Prestressed counter-pulling anchor pipe supporting structure for rock pillar in small-spacing tunnel

Abstract

This invention provides a prestressed tie-bar anchor support structure for rock columns in tunnels with small clearance. It includes multiple prestressed tie-bar anchors transversely intersecting within the rock column between the tunnel's initial and subsequent passages. Each prestressed tie-bar anchor includes an anchor body, a sleeve, a washer, a nut, a sealing sleeve, and a grout stopper. This invention, by transversely intersecting the prestressed tie-bar anchors within the rock column, not only effectively applies prestress to reinforce the rock column but also allows grout to be injected into the anchor holes through openings in the sleeves, filling numerous cracks in the rock column's internal structure that may be caused by disturbance. This further enhances the strength and stability of the rock column, ultimately improving the quality of tunnel construction with small clearance.

Description

Technical Field

[0001] This utility model relates to the field of tunnel construction technology, and in particular to a prestressed tie-anchor pipe support structure for rock columns in tunnels with small clearance. Background Technology

[0002] In areas with extremely complex terrain and geological conditions, and where mountainous regions constitute a large proportion, small-clearance tunnels have emerged as a special tunnel structure type between ordinary separated tunnels and arch tunnels. Due to their unique advantages, they have received widespread attention in tunnel engineering construction. With the continuous development of urban tunnel construction, and constrained by connection conditions, ultra-small-clearance tunnels have become an important direction in contemporary tunnel construction development.

[0003] When the clearance between two tunnels in a narrow-clearance tunnel is less than 1.5 times the tunnel span, the construction of the subsequent tunnel will cause secondary disturbance to the surrounding rock. In existing technologies, tie rods are used to apply prestress to the central rock column, transforming it into a triaxial stress state, but the stability provided is limited. Because the central rock column in a narrow-clearance tunnel is subjected to multiple disturbances from the subsequent tunnels, its internal structure may develop many cracks due to the disturbances, significantly reducing the stability of the central rock column. Therefore, finding a technology that can both repair the cracks generated in the central rock column and improve its stability by applying external forces is crucial. Utility Model Content

[0004] The purpose of this utility model is to address the shortcomings of the aforementioned background technology by providing a solution for tunnel construction with small clearance that can both repair cracks in the rock pillar and improve the stability of the rock pillar by applying external force.

[0005] To achieve the above objectives, this utility model provides a prestressed tie-anchor pipe support structure for rock columns in tunnels with small clearance, comprising multiple prestressed tie-anchor pipes that are transversely arranged in the middle rock column between the tunnel's lead tunnel and the tunnel's rear tunnel. Each prestressed tie-anchor pipe includes an anchor body, a sleeve, a pad, a nut, a sealing sleeve, and a grout stopper.

[0006] The anchor bolt body is provided with a grouting channel, which connects both ends of the anchor bolt body;

[0007] The sleeve is fitted over the outside of the anchor bolt body. The length of the sleeve is less than the length of the anchor bolt body. Both ends of the anchor bolt body can extend out from both ends of the sleeve. The sleeve has an opening for allowing grout to penetrate into the anchor hole.

[0008] The pads are disposed at both ends of the anchor bolt body, and the nuts are disposed at both ends of the anchor bolt body. Both the pads and the nuts are located outside the sleeve. The pads are provided with through holes, and the nuts are provided with threaded holes. Both the pads and the nuts are sleeved on the anchor bolt body, and the nuts are threadedly engaged with the anchor bolt body.

[0009] The sealing sleeve can be selectively fitted onto one end of the anchor bolt body to seal one end of the anchor bolt body.

[0010] The grout-stopping plugs are disposed at both ends of the sleeve and are used to seal the opening of the anchor hole. The gap between the sleeve, the grout-stopping plugs and the anchor body is connected to the grouting channel.

[0011] Furthermore, the prestressed tie-bar anchor pipe support structure for rock columns in the small clearance tunnel also includes a connecting sleeve, which is sleeved on the anchor body and used to connect two sections of the anchor body. The connecting sleeve is provided with a grout outlet hole and is located inside the casing.

