Stress relieving method for high-ground-stress TBM construction tunnel based on anchor rod support and rock mass joint cutting

Abstract

The invention discloses a stress relieving method for a high ground stress TBM (tunnel boring machine) construction tunnel based on anchor rod support and rock mass joint cutting, which comprises the following steps of: supporting high-strength anchor rods, a reinforcing mesh, a W-shaped steel belt and an energy absorption tray on the surface of surrounding rock which possibly generates stress concentration in a combined manner, and performing joint cutting on a rock mass between two adjacent rows of high-strength anchor rods by using rock cutting equipment. When stress concentration occurs in the surrounding rock, the high-strength anchor rod breaks the rock from the interior of the surrounding rock, so that stress is released, and meanwhile the energy absorption tray and the W-shaped steel belt are combined to absorb the stress. The rock mass kerfs release stress through the prefabricated fractures. By means of the method, the stress gathered in the rock mass can be released and transferred for the high-stress surrounding rock, high-strength, high-rigidity and high-reliability supporting can be conducted on the surrounding rock, and the technical problem that the stress gathered in the rock mass cannot be well released and transferred when a tunnel is built in a high ground stress area is solved.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel construction, and in particular to a stress relief method for a high-ground stress TBM construction tunnel based on anchor support and rock mass cutting. Background Art

[0002] In recent years, a large number of underground space (tunnel) projects have been built in my country's infrastructure projects such as high-speed railways, mining, large-scale water conservancy and hydropower. The coupling of temperature field, stress field, seepage field and other fields caused by deep burial, high and low temperature, fluid, high ground stress, etc., leads to large deformation of surrounding rock in underground space, rock burst, collapse cavity, sudden mud and water gushing and other extreme geological conditions frequently occur. Therefore, it is particularly important to ensure the safe, efficient and economical production of underground projects.

[0003] Anchor support is one of the most common support methods in underground engineering, with the characteristics of fast construction speed, economy and high efficiency. It has a strong and effective support effect for broken surrounding rocks, and has the effect of releasing stress by drilling for high ground stress surrounding rocks.

[0004] In the prior art, the Chinese invention patent "A high pre-tension anchor rod and anchor cable combined support device and method" with publication number CN114876536A discloses that the high pre-anchor high pre-tension anchor rod and anchor cable combined support device has a certain support effect on high-stress surrounding rock, but it cannot release the energy accumulated by high stress in the surrounding rock, and has certain limitations. The Chinese invention patent "A stress transfer structure and a tunnel support structure capable of transferring high stress of surrounding rock and resisting large deformation of surrounding rock" with publication number CN118517291A discloses a stress transfer structure, which uses a horizontally arranged stress transfer structure, a pressure relief hole pressure relief structure, a vertically arranged stress transfer structure and a long and short anchor rod combined support structure to work together to achieve fine control and stabilization of the high ground stress environment. However, this stress transfer structure transfers part of the stress without releasing the stress, and the structure is prone to instability in the later stage, and there are certain safety hazards for workers in production operations. Therefore, for high-stress surrounding rock, it is particularly important to release and transfer the stress accumulated in the rock mass and to provide high-strength, high-rigidity and high-reliability support for the surrounding rock. Summary of the invention

[0005] In view of the above problems, the present invention is proposed to provide a stress relief method for a high-ground stress TBM construction tunnel based on anchor support and rock cutting, which overcomes the above problems or at least partially solves the above problems. The method can release and transfer the stress accumulated in the rock mass for high-stress surrounding rock, and can support the surrounding rock with high strength, high rigidity and high reliability, thereby solving the technical problem that the stress accumulated in the rock mass cannot be well released and transferred when constructing a tunnel in a high-ground stress area.

