Full-length anchoring fixed-point yielding support anchor rod and application thereof in roadway support

Abstract

The invention belongs to the field of coal mine tunnel anchor rod supporting, and particularly relates to a full-length anchoring fixed-point yielding supporting anchor rod which comprises a lower rod body and an upper rod body which are provided with external threads, a connecting groove and a first connector are sequentially arranged at the upper end of the lower rod body, a grouting channel is formed in the lower rod body, and a grouting hole is formed in the connecting groove; the grouting hole is communicated with the grouting channel; the interior of the lower end of the upper rod body is hollow to form a containing cavity capable of containing the connecting groove and the first connector, the inner diameter of the lower end of the containing cavity is increased to form a second connector, the other parts form a connecting cavity, and the connecting cavity is in threaded connection with the first connector; when the anchor rod is screwed in, the lower rod body and the upper rod body move in the similar direction. Full-length anchoring and fixed-point yielding of the anchor rod can be achieved, the anchor rod can be directly rotated to be drilled and installed, the yielding effect is generated through the yielding structure when a roadway is separated, then a rock stratum between the upper portion and the lower portion of a separated layer is connected through grouting, and the supporting effect is improved.

Description

Technical Field

[0001] The invention belongs to the field of coal mine tunnel anchor support, and in particular relates to a full-length anchor fixing point yielding support anchor and application thereof in tunnel support. Background Art

[0002] The tunnel is a safe passage for pedestrians, ventilation and transportation in coal mines. During the excavation process, the initial stress equilibrium state of the original rock is broken and redistributed, causing deformation and damage to the surrounding rock of the tunnel, which brings certain safety hazards to coal mining.

[0003] As far as the tunnel surrounding rock control is concerned, on the one hand, the bearing capacity of the tunnel surrounding rock itself should be fully mobilized, and on the other hand, certain support methods should be adopted to achieve the reinforcement and stabilization of the tunnel surrounding rock. With the continuous development of tunnel surrounding rock support technology, a variety of support methods have been formed, including wood support, masonry support, steel support and anchor support. The application of these support methods, on the one hand, effectively suppresses the deformation of the tunnel surrounding rock, and on the other hand, realizes the reinforcement of the tunnel surrounding rock and better mobilizes the self-bearing capacity of the tunnel surrounding rock. Among them, anchor support is widely used due to its advantages of low support cost, fast construction operation and good control effect, and has achieved good surrounding rock control effect.

[0004] As a high-strength, high-rigidity active support method, the full-length anchor bolt has high support stiffness and is highly sensitive to the deformation and damage of the tunnel surrounding rock. It can achieve timely support, inhibit the occurrence of unbalanced deformation of the tunnel surrounding rock, and reduce the deformation of the tunnel surrounding rock. On the other hand, it can reduce the prestress loss during the anchor support process, reduce the corrosion and damage of the anchor bolt by factors such as mine water, increase the effective control range of the anchor support on the tunnel surrounding rock, and improve the durability of the anchor support system.

[0005] However, when supporting the tunnel, even with support methods such as anchor rods, it is impossible to avoid deformation. Sometimes, it is appropriate to allow the surrounding rock of the tunnel to deform to a certain extent and allow the anchor rod to adapt to this deformation. Further anchoring and reinforcement will be beneficial to further support after the surrounding rock deformation. Therefore, yielding anchor rods, especially anchor rods that can be grouted after yielding, came into being.

[0006] However, due to the limitation of the yield structure, yield anchor rods are rarely used for full-length anchor rods. Although some existing technologies also use the yield structure for full-length anchor rods, the full-length anchor rods including the yield structure are troublesome to install, and holes need to be drilled before the anchor rods are installed, resulting in the tightness of the anchor rod installation needs to be improved. In addition, the position of the yield structure is set arbitrarily, and the appropriate yield position is not selected based on the deformation of the rock formation. This will cause some yield structures to be unable to produce the yield effect, while the yield structure is not set at the position where yield is required. Summary of the invention

[0007] In view of the above technical problems, the present invention proposes a full-length anchor fixing point pressure-releasing support anchor rod, comprising a lower rod body and an upper rod body with the same outer diameter, wherein the outer periphery of the lower rod body and the upper rod body is provided with a continuous thread with the same rotation direction;

