Multi-stage sequential full-recovery tunnel face advance anchor and its application method

Abstract

The present invention relates to a multi-section sequential fully recoverable tunnel face advance anchor and its application method, which is applicable to the field of tunnel support, and comprises a mechanical inner anchor head for being arranged in a hole in a surrounding rock, an anchor rod body composed of a plurality of rod-shaped components and a connecting piece is installed on the mechanical inner anchor head, and an anchor rod tray is sleeved on the end of the anchor rod body passing through the hole in the surrounding rock and an anchor rod nut is installed. The anchor rod can overcome the shortcomings of being difficult to cut or easy to break and having poor economic effect, and the application method is simple.

Description

Technical Field

[0001] The invention relates to a multi-section sequentially fully recoverable tunnel face advance anchor rod and an application method thereof, and is applicable to the field of tunnel support. Background Art

[0002] Tunnels with weak surrounding rocks are characterized by fast deformation rate, large magnitude, and long convergence time. The surrounding rocks are usually difficult to stabilize themselves. In order to meet the requirements of tunnel excavation, it is usually necessary to support the face to achieve short-term stability of the face. Face anchors can not only provide restraining pressure perpendicular to the face direction, transform the face from a plane stress state to a more stable three-dimensional stress state, and improve the stress form of the face surrounding rock, but also can enhance the connection between the surface surrounding rock of the face and the deep surrounding rock, improve the shear strength of the face surrounding rock, and enhance the stability of the face.

[0003] The materials of the face anchors currently used are mostly steel and fiberglass plastic. The steel face anchors have high rigidity and tensile strength. Although they can play a good supporting role, they are difficult to dig in actual application. Before deployment, they often need to be specially treated such as reserved notches to meet the needs of face excavation, resulting in cumbersome construction process and poor economic benefits. Although the fiberglass anchor has the characteristics of high tensile strength and low shear strength, it can meet the needs of face excavation while ensuring the support effect. However, its low shear strength also makes it very easy to break when used in weak surrounding rocks with developed joints and fissures, and loses the support effect.

[0004] Tunnel excavation is a continuous cycle of operations, which requires the face anchors to be continuously cut and repeatedly laid out during the support process. Since the cut anchors cannot be reused, when there are too many face anchors laid out, the economic effect of the support measure will be greatly reduced. Summary of the invention

[0005] The purpose of the present invention is to provide a multi-section sequential fully recoverable tunnel face advance anchor and an application method thereof, wherein the anchor can overcome the disadvantages of being difficult to cut or easy to break brittlely and having poor economic effect, and the application method is simple.

[0006] The technical solution of the present invention is: a multi-section sequentially fully recoverable tunnel face advance anchor, including a mechanical inner anchor head for being set in a hole in the surrounding rock, an anchor rod body composed of a plurality of rod-shaped components and connecting parts is installed on the mechanical inner anchor head, and an anchor rod tray is sleeved on the end of the anchor rod body passing through the hole in the surrounding rock and an anchor rod nut is installed.

[0007] Furthermore, the rod-shaped component is a hot-rolled ribbed steel bar, both ends of the rod-shaped component are provided with external threads, and the connecting piece is a hollow steel pipe and is provided with internal threads matching the external threads.

[0008] Furthermore, the rod-shaped member is a left-handed or right-handed precision-rolled threaded steel bar, the connecting piece is a hollow steel pipe provided with an internal thread, and the entire length of the rod-shaped member is provided with an external thread that matches the internal thread of the connecting piece.

[0009] Furthermore, the anchor rod tray is a metal butterfly tray, and holes are reserved on the anchor rod tray for the anchor rod body to pass through.

[0010] Furthermore, the internal thread of the anchor nut corresponds to the external thread of the rod body component.

[0011] An application method of a multi-section sequential full-recovery tunnel face advance anchor bolt comprises the following steps:

[0012] (1) The length of each rod-shaped member is determined according to the excavation volume of the tunnel face per cycle, and the number of rod-shaped members contained in each anchor bolt is determined according to the designed advance support length of the tunnel face;

[0013] (2) Connecting the rod-shaped members of the above length and number through connectors to form an anchor rod body, and installing a mechanical inner anchor head;

[0014] (3) After drilling a hole at the location to be reinforced on the tunnel face, insert the combination of the anchor rod body and the mechanical inner anchor head, and anchor the mechanical inner anchor head to the surrounding rock of the borehole. Then install the anchor tray and anchor nut, and start maintaining the stability of the tunnel face through multiple sections of fully recoverable tunnel face advance anchors.