[0006] Specifically, the present invention provides a stress relief method for a high-ground stress TBM construction tunnel based on anchor support and rock cutting, the method comprising an anchor support structure for transferring the accumulated stress in the surrounding rock; the anchor support structure comprises a high-strength anchor, an energy absorbing tray, a "W"-shaped steel belt, a steel mesh and a nut; the method comprises:

[0007] In areas where stress concentration may occur, multiple rows of high-strength anchors are installed along the longitudinal direction of the tunnel, and the anchoring sections of the multiple rows of high-strength anchors located in the surrounding rock are anchored;

[0008] In the middle position between every two adjacent rows of high-strength anchors, use rock cutting equipment to cut the surrounding rock along the tunnel circumference;

[0009] The steel mesh, "W"-shaped steel belt and energy-absorbing tray are passed through the free section at the tail of the high-strength anchor rod in sequence and finally locked with a nut.

[0010] Optionally, the high-strength anchor rod is in the shape of a triangular prism, and is used to cut the rock mass inside the surrounding rock through the edges on the surface of the high-strength anchor rod when the high-strength anchor rod is subjected to transverse force, thereby releasing part of the stress.

[0011] Optionally, the energy absorbing tray is hemispherical, with its opening facing the surrounding rock, and is used to absorb part of the stress when the surrounding rock releases stress toward the free surface.

[0012] Optionally, the method further comprises: obtaining, by theoretical calculation, the anchor length, diameter, spacing and row spacing of the multiple rows of high-strength anchors installed in the stress concentration area.

[0013] Optionally, the surrounding rock is cut along the circumferential direction of the tunnel, which specifically includes: the depth of the cut is determined according to the range of the loose circle of the surrounding rock; the length of the cut is greater than the length of the "W"-shaped steel belt.

[0014] Optionally, a steel mesh, a "W"-shaped steel belt and an energy-absorbing tray are sequentially passed through the tail of the high-strength anchor rod, and specifically include: the steel mesh is installed close to the surrounding rock and is tied and connected with the tails of multiple high-strength anchor rods to prevent gravel from falling and ensure construction safety in the tunnel.

[0015] Optionally, the steel mesh, the "W"-shaped steel belt and the energy absorbing tray are sequentially passed through the tail of the high-strength anchor rod, and specifically include:

[0016] There are multiple through holes in the middle of the "W"-shaped steel belt, and the free section of the tail of a high-strength anchor rod passes through a through hole; after installation, the "W"-shaped steel belt forms an "arch" support, which has a strong support effect and stress absorption effect.

[0017] Optionally, nut locking is adopted, which specifically includes: the free section at the tail of the high-strength anchor rod is connected to the nut through a thread, and by tightening the nut, the steel mesh, the "W"-shaped steel belt and the energy-absorbing tray are continuously brought close to the surrounding rock to achieve a locking effect.

[0018] Optionally, the method also includes: determining high geostress sections according to a geological survey (quality) report of a TBM tunnel construction project; and determining areas where stress concentration may occur in the high geostress sections through numerical simulation.

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

[0020] (1) High-strength anchor rods and energy-absorbing trays are combined to form anchor support. High-strength anchor rods can not only provide support inside the surrounding rock, but also play a role in breaking the rock. When the surrounding rock is deformed, the high-strength anchor rods and energy-absorbing trays play a joint supporting role on the surrounding rock. When stress concentration occurs in the surrounding rock, the high-strength anchor rods can break the rock from the inside of the surrounding rock and release some of the stress, while the energy-absorbing tray can absorb some of the stress.

[0021] (2) The "W"-shaped steel belt and steel mesh are inserted in the free section of the anchor rod tail, which has an arching effect and forms an "arch" support. The "W"-shaped steel belt has a strong supporting effect in the surrounding rock support process, and also has a strong energy absorption effect. It can convert the high stress in the surrounding rock into the potential energy of the "W"-shaped steel belt to reduce the risks or disasters caused by stress concentration in the surrounding rock. When the surrounding rock has rock burst or collapse due to stress concentration, the steel mesh can hold the fallen rocks in the surrounding rock and reduce the danger during tunnel construction.

