Tunnel anchor bolt pressure anchor and construction method

Abstract

The present invention provides a tunnel anchor yielding anchor and a construction method, belonging to the field of tunnel engineering technology. The tunnel anchor yielding anchor comprises a prestressed anchor and a support shell; the support shell is an arc-shaped structure with an opening facing downward, the open end of the support shell is fitted on the surrounding rock wall, and a yielding filling layer is provided in the support shell, and the yielding filling layer has the freedom to bend along the thickness direction; the first end of the prestressed anchor penetrates the center of the support shell along the radial direction of the tunnel and extends into the surrounding rock for fixing; the second end of the prestressed anchor is fitted and fixed to the outside of the support shell. The tunnel anchor yielding anchor provided by the present invention combines the support shell and the prestressed anchor, the prestressed anchor applies a supporting force to the surrounding rock to form an active supporting force, and the yielding filling layer of the support shell is buckled and deformed along its thickness direction after being compressed, bearing the pressure applied by the surrounding rock, and achieving the purpose of yielding; the effective combination of the prestressed device and the yielding device is achieved, and the stability of the support structure is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel engineering, and more specifically, relates to a tunnel anchor rod pressure-yielding anchor and a construction method. Background Art

[0002] In high-altitude stress soft rock tunnel projects, large deformation and fast deformation rate often occur during excavation and construction. The existing conventional tunnel support measures are difficult to meet the needs of stable and safe support, resulting in collapse and serious support deformation during tunnel construction. The support has to be replaced or multi-layer support measures have to be taken. Under the concept of yielding support, the annular retractable steel frame and radial prestressed yielding anchor rods have become the main measures to solve the problem of large deformation of soft rock in tunnels.

[0003] Most of the existing yielding anchors are rod sliding yielding anchors, in which the front and rear sections of the rod slide relative to each other to achieve yielding deformation. Therefore, the anchor can only be anchored in the form of end anchors and cannot achieve full-length anchoring, which is not conducive to the anchoring of the anchor. Summary of the invention

[0004] The object of the present invention is to provide a tunnel bolt pressure-yielding anchor and a construction method, aiming to achieve the pressure-yielding function of the anchor and improve the anchor support effect.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a tunnel anchor pressure-yielding anchor and a construction method, including a prestressed anchor and a support shell; the support shell is an arc-shaped structure, the open end of the support shell is attached to the surrounding rock wall, and the support shell has a pressure-yielding filling layer, and the pressure-yielding filling layer has the freedom to bend along the thickness direction; the first end of the prestressed anchor penetrates the center of the support shell along the radial direction of the tunnel and extends into the surrounding rock for fixation; the second end of the prestressed anchor is attached to the outer side of the support shell and fixed.

[0006] As another embodiment of the present application, the pressure-releasing filling layer is a porous structure.

[0007] As another embodiment of the present application, the pressure-yielding filling layer is made of metal, and the pressure-yielding filling layer is compressible along the thickness direction of the shell; the pressure-yielding filling layer is a honeycomb plate structure or a corrugated plate structure with multiple layers connected in sequence.

[0008] As another embodiment of the present application, the support shell includes an outer arc plate and an inner arc plate, the outer arc plate and the inner arc plate are spaced apart and connected by means of a sealing end plate, the sealing end plate is attached to the surrounding rock wall, and the outer arc plate, the inner arc plate and the sealing end plate enclose a mezzanine space for accommodating the pressure-releasing filling layer.

[0009] As another embodiment of the present application, the thickness of the outer arc plate is smaller than the thickness of the inner arc plate; the thickness of the outer arc plate gradually becomes thinner from the center toward the edge.

[0010] As another embodiment of the present application, the support shell is a hemispherical structure, the end face of the open end of the support shell is in contact with the surrounding rock at the top of the tunnel, and the closed end of the support shell faces downward; the circumference of the support shell is connected to the surrounding rock by means of anchor bolts; the prestressed anchor rod and the upper and lower ends of the support shell are provided with limiting structures.

