Fixed-point pressure-yielding support anchor cable and fixed-point pressure-yielding support method for tunnels

Abstract

The present invention belongs to the field of anchor cable support for coal mine tunnels, and specifically relates to a fixed-point pressure-yielding support anchor cable and a fixed-point pressure-yielding support method for tunnels, including an anchor portion, wherein the anchor portion includes an anchor body, a drilling head is provided at the top of the anchor body, and the inner diameter of the bottom end is reduced to form an anchor connector; a hollow pressure-yielding sleeve is provided, which is composed of a connecting tube, a pressure-yielding cone tube, and a sealing head from top to bottom; an anchor cable portion is provided, which is composed of a pressure-yielding section, a grouting section, and a hollow section from top to bottom; the pressure-yielding section and the grouting section are initially located in the pressure-yielding sleeve, and after pressure-yielding, a pressure-yielding sleeve in the grouting section is located in the delamination zone, and grouting can be injected into the delamination zone through the grouting section. The present invention can adapt to the working conditions where deep anchor cable support is required due to large deformation of the tunnel surrounding rock; and it can achieve both full-length anchoring of the anchor cable and fixed-point pressure-yielding, and can also be directly drilled for construction, greatly improving the support effect.

Description

Technical Field

[0001] The invention belongs to the field of coal mine roadway anchor cable support, and in particular relates to a fixed-point pressure-yielding support anchor cable and a roadway fixed-point pressure-yielding support method. Background Art

[0002] A roadway is an underground passage constructed during coal mining. It includes development roadways, preparation roadways, and mining roadways. Mining roadways primarily serve their corresponding mining faces and have a relatively short service life, typically constructed within coal seams. To improve coal recovery rates, reduce the number of coal pillars required, and reduce roadway excavation work, gob-side roadway retention is a common method for mining roadway layout. This method allows the haul roadway of the previous working face to continue serving the subsequent working face as a return air roadway.

[0003] Due to their short service life, mining roadways are generally supported with anchor rods and / or anchor cables, which offer advantages such as good support effectiveness, rapid support speed, high degree of mechanization, and low cost. Anchor rods are short and rigid, making them easy to construct. Anchor cables are longer and are often made of twisted steel wire, which has slightly lower rigidity and cannot be directly drilled into the tunnel. They are also inconvenient to install after drilling. However, anchor cables offer great anchoring depth and excellent anchoring effectiveness. Therefore, for some difficult-to-support tunnels, anchor cables combined with anchor rods offer superior support effectiveness compared to anchor rods alone, such as in gob-side entryways.

[0004] Anchor rods and / or cables can effectively control deformation of the surrounding rock of a roadway, but they cannot completely prevent deformation and can sometimes only slow it down. Properly allowing the surrounding rock to deform to a certain degree and allowing the anchor rods or cables to adapt to this deformation, followed by further anchoring and reinforcement, can actually help support the roadway rock after deformation. Therefore, yielding anchor rods and cables, especially those that can be grouted after yielding, have emerged.

[0005] For gob-side tunneling, one side is solid coal and the other side is a backfill retaining wall, wherein the backfill retaining wall is constructed of backfill materials. Affected by the water extraction and compression deformation of the backfill materials, the deformation of the gob-side tunneling on the side of the backfill retaining wall is relatively large, and the surrounding rock affected by the deformation is relatively far, so anchor cable support is often used. However, due to the large deformation of the gob-side tunneling on the side of the backfill retaining wall, delamination will occur in the roof rock layer, especially between the basic roof and the direct roof, which will cause the anchor cable to be broken or the fastening device in the tunnel to be pulled off, thereby reducing the anchoring effectiveness of the anchor cable. The pressure-yielding anchor cable proposed in the prior art can adapt to this working condition, but the pressure-yielding structure of the anchor cable is generally set at the bottom, that is, near the orifice, and the position where pressure-yielding is required is located in the delamination layer, which results in the pressure-yielding structure not having a pressure-yielding effect, while the position where pressure-yielding is required lacks a pressure-yielding structure. In addition, a large amount of overhanging in the direct roof is prone to sudden fracture and impact, which is not conducive to tunnel safety.