[0012] Furthermore, the connecting sleeve is provided with an internal thread, and the connecting sleeve is threadedly connected to the anchor rod body.

[0013] Furthermore, the sealing sleeve is provided with internal threads, and the sealing sleeve is threadedly connected to the anchor rod body.

[0014] Furthermore, the stop plug is made of an elastic material.

[0015] Furthermore, the pad is a square pad, and the nut is an internal hexagonal nut.

[0016] The above-mentioned solution of this utility model has the following beneficial effects:

[0017] The prestressed tie-anchor pipe support structure for rock columns in tunnels with small clearance provided by this utility model, through the transverse through-hole installation of prestressed tie-anchor pipes inside the rock column, can not only effectively apply prestress to reinforce the rock column, but also allow grout to enter the anchor hole through the opening of the casing by grouting the anchor rod body, filling many cracks in the internal structure of the rock column that may be caused by disturbance, further improving the strength and stability of the rock column, and ultimately improving the quality of tunnel construction with small clearance.

[0018] Other beneficial effects of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0019] Figure 1 This is a construction diagram of the present invention;

[0020] Figure 2This is a schematic diagram of the prestressed tie-bar anchor pipe structure of this utility model;

[0021] Figure 3 This is a schematic diagram of the internal structure of the prestressed tie-bar anchor pipe of this utility model;

[0022] Figure 4 This is a schematic diagram of the connecting sleeve of this utility model;

[0023] Figure 5 This is a schematic diagram of the sealing sleeve of this utility model.

[0024] [Explanation of Labels in the Attached Image]

[0025] 1-Tunnel pre-exit tunnel; 2-Tunnel post-exit tunnel; 3-Anchor bolt body; 4-Sleeve; 5-Pad; 6-Nut; 7-Connecting sleeve; 8-Sealing sleeve; 9-Opening; 10-Grouting hole; 11-Grouting stop plug. Detailed Implementation

[0026] To make the technical problems, solutions, and advantages of this utility model clearer, a detailed description will be provided below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0027] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a locking connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0029] like Figures 1-3 As shown, an embodiment of this utility model provides a prestressed tie-bar anchor pipe support structure for rock columns in tunnels with small clearance. The tunnels with small clearance include a preliminary tunnel 1 and a follow-up tunnel 2, and a central rock column located between them. The prestressed tie-bar anchor pipe support structure for rock columns in tunnels with small clearance includes multiple prestressed tie-bar anchor pipes that are transversely arranged inside the central rock column. Each prestressed tie-bar anchor pipe includes an anchor body 3, a sleeve 4, a pad 5, a nut 6, a connecting sleeve 7, and a sealing sleeve 8. The sleeve 4 is fitted outside the anchor body 3 and has an opening 9. When grouting is performed on the prestressed tie-bar anchor pipe, the grout can penetrate and inject into the surrounding rock mass of the central rock column, thereby filling the cracks in the central rock column and strengthening it.

[0030] It should be noted that the length of the sleeve 4 is less than the length of the anchor bolt body 3. Therefore, both ends of the anchor bolt body 3 can extend from both ends of the sleeve 4. Two sets of washers 5 and nuts 6 are provided, each set located at one end of the anchor bolt body 3 and outside the sleeve 4. The washer 5 has a through hole, and the nut 6 has a threaded hole. Both the washer 5 and the nut 6 are fitted onto the anchor bolt body 3, with the nut 6 located further out of the washer 5 relative to the anchor bolt body 3. The threaded hole of the nut 6 is threadedly engaged with the anchor bolt body 3 (which has external threads) to anchor and lock the anchor bolt body 3. The washer 5 is used to increase the contact area between the nut 6 and the rock mass, thereby improving anchoring stability.

