Double-row pile protecting and reinforcing structure for shallow-buried unsymmetrical-pressure tunnel portal

Abstract

The invention provides a double-row pile protecting and reinforcing structure for a shallow-buried unsymmetrical-pressure tunnel portal, and belongs to the technical field of tunnels, front-row piles (a combination of steel pipe piles and steel sheet piles) are used for directly resisting pressure of soil on the near mountain side, rear-row steel sheet piles are used for providing anchoring counter-force, and a cooperative stress system is formed by combining pre-stressed anchor cables; the anti-bias stability of the tunnel portal is obviously improved; meanwhile, segmental construction of arch feet and pile-arch integrated pouring (1-2 meters per segment) are adopted, mountain disturbance is reduced, temperature cracks are avoided, and structural integrity is enhanced; in addition, due to the factorization prefabrication of the double-row piles and the small locking opening construction technology, the efficiency is greatly improved, and the manufacturing cost is reduced. According to the scheme, deviation of the hole towards the shallow buried side is restrained from the source, and safety and economical efficiency are both achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnels, in particular to a double-row pile protection and reinforcement structure for a shallow-buried bias-pressure tunnel opening. Background Art

[0002] As my country's tunneling projects expand into regions with complex geology, the construction of shallow, bias-loaded tunnels has increased significantly. Due to the thin overburden and uneven rock and soil pressure on both sides of the mountain (known as the bias-load effect), the portal sections of these tunnels are prone to landslides, surface cracking, and subsidence during construction, and even roof collapse accidents during operation. Traditional protective measures, such as single pipe-roof support, can reinforce the vault area, but their ability to resist lateral pressure is weak and makes it difficult to balance the bias-load. Independent anti-slide piles also have poor structural integrity and insufficient pile-soil synergy, which can easily cause the portal to shift toward the shallower side.

[0003] While existing technologies such as gravity retaining walls or single-row piles can partially alleviate lateral pressure, they suffer from long construction periods, significant mountain disturbance, and poor economic efficiency. Especially for tunnel portals with significant lateral pressure, these methods are unable to effectively control the displacement of the arch foot, exacerbating the risk of structural instability.

[0004] Therefore, there is an urgent need for a hole reinforcement technology that combines efficient construction, strong integrity and precise anti-bias pressure capability. Summary of the Invention

[0005] The purpose of the present invention is to provide a double-row pile protection and reinforcement structure for a shallow buried biased tunnel entrance, so as to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The present invention provides a double-row pile protection and reinforcement structure for a shallow buried bias-pressure tunnel entrance, comprising:

[0008] A guard arch is provided at the tunnel entrance and extends into the mountain;

[0009] A pipe shed, comprising grouting steel pipes distributed in the protective arch, the grouting steel pipes being inserted into the mountain through guide holes, and cement slurry being poured into the grouting steel pipes;

[0010] A double-row pile structure is located outside the protective arch and is arranged close to the mountain.

[0011] Preferably, the protective arch includes a circumferential arch crown, an arch foot on the near-mountain side and an arch foot on the far-mountain side, and the arch foot on the near-mountain side and the arch foot on the far-mountain side are both arranged at the bottom of the circumferential arch crown.

[0012] Preferably, the double-row pile structure includes a front row of piles and a rear row of piles, the front row of piles is arranged close to the arch foot on the mountain side, the rear row of piles is located away from the guard arch and arranged opposite to the front row of piles, and a prestressed anchor cable structure is provided between the front row of piles and the rear row of piles.

[0013] Preferably, the distance between the front row of piles and the rear row of piles is greater than or equal to the tunnel radius.

[0014] Preferably, the front row of piles includes a front row of steel pipe piles and a front row of steel sheet piles, which are alternately connected by tongue and groove of steel pipe piles.

[0015] Preferably, the rear row of piles comprises a rear row of steel sheet piles connected side by side.

[0016] Preferably, the prestressed anchor cable structure includes an anchor cable, which passes through the front row steel sheet piles and the rear row steel sheet piles. The end of the anchor cable close to the front row steel sheet piles is fixed by the front row pile waist beam and the front row anchor head, and the end of the anchor cable close to the rear row steel sheet piles is fixed by the rear row pile waist beam and the rear row anchor head, and prestress is applied.

[0017] Preferably, the front row pile waist beam is fixed to the side of the front row steel sheet piles through a supporting corbel.

[0018] Preferably, the guard arch and the front row of piles are cast as a whole by concrete, and the height of the front row of steel pipe piles is the same as that of the guard arch.