[0015] (4) When the tunnel face is stable, the initial support of the tunnel surrounding rock is carried out. After the initial support is completed, when the tunnel face continues to be excavated, the anchor nuts and anchor trays are removed, and the tunnel face is blasted or mechanically excavated;

[0016] (5) After excavation is completed, the rod-shaped member and the connecting parts extending out of the tunnel face are removed and recycled, and the tray and the fastening nut are reinstalled on the remaining anchor rod body. The multiple sections of fully recoverable tunnel face advance anchors are used to maintain the stability of the tunnel face again;

[0017] (6) Repeat the above steps (4) and (5) until all the rod-shaped components of the anchor rod are dug out; when the last section of the rod-shaped component is dug out, the mechanical inner anchor head is recovered;

[0018] (7) The disassembled components can be reassembled to form a new multi-section, fully recoverable tunnel face advance anchor.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] (1) A mechanical inner anchor head is installed at the bottom, so that the anchor rod can be installed quickly and play a supporting role as soon as possible;

[0021] (2) The anchor rods are made of steel, which is not easy to break under the conditions of surrounding rock squeezing and shearing, thus ensuring the support strength;

[0022] (3) The bolt body has a multi-section connection structure, so that the bolt body can be disassembled section by section as the tunnel excavation progresses. The disassembled bolt body, mechanical inner anchor head, bolt tray and bolt nut can all be recycled.

[0023] Therefore, when the present invention is applied to the tunnel face support, it can transform the traditional anchor rod cutting process into a process of sequentially recovering multiple sections of the anchor rod on the basis of ensuring the support strength, thereby realizing the recovery and reuse of the entire anchor rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the anchor rod of the present invention installed in the anchor hole;

[0025] Figure 2 This is a schematic diagram of the rod-shaped components of the present invention connected by connecting pieces (the component joint is cut away by 1 / 4 to show the internal structure);

[0026] In the figure: 1-anchor nut; 2-anchor tray; 3-connector; 4-rod-shaped member; 5-mechanical inner anchor head; 6-surrounding rock; 7-hole. DETAILED DESCRIPTION

[0027] In order to make the above features and advantages of the present invention more understandable, embodiments are given below with reference to the accompanying drawings for detailed description, but the present invention is not limited thereto.

[0028] refer to Figure 1 and Figure 2

[0029] A multi-stage sequentially fully recoverable tunnel face advance anchor comprises a mechanical inner anchor head 5 for being set in a hole 7 in a surrounding rock 6, an anchor rod body consisting of a plurality of rod-shaped components 4 and a connector 3 is installed on the mechanical inner anchor head, an anchor rod tray 2 is sleeved on the end of the anchor rod body passing through the hole in the surrounding rock and an anchor rod nut 1 is installed.

[0030] In this embodiment, the rod-shaped member is a hot-rolled ribbed steel bar, both ends of the rod-shaped member are provided with external threads, and the connecting piece is a hollow steel pipe and is provided with internal threads matching the external threads.

[0031] In this embodiment, the rod-shaped member is a left-handed or right-handed precision-rolled threaded steel bar, the connecting piece is a hollow steel pipe with an internal thread, and the entire length of the rod-shaped member has an external thread that matches the internal thread of the connecting piece.

[0032] In this embodiment, the anchor rod tray is a metal butterfly tray, and holes are reserved on the anchor rod tray for the anchor rod body to pass through.

[0033] In this embodiment, the internal thread of the anchor nut corresponds to the external thread of the rod body component.

[0034] In this embodiment, the mechanical inner anchor head is a traditional mechanical inner anchor head.

[0035] An application method of a multi-section sequential full-recovery tunnel face advance anchor bolt comprises the following steps:

[0036] (1) The length of each rod-shaped member is determined according to the excavation volume of the tunnel face per cycle, and the number of rod-shaped members contained in each anchor bolt is determined according to the designed advance support length of the tunnel face;

[0037] (2) Connecting the rod-shaped members of the above length and number through connectors to form an anchor rod body, and installing a mechanical inner anchor head;

[0038] (3) After drilling a hole at the location to be reinforced on the tunnel face, insert the combination of the anchor rod body and the mechanical inner anchor head, and anchor the mechanical inner anchor head to the surrounding rock of the borehole. Then install the anchor tray and anchor nut, and start maintaining the stability of the tunnel face through multiple sections of fully recoverable tunnel face advance anchors.