[0031] In this embodiment, the anchor bolt body 3 itself is also hollow, with grouting channels. Both ends of the grouting channels extend to both ends of the anchor bolt body 3 and communicate with the outside. Meanwhile, as... Figure 4 As shown, the connecting sleeve 7 is fitted onto the anchor body 3, and is used to connect two sections of the anchor body 3 so that the combined anchor body 3 reaches the required length. The connecting sleeve 7 also has a grout outlet 10, which connects to the end of the anchor body 3 (i.e., the grouting channel) when connecting the two sections of the anchor body 3. Simultaneously, as... Figure 5 As shown, the sealing sleeve 8 can be fitted onto one end of the anchor bolt body 3 to seal the corresponding end of the anchor bolt body 3, preventing grout from flowing out of the corresponding end to the outside when grout is injected from the other end of the anchor bolt body.

[0032] Understandably, the outer diameter of the connecting sleeve 7 is set to be smaller than the inner diameter of the sleeve 4, and after installation, the connecting sleeve 7 is also located inside the sleeve 4. Simultaneously, both the inner surfaces of the connecting sleeve 7 and the sealing sleeve 8 are provided with internal threads, thus ensuring a secure threaded connection with the anchor bolt body 3. After the grout is injected into the grouting channel of the anchor bolt body 3, it first enters the connecting sleeve 7 through the grouting channel, then flows out of the grout outlet 10 (including a small amount from the thread gap) to the outside of the connecting sleeve 7, reaching the space between the anchor bolt body 3 and the sleeve 4, and then enters the anchor hole through the opening 9 of the sleeve 4, filling the gaps in the rock mass. The corresponding end face of the sealing sleeve 8 can be provided with an elastic material (e.g., rubber) so that when the end face of the sealing sleeve contacts the end face of the anchor bolt body 3, it can seal the corresponding end of the grouting channel, preventing grout from flowing out from the corresponding end of the anchor bolt body 3. It should be noted that during grouting, both the tunnel 1 and the tunnel 2 have been completed, and the two ends of the anchor body 3 are located in the tunnel 1 and the tunnel 2 respectively. Therefore, when grouting one end of the anchor body 3, it is necessary to prevent the grout from falling into the tunnel where the other end is located.

[0033] In this embodiment, both ends of the sleeve 4 are also provided with grout-stopping plugs 11. The grout-stopping plugs 11 have through holes and are fitted onto the anchor bolt body 3. The grout-stopping plugs 11 are made of elastic material to seal the positions of both ends of the sleeve 4 and the opening of the anchor hole, preventing grout from flowing out of the anchor hole into the tunnel, and also preventing grout from flowing into the outside of the anchor hole through the gap between the end of the sleeve 4 and the anchor bolt body 3 and the pad 5. It is understood that before installing the pad 5 and the nut 6, the grout-stopping plug 11 is inserted into the end of the sleeve 4, and then the pad 5 and the nut 6 are installed. After anchoring and locking, the clamping force of the pad 5 can completely seal the opening of the anchor hole with the grout-stopping plug 11.

[0034] In one specific embodiment, the outer diameter of the anchor bolt body 3 is set to 28mm. The outer diameter of the sleeve 4 is set to 45mm, and the sleeve 4 is also made of steel. When the sleeve 4 is installed with the anchor bolt body 3, the length of the anchor bolt body 3 extending out of the sleeve 4 can be set to 25cm. The connecting sleeve 7 and the sealing sleeve 8 can also be made of steel, etc. The pad 5 is a square pad 5, and the nut 6 is an internal hex nut 6, etc., which can be consistent with the conventional anchor bolt settings in the prior art.

[0035] The specific construction process of the prestressed tie-anchor pipe support structure for rock columns in small-clearance tunnels provided in this embodiment is as follows: After the tunnel's initial tunnel 1 is excavated and supported, the prestressed tie-anchor pipe is driven into the preset position of the central rock column. At this time, one end (i.e., the initial tunnel end) is first anchored and fixed. After the subsequent tunnel is also excavated and supported, the prestressed tie-anchor pipe achieves complete lateral penetration of the central rock column. Subsequently, the other end (i.e., the subsequent tunnel end) is installed with a grout stopper 11, a pad 5, and a nut 6, applying the prestress required by design to the prestressed tie-anchor pipe, so that the central rock column is in a favorable compressive state.