[0011] As another embodiment of the present application, the support shell is an arc-shaped structure with an opening toward one side of the surrounding rock, and the pressure-yielding anchor includes two cross-connected support shells, and the pressure-yielding filling layers in the two support shells are connected; the prestressed anchor rod vertically penetrates the center of the connection between the two support shells and fixes the support shells to the surrounding rock.

[0012] The beneficial effects of the tunnel anchor rod pressure-yielding anchor provided by the present invention are as follows: compared with the prior art, the tunnel anchor rod pressure-yielding anchor of the present invention has an arc-shaped support shell that fits the lower end surface of the surrounding rock; the support shell is combined with the prestressed anchor rod, the prestressed anchor rod applies a supporting force to the surrounding rock to form an active supporting force, and the pressure-yielding filling layer of the support shell is bent and deformed along its thickness direction after being subjected to external pressure, bearing the pressure applied by the surrounding rock to achieve the purpose of pressure relief; the effective combination of the prestressed device and the pressure-yielding device is realized, and the stability of the support structure is improved.

[0013] A tunnel anchor rod pressure-yielding anchor construction method is also provided, which uses the tunnel anchor rod pressure-yielding anchor and comprises the following steps:

[0014] S1. Install prestressed anchor rods and support shells;

[0015] S2, prestressed anchor releases prestress;

[0016] S3. When the surrounding rock load exceeds the bearing capacity of the prestressed anchor rod, the upper end of the support shell is deformed first, causing the pressure filling layer to be compressed;

[0017] S4. The support shell continues to compress and deform until the surrounding rock pressure and the support force reach a force balance and the support shell reaches a stable state.

[0018] As another embodiment of the present application, the yield stress of the support shell is greater than the initial stress of the prestressed anchor rod, and the yield stress of the support shell is less than the bearing capacity of the prestressed anchor rod.

[0019] The beneficial effects of the tunnel anchor yielding anchor construction method provided by the present invention are: compared with the prior art, the tunnel anchor yielding anchor construction method of the present invention adopts the above-mentioned tunnel anchor yielding anchor, and has all the beneficial effects thereof; the support shell and the prestressed anchor are combined, the prestressed anchor exerts a supporting force on the surrounding rock to form an active supporting force, and the yielding filling layer of the support shell bends and deforms along its thickness direction after being compressed, bearing the pressure exerted by the surrounding rock, thereby achieving the purpose of yielding; the effective combination of the prestressed device and the yielding device is realized, thereby improving the stability of the support structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0021] Figure 1 A schematic structural diagram of a tunnel bolt pressure-yielding anchor provided in the first embodiment of the present invention;

[0022] Figure 2 A schematic structural diagram of a tunnel bolt yield anchor provided in accordance with the second embodiment of the present invention.

[0023] In the figure: 1. Support shell; 11. Outer curved plate; 12. Inner curved plate; 2. Prestressed anchor rods; 3. Pressure-releasing filling layer. DETAILED DESCRIPTION

[0024] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] See also Figure 1 and Figure 2 The tunnel anchor yielding anchor and construction method provided by the present invention are now described. The tunnel anchor yielding anchor comprises a prestressed anchor 2 and a support shell 1; the support shell 1 is an arc-shaped structure with an opening facing downward, the open end of the support shell 1 is attached to the surrounding rock wall, and a yielding filling layer 3 is provided in the support shell 1, and the yielding filling layer 3 has the degree of freedom to bend along the thickness direction; the first end of the prestressed anchor 2 passes through the center of the support shell 1 along the radial direction of the tunnel and extends into the surrounding rock for fixing; the second end of the prestressed anchor 2 is attached to the outer side of the support shell 1 and fixed.