[0039] (4) When the tunnel face is stable, the initial support of the tunnel surrounding rock is carried out. After the initial support is completed, when the tunnel face continues to be excavated, the anchor nuts and anchor trays are removed, and the tunnel face is blasted or mechanically excavated;

[0040] (5) After excavation is completed, the rod-shaped member and the connecting parts extending out of the tunnel face are removed and recycled, and the tray and the fastening nut are reinstalled on the remaining anchor rod body. The multiple sections of fully recoverable tunnel face advance anchors are used to maintain the stability of the tunnel face again;

[0041] (6) Repeat the above steps (4) and (5) until all the rod-shaped components of the anchor rod are dug out; when the last section of the rod-shaped component is dug out, the mechanical inner anchor head is recovered;

[0042] (7) The disassembled components can be reassembled to form a new multi-section, fully recoverable tunnel face advance anchor.

[0043] The above description is only a preferred embodiment of the present invention. For ordinary technicians in this field, according to the teachings of the present invention, designing different forms of multi-section sequentially fully recoverable tunnel face advance anchors does not require creative labor. Without departing from the principles and spirit of the present invention, all equal changes, modifications, substitutions and variations made within the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. An application method of a multi-stage sequential fully recoverable tunnel face advance anchor, comprising a mechanical inner anchor head for setting in a hole in a surrounding rock, characterized in that: The mechanical inner anchor head is provided with an anchor rod body composed of a plurality of rod-shaped components and a connecting piece, and an anchor rod tray is sleeved on the end of the anchor rod body passing through the surrounding rock hole and an anchor rod nut is installed; the rod-shaped component is a hot-rolled ribbed steel bar, and both ends of the rod-shaped component are provided with external threads, and the connecting piece is a hollow steel pipe and is provided with an internal thread matching the external thread; the application method comprises the following steps: (1) The length of each rod-shaped member is determined according to the excavation volume of the tunnel face per cycle, and the number of rod-shaped members contained in each anchor bolt is determined according to the designed advance support length of the tunnel face; (2) Connecting the rod-shaped members of the above length and number through connectors to form an anchor rod body, and installing a mechanical inner anchor head; (3) After drilling a hole at the location to be reinforced on the tunnel face, insert the combination of the anchor rod body and the mechanical inner anchor head, and anchor the mechanical inner anchor head to the surrounding rock of the borehole. Then install the anchor tray and anchor nut, and start maintaining the stability of the tunnel face through multiple sections of fully recoverable tunnel face advance anchors. (4) When the tunnel face is stable, the initial support of the tunnel surrounding rock is carried out. After the initial support is completed, when the tunnel face continues to be excavated, the anchor nuts and anchor trays are removed, and the tunnel face is blasted or mechanically excavated; (5) After excavation is completed, the rod-shaped member and the connecting parts extending out of the tunnel face are removed and recycled, and the tray and the fastening nut are reinstalled on the remaining anchor rod body. The multiple sections of fully recoverable tunnel face advance anchors are used to maintain the stability of the tunnel face again; (6) Repeat the above steps (4) and (5) until all the rod-shaped components of the anchor rod are dug out; when the last section of the rod-shaped component is dug out, the mechanical inner anchor head is recovered; (7) The disassembled components can be reassembled to form a new multi-section, fully recoverable tunnel face advance anchor.

2. The application method of the multi-stage sequential fully recoverable tunnel face advance anchor bolt according to claim 1 is characterized in that: The rod-shaped member is a left-handed or right-handed precision-rolled threaded steel bar, the connecting piece is a hollow steel pipe provided with an internal thread, and the entire length of the rod-shaped member is provided with an external thread that matches the internal thread of the connecting piece.

3. The application method of the multi-stage sequential fully recoverable tunnel face advance anchor bolt according to claim 1 or 2 is characterized in that: The anchor rod tray is a metal butterfly tray, and holes are reserved on the anchor rod tray for the anchor rod body to pass through.

4. The application method of the multi-stage sequential fully recoverable tunnel face advance anchor bolt according to claim 1 or 2 is characterized in that: The internal thread of the anchor nut corresponds to the external thread of the rod body component.

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