[0022] (3) The rock cutting equipment cuts a slit between two rows of anchor supports. The depth of the slit is determined according to the range of the loosening zone of the surrounding rock. The length of the slit is greater than the length of the "W"-shaped steel belt. The high stress area of ​​the surrounding rock is released by prefabricated cracks.

[0023] (4) After the method of the present invention is adopted, the surrounding rock immediately enters a stress-relieving state. At the same time, this method can also solve the problem of time-delayed rock burst.

[0024] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0026] Figure 1 It is a flow chart of a stress relief method based on anchor support and rock mass cutting in a high ground stress TBM construction tunnel according to one embodiment of the present invention;

[0027] Figure 2The present invention is a schematic structural diagram of an anchor support structure of a high ground stress TBM construction tunnel based on anchor support and rock cutting stress relief method according to an embodiment of the present invention.

[0028] In the figure: 1. high-strength anchor rod; 2. energy-absorbing tray; 3. "W"-shaped steel belt; 4. nut; 5. steel mesh; 6. surrounding rock. DETAILED DESCRIPTION

[0029] Refer to the following Figure 1 to Figure 2 To describe a stress relief method for a high-ground stress TBM construction tunnel based on anchor support and rock cutting according to an embodiment of the present invention. In the description of this embodiment, it should be understood that the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features, that is, include one or more of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. When a feature "includes or contains" one or some of the features it covers, unless otherwise specifically described, this indicates that other features are not excluded and may further include other features.

[0030] Unless otherwise clearly defined and limited, the terms "set", "install", "connect", "connect", "fix", "couple" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. A person skilled in the art should be able to understand the specific meanings of the above terms in the present invention according to the specific circumstances.

[0031] In addition, in the description of this embodiment, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them. That is, in the description of this embodiment, the first feature being "above", "above", and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature being "below", "below", or "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0032] In the description of the present embodiment, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0033] Figure 1 FIG. 1 is a flow chart of a stress relief method for a high-ground stress TBM tunnel construction based on anchor support and rock mass cutting according to an embodiment of the present invention. Figure 1 As shown, and refer to Figure 2 The embodiment of the present invention provides a stress relief method for a high-ground stress TBM construction tunnel based on anchor support and rock cutting, the method comprising an anchor support structure for transferring the accumulated stress in the surrounding rock 6. The anchor support structure comprises a high-strength anchor 1, an energy absorbing tray 2, a "W"-shaped steel belt 3, a steel mesh 5 and a nut 4.

[0034] like Figure 1 As shown, in step S100, multiple rows of high-strength anchor rods 1 are installed longitudinally along the tunnel in the area where stress concentration may occur, and the anchoring sections of the multiple rows of high-strength anchor rods 1 located in the surrounding rock 6 are fully anchored, specifically including:

[0035] Before tunnel excavation, the high geostress section is determined according to the geological survey (quality) report of the TBM construction tunnel project, and the area where stress concentration may occur in the high geostress section is determined through numerical simulation. After the TBM tunnel is excavated in the high geostress section, multiple rows of high-strength anchor rods 1 are installed along the longitudinal direction of the tunnel in the area where stress concentration may occur, and the anchoring section of the multiple rows of high-strength anchor rods 1 located in the surrounding rock 6 is anchored throughout its length.

[0036] Specifically, the anchor length, diameter, spacing and row spacing of the high-strength anchor rods 1 in the stress concentration area are obtained through theoretical calculations (suspension theory, composite beam theory, etc.).

[0037] Specifically, the installation of the high-strength anchor rod 1 includes drilling, installation and anchoring. The specific steps include: using a drilling machine to drill an anchor rod hole at a predetermined position, the anchor rod hole is a circular hole; loading a resin roll or other anchoring agent into the drilled hole; inserting the anchor rod into the drilled hole, ensuring that the anchor rod is in close contact with the hole wall and avoiding rotation during the insertion process; using a stirrer to stir the anchoring agent, and the installation of the anchor rod is completed after the anchoring agent solidifies.