[0019] The present invention also provides a construction method for a double-row pile protection and reinforcement structure for a shallow buried biased tunnel portal, comprising the following steps:

[0020] Step 1: Pre-process the mountain slope;

[0021] Step 2: Construct the circumferential arch of the protective arch, with its outer end exposed outside the mountain;

[0022] Step 3: Install the grouting steel pipe through the pilot hole and inject grout;

[0023] Step 4: Excavate the pit on the near mountain side in sections, cast the arch foot on the far mountain side and connect the circumferential arch crown;

[0024] Step 5: Use a pile driver to drive in the front row of steel pipe piles, front row of steel sheet piles and rear row of steel sheet piles;

[0025] Step 6: Set up the front row pile waist beam and the rear row pile waist beam at the corresponding positions of the front row steel sheet piles and the rear row steel sheet piles, and install the supporting corbels;

[0026] Step 7: Install the anchor cable and secure the front anchor head;

[0027] Step 8: Apply prestress to the anchor cables and then fix the rear row anchor heads;

[0028] Step 9: Excavate the pit on the far mountain side in sections and cast the arch foot on the far mountain side;

[0029] Step 10: Cast the front row piles and the guard arch in sections as a whole;

[0030] Step 11: Backfill the double rows of piles and the area above the arch with plain soil.

[0031] Compared with the prior art, the present invention has achieved the following beneficial technical effects:

[0032] The present invention provides a double-row pile protection and reinforcement structure for shallow-buried biased tunnel portals. The front row of piles (a combination of steel pipe piles and steel sheet piles) directly resists the soil pressure near the mountain side, while the rear row of steel sheet piles provides anchor pull reaction force. Combined with prestressed anchor cables, a coordinated force system is formed, significantly improving the anti-biased pressure stability of the tunnel portal. At the same time, the arch foot is constructed in sections and the pile-arch integrated casting (each section is 1-2 meters) is used to reduce mountain disturbance and avoid temperature cracks, thereby enhancing the integrity of the structure. In addition, the factory prefabrication of the double-row piles and the small lock-mouth construction technology greatly improve efficiency and reduce costs. This solution fundamentally suppresses the deviation of the portal to the shallow buried side, combining safety and economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. 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 any creative work.

[0034] Figure 1 This is a front view of the double-row pile protection and reinforcement structure for a shallow buried biased tunnel entrance provided by the present invention;

[0035] Figure 2 A top view of a double-row pile protection and reinforcement structure for a shallow-buried biased tunnel entrance provided by the present invention;

[0036] Figure 3 A diagram showing the grouting steel pipe structure in a double-row pile protection and reinforcement structure for a shallow-buried biased tunnel portal provided by the present invention;

[0037] Figure 4 This is a structural diagram of the front row of steel pipe piles in a double-row pile protection and reinforcement structure for a shallow-buried biased tunnel portal provided by the present invention;

[0038] Figure 5 Anchorage diagram of the front row of steel sheet piles in the double-row pile protection and reinforcement structure for shallow-buried biased tunnel portals provided by the present invention;

[0039] Figure 6Anchorage diagram of the rear row of steel sheet piles in the double-row pile protection and reinforcement structure for shallow-buried biased tunnel portals provided by the present invention;

[0040] In the figure: 1-arch guard, 2-grouting steel pipe, 3-guide hole, 4-circumferential arch crown, 5-arch foot on the near mountain side, 6-arch foot on the far mountain side, 7-front row steel pipe piles, 8-front row steel sheet piles, 9-anchor cable, 10-rear row steel sheet piles, 11-front row pile waist beam, 12-rear row pile waist beam, 13-front row anchor head, 14-rear row anchor head, 15-steel pipe pile tongue and groove, 16-support corbel. DETAILED DESCRIPTION

[0041] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections. In the description of the present invention, it should be understood that the orientations or positional relationships indicated by the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0042] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] The purpose of the present invention is to provide a double-row pile protection and reinforcement structure for a shallow buried biased tunnel opening, so as to solve the problems existing in the prior art.

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] Example 1:

[0047] This embodiment provides a double-row pile protection and reinforcement structure for shallow buried biased tunnel openings, such as Figure 1-3 Shown, including:

[0048] Guard arch 1, which is set at the tunnel entrance and extends into the mountain;

[0049] The pipe shed includes grouting steel pipes 2 distributed in the arch 1. The grouting steel pipes 2 penetrate into the mountain through the guide holes 3. Cement slurry is poured into the grouting steel pipes 2.

[0050] The double-row pile structure is located outside the protective arch 1 and is set close to the mountain.

[0051] As an embodiment, the protective arch 1 includes a circumferential arch crown 4 , a near-mountain-side arch foot 5 and a far-mountain-side arch foot 6 , and both the near-mountain-side arch foot 5 and the far-mountain-side arch foot 6 are arranged at the bottom of the circumferential arch crown 4 .