[0036] During grouting reinforcement, one end of the anchor bolt body 3 is first sealed with a sealing sleeve 8, and then pressure grouting begins from the other end of the anchor bolt body 3. Cement mortar can be used as the grouting material, with a water-cement ratio controlled at 1:1, and the grouting pressure maintained within the range of 1–2 MPa. It is important to emphasize that a field grouting test must be conducted before formal grouting construction to verify and ultimately determine suitable grouting parameters. As grouting continues, once the anchor bolt body 3 is completely filled with grout, the grout enters the connecting sleeve 7 and overflows from the grout outlet 10. The overflowing grout then fills the annular gap between the sleeve 4 and the anchor bolt body 3, and then continues to penetrate and solidify into the interior of the central rock column through the pre-reserved opening 9 on the sleeve 4. This series of processes ultimately effectively improves the integrity, strength, and stability of the central rock column.

[0037] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0038] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A pre-stressed counter-pulled anchor pipe supporting structure for rock pillars in a small-spacing tunnel, characterized in that, It includes multiple prestressed tie rods that are transversely intersected in the rock column between the tunnel pre-exit tunnel (1) and the tunnel post-exit tunnel (2). The prestressed tie rods include anchor body (3), sleeve (4), pad (5), nut (6), sealing sleeve (8), and grout stop plug (11). The anchor body (3) is provided with a grouting channel, which connects the two ends of the anchor body (3); The sleeve (4) is sleeved outside the anchor body (3). The length of the sleeve (4) is less than the length of the anchor body (3). Both ends of the anchor body (3) can extend out from both ends of the sleeve (4). The sleeve (4) has an opening (9) for allowing grout to penetrate into the anchor hole. The pad (5) is disposed at both ends of the anchor body (3), and the nut (6) is disposed at both ends of the anchor body (3). The pad (5) and the nut (6) are both located outside the sleeve (4). The pad (5) is provided with a through hole, and the nut (6) is provided with a screw hole. The pad (5) and the nut (6) are both sleeved on the anchor body (3), and the nut is threadedly engaged with the anchor body (3). The sealing sleeve (8) can be selectively fitted onto one end of the anchor body (3) to seal one end of the anchor body (3); The grout stopper (11) is disposed at both ends of the sleeve (4). The grout stopper (11) is used to seal the opening of the anchor hole. The gap between the sleeve (4), the grout stopper (11) and the anchor body (3) is connected to the grouting channel.

2. The prestressed tie-rod support structure for rock columns in a tunnel with small clearance as described in claim 1, characterized in that, The prestressed tie-anchor pipe support structure for rock columns in the small clearance tunnel also includes a connecting sleeve (7), which is sleeved on the anchor body (3). The connecting sleeve (7) is used to connect two sections of the anchor body (3). The connecting sleeve (7) is provided with a grout outlet (10) and is located inside the casing (4).

3. The prestressed tie-bar anchor pipe support structure for rock columns in a tunnel with small clearance as described in claim 2, characterized in that, The connecting sleeve (7) is provided with an internal thread, and the connecting sleeve (7) is threadedly connected to the anchor rod body (3).

4. The prestressed tie-rod support structure for rock columns in a tunnel with small clearance as described in claim 1, characterized in that, The sealing sleeve (8) is provided with internal threads, and the sealing sleeve (8) is threadedly connected to the anchor body (3).

5. The prestressed tie-bar anchor pipe support structure for rock pillars in a tunnel with small clearance as described in claim 1, characterized in that, The stop plug (11) is made of an elastic material.

6. The prestressed tie-bar anchor pipe support structure for rock columns in a tunnel with small clearance as described in claim 1, characterized in that, The pad (5) is a square pad, and the nut (6) is an internal hexagonal nut.

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