[0006] Therefore, how to improve the convenience of anchor cable installation and achieve fixed-point pressure relief of the anchor cable is a difficult problem that needs to be solved in this field. Summary of the Invention

[0007] In response to the above technical problems, the present invention proposes a fixed-point pressure-yielding support anchor cable, comprising an anchor portion, wherein the anchor portion comprises an anchor body, the top end of the anchor body is provided with a drilling head, and the bottom end has an inner diameter reduced to form an anchor connector;

[0008] It also includes a hollow pressure relief sleeve, which comprises a connecting tube, a pressure relief cone and a sealing head from top to bottom. The connecting tube can be connected to the anchor rod connector; the outer diameter of the bottom section of the sealing head is reduced to form a sleeve connector;

[0009] It also includes an anchor cable part, which is composed of a pressure-releasing section, a grouting section and a hollow section from top to bottom; a pressure-releasing cone block is fixed to the outer periphery of the pressure-releasing section, and the pressure-releasing cone block is seated in the pressure-releasing cone cylinder; the grouting section is located in the pressure-releasing cone cylinder and the sealing head in the initial state, and the grouting section includes a central grouting pipe, and the grouting pipe is provided with grouting holes; the hollow section is located below the sealing head, and the hollow section includes a central grouting pipe.

[0010] Preferably, the drilling head is a conical drill bit, and the outer diameter of the drilling head is not greater than the outer diameter of the anchor body.

[0011] Preferably, a drilling thread is provided on the outer periphery of the anchor body.

[0012] Preferably, the outer diameter of the pressure-releasing sleeve is the same as that of the anchor rod body.

[0013] Preferably, the inner diameter of the yield cone gradually decreases from top to bottom, forming an inverted frustum structure.

[0014] Preferably, the inner diameter of the top end of the pressure-releasing cone is the same as the inner diameter of the connecting tube.

[0015] Preferably, the inner diameter of the sealing head is consistent and smaller than the minimum inner diameter of the pressure-releasing cone, forming a step.

[0016] Preferably, the pressure relief cone is an inverted frustum.

[0017] Preferably, the pressure-relief section includes a solid rod in the center and a steel wire wrapped around the rod.

[0018] Preferably, the outer periphery of the grouting section is sealedly connected to the inner wall of the sealing head at least in an initial state.

[0019] Preferably, the grouting section is formed by spirally and evenly winding a plurality of steel wires on a grouting pipe, and gaps are formed between the plurality of steel wires by changing the winding parameters of the steel wires, thereby providing an outflow channel for the grouting hole.

[0020] Preferably, in the grouting section, an expansion ring is sleeved on the outer periphery of the grouting pipe, thereby increasing the outer diameter of the grouting pipe, forming gaps between the multiple steel wires, and providing outflow channels for the grouting holes.

[0021] Preferably, the hollow section is formed by spirally and tightly winding a plurality of steel wires on the grouting pipe.

[0022] Preferably, a slurry stopper, a tray and a fastening nut are sequentially sleeved on the outer periphery of the lower portion of the hollow section.

[0023] Preferably, a slurry plug is provided at the lower end of the grouting channel of the hollow section.

[0024] The present invention also proposes a fixed-point pressure-yielding support method for a tunnel based on a fixed-point pressure-yielding support anchor cable, comprising the following steps:

[0025] S1: Gob-side lane retention;

[0026] S2: Assemble the anchor cable, use the hollow drill pipe to connect the sleeve connector, place the anchor cable part in the inner cavity of the drill pipe, directly drill into the construction, construct the anchor part and the pressure sleeve in the direct top, and rotate the drill pipe in the opposite direction to withdraw;

[0027] S3: anchor cable part;

[0028] S4: Delamination occurs between the basic top and the direct top, the anchor cable part moves relative to the anchor rod part, the grouting hole moves to release the pressure sleeve, and the cementitious filling material is injected into the delamination layer from the grouting channel.

[0029] Preferably, step S2, or, using a hollow drill rod to connect the anchor rod connector, directly drilling construction, constructing the anchor rod part in the basic top, and reserving a pressure sleeve installation position in the basic top, reversely rotating the drill rod to withdraw; assembling the pressure sleeve and the anchor cable part, using a hollow drill rod to connect the sleeve connector, placing the anchor cable part in the inner cavity of the drill rod, sending the pressure sleeve to the anchor rod connector, rotating the drill rod to connect the connecting tube and the anchor rod connector, and reversely rotating the drill rod to withdraw.

[0030] Preferably, in step S3, grouting is injected into the gap between the outer periphery of the hollow section of the anchor cable and the drill hole.

[0031] Preferably, in step S3, the anchoring method is to install a slurry stopper, a tray, and a fastening nut.

[0032] Preferably, in step S4, the yield length of the fixed-point yield support anchor cable needs to adapt to the amount of delamination generated.

