Umbrella rib type grouting anchor rod for supporting broken surrounding rock and grouting reinforcement method

Abstract

The invention discloses an umbrella rib type grouting anchor rod for supporting broken surrounding rocks and a grouting reinforcement method, and relates to the technical field of coal mine underground roadway surrounding rock control. The umbrella rib type grouting anchor rod comprises a replaceable pressure transmitting device, a steel hollow shell, an umbrella rib type grouting device and a central slurry conveying pipe. In an actual underground application scene, a roadway section which is supported by using a grouting anchor rod in advance is selected, drilling detection is carried out, a broken roof rock stratum to be grouted is measured, then an umbrella rib type grouting anchor rod is used for anchoring, accurate differential grouting reinforcement is carried out according to the actual breaking condition, umbrella rib type four-direction splitting grouting is matched, and the grouting effect of the broken roof rock stratum to be grouted is achieved. The anchoring force of the underground coal mine tunnel broken roof is enhanced; the row distance between anchor rod supports is accurately controlled through the slurry diffusion distance, and a dot-matrix gridding grouting reinforcement group is formed; and targeted grouting reinforcement of the equipment on the broken roof is effectively achieved, a grouting network is formed, the anchoring force of the anchor rod during coal mining under the broken roof is improved, and the safety of production operation is improved.

Description

Technical Field

[0001] The invention relates to the technical field of surrounding rock control of underground coal mine tunnels, and in particular to an umbrella-shaped grouting anchor rod for broken surrounding rock support and a grouting reinforcement method. Background Art

[0002] Grouting technology has been widely used in foundation reinforcement, tunnel lining consolidation, groundwater control, etc. in underground projects. After the grouting slurry solidifies and hardens, it can play a role in cementation and plugging, making the stratum stable and isolating the water source to ensure smooth construction on site. With the continuous advancement of science and technology, the application scope of this technology has become wider and wider. Broken surrounding rocks are often encountered during the excavation of underground tunnels in coal mines. The use of traditional anchor rods and anchor cable support methods often leads to the risk of insufficient anchoring force and water conduction in the cracks of the broken surrounding rocks, which can easily cause safety accidents such as roof falls.

[0003] In order to solve the problem that traditional support methods have poor adaptability to broken surrounding rocks, coal mines currently usually use grouting reinforcement measures to reinforce the surrounding rocks of tunnels. However, some existing grouting support equipment, such as grouting anchors, hollow grouting anchor cables, etc., can achieve in-hole grouting and improve the integrity of the surrounding rock to a certain extent, but their grouting form is single and the targeting of different layers is poor, especially the overall control effect on large-scale water-conducting fissures is weak. For example, under the conditions of water-rich roof tunnels, the existing grouting support equipment cannot effectively suspend the broken roof and play a significant role in blocking water from the aquifer above, resulting in serious safety accidents such as roof collapse and water inrush in the tunnel, which brings huge challenges to mine production. Therefore, it is urgent to invent an anchor rod that can support broken surrounding rocks with a reliable structure, strong anchoring force, and high working efficiency, so as to provide technical support for safe and efficient excavation construction of underground tunnels in coal mines. Summary of the invention

[0004] In view of the above problems, the present invention discloses an umbrella-rib type grouting anchor rod and a grouting reinforcement method for broken surrounding rock support. The broken roof is treated by directional grouting, and an umbrella-rib type grouting device is used to perform four-way in-hole grouting. Horizontal directional splitting grouting is formed at the end of the external bone probe to form horizontal grouting diffusion, which effectively realizes the targeted grouting reinforcement of the broken roof by the equipment, forms a grouting network, improves the anchoring force of the anchor rod when mining coal under the broken roof, and improves the safety of production operations.

[0005] According to the purpose of the present invention, an umbrella-shaped grouting anchor for broken surrounding rock support is provided, comprising a replaceable pressure transmission device, