A method and device for reinforcing rock wedges and gullies in a small-clearance tunnel

Abstract

The present application relates to the technical field of initial support construction of extremely small net distance tunnel engineering, and particularly relates to a method and device for reinforcing rock sandwich and goose-shaped area in extremely small net distance tunnel, which comprises a wedge-shaped anchoring groove reserved in the stress weak area of rock sandwich between tunnel sections; a through hole is drilled in the wedge-shaped anchoring groove; an R32N precision rolled threaded steel is inserted; a pad is installed at the threaded steel end head on both sides of the rock sandwich, so that the pad is closely attached to the bottom plane of the anchoring groove; a nut and a nut force applying adapter are installed, and prestress is applied to complete the prestress reinforcement of the active R32N precision rolled threaded steel pull rod, the wedge-shaped anchoring groove reserved in the stress weak area of rock sandwich between tunnel sections and the prestress reinforcement by using the R32N precision rolled threaded steel, and the outer inserted pipe shed and the inclined cantilever type grouting guide pipe applied in the goose-shaped area, which effectively improve the stability and safety of the tunnel, these reinforcement measures not only reduce the risks such as collapse and landslide in the construction process, but also improve the construction efficiency and engineering quality, prolong the service life of the tunnel and reduce the maintenance cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of initial support construction of extremely small clear distance tunnel engineering, in particular to a method and device for reinforcing rock sandwich and goose-shaped area in extremely small clear distance tunnel. BACKGROUND

[0002] With the rapid development of railway engineering, due to the limitation of topography, geology, line condition and bridge-tunnel connection, many tunnels are designed as extremely small clear distance single line parallel. In the process of excavation and support of extremely small clear distance tunnel, the rock sandwich and goose-shaped area between the two tunnel sections are the stress weak areas, which are affected by clear distance, blasting disturbance, surrounding rock and other factors, and there is a certain risk. In order to solve the above problems, a method and device for reinforcing rock sandwich and goose-shaped area in extremely small clear distance tunnel are provided. SUMMARY

[0003] In view of the above or the existing technology, due to the limitation of topography, geology, line condition and bridge-tunnel connection, many tunnels are designed as extremely small clear distance single line parallel. In the process of excavation and support of extremely small clear distance tunnel, the rock sandwich and goose-shaped area between the two tunnel sections are the stress weak areas, which are affected by clear distance, blasting disturbance, surrounding rock and other factors, and there is a certain risk. In order to solve the above problems, a method and device for reinforcing rock sandwich and goose-shaped area in extremely small clear distance tunnel are provided.

[0004] Therefore, the purpose of the present application is to provide a method and device for reinforcing rock sandwich and goose-shaped area in extremely small clear distance tunnel.

[0005] To solve the above technical problems, the present application provides the following technical scheme: the method comprises the following steps:

[0006] a. Reserving a wedge-shaped anchoring groove in the stress weak area of the rock sandwich between the sections of the extremely small clear distance tunnel;

[0007] b. Drilling a through hole in the wedge-shaped anchoring groove;

[0008] c. Inserting R32N precision rolled threaded steel;

[0009] d. Installing a backing plate at the end of the threaded steel on both sides of the rock sandwich, so that the backing plate is in close contact with the bottom plane of the anchoring groove;

[0010] e. Installing a nut and a nut force applying adapter, and applying prestress to complete the active R32N precision rolled threaded steel rod prestressed reinforcement.

[0011] As a preferred scheme of the method for reinforcing rock sandwich and goose-shaped area in extremely small clear distance tunnel, the nut force applying adapter comprises a nut outer adapter sleeve and a threaded steel welded at one end thereof, and an extended welded nut of the same size.

[0012] As a preferred embodiment of the reinforcement method for interbedded rock and goose-shaped areas in tunnels with minimal clearance according to the present invention, in the stress-weak area of ​​the goose-shaped area between the tunnel sections with minimal clearance, during the initial support of the tunnel, an externally inserted pipe roof is constructed from the arch waist of the tunnel to the arch top area of ​​the tunnel.

[0013] As a preferred embodiment of the method for reinforcing interbedded rock and goose-shaped areas in tunnels with minimal clearance according to the present invention, wherein: after the initial support of the pilot tunnel is completed, a hole is drilled through the interbedded rock at the waist of the pilot tunnel to the arch of the subsequent tunnel, and a guide pipe is inserted.

[0014] As a preferred embodiment of the reinforcement method for interbedded rock and goose-shaped areas in tunnels with minimal clearance according to the present invention, the end of the guide pipe is fixed by welding together a "well" shaped fixing frame and a "hoof" shaped anchor joint.

[0015] As a preferred embodiment of the reinforcement method for interbedded rock and goose-shaped areas in tunnels with minimal clearance according to the present invention, the method involves: active pre-reinforcement by grouting inside the guide pipe, thereby completing the active pre-reinforcement of the inclined grouting guide pipe in tunnels with minimal clearance.