[0033] Beneficial technical effects: 1. The fixed-point pressure-yielding support anchor cable of the present invention combines the directly drilled anchor rod and the anchor cable into one, and is connected through a pressure-yielding structure, which can adapt to the working conditions where the tunnel surrounding rock is greatly deformed and deep anchor cable support is required; and it can achieve both full-length anchoring of the anchor cable and fixed-point pressure-yielding. The full-length anchoring can improve the anchoring performance of the anchor cable, and the fixed-point pressure-yielding can allow the anchor cable to yield at the designed position, avoiding the problem that the pressure-yielding structure cannot yield.

[0034] 2. The fixed-point yielding support anchor cable of the present invention does not require prior drilling before installation. Instead, the anchor cable can be directly rotated and drilled. The anchor portion can then be drilled, and the anchor is installed as soon as the drill rig reaches the designed position. The anchor portion has a high anchoring strength. In the later stage of the roadway, when separation occurs, the yielding structure causes the anchor portion and the anchor cable to move relative to each other, generating a yielding effect. The grouting hole is exposed to the separation layer, and the rock layers above and below the separation layer are connected through grouting, thereby improving the support effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the overall structure of the fixed-point pressure-yielding support anchor cable of the present invention;

[0036] Figure 2 This is a schematic diagram of the structure of the fixed-point pressure support anchor cable separation of the present invention;

[0037] Figure 3 This is a schematic diagram of the structure of the anchor section in the fixed-point pressure-yielding support anchor cable of the present invention;

[0038] Figure 4 This is a schematic diagram of the structure of the pressure-relieving sleeve in the fixed-point pressure-relieving support anchor cable of the present invention;

[0039] Figure 5This is a schematic diagram of the structure of the anchor cable segment in the fixed-point pressure-yielding support anchor cable of the present invention;

[0040] Figure 6 Schematic cross-sectional view of the yield section in the anchor cable section of the present invention;

[0041] Figure 7 Schematic cross-sectional view of the grouting section in the anchor cable section of the present invention;

[0042] Figure 8 Schematic diagram of the cross section of the hollow section of the anchor cable segment of the present invention;

[0043] Figure 9 This is a schematic diagram of the initial state of the fixed-point pressure-yielding support anchor cable in the goaf-side tunnel construction of the present invention;

[0044] Figure 10 This is a schematic diagram of the fixed-point pressure-yielding support anchor cable of the present invention in the pressure-yielding state during construction in a goaf-side roadway;

[0045] In the figure, there are drilling head 11, anchor rod body 12, anchor rod connector 13; connecting tube 21, pressure relief cone 22, sealing head 23, sleeve connector 24; limiting head 31, pressure relief cone block 32, pressure relief section 33, grouting section 34, grouting hole 35, hollow section 36; steel wire 41, solid rod 42, grouting pipe 43, grouting channel 44, expansion ring 45; slurry stopper 51, tray 52, fastening nut 53, slurry plug 54; solid coal 6, basic roof 7, direct roof 8, gob-side entry retaining wall 9; gob-side entry 10; separation layer 78. DETAILED DESCRIPTION

[0046] The present invention will be further described below with reference to the accompanying drawings.

[0047] Example 1

[0048] like Figure 1-8 As shown, the present invention proposes a fixed-point pressure-yielding support anchor cable, comprising an anchor portion and an anchor cable portion. A pressure-yielding sleeve is provided at the bottom end of the anchor portion, and the top end of the anchor cable is provided in the pressure-yielding sleeve to form a pressure-yielding structure; the details are as follows:

[0049] like Figure 1-3 As shown, the anchor portion includes an anchor body 12, a drilling head 11 is detachably or integrally formed at the top end of the anchor body 12, the drilling head 11 is a conical drill bit, and the outer diameter of the drilling head 11 is not larger than the outer diameter of the anchor body 12; an anchor connector 13 is provided at the bottom end of the anchor body 12, the outer diameter of the anchor connector 13 is smaller than the outer diameter of the anchor body 12; the anchor connector 13 can be connected to a drill rod; the outer periphery of the anchor body 12 is provided with a drilling thread;