[0052] As an implementation method, the double-row pile structure includes a front row of piles and a rear row of piles. The front row of piles is arranged close to the arch foot 5 on the mountain side, and the rear row of piles is located away from the protective arch 1 and is arranged opposite to the front row of piles. A prestressed anchor cable structure is provided between the front row of piles and the rear row of piles. Among them, the front row of piles mainly bears soil pressure, and the rear row of piles mainly provides anchor tension for the front row of piles, while bearing a certain amount of soil pressure. This structure can effectively resist the mountain bias and prevent the entire cave entrance from shifting to the shallow buried side.

[0053] As an implementation method, the distance between the front row of piles and the rear row of piles is greater than or equal to the tunnel radius to achieve sufficient pressure bearing effect.

[0054] As an implementation method, Figure 2 and 4 As shown, the front row of piles includes a front row of steel pipe piles 7 and a front row of steel sheet piles 8, which are alternately connected by steel pipe pile tongue and groove 15.

[0055] As an embodiment, the rear row piles include rear row steel sheet piles 10 connected side by side, and the front row steel sheet piles 8 and the rear row steel sheet piles 10 are hot-rolled U-shaped steel sheet piles, which are driven into the piles using a small lock mouth.

[0056] As an implementation method, Figure 2 、 5As shown in Figure 6, the prestressed anchor cable structure includes an anchor cable 9, which can be made of prestressed steel strands or steel bars. The anchor cable 9 passes through the front row steel sheet piles 8 and the rear row steel sheet piles 10, which can be achieved by punching holes in the steel sheet piles. The end of the anchor cable 9 close to the front row steel sheet piles 8 is fixed by the front row pile waist beam 11 and the front row anchor head 13, and the end of the anchor cable 9 close to the rear row steel sheet piles 10 is fixed by the rear row pile waist beam 12 and the rear row anchor head 14, and prestress is applied.

[0057] As an implementation method, Figure 5 As shown, the front row pile waist beam 11 is fixed to the side of the front row steel sheet piles 8 through the supporting corbel 16.

[0058] As an implementation method, the guard arch 1 and the front row of piles are cast into a whole by concrete, and the height of the front row of steel pipe piles 7 is the same as that of the guard arch 1 .

[0059] Example 2:

[0060] This embodiment provides a construction method for a double-row pile protection and reinforcement structure for a shallow-buried biased tunnel portal according to the first embodiment, comprising the following steps:

[0061] Step 1: Pre-process the mountain slope;

[0062] Step 2: construct the circumferential arch 4 of the protective arch 1, with its outer end exposed outside the mountain;

[0063] Step 3: Install the grouting steel pipe 2 through the guide hole 3 and inject grout;

[0064] Step 4: Excavate the trench on the near mountain side in sections, cast the arch foot 6 on the far mountain side and connect it with the annular arch crown 4;

[0065] Step 5: Use a pile driver to drive in the front row steel pipe piles 7, the front row steel sheet piles 8 and the rear row steel sheet piles 10;

[0066] Step 6: Install the front row pile waist beam 11 and the rear row pile waist beam 12 at the corresponding positions of the front row steel sheet piles 8 and the rear row steel sheet piles 10, and install the supporting corbels 16;

[0067] Step 7: Install the anchor cable 9 and fix the front anchor head 13;

[0068] Step 8: Apply prestress to the anchor cable 9 and then fix the rear anchor head 14;

[0069] Step 9: Excavate the far mountain side pit in sections and cast the far mountain side arch foot 5;

[0070] Step 10: Cast the front row piles and the guard arch 1 in sections as a whole;

[0071] Step 11: Backfill the double rows of piles and the area above the guard arch 1 with plain soil.

[0072] In this embodiment, the arch foot 6 on the near-mountain side and the arch foot 5 on the far-mountain side are constructed in sections, and the length of each section is 1-2 meters. The arch foot 6 on the near-mountain side is cast by section, and the arch foot 6 on the near-mountain side is cast in sections when the first pit is excavated, which disperses the disturbance of the overall excavation on the mountain. At the same time, the section excavation of the first pit and the section casting of the arch foot 6 on the near-mountain side are carried out simultaneously, which can effectively utilize the concrete curing time for excavation, reduce the construction period, and improve construction efficiency.

[0073] Furthermore, when the front row of piles and the guard arch 1 are cast as one, segmented construction is carried out, with each segment being 1-2 meters long. The segmented construction can effectively avoid temperature cracks, improve the overall quality of the structure, and enhance the ability to resist lateral pressure.

