can be adaptively spliced together to form a box-type steel-concrete support arch frame capable of handling large-section tunnels in weak surrounding rock.
[0050] Therefore, this application can not only solve the serious problems of large deformation and large convergence encountered in the excavation and support of large-section tunnels in soft rock, but also be used for the portal excavation and support of shallow buried tunnels and mining tunnels. It can avoid damage to the completed support system caused by tunnel convergence and other external forces to a certain extent, thereby ensuring the quality and safety of tunnel construction.
[0051] The above are all preferred embodiments of this utility model, and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape and principle of this utility model should be covered within the scope of protection of this utility model.
Claims
1. An arch frame unit, characterized in that, include: I-beam (1), pre-processed into an arc-shaped structure; Ribs (2) are provided on both sides of the web of the I-beam (1). The top and bottom of the ribs (2) are respectively connected to the flanges at both ends of the I-beam (1), which can block the openings on both sides of the I-beam (1) and form a cavity inside. Grouting pipe (6) is installed through the rib plate (2) and is used to fill the cavity with concrete filler. The connectors are located at both ends of the I-beam (1) and can seal the end openings of the I-beam (1) and splice adjacent arch frame units to form a steel arch frame.
2. The arch frame unit according to claim 1, characterized in that: The connector includes a connecting plate (3), bolt holes (4) and high-strength bolts (5). Both ends of the I-beam (1) are provided with connecting plates (3) that can seal their own ends. The connecting plate (3) is provided with multiple bolt holes (4). The high-strength bolts (5) are threaded into the bolt holes (4). The high-strength bolts (5) pass through the bolt holes (4) on the connecting plate (3) of the adjacent arch frame unit, so that the adjacent arch frame units can be connected.
3. An arch frame unit according to claim 2, characterized in that: The thickness of the connecting plate (3) is 10mm, the diameter of the bolt hole (4) is 25mm, and the specification of the high-strength bolt (5) is M20.
4. An arch frame unit according to claim 1, characterized in that: The concrete filler includes C40 micro-expansion fine aggregate concrete.
5. An arch frame unit according to claim 1, characterized in that: The rib (2) is made of 8mm steel plate.
6. An arch frame unit according to claim 1, characterized in that: The port of the grouting pipe (6) is made using a threading process.
7. A support arch for large-section tunnels in soft rock, characterized in that, include: Multiple arch frame units according to any one of claims 1 to 6 are sequentially spliced to form a whole steel arch frame. The steel arch frame is installed inside the excavated tunnel and can provide support for the tunnel wall of the excavated tunnel. The concrete filling layer (7) is placed inside the cavity of the arch frame unit, so that the concrete filling layer (7) and the steel arch frame cooperate to form the support structure for the excavated tunnel.
8. A support arch for large-section tunnels in soft rock according to claim 7, characterized in that: During the assembly of multiple arch frame units, anchor pipes are used to fix the arch frame units located at the waist of the arch.
9. A support arch for large-section tunnels in soft rock according to claim 7, characterized in that: The number and curvature of the arch frame units are adjusted according to the dimensions of the excavation section. If the tunnel is excavated using the drill and blast method, multiple arch frame units are spliced together to form an arch structure to adapt to the cross-section of the excavated tunnel. If the tunnel is excavated using an open-face TBM, multiple arch frame units are spliced together to form a circular structure to adapt to the cross-section of the excavated tunnel.