[0050] like Figure 1-2 、 Figure 4As shown, the pressure-releasing sleeve is a hollow cylinder, preferably with the same outer diameter as the anchor rod body 12. The pressure-releasing sleeve is divided into three sections from top to bottom, namely a connecting tube 21, a pressure-releasing cone 22, and a sealing head 23. The inner diameter of the connecting tube 21 is the same as the outer diameter of the anchor rod connector 13, and can be connected by a fixed connection method such as threaded connection or welding; the inner diameter of the pressure-releasing cone 22 gradually decreases from top to bottom, forming an inverted frustum structure; the inner diameter of the top end of the pressure-releasing cone 22 is the same as the inner diameter of the connecting tube 21; the inner diameter of the sealing head 23 is consistent and smaller than the minimum inner diameter of the pressure-releasing cone 22, forming a step; the outer diameter of the bottom section of the sealing head 23 is reduced to form a sleeve connector 24, the outer diameter of the sleeve connector 24 is the same as the outer diameter of the anchor rod connector 13, and the sleeve connector 24 can be connected to the drill pipe;

[0051] like Figure 1-2 、 Figure 5-6 As shown, the anchor portion is divided into three sections from top to bottom, namely, a pressure-releasing section 33, a grouting section 34 and a hollow section 36; a pressure-releasing cone block 32 is fixed to the outer periphery of the pressure-releasing section 33, the outer diameter of the pressure-releasing cone block 32 forms an inverted cone, and the pressure-releasing cone block 32 sits in the pressure-releasing cone cylinder 22, the maximum outer diameter of the pressure-releasing cone block 32 is the same as the maximum inner diameter of the pressure-releasing cone cylinder 22, the length of the pressure-releasing cone block 32 is slightly smaller than the pressure-releasing section 33, the top end of the pressure-releasing section 33 exceeds the top end of the pressure-releasing cone block 32, and a limit head 31 is provided on the exceeding part to prevent the anchor portion from escaping from the pressure-releasing cone cylinder 22; as shown Figure 6 The cross-sectional structure of the pressure-releasing section 33 includes a solid rod 42 in the center, and a plurality of steel wires 41 are spirally and evenly wound tightly around the solid rod 42 to form the pressure-releasing section 33 of the anchor cable. The manufacturing method of the anchor cable is well known in the art and will not be described in detail here.

[0052] like Figure 1-2 、 Figure 5 、 Figure 7 As shown, the grouting section 34 is located inside the pressure-releasing cone 22 and the sealing head 23 in the initial state, and the outer periphery of the grouting section 34 is sealed to the inner wall of the sealing head 23 at least in the initial state, and a sealing material can be provided on the inner wall of the sealing head; Figure 7As shown, the cross-sectional structure of the grouting section 34 includes a grouting pipe 43 in the center. The grouting pipe 43 is a hollow structure with a grouting channel 44 at the center. The grouting pipe 43 is provided with a grouting hole 35. The grouting hole 35 is provided on the grouting pipe 43 of the grouting section 34 as needed and is connected to the grouting channel 44. In the embodiment of the present invention, the grouting hole 35 is provided at the portion corresponding to the pressure cone 22; a plurality of steel wires 41 are spirally and evenly wound around the grouting pipe 43, and the plurality of steel wires 41 are spirally and evenly wound around the grouting pipe 43 by changing the winding parameters of the steel wires 41. Gaps are formed between the steel wires 41 to provide a flow channel for the grouting holes 35; preferably, an expansion ring 45 is sleeved on the outer periphery of the grouting pipe 43 to increase the outer diameter of the grouting pipe 43, so that gaps are formed between the multiple steel wires 41 to provide a flow channel for the grouting holes 35; the expansion ring 45 is provided along the axis of the grouting section 34 as needed, or it can be avoided only at the location where the grouting holes 35 are provided and provided at other locations. The lengths of the multiple expansion rings 45 can also be set according to specific needs and do not need to be all the same;

[0053] like Figure 1-2 、 Figure 5 、 Figure 8 As shown, the hollow section 36 is located below the sealing head 23. The cross-sectional structure of the hollow section 36 includes a grouting pipe 43 in the center. The grouting pipe 43 is a hollow structure with a grouting channel 44 in the center. A plurality of steel wires 41 are spirally and evenly wound tightly around the grouting pipe 43 to form the hollow section 36 of the anchor portion. A grouting plug 51, a tray 52 and a fastening nut 53 are sequentially sleeved on the outer periphery of the lower part of the hollow section 36, and a grouting plug 54 is provided at the lower end of the grouting channel 44.

[0054] Among them, the grouting pipe 43 of the grouting section 34 and the hollow section 36 uses one, or the grouting pipe 43 of the grouting section 34 and the adjacent ends of the grouting pipe 43 of the hollow section 36 are seamlessly connected; the solid rod 42 is inserted into the grouting pipe 43 of the grouting section 34 to seal the top of the grouting pipe 43 of the grouting section 34, or the top of the grouting pipe 43 of the grouting section 34 is sealed.