[0026] Compared with the prior art, the tunnel anchor yielding anchor provided by the present invention has a support shell 1 fixed on the surrounding rock wall by means of a prestressed anchor 2. The prestressed anchor 2 applies a supporting force to the surrounding rock to form an active supporting force. The yielding filling layer 3 of the support shell 1 is bent and deformed along its thickness direction after being subjected to external pressure, bearing the pressure applied by the surrounding rock, thereby achieving the purpose of yielding pressure. The effective combination of the prestressed device and the yielding device is realized, thereby improving the stability of the support structure.

[0027] The prestressed anchor rod 2 can be an existing anchor rod, and the prestressed anchor rod 2 extends into the surrounding rock along the radial direction of the tunnel to form radial support for the tunnel. The first end of the prestressed anchor rod 2 is fixed in the surrounding rock, and the second end of the prestressed anchor rod 2 extends from the surrounding rock into the tunnel. The support shell 1 is installed at the second end of the prestressed anchor rod 2, and the open end of the support shell is attached to the surrounding rock wall of the tunnel, so that the middle part of the arc-shaped support shell 1 protrudes toward the tunnel.

[0028] The prestressed anchor rod 2 can be a rod or an anchor pipe. The first end of the prestressed anchor rod 2 is anchored in the rock mass, and the second end of the prestressed anchor rod 2 passes through the support shell 1 and is fixed to the surface of the surrounding rock with the help of anchor bolts. The anchor bolts are located in the circumference of the support shell 1.

[0029] An elastic member may be provided inside the rod of the prestressed anchor rod 2, and the prestressing force can be released by releasing the elastic member. The prestressed anchor rod 2 can be set as a retractable sleeve rod structure, and an elastic member is added to the inner cavity of the sleeve rod. The elastic member is always kept in a compressed state during construction. After the construction is completed, the elastic member is released, and the sleeve rod is driven by the elastic member to extend to apply prestress to the surrounding rock.

[0030] The prestressed anchor rod 2 can also be realized by installing a hydraulic or pneumatic jack in the hollow casing. After the prestressed anchor rod 2 is installed, the jack is opened to release the prestress.

[0031] The second end of the prestressed anchor rod 2 is provided with a limiting annular step. The prestressed anchor rod 2 penetrates the support shell 1 from top to bottom, so that the limiting annular step fits on the outer end surface of the support shell 1. The lower end of the prestressed anchor rod 2 extends from the lower end of the support shell 1, and a limiting structure such as a nut is installed on the extended part. Optionally, a washer is added to the limiting annular step, and the washer increases the contact area between the limiting annular step and the support shell 1. A washer is also provided at the lower end of the support shell 1, and the washer is fixed to the prestressed anchor rod 2 through a nut and other structures.

[0032] The support shell 1 includes an outer shell and a mezzanine space, and the outer shell includes an outer curved plate 11, an inner curved plate 12 and a sealing end plate; the outer curved plate 11 and the inner curved plate 12 are arranged at intervals and connected by means of the sealing end plate, and the sealing end plate fits the surrounding rock. The opening of the support shell 1 faces the surrounding rock, and the inner curved plate 12 is parallel to the outer curved plate 11 and serves as a supporting structure. The sealing end plate forms an outer edge structure protruding outward on the side close to the outer curved plate 11, and the outer edge structure fits the surrounding rock.

[0033] The outer curved plate 11 and the inner curved plate 12 are arranged in parallel to form an interlayer space for accommodating the pressure-releasing filling layer 3 with the help of the sealing end plate. The pressure-releasing filling layer 3 can achieve buckling deformation in the thickness direction under the action of external force and form a rebound force on the outside to achieve the purpose of pressure-releasing. After the outer curved plate 11 is squeezed and deformed, the outer curved plate 11 deforms toward the interlayer space, and the outer curved plate 11 squeezes the pressure-releasing filling layer 3 located in the interlayer space; the pressure-releasing filling layer 3 is deformed, but because the pressure-releasing filling layer 3 applies a reverse squeezing force to the surrounding rock while deforming, as the force applied by the surrounding rock reaches the maximum value, the deformation of the pressure-releasing filling layer 3 reaches the maximum, and finally the pressure-releasing filling layer 3 and the surrounding rock reach a state of equilibrium.