[0038] like Figure 1As shown, in step S200, at the middle position between each two adjacent rows of high-strength anchor bolts 1, the surrounding rock 6 is cut along the tunnel circumference by using rock cutting equipment, which specifically includes:

[0039] At the middle position between each two adjacent rows of high-strength anchors 1, the surrounding rock 6 is cut along the circumferential direction of the tunnel using rock cutting equipment. The depth of the cut is determined according to the range of the loosening circle of the surrounding rock 6, and the length of the cut is greater than the length of the "W"-shaped steel belt 3. Cutting the rock mass at the middle position between the two adjacent rows of high-strength anchors 1 is to release the stress of the high stress area of ​​the surrounding rock 6 in the form of prefabricated cracks, and the rock mass cut has the effect of a stress release hole.

[0040] Specifically, the range of the loosening zone of the surrounding rock 6 can be obtained through numerical simulation or theoretical calculation.

[0041] Specifically, the length of the slit is greater than the length of the “W”-shaped steel strip 3 in order to expand the range of stress release.

[0042] like Figure 1 As shown, in step S300, the steel mesh 5, the "W"-shaped steel belt 3 and the energy absorbing tray 2 are sequentially passed through the free section at the tail of the high-strength anchor rod 1, and finally locked with the nut 4, which specifically includes:

[0043] The steel mesh 5, "W"-shaped steel belt 3 and energy-absorbing tray 2 pass through the free section at the tail of the high-strength anchor rod 1 in sequence. The steel mesh 5 is installed close to the surrounding rock 6 and is tied and connected with the tails of multiple high-strength anchor rods 1 to prevent the falling of gravel and ensure the safety of construction in the tunnel. There are multiple through holes in the middle of the "W"-shaped steel belt 3, and the tail of a high-strength anchor rod 1 passes through a through hole. After the installation of the "W"-shaped steel belt 3, an "arch" support is formed, which has a strong support effect and stress absorption effect. The free section at the tail of the high-strength anchor rod 1 is connected to the nut 4 through a thread. By tightening the nut 4, the steel mesh 5, "W"-shaped steel belt 3 and energy-absorbing tray 2 are constantly close to the surrounding rock 6 to achieve a locking effect. After locking the nut 4, a spray-mixed steel arch frame is applied to complete the initial support of the TBM tunnel.

[0044] Specifically, when the surrounding rock 6 is deformed, the high-strength anchor 1 and the energy-absorbing tray 2 play a joint supporting role on the surrounding rock 6. When stress concentration occurs in the surrounding rock 6, the high-strength anchor 1 actively breaks the rock from the inside of the surrounding rock 6 to release part of the stress; at the same time, when the surrounding rock 6 releases stress to the free surface, the energy-absorbing tray 2 absorbs part of the stress.

[0045] like Figure 2 As shown, the anchor support structure includes a high-strength anchor 1, an energy absorbing tray 2, a "W"-shaped steel belt 3, a steel mesh 5 and a nut 4. The high-strength anchor 1 is divided into an anchoring section and a free section. The part located inside the surrounding rock 6 is the anchoring section, and the part located outside the surrounding rock 6 is the free section. The steel mesh 5, the "W"-shaped steel belt 3 and the energy absorbing tray 2 are installed in the free section of the high-strength anchor 1 in sequence.

[0046] The steel mesh 5 is closely attached to the surface of the surrounding rock 6 and is tied and connected with the free sections of multiple rows of high-strength anchors 1. When the surrounding rock 6 experiences rock burst or collapse due to stress concentration, the steel mesh 5 can catch the fallen rocks in the surrounding rock 6, reduce the danger in the production process, and ensure the safety of construction in the tunnel.

[0047] There are multiple through holes in the middle of the "W"-shaped steel belt 3, and a free section at the tail of a high-strength anchor rod 1 passes through a through hole. The "W"-shaped steel belt 3 is a circumferential support with an arching effect. After installation, an "arch" support is formed, which has a strong support effect and stress absorption effect. The "W"-shaped steel belt 3 has a strong support effect in the surrounding rock 6 support process, and has a strong energy absorption effect. It can convert the high stress in the surrounding rock 6 into the potential energy of the "W"-shaped steel belt 3 to reduce the risks or disasters caused by stress concentration in the surrounding rock 6.