[0008] The outer diameter of the upper end of the lower rod body is reduced to form a connecting groove, and a first connecting head is provided at the upper end of the connecting groove, and the outer diameter of the first connecting head is larger than the outer diameter of the connecting groove and smaller than the outer diameter of the lower rod body; a grouting channel is provided inside the lower rod body, and a grouting hole is provided in the connecting groove, and the grouting hole is connected to the grouting channel;

[0009] The lower end of the upper rod body is hollow inside to form a receiving chamber that can accommodate the connecting groove and the first connecting head. The inner diameter of the lower end of the receiving chamber becomes larger to form the second connecting head, and the remaining part forms a connecting chamber, which is threadedly connected to the first connecting head. When the anchor rod is screwed in, the connecting chamber and the first connecting head are threadedly connected in a manner that causes the lower rod body and the upper rod body to move in similar directions.

[0010] Preferably, the grouting channel extends from the lower end of the lower rod body at least into the connecting groove.

[0011] Preferably, a grouting plug is provided at the lower end of the grouting channel, a nut and a gasket are provided at the lower periphery of the lower rod body, and the nut and the periphery of the lower rod body are threadedly connected.

[0012] Preferably, the second connecting head and the connecting groove are threadedly connected, and the threaded connection between the connecting cavity and the first connecting head and the threaded connection between the second connecting head and the connecting groove can enable the lower rod body and the upper rod body to move toward and away from each other in a certain amount.

[0013] Preferably, the second connecting head can move to the lowermost end of the connecting groove.

[0014] Preferably, a drill bit is detachably or integrally formed at the top end of the upper rod body, and the outer diameter of the drill bit is not greater than the outer diameter of the upper rod body.

[0015] The present invention also proposes a full-length anchor fixing point pressure-yielding tunnel support method based on the full-length anchor fixing point pressure-yielding support anchor rod, comprising the following steps:

[0016] S1: Determine the location of the separation layer in the upper roof of the tunnel, wherein the upper rock layer of the separation layer is defined as the first roof rock layer, and the lower rock layer is defined as the second roof rock layer;

[0017] S2: Design the required displacement of the upper rod relative to the lower rod based on the delamination at the anchor installation location;

[0018] S3: Determine that the length of the lower rod is slightly greater than the length of the second roof rock layer;

[0019] S4: After the tunnel is constructed, the anchor rod is directly rotated and drilled into the designed position of the tunnel roof, and the upper rod body is completely and only located in the first roof rock layer, and the lower rod body is only located in the second roof rock layer. The part exposed from the second roof rock layer is sleeved with a pad and then the nut is screwed to fix it;

[0020] S5: When the second roof rock layer is separated from the first roof rock layer, filling material is injected into the separation layer from the grouting channel through the grouting hole.

[0021] Preferably, in step S2, the deflection value w1 of the first roof rock layer, the deflection value w2 of the second roof rock layer, and the maximum deflection value w3 that the second roof rock layer can withstand at the anchor rod installation position are determined;

[0022] Preferably, in step S2, if w 2≤ w3, then the displacement of the upper rod on the lower rod should not exceed w2-w1; if w 2＞ w3, then the displacement of the upper rod relative to the lower rod is designed not to exceed w3-w1.

[0023] Preferably, in step S2, one or more anchor rods are arranged along the width direction of the tunnel according to the design.

[0024] Preferably, in step S5, a cementitious filling material is injected.

[0025] Beneficial technical effects: 1. The full-length anchor fixed-point pressure-yielding support anchor rod of the present invention can realize both full-length anchoring of the anchor rod and fixed-point pressure-yielding. The full-length anchoring can improve the anchoring performance of the anchor rod, and the fixed-point pressure-yielding can allow the anchor rod to yield at the designed position, avoiding the problem that the pressure-yielding structure cannot yield.

[0026] 2. The full-length anchoring of the present invention allows the compression anchor rod to be installed without drilling holes first. Instead, the anchor rod can be directly rotated for drilling and installation. The anchor rod itself can be drilled, and the installation of the anchor rod is achieved when it is drilled to the designed position.

[0027] 3. The anchor bolt pressure-releasing structure of the present invention adopts a threaded connection structure, the thread rotation direction matches the external thread of the anchor bolt, and the upper rod body and the lower rod body are close when the anchor bolt is drilled and installed, and the connection groove does not leak. When separation occurs in the tunnel at a later stage, the upper rod body and the lower rod body move relative to each other through the pressure-releasing structure, generating a pressure-releasing effect.