[0034] The thickness and strength of the inner curved plate 12 are greater than those of the outer curved plate 11. In the above-mentioned pressure-releasing process, the outer curved plate 11, the pressure-releasing filling layer 3 and the inner curved plate 12 are deformed as a whole, and the deformation amount of the inner curved plate 12 is the smallest.

[0035] The pressure-releasing filling layer 3 in the interlayer space of the supporting shell 1 is a porous structure. Alternatively, the pressure-releasing filling layer 3 is made of metal and is compressible along the thickness direction of the shell; the pressure-releasing filling layer 3 is a honeycomb plate structure or a corrugated plate structure with multiple layers connected in sequence.

[0036] The material of the pressure-releasing filling layer 3 needs to have supporting strength and compressibility. In the first embodiment, the pressure-releasing filling layer 3 can be made of non-metallic materials, such as artificial SAP hole concrete and the like. In the second embodiment, the pressure-releasing filling layer 3 can be made of metal materials, such as foam metal, honeycomb metal plate, corrugated metal plate and metal block structure.

[0037] The porosity of foam metal reaches more than 90%, and it is a porous metal with certain strength and rigidity. It has the property of being compressible.

[0038] When a honeycomb metal plate is arranged in the pressure-releasing filling layer 3, the aperture direction of the honeycomb metal plate is perpendicular to the thickness direction of the pressure-releasing filling layer 3, and the aperture of the honeycomb metal plate gradually decreases from the outside to the inside along the thickness direction. The honeycomb metal plate can be made of steel plate. The honeycomb metal plate is composed of a whole and a plurality of pieces. When the honeycomb metal plate is composed of a plurality of pieces, two adjacent honeycomb metal plates are welded and fixed. The honeycomb metal plate is connected to the inner curved plate 12, and the honeycomb metal plate is connected to the outer curved plate 11 by welding or bolts.

[0039] When a corrugated metal plate is arranged in the yield filling layer 3, multiple corrugated metal plates are stacked in the thickness direction, and multiple corrugated metal plates are stacked in an interlaced manner to form a gap between two adjacent corrugated metal plates, so as to avoid the two corrugated metal plates from being closely fitted and losing the yield deformation. The arc diameter corresponding to the corrugations of the multiple corrugated metal plates gradually decreases from the outside to the inside along the thickness direction of the yield filling layer 3. Two adjacent corrugated metal plates, the corrugated metal plate and the inner arc plate 12, and the corrugated metal plate and the outer arc plate 11 can all be connected by welding.

[0040] The metal block structure is provided with an array of relief holes, which can realize the compression deformation of the metal block. The diameter of the relief holes gradually decreases from the outside to the inside along the radial direction of the support shell 1, so that the bearing capacity of the pressure-releasing filling layer 3 gradually increases from the outside to the inside. When subjected to force, the outer arc plate 11 and the outer structure of the pressure-releasing filling layer 3 are first compressed and deformed.

[0041] The support shell 1 achieves a gradient structure of rigidity on the outside and flexibility on the inside by filling the pressure-yielding filling layer 3 in the interlayer space of the shell, so that it can bear the surrounding rock load and deform in an orderly manner.

[0042] In some possible embodiments, see Figure 1 and Figure 2 Regarding the outer shell structure of the supporting shell 1, the thickness of the outer arc plate 11 is smaller than the thickness of the inner arc plate 12; the thickness of the outer arc plate 11 gradually becomes thinner from the center toward the edge.

[0043] The outer curved plate 11 and the inner curved plate 12 of the support shell 1 are both made of steel plates, and the thickness of the outer curved plate 11 gradually changes from thin to thick from the edge to the center, forming a gradual gradient structure in the horizontal direction of the anchor. The outer curved plate 11 of the support shell 1 is slightly thinner than the inner curved plate 12. Under the action of load, the outer curved plate 11 can reach the yield strength first, and the buckling deformation of the outer curved plate 11 realizes the compression deformation of the anchor.

[0044] When subjected to surrounding rock pressure, the outer arc plate 11 is deformed first and transmits force to the pressure-releasing filling layer 3. With the help of the pressure-releasing filling layer 3, the pressure of the surrounding rock is buffered and support balance is achieved, so that the support shell 1 forms a stable state.

[0045] When the load reaches a certain value, the thinner part of the outer curved plate 11 of the support shell 1 begins to buckle and deform, causing the relative deformation between the anchor as a whole and the surrounding rock. The entire anchor undergoes compression deformation relative to the surrounding rock surface. When the anchor continues to bear the load, when the load further increases to a certain value, the outer curved plate 11 and the inner curved plate 12 of the support shell 1 deform to a certain extent, and the buckling deformation stops. At this time, the outer curved plate 11 of the support shell 1 reaches a buckled state.

[0046] In some possible embodiments, see Figure 1 The support shell 1 is a hemispherical structure, and the end face of the open end of the support shell 1 fits with the surrounding rock at the top of the tunnel; the closed end of the support shell 1 faces downward; the circumference of the support shell 1 is connected to the surrounding rock by means of anchor bolts; the prestressed anchor rod 2 and the upper and lower ends of the support shell 1 are provided with limiting structures.

[0047] When the support shell 1 is a hemispherical structure, the open end of the support shell 1 faces one side of the surrounding rock. The outer curved plate 11 and the inner curved plate 12 are both hemispherical, and the end surface of the open end is attached to the surrounding rock. The interlayer space formed between the outer curved plate 11 and the inner curved plate 12 of the hemispherical structure is used to fill the pressure-releasing filling layer.

[0048] In addition, in some other possible embodiments, please refer to Figure 2 The support shell 1 is an arc-shaped plate-like structure, and the opening of the arc-shaped structure faces one side of the surrounding rock. The pressure-yielding anchor includes two cross-connected support shells 1, and the pressure-yielding filling layers 3 in the two support shells 1 are connected; the prestressed anchor rod 2 vertically penetrates the center of the connection between the two support shells 1 and fixes the support shells 1 on the surrounding rock.

[0049] Both support shells 1 are arc-shaped plate-like structures. The circumferences of the two support shells 1 are set at an angle with the axial direction of the tunnel, and the two support shells 1 are symmetrically set along the axial direction of the tunnel. The length directions of the two support shells 1 are vertical. The two support shells 1 are cross-connected to form a cross-beam structure. The outer arc surfaces 11 of the two support shells 1 are flush, the inner arc surfaces 12 are flush, and the interlayer spaces are connected. An integral pressure-releasing filling layer 3 is formed in the connected interlayer spaces. Corrugated steel plates can be used in the pressure-releasing filling layer 3. The corrugated steel plates are horizontally arranged and staggered and stacked in the longitudinal direction. The pressure-releasing filling layer 3 formed by stacking the corrugated steel plates can be compressed and deformed under load.

[0050] The support shell 1 also includes a first vertical end plate arranged on both sides of the support shell 1 in the width direction. The first vertical end plate is a steel plate recessed toward the inner side of the interlayer space. Under the action of pressure, the first vertical end plate bends and deforms into the interlayer space, thereby avoiding problems such as outward expansion and deformation of the support shell 1 and squeezing the side of the anchor to spray concrete.

[0051] To ensure that the anchor is in close contact with the surrounding rock, the ends of the inner curved plate 12 and the outer curved plate 11 in the length direction are wrapped with a second vertical end plate, and the second vertical end plate has the same structure as the first vertical end plate located in the width direction of the support shell 1. The edge of the second vertical end plate close to the outer curved plate 11 is provided with an outer edge protrusion protruding outward, and the outer edge protrusion is in close contact with the surrounding rock.

[0052] Or the end of the outer arc plate 11 extends downward to be flush with the end of the inner arc plate 12, and the ends of the two in the length direction are connected by means of a sealing end plate, and the outer edge of the sealing end plate has a protrusion protruding outward, and the protrusion fits the surrounding rock.

[0053] A tunnel anchor rod pressure-yielding anchor construction method is also provided, which uses the tunnel anchor rod pressure-yielding anchor and comprises the following steps:

[0054] S1, installing the prestressed anchor rod 2 and the support shell 1;

[0055] S2, prestressed anchor rod 2 releases prestress;

[0056] S3. When the surrounding rock load exceeds the bearing capacity of the prestressed anchor rod 2, the upper end of the support shell 1 is deformed first, so that the pressure filling layer 3 is compressed;

[0057] S4. The support shell 1 continues to compress and deform until the surrounding rock pressure and the support force reach a force balance, and the support shell 1 reaches a stable state.

[0058] Compared with the prior art, the tunnel anchor pressure-yielding anchor construction method provided by the present invention adopts the above-mentioned tunnel anchor pressure-yielding anchor and has all the beneficial effects thereof; the support shell 1 and the prestressed anchor 2 are combined, the prestressed anchor 2 applies a supporting force to the surrounding rock to form an active supporting force, and the pressure-yielding filling layer 3 of the support shell 1 is bent and deformed along its thickness direction after being compressed, bearing the pressure applied by the surrounding rock, thereby achieving the purpose of pressure-yielding; the effective combination of the prestressed device and the pressure-yielding device is realized, and the stability of the support structure is improved.

[0059] First, the support shell 1 and the prestressed anchor rod 2 are prepared. The prestressed anchor rod 2 can use the existing anchor rod. The yield anchor and the prestressed anchor rod 2 are installed on the tunnel excavation surface.

[0060] After installation is completed, the prestress in the prestressed anchor rod 2 is released, and the prestressed anchor rod 2 applies prestress to the surrounding rock at its upper end.

[0061] As time goes by, the surrounding rock begins to deform gradually and continues to squeeze toward the tunnel excavation surface, and the load of the surrounding rock is borne by the prestressed anchor rod 2. The prestressed anchor rod 2 shrinks after being compressed.

[0062] When the surrounding rock load continues to increase to a certain value, the thinner part of the outer side of the support shell 1 begins to buckle and deform to achieve pressure relief. The center of the outer curved plate 11 of the support shell 1 is the thinnest and the force is concentrated, so the outer curved plate 11 of the support shell 1 buckles and deforms first, and then the outer curved plate 11 squeezes the pressure relief filling layer 3, driving the pressure relief filling layer 3 to be squeezed and deformed.

[0063] When the surrounding rock load reaches the maximum, the outer arc plate 11 and the pressure-releasing filling layer 3 of the support shell 1 are compressed and deformed and exert a reverse bearing force on the surrounding rock. The surrounding rock load and the bearing capacity of the deformed support shell 1 are balanced, and the support shell 1 realizes the pressure-releasing energy release function.

[0064] The deformation and stress coordination mechanism between the prestressed anchor 2 and the yielding anchor and the surrounding rock includes: the stress coordination relationship between the prestressed anchor 2 and the yielding anchor and the stress coordination relationship between the prestressed anchor 2 and the gradient yielding anchor.

[0065] The initial prestress of the prestressed anchor rod 2 is less than the initial pressure relief force of the anchor rod; the initial pressure relief force of the support shell 1 is less than the bearing capacity of the anchor rod. The buckling deformation of the outer edge convexity of the sealing end plate of the support shell 1 is coordinated with the buckling deformation of the outer arc plate 11. The initial pressure relief force of the anchor rod should be between the prestress of the anchor rod and the bearing capacity of the anchor rod. The bearing capacity of the anchor rod is the smaller of the anchoring force and the tensile bearing capacity of the anchor rod body.

[0066] The buckling stress of the outer curved plate 11 of the anchor should be smaller than the buckling stress of the outer curved plate 11 to ensure that the raised outer edge of the sealing end plate buckles and deforms first, and then the outer curved plate 11 buckles and deforms to achieve the goal of coordinated pressure relief.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. Tunnel bolt yield anchor, characterized in that: The invention comprises a prestressed anchor rod (2) and a support shell (1); the support shell (1) is an arc-shaped structure, the open end of the support shell (1) is fitted on the surrounding rock wall, the support shell (1) has a pressure-releasing filling layer (3), and the pressure-releasing filling layer (3) has the degree of freedom to bend along the thickness direction; the first end of the prestressed anchor rod (2) passes through the center of the support shell (1) along the radial direction of the tunnel and extends into the surrounding rock for fixing; the second end of the prestressed anchor rod (2) is fitted and fixed to the outer side of the support shell (1); the support shell (1) comprises an outer arc plate (1 1) and an inner curved plate (12), the outer curved plate (11) and the inner curved plate (12) are arranged at intervals and connected by means of a sealing end plate, the sealing end plate is attached to the surrounding rock wall, the outer curved plate (11), the inner curved plate (12) and the sealing end plate enclose a sandwich space for accommodating the pressure-releasing filling layer (3); the thickness of the outer curved plate (11) is less than the thickness of the inner curved plate (12); the thickness of the outer curved plate (11) gradually becomes thinner from the center to the edge; the bearing capacity of the pressure-releasing filling layer gradually increases from the outside to the inside, When subjected to stress, first, the outer arc plate and the outer structure of the pressure-releasing filling layer are compressed and deformed; the support shell (1) is an arc-shaped structure with an opening toward one side of the surrounding rock; the pressure-releasing anchor comprises two cross-connected support shells (1), and the pressure-releasing filling layers (3) in the two support shells (1) are connected; the prestressed anchor rod (2) vertically penetrates the center of the connection between the two support shells (1) and fixes the support shell (1) on the surrounding rock; the support shell (1) also comprises a first vertical end plate arranged on both sides of the width direction of the support shell (1), and the first vertical end plate is provided on both sides of the width direction of the support shell (1). The end plate is a steel plate that is recessed toward the inner side of the interlayer space. Under the action of pressure, the first vertical end plate is bent and deformed toward the interlayer space, thereby preventing the support shell (1) from expanding and deforming outwards. To ensure that the anchor is in close contact with the surrounding rock, the ends of the inner curved plate (12) and the outer curved plate (11) in the length direction are wrapped with a second vertical end plate, and the second vertical end plate has the same structure as the first vertical end plate located in the width direction of the support shell (1). The edge of the second vertical end plate on one side close to the outer curved plate (11) is provided with an outer edge protrusion that protrudes outwards, and the outer edge protrusion is in close contact with the surrounding rock.

2. The tunnel bolt yield anchor according to claim 1, characterized in that: The pressure-releasing filling layer (3) is made of metal, and the pressure-releasing filling layer (3) is compressible along the thickness direction of the shell; the pressure-releasing filling layer (3) is a honeycomb plate structure or a corrugated plate structure with multiple layers connected in sequence.

3. The tunnel bolt pressure anchor construction method is characterized by: The tunnel bolt pressure-releasing anchor as claimed in any one of claims 1 to 2 is adopted, comprising the following steps: S1, installing the prestressed anchor rod (2) and the support shell (1); S2, prestressed anchor rod (2) releases prestress; S3. When the surrounding rock load exceeds the bearing capacity of the prestressed anchor rod (2), the upper end of the support shell (1) is deformed first, so that the pressure filling layer (3) is compressed; S4. The support shell (1) continues to compress and deform until the surrounding rock pressure and the support force reach a force balance, and the support shell (1) reaches a stable state.

4. The tunnel bolt pressure-releasing anchor construction method according to claim 3, characterized in that: The yield stress of the support shell (1) is greater than the initial stress of the prestressed anchor rod (2), and the yield stress of the support shell (1) is less than the bearing capacity of the prestressed anchor rod (2).

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