[0055] Example 2

[0056] like Figure 9 As shown, the present invention also proposes a fixed-point pressure-yielding support method for a tunnel based on a fixed-point pressure-yielding support anchor cable, comprising the following steps:

[0057] S1: A gob-side entry retaining 10 is performed. One side of the gob-side entry retaining 10 is the solid coal 6 of the working face to be mined, and the other side is the gob-side entry retaining wall 9. The gob-side entry retaining wall 9 is formed by filling material, and the other side of the gob-side entry retaining wall 9 is the goaf (not shown in the figure);

[0058] S2: Assemble the anchor cable of the present invention and use a hollow drill rod connecting sleeve connector 24. The outer diameter of the drill rod does not exceed the anchor portion and the pressure relief sleeve. Place the anchor cable portion in the inner cavity of the drill rod. At this time, the drill rod, the anchor portion, and the pressure relief sleeve form a rigid structure. Drilling construction is directly carried out. The anchor portion and the pressure relief sleeve are constructed in the hard basic top 7. The bottom end of the pressure relief sleeve is located at the interface between the basic top 7 and the direct top 8. The direct top 8 contains multiple rock layers. Then, the drill rod is rotated in the opposite direction to separate the drill rod from the pressure relief sleeve and withdraw the drill rod.

[0059] or

[0060] A hollow drill rod is used to connect the anchor rod connector 13. The outer diameter of the drill rod does not exceed the anchor rod part. The drilling construction is carried out directly. The anchor rod part is constructed in the hard basic top 7. A pressure-releasing sleeve installation position is reserved in the basic top 7 so that the bottom end of the pressure-releasing sleeve can be located at the interface between the basic top 7 and the direct top 8. The direct top 8 contains multiple rock formations. The drill rod is then rotated in the opposite direction to separate the drill rod from the anchor rod part and withdraw the drill rod. The pressure-releasing sleeve and the anchor cable part are assembled. A hollow drill rod connecting sleeve connector 24 is used to place the anchor cable part in the inner cavity of the drill rod. The pressure-releasing sleeve is sent to the anchor rod connector 13. The drill rod is rotated to connect the connecting tube 21 and the anchor rod connector 13. The drill rod is rotated in the opposite direction to separate the drill rod from the pressure-releasing sleeve and withdraw the drill rod.

[0061] S3: Grouting is performed into the gap between the outer periphery of the hollow section 36 of the anchor cable and the drill hole to reinforce the hollow section 36 of the anchor cable, and a grouting plug 51, a tray 52, a fastening nut 53, and a grouting plug 54 are installed;

[0062] S4: As Figure 10 As shown, later on, with the passage of time, affected by the water extraction and compressive deformation of the filling material, the deformation of the goaf-retained tunnel on the side of the filling retaining wall 9 is larger, so a separation layer 78 will be generated between the basic top 7 and the direct top 8. During this process, the anchor cable part moves relative to the anchor rod part, and the pressure-yielding cone block 32 of the anchor cable part moves downward relative to the pressure-yielding cone cylinder 22. The grouting hole 35 moves out of the pressure-yielding sleeve, and the grouting hole 35 is exposed in the separation layer 78. The grouting plug 54 is opened, and the cementitious filling material is injected into the separation layer from the grouting channel. The cementitious filling material plays the role of filling the separation layer 78 on the one hand, and can play the role of connecting the basic top 7 and the direct top 8 on the other hand. Among them, the pressure-yielding length of the fixed-point pressure-yielding support anchor cable needs to adapt to the amount of separation layer generated.

[0063] 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. However, any technical solution that is the same or similar to that of the present application falls within the scope of protection of the present invention.