[0074] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] It should be noted that the components mentioned in the above embodiments are all universal standard parts or components known to those skilled in the art, and their structures and principles can be known to those skilled in the art through technical manuals or conventional experimental methods.

[0076] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be understood as limiting the present invention.

Claims

1. A double-row pile protection and reinforcement structure for shallow buried bias-pressure tunnel portals, characterized by: include: A protective arch (1), the protective arch (1) being arranged at the tunnel entrance and extending into the interior of the mountain; A pipe shed, the pipe shed comprising grouting steel pipes (2) distributed in the protective arch (1), the grouting steel pipes (2) penetrating into the mountain through guide holes (3), and cement slurry poured into the grouting steel pipes (2); A double-row pile structure is located outside the protective arch (1) and is arranged close to the mountain.

2. The double-row pile protection and reinforcement structure for shallow buried biased tunnel portals according to claim 1 is characterized in that: The protective arch (1) comprises a circumferential arch top (4), a near-mountain side arch foot (5) and a far-mountain side arch foot (6); the near-mountain side arch foot (5) and the far-mountain side arch foot (6) are both arranged at the bottom of the circumferential arch top (4).

3. The double-row pile protection and reinforcement structure for shallow buried biased tunnel portals according to claim 2 is characterized in that: The double-row pile structure comprises a front row of piles and a rear row of piles, wherein the front row of piles is arranged close to the arch foot (5) on the mountain side, and the rear row of piles is located away from the protective arch (1) and is arranged opposite to the front row of piles, and a prestressed anchor cable structure is provided between the front row of piles and the rear row of piles.

4. The double-row pile protection and reinforcement structure for shallow buried bias-pressure tunnel portals according to claim 3 is characterized in that: The distance between the front row of piles and the rear row of piles is greater than or equal to the tunnel radius.

5. The double-row pile protection and reinforcement structure for shallow buried biased tunnel portals according to claim 3 is characterized in that: The front row of piles comprises a front row of steel pipe piles (7) and a front row of steel sheet piles (8), which are alternately connected via steel pipe pile tongue and groove (15).

6. The double-row pile protection and reinforcement structure for shallow buried biased tunnel portals according to claim 5 is characterized in that: The rear row of piles comprises rear row steel sheet piles (10) connected side by side.

7. The double-row pile protection and reinforcement structure for shallow buried bias-pressure tunnel portals according to claim 6 is characterized in that: The prestressed anchor cable structure includes an anchor cable (9), which passes through the front row steel sheet piles (8) and the rear row steel sheet piles (10). The end of the anchor cable (9) close to the front row steel sheet piles (8) is fixed by a front row pile waist beam (11) and a front row anchor head (13), and the end of the anchor cable close to the rear row steel sheet piles (10) is fixed by a rear row pile waist beam (12) and a rear row anchor head (14), and prestress is applied.

8. The double-row pile protection and reinforcement structure for shallow buried bias-pressure tunnel portals according to claim 7 is characterized in that: The front row pile waist beam (11) is fixed to the side of the front row steel sheet pile (8) through a supporting corbel (16).

9. The double-row pile protection and reinforcement structure for shallow buried bias-pressure tunnel portals according to claim 8, characterized in that: The guard arch (1) and the front row piles are cast into a whole by concrete, and the height of the front row steel pipe piles (7) is the same as that of the guard arch (1).

10. A construction method for a double-row pile protection and reinforcement structure for a shallow-buried bias-pressure tunnel portal, characterized by: The following steps are involved: Step 1: Pre-process the mountain slope; Step 2: construct the circumferential arch (4) of the protective arch (1), with its outer end exposed outside the mountain; Step 3: Install the grouting steel pipe (2) through the guide hole (3) and inject grout; Step 4: Excavate the pit on the near mountain side in sections, cast the arch foot (6) on the far mountain side and connect it to the annular arch (4); Step 5: Use a pile driver to drive in the front row of steel pipe piles (7), the front row of steel sheet piles (8) and the rear row of steel sheet piles (10); Step 6: Install the front row pile waist beam (11) and the rear row pile waist beam (12) at the corresponding positions of the front row steel sheet piles (8) and the rear row steel sheet piles (10), and install the supporting brackets (16); Step 7: Install the anchor cable (9) and fix the front row anchor head (13); Step 8: applying prestress to the anchor cable (9) and then fixing the rear row anchor head (14); Step 9: Excavate the far mountain side pit in sections and cast the far mountain side arch foot (5); Step 10: Cast the front row piles and the guard arch (1) in sections to form a whole; Step 11: Backfill the double-row piles and the area above the guard arch (1) with plain soil.

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