[0048] At this point, those skilled in the art should recognize that, although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all these other variations or modifications.

Claims

1. A stress relief method for a high-ground stress TBM tunnel based on anchor support and rock mass cutting, characterized in that: It includes an anchor support structure for transferring the accumulated stress in the surrounding rock; the anchor support structure includes a high-strength anchor, an energy-absorbing tray, a "W"-shaped steel belt, a steel mesh and a nut; The method includes: In areas where stress concentration may occur, multiple rows of high-strength anchor rods are installed along the longitudinal direction of the tunnel, and the anchoring sections of the multiple rows of high-strength anchor rods located in the surrounding rock are anchored; At the middle position of each two adjacent rows of high-strength anchor rods, using rock cutting equipment, cut the surrounding rock along the tunnel circumference; The steel mesh, the "W"-shaped steel belt and the energy-absorbing tray are sequentially passed through the free section at the tail of the high-strength anchor rod and finally locked with the nut.

2. A stress relief method for high ground stress TBM construction tunnel based on anchor support and rock mass cutting according to claim 1, characterized in that: The high-strength anchor rod is in the shape of a triangular prism, and is used to cut the rock mass inside the surrounding rock through the edges on the surface of the high-strength anchor rod when the high-strength anchor rod is subjected to transverse force, thereby releasing part of the stress.

3. A stress relief method for high ground stress TBM construction tunnel based on anchor support and rock mass cutting according to claim 1, characterized in that: The energy absorbing tray is hemispherical, with its opening facing the surrounding rock, and is used to absorb part of the stress when the surrounding rock releases stress to the free surface.

4. A stress relief method for high ground stress TBM construction tunnel based on anchor support and rock mass cutting according to claim 1, characterized in that: The method further comprises: The anchor length, diameter, spacing and row spacing of the multiple rows of high-strength anchors installed in the stress concentration area are obtained through theoretical calculation.

5. A stress relief method for high ground stress TBM tunnel construction based on anchor support and rock mass cutting according to claim 1, characterized in that: The surrounding rock is cut along the tunnel circumference, including: The depth of the cut is determined according to the range of the surrounding rock loosening zone; the length of the cut is greater than the length of the "W"-shaped steel belt.

6. A stress relief method for high ground stress TBM tunnel construction based on anchor support and rock mass cutting according to claim 1, characterized in that: The steel mesh, the "W"-shaped steel belt and the energy absorbing tray sequentially pass through the tail of the high-strength anchor rod, and specifically include: The steel mesh is installed close to the surrounding rock and is tied and connected with the tails of a plurality of high-strength anchor rods to prevent gravel from falling and ensure construction safety in the tunnel.

7. A stress relief method for high ground stress TBM tunnel construction based on anchor support and rock mass cutting according to claim 6, characterized in that: Specifically include: The "W"-shaped steel belt has a plurality of through holes in the middle, and a free section at the tail of the high-strength anchor rod passes through one of the through holes; after installation, the "W"-shaped steel belt forms an "arch" support, which has a strong support effect and stress absorption effect.

8. The stress relief method for high ground stress TBM tunnel construction based on anchor support and rock mass cutting according to claim 1, characterized in that: The nut locking method further includes: The free section at the tail of the high-strength anchor rod is connected to the nut through a thread. By tightening the nut, the steel mesh, the "W"-shaped steel belt and the energy-absorbing tray are continuously brought close to the surrounding rock to achieve a locking effect.

9. A stress relief method for high ground stress TBM tunnel construction based on anchor support and rock mass cutting according to claim 1, characterized in that: The method further comprises: Determine the high geostress section based on the geological survey (quality) report of the TBM construction tunnel project; determine the area where stress concentration may occur in the high geostress section through numerical simulation.

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