[0028] 4. The full-length anchor fixed point pressure-yielding tunnel support method of the present invention, in conjunction with the full-length anchor fixed point pressure-yielding support anchor rod of the present invention, sets the pressure-yielding position at the separation position, so that the pressure-yielding position can play a pressure-yielding effect, and later on, grouting is used to connect the rock layers above and below the separation layer to improve the support effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the contraction state of the full-length anchor fixing point compression support anchor rod of the present invention;

[0030] Figure 2 It is a schematic diagram of the full-length anchor fixing point yielding support anchor rod of the present invention in a partially yielding (extending) state;

[0031] Figure 3 This is a schematic diagram of the full-length anchor fixing point yielding support anchor rod of the present invention in a completely yielding (extended) state;

[0032] Figure 4 It is a schematic diagram of the initial state of the full-length anchor fixing point yielding support anchor rod of the present invention when supporting the tunnel;

[0033] Figure 5 It is a schematic diagram of the pressure-yielding state of the full-length anchor fixing point pressure-yielding support anchor rod of the present invention when supporting the tunnel;

[0034] In the figure, there are a slurry plug 1, a nut 2, a pad 3, a lower rod body 4, a connecting groove 41, a first connecting head 42, a grouting channel 43, a grouting hole 44, an upper rod body 5, a connecting cavity 51, a second connecting head 52, and a drill bit 6; a first roof rock layer 7, a second roof rock layer 8, a coal seam 9, a tunnel 10, and a separation layer 11. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings.

[0036] Embodiment 1

[0037] like Figure 1-3 As shown, the present invention proposes a full-length anchor fixing point pressure-yielding support anchor rod, comprising a lower rod body 4 and an upper rod body 5 with the same outer diameter, wherein the outer periphery of the lower rod body 4 and the upper rod body 5 is provided with a continuous thread with the same rotation direction;

[0038] The outer diameter of the upper end of the lower rod body 4 is reduced to form a connecting groove 41, and the upper end of the connecting groove 41 (the upper top of the lower rod body 4) is provided with a first connecting head 42, and the outer diameter of the first connecting head 42 is larger than the outer diameter of the connecting groove 41 and smaller than the outer diameter of the lower rod body 4; the lower rod body 4 is a hollow rod body, and a grouting channel 43 is provided inside. The hollow part of the lower rod body 4, that is, the grouting channel 43, extends from the lower end of the lower rod body 4 to at least into the connecting groove 41, and in this embodiment, extends to the middle of the length direction of the connecting groove 41; the connecting groove 41 is provided with a grouting hole 44, and the grouting hole 44 is connected with the grouting channel 43, and the lower end of the grouting channel 43 is provided with a grouting plug 1, and the lower periphery of the lower rod body 4 is also provided with a nut 2 and a gasket 3, and the nut 2 is threadedly connected to the outer periphery of the lower rod body 4;

[0039] The lower end of the upper rod body 5 is hollow inside to form a receiving chamber that can accommodate the connecting groove 41 and the first connecting head 42. The inner diameter of the lower end of the receiving chamber becomes larger to form a second connecting head 52, and the remaining part forms a connecting chamber 51. The inner diameter of the connecting chamber 51 is substantially the same as the outer diameter of the first connecting head 42, and the connecting chamber 51 is threadedly connected to the first connecting head 42; the inner diameter of the second connecting head 52 is substantially the same as the outer diameter of the connecting groove 41, and preferably the second connecting head 52 is threadedly connected to the connecting groove 41, and the threaded connection between the connecting chamber 51 and the first connecting head 42 and the second connecting head 52 and the connecting groove The 41 threaded connection can make the lower rod body 4 and the upper rod body 5 move towards and away from each other in a certain amount; and when the anchor rod is rotated and drilled through the threads arranged on the outer periphery of the lower rod body 4 and the upper rod body 5, the threaded connection between the connecting cavity 51 and the first connecting head 42 and the threaded connection between the second connecting head 52 and the connecting groove 41 can make the lower rod body 4 and the upper rod body 5 move in similar directions; the second connecting head 52 can move to the lowest end of the connecting groove 41; a drill bit 6 can be detachably or integrally provided at the top end of the upper rod body 5, and the outer diameter of the drill bit 6 is not larger than the outer diameter of the upper rod body 5.