[0016] As a preferred embodiment of the method for reinforcing interbedded rock and goose-shaped zones in tunnels with minimal clearance according to the present invention, it includes:

[0017] a. Nut connector sleeve;

[0018] b. Threaded steel welded to one end of the sleeve of the nut connector;

[0019] c. Extend the equivalent size nut welded onto the threaded steel.

[0020] As a preferred embodiment of the method for reinforcing interbedded rock and goose-shaped zones in tunnels with minimal clearance according to the present invention, wherein: a. a guide pipe;

[0021] b. The "well" shaped fixing bracket at the end of the catheter;

[0022] c. The "hoof" shaped anchor joint is welded and fixed together with the "well" shaped fixing frame.

[0023] As a preferred embodiment of the reinforcement method for interbedded rock and goose-shaped zones in tunnels with minimal clearance according to the present invention, the contact area between the pad and the bottom plane of the anchoring groove is not less than 90%; the prestress is applied by a hydraulic jack to ensure uniform distribution of prestress; the diameter of the externally inserted pipe roof is 100-200 mm and the wall thickness is 5-10 mm; the length of the inclined grouting pipe is 2-5 meters and the diameter of the pipe matches the borehole diameter; the material of the "well" shaped fixing frame and the "hoof" shaped anchor joint is high-strength alloy steel; the grouting material is cement-water glass slurry with a ratio of cement:water glass = 1:0.5.

[0024] As a preferred embodiment of the reinforcement method for interbedded rock and goose-shaped areas in tunnels with minimal clearance according to the present invention, wherein: a. hydraulic jack;

[0025] b. Pressure gauge connected to the hydraulic jack;

[0026] c. A control system used to control the application of prestress.

[0027] The beneficial effects of the reinforcement method for interbedded rock and goose-shaped zones in tunnels with minimal clearance according to this invention are as follows: By reserving wedge-shaped anchoring grooves in the stress-weak areas of the interbedded rock between tunnel sections and using R32N precision-rolled threaded steel for prestressing reinforcement, and by constructing externally inserted pipe roofs and inclined grouting pipes in the goose-shaped zones, the stability and safety of the tunnel are effectively improved. These reinforcement measures not only reduce the risks of collapse and landslides during construction, but also improve construction efficiency and project quality, extend the service life of the tunnel, and reduce maintenance costs. Furthermore, this method has wide applicability and is suitable for tunnel projects with minimal clearance under various geological conditions. It embodies technological innovation, conforms to the concept of green construction, is environmentally friendly, and has significant economic benefits. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the prestressed reinforcement of threaded steel tie rods in medium-density rock.

[0030] Figure 2 A schematic diagram of an adapter for applying force to a nut.

[0031] Figure 3 Reinforcement of pipe sheds in the Yanxing area Figure 1 .

[0032] Figure 4 For the reinforcement of pipe sheds in Yanxing District Figure 2 .

[0033] Figure 5 This is a schematic diagram of the active pre-reinforcement position of the inclined grouting conduit.

[0034] Figure 6 The diagram shows the welding and fixing of the conduit together with the "well" shaped fixing frame and the "hoof" shaped anchor joint. Detailed Implementation

[0035] In order to make the above objectives, features and advantages of the present application more obvious and comprehensible, specific embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0036] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other manners different from those described herein, and those skilled in the art can make similar generalizations without departing from the spirit and scope of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0037] Secondly, "one embodiment" or "embodiment" referred to herein means that specific features, structures or characteristics can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an embodiment that is independent or alternative to other embodiments.

[0038] In Example 1, in a single-line minimum-clearance tunnel project, for the weak stress area of the middle sandwiched rock, first, a wedge-shaped anchoring groove with a width of 0.5 meters and a depth of 1.5 meters is reserved between the tunnel sections. Then, a through hole with a diameter of 32 millimeters is drilled in the groove, and the hole depth is consistent with the anchoring groove depth. Then, a R32N precision rolled threaded steel with a length of 2 meters is inserted, ensuring that both ends protrude from the anchoring groove. A pad plate with a size of 0.3 meters x 0.3 meters and a thickness of 10 millimeters is installed at the end of the threaded steel, and the pad plate is in close contact with the bottom plane of the anchoring groove. Finally, a nut and its force adapter are installed, and the pre-stress is applied by a hydraulic jack. After the pre-stress reaches the design value, the nut is tightened, and the reinforcement is completed.