Claims

1. A fixed-point pressure-yielding support method for a tunnel, using a fixed-point pressure-yielding support anchor cable, comprising an anchor portion, the anchor portion comprising an anchor body, the top end of the anchor body being provided with a drilling head, and the bottom end having a reduced inner diameter being provided with an anchor connector; It also includes a hollow pressure relief sleeve, which comprises a connecting tube, a pressure relief cone and a sealing head from top to bottom. The connecting tube can be connected to the anchor rod connector; the outer diameter of the bottom section of the sealing head is reduced to form a sleeve connector; The anchor cable also includes an anchor cable portion, which is composed of a pressure-releasing section, a grouting section, and a hollow section from top to bottom. A pressure-releasing cone block is fixed to the periphery of the pressure-releasing section, and the pressure-releasing cone block is seated in the pressure-releasing cone cylinder. The grouting section is located in the pressure-releasing cone cylinder and the sealing head in an initial state. The grouting section includes a central grouting pipe, and the grouting pipe is provided with grouting holes. The hollow section is located below the sealing head, and the hollow section includes a central grouting pipe. It is characterized in that The tunnel fixed-point pressure-yielding support method comprises the following steps: S1: Gob-side lane retention; S2: Assemble the anchor cable, use the hollow drill pipe to connect the sleeve connector, place the anchor cable part in the inner cavity of the drill pipe, directly drill into the construction, construct the anchor part and the pressure sleeve in the direct top, and the bottom end of the pressure sleeve is located at the interface between the basic top and the direct top. Rotate the drill pipe in the opposite direction to withdraw; S3: anchor cable part; S4: When delamination occurs between the basic roof and the immediate roof of the later tunnel, the anchor cable part moves relative to the anchor rod part through the pressure-releasing structure, generating a pressure-releasing effect. The grouting hole moves out of the pressure-releasing sleeve and is exposed to the delamination layer. The cementitious filling material from the grouting channel into the delamination layer connects the rock layers above and below the delamination layer.

2. The tunnel fixed-point pressure-yielding support method according to claim 1 is characterized in that: The drilling head is a conical drill bit, and the outer diameter of the drilling head is not greater than the outer diameter of the anchor body; and / or the outer periphery of the anchor body is provided with a drilling thread.

3. The fixed-point pressure-yielding support method for a roadway according to claim 1 is characterized in that: The outer diameter of the pressure-releasing sleeve is the same as that of the anchor rod body; and / or, the inner diameter of the top end of the pressure-releasing cone is the same as that of the connecting tube; and / or, the inner diameter of the sealing head is consistent and smaller than the minimum inner diameter of the pressure-releasing cone, forming a step.

4. The tunnel fixed-point pressure-yielding support method according to claim 1 or 3, characterized in that: The inner diameter of the pressure-releasing cone gradually decreases from top to bottom to form an inverted frustum structure, and / or the pressure-releasing cone is an inverted frustum.

5. The tunnel fixed-point pressure-yielding support method according to claim 1 is characterized in that: The pressure-releasing section includes a solid rod in the center and a steel wire wound around it; and / or, the grouting section is formed by evenly winding a plurality of steel wires spirally around a grouting pipe, and gaps are formed between the plurality of steel wires by changing the winding parameters of the steel wires, thereby providing an outflow channel for the grouting hole; and / or, the hollow section is formed by evenly and tightly winding a plurality of steel wires spirally around a grouting pipe.

6. The tunnel fixed-point pressure-yielding support method according to claim 1 is characterized in that: The outer periphery of the grouting section is sealedly connected to the inner wall of the sealing head at least in the initial state; and / or, the outer periphery of the lower part of the hollow section is also sequentially sleeved with a slurry stopper, a tray and a fastening nut; and / or, a slurry stopper is provided at the lower end of the grouting channel of the hollow section.

7. The tunnel fixed-point pressure-yielding support method according to claim 5 is characterized in that: In the grouting section, an expansion ring is sleeved on the outer periphery of the grouting pipe, thereby increasing the outer diameter of the grouting pipe, forming gaps between the multiple steel wires, and providing outflow channels for the grouting holes.

8. The tunnel fixed-point pressure-yielding support method according to claim 1 is characterized in that: Step S2, or, use a hollow drill rod to connect the anchor rod connector, directly drill into the construction, construct the anchor rod part in the basic top, and reserve a pressure sleeve installation position in the basic top, the bottom end of the pressure sleeve is located at the interface between the basic top and the direct top, and reversely rotate the drill rod to exit; assemble the pressure sleeve and the anchor cable part, use a hollow drill rod to connect the sleeve connector, place the anchor cable part in the inner cavity of the drill rod, send the pressure sleeve to the anchor rod connector, rotate the drill rod to connect the connecting tube and the anchor rod connector, and reversely rotate the drill rod to exit.

9. The fixed-point pressure-yielding support method for a tunnel according to claim 1 or 8, characterized in that: In step S3, grouting is performed into the gap between the outer periphery of the hollow section of the anchor cable and the drill hole; and / or, in step S3, the anchoring method is to install a grouting plug, a tray, and a tightening nut; and / or, in step S4, the yield length of the fixed-point yield support anchor cable needs to adapt to the amount of delamination generated.

Images