[0040] Embodiment 2

[0041] like Figure 4-5 As shown, the present invention also proposes a full-length anchor fixing point pressure-yielding tunnel support method based on the full-length anchor fixing point pressure-yielding support anchor rod, comprising the following steps:

[0042] S1: Determine the location of the separation layer 11 in the upper roof of the tunnel 10 constructed in the coal seam 9, wherein the upper rock layer of the separation layer 11 is defined as the first roof rock layer 7, and the lower rock layer is defined as the second roof rock layer 8;

[0043] S2: Determine the deflection value w1 of the first roof rock layer 7 at the anchor installation position, the deflection value w2 of the second roof rock layer 8 at the anchor installation position, and the maximum deflection value w3 that the second roof rock layer 8 can withstand at the anchor installation position. When the maximum deflection value of the second roof rock layer 8 exceeds w3, the second roof rock layer is damaged;

[0044] The anchor rod can be installed at any position in the width direction of the tunnel 10 according to design requirements ( Figure 4-5 The middle position is shown in the figure), and one or more are set along the width direction according to design requirements;

[0045] If 2≤ w3, the displacement of the upper rod body 4 relative to the lower rod body 5 is designed to be no more than w2-w1, which can be w2-w1, or 0.9 times or 0.8 times w2-w1; no specific limitation is made here, which can be determined according to the actual project, allowing the top rock layer of the tunnel 10 to be depressurized but not completely depressurized;

[0046] If 2＞ w3, the displacement of the upper rod body 4 relative to the lower rod body 5 is designed to be no more than w3-w1, which can be w3-w1, or 0.9 times or 0.8 times w3-w1; no specific limitation is made here, which can be determined according to the actual project, allowing the top rock layer of the tunnel 10 to be depressurized but not completely depressurized;

[0047] Here, the displacement that the upper rod body 4 can generate relative to the lower rod body 5 refers to the distance that the first connector 42 can move relatively in the connecting cavity 51 (also the distance that the second connector 52 can move relatively in the connecting groove 41);

[0048] S3: Determine the length of the lower rod body 4 excluding the connection groove 41 and the first connection head 42, which is slightly longer than the length of the second top plate rock layer 8. The portion longer than the second top plate rock layer 8 is used as an external anchor end for installing the pad 3 and the nut 2;

[0049] Determine the length of the upper rod body 5, the length of the upper rod body 5 can ensure the support effect of the entire anchor rod, so that it can withstand the downward pulling force applied to the anchor rod by the second top plate rock layer 8, and ensure that the anchor rod does not fail;

[0050] S4: Figure 4 As shown, after the tunnel 10 is constructed, the anchor rod is directly constructed on the designed position of the top plate of the tunnel 10 by using an anchor drilling machine, and the upper rod body 5 is completely and only located in the first top plate rock layer 7, and the lower rod body 4 is only located in the second top plate rock layer 8. The part of the second top plate rock layer 8 exposed is sleeved with the backing plate 3 and then the nut 2 is screwed to fix it;

[0051] The anchor drilling machine rotates the anchor in a direction such that the anchor can be screwed into the tunnel roof rock layer through its peripheral thread, and this rotation direction causes the lower rod body 4 and the upper rod body 5 to be in a similar motion, that is, the connecting groove 41 and the first connecting head 42 are completely located in the accommodating cavity;

[0052] S5: Figure 5 As shown, later, with the passage of time, the second roof rock layer 8 produces a separation 11 relative to the first roof rock layer 7, and the lower rod body 4 is pulled by the second roof rock layer 8 to produce relative movement with the upper rod body 5, that is, the first connecting head 42 produces relative sliding in the connecting cavity 51; when the lower rod body 4 and the upper rod body 5 move relative to each other to a set distance, that is, when the first connecting head 42 slides to the second connecting head 52; the cementitious filling material is injected into the separation layer 11 from the grouting channel 43 through the grouting hole 44, and the cementitious filling material can play the role of filling the separation layer 11 on the one hand, and can play the role of connecting the first roof rock layer 7 and the second roof rock layer 8 on the other hand.

[0053] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of methods under the inspiration of the present invention. Any technical solution that is the same or similar to that of the present application falls within the protection scope of the present invention.

Claims

1. A full-length anchor fixing point pressure-yielding support anchor rod, characterized in that: It comprises a lower rod body and an upper rod body with the same outer diameter, wherein the outer peripheries of the lower rod body and the upper rod body are provided with threads with the same and continuous rotation direction; The outer diameter of the upper end of the lower rod body is reduced to form a connecting groove, and a first connecting head is provided at the upper end of the connecting groove, and the outer diameter of the first connecting head is larger than the outer diameter of the connecting groove and smaller than the outer diameter of the lower rod body; a grouting channel is provided inside the lower rod body, and a grouting hole is provided in the connecting groove, and the grouting hole is connected to the grouting channel; The lower end of the upper rod body is hollow inside to form a receiving chamber that can accommodate the connecting groove and the first connecting head. The inner diameter of the lower end of the receiving chamber becomes larger to form the second connecting head, and the remaining part forms a connecting chamber, which is threadedly connected to the first connecting head. When the anchor rod is screwed in, the connecting chamber and the first connecting head are threadedly connected in a manner that causes the lower rod body and the upper rod body to move in similar directions.

2. The full-length anchor fixing point yielding support anchor rod according to claim 1 is characterized in that: The grouting channel extends from the lower end of the lower rod body at least to the connecting groove.

3. The full-length anchor fixing point pressure-yielding support anchor rod according to claim 1 or 2, characterized in that: A grout plug is arranged at the lower end of the grouting channel, a nut and a pad are arranged at the lower periphery of the lower rod body, and the nut is threadedly connected to the periphery of the lower rod body.

4. The full-length anchor fixing point yielding support anchor rod according to claim 1 is characterized in that: The second connecting head is threadedly connected to the connecting groove, and the threaded connection between the connecting cavity and the first connecting head and the threaded connection between the second connecting head and the connecting groove can enable the lower rod body and the upper rod body to move toward and away from each other in a certain amount.

5. The full-length anchor fixing point yielding support anchor rod according to claim 1, characterized in that: The second connecting head can move to the lowermost end of the connecting groove.

6. The full-length anchor fixing point yielding support anchor rod according to claim 1, characterized in that: A drill bit can be detachably or integrally formed at the top end of the upper rod body, and the outer diameter of the drill bit is not greater than the outer diameter of the upper rod body.

7. A full-length anchor fixing point pressure-yielding tunnel support method, using the full-length anchor fixing point pressure-yielding support anchor rod according to any one of claims 1 to 6, characterized in that: The steps include: S1: Determine the location of the separation layer in the upper roof of the tunnel, wherein the upper rock layer of the separation layer is defined as the first roof rock layer, and the lower rock layer is defined as the second roof rock layer; S2: Design the required displacement of the upper rod relative to the lower rod based on the delamination at the anchor installation location; S3: Determine that the length of the lower rod is slightly greater than the length of the second roof rock layer; S4: After the tunnel is constructed, the anchor rod is directly rotated and drilled into the designed position of the tunnel roof, and the upper rod body is completely and only located in the first roof rock layer, and the lower rod body is only located in the second roof rock layer. The part exposed from the second roof rock layer is sleeved with a pad and then the nut is screwed to fix it; S5: When the second roof rock layer is separated from the first roof rock layer, filling material is injected into the separation layer from the grouting channel through the grouting hole.

8. The full-length anchor fixed point pressure-releasing tunnel support method according to claim 7 is characterized in that: In step S2, the deflection value w1 of the first roof rock layer, the deflection value w2 of the second roof rock layer, and the maximum deflection value w3 that the second roof rock layer can withstand at the anchor installation position are determined; if w 2≤ w3, then the displacement of the upper rod on the lower rod should not exceed w2-w1; if w 2＞ w3, then the displacement of the upper rod relative to the lower rod is designed not to exceed w3-w1.

9. The full-length anchor fixed point pressure-releasing tunnel support method according to claim 7 is characterized in that: In step S2, one or more anchor rods are arranged along the width direction of the tunnel according to the design.

10. The full-length anchor fixed point pressure-releasing tunnel support method according to claim 7, characterized in that: In step S5, a cementitious filling material is injected.

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