[0039] In Example 2, in the goose-shaped area of the minimum-clearance tunnel, after the initial support of the first tunnel is completed, an external insertion type pipe shed is applied from the arch waist of the rear tunnel to the arch top area of the first tunnel. The pipe shed is made of steel pipe with a diameter of 150 millimeters, a wall thickness of 8 millimeters, a length of 3 meters, and a spacing of 0.5 meters. The pipe shed is at an angle of 45 degrees to the tunnel axis, and a hole is drilled at the predetermined position by a pneumatic drill, with a hole diameter slightly larger than the outer diameter of the pipe shed and a hole depth of 0.5 meters longer than the length of the pipe shed. The pipe shed is inserted into the hole, with the end of the pipe shed penetrating 0.5 meters into the arch top area of the first tunnel, ensuring that the pipe shed is in close contact with the surrounding rock, providing advanced support and stability support.

[0040] Example 3: In the area where the arch of the initial tunnel slopes through the interlocking rock to the arch of the subsequent tunnel, active pre-reinforcement is implemented using a sloping grouting guide pipe. First, a 50 mm diameter hole is drilled in the arch waist area of ​​the initial tunnel, with a depth of 3 meters. Then, a 3-meter-long guide pipe, with a diameter matching the borehole diameter, is inserted. The end of the guide pipe is fixed by welding together a "well"-shaped fixing frame and a "hoof"-shaped anchor joint to ensure its stability. Next, cement-water glass grout is injected through the guide pipe, with a cement:water glass ratio of 1:0.5. The grouting pressure is controlled at 0.5-1.0 MPa until the grout overflows from cracks around the tunnel, completing the active pre-reinforcement.

[0041] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (e.g., changes in the size, dimensions, structure, shape, and proportions of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application). For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of elements may be inverted or otherwise altered, and the nature or number or position of discrete elements may be changed or altered. Therefore, all such modifications are intended to be included within the scope of the invention. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and not only structurally equivalent but also equivalent in structure. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of the invention. Therefore, the present invention is not limited to the specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0042] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of actual embodiments (i.e., those features that are not relevant to the best mode of carrying out the invention as currently considered, or those features that are not relevant to implementing the invention) may be omitted.

[0043] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.

[0044] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for reinforcing interbedded rock and goose-shaped zones in tunnels with minimal clearance, characterized in that, The method includes the following steps: a. In areas with weak rock stress between tunnel sections with minimal clearance, wedge-shaped anchoring grooves should be reserved. b. Drill through holes in the wedge-shaped anchor groove; c. Insert R32N precision-rolled threaded steel; d. Install pads on the ends of the threaded steel bars on both sides of the middle interlocking rock to ensure that the pads are in close contact with the bottom plane of the anchoring groove; e. Install the nuts and their force-applying adapters, and apply prestress to complete the prestressed reinforcement of the active R32N precision-rolled threaded steel tie rod; The nut force-applying adapter includes a nut outer adapter sleeve and a threaded steel welded to one end thereon, as well as an extended welded nut of the same size. In the weak stress area of ​​the goose-shaped zone between tunnel sections with extremely small clearance, when the initial support of the first tunnel is being carried out, an externally inserted pipe roof is constructed from the arch waist of the second tunnel to the arch top area of ​​the first tunnel. Once the initial support work for the pilot tunnel is completed, drill a hole through the interlocking rock at the waist of the pilot tunnel to the arch of the subsequent tunnel and insert a guide pipe. The end of the conduit is fixed together by welding a "well" shaped fixing bracket and a "hoof" shaped anchor joint.

2. The method according to claim 1, characterized in that, Active pre-reinforcement by grouting inside the guide pipe completes the active pre-reinforcement of the inclined grouting guide pipe in tunnels with minimal clearance.

3. The method according to claim 2, characterized in that, Nut-applying adapter includes: a. Nut connector sleeve; b. Threaded steel welded to one end of the sleeve of the nut connector; c. Extend the equivalent-sized nut welded onto the threaded steel.

4. The method according to claim 3, characterized in that, The inclined grouting conduit includes: a. catheter; b. A "well" shaped bracket for fixing the catheter tip; c. The "hoof" shaped anchor joint that is welded and fixed together with the "well" shaped fixing frame.

5. The method according to claim 4, characterized in that, The contact area between the pad and the bottom plane of the anchoring groove is not less than 90%; the prestress is applied by a hydraulic jack to ensure uniform distribution of prestress; the diameter of the externally inserted pipe roof is 100-200 mm and the wall thickness is 5-10 mm; the length of the inclined grouting pipe is 2-5 meters and the diameter of the pipe matches the diameter of the borehole; the material of the "well" shaped fixing frame and the "hoof" shaped anchor joint is high-strength alloy steel; the grouting material is cement-water glass slurry with a ratio of cement:water glass = 1:0.

5.

6. The method according to claim 5, characterized in that, This includes a prestressing application system for reinforcing tunnels with minimal clearance, comprising: a. Hydraulic jack; b. Pressure gauge connected to the hydraulic jack; c. A control system for controlling the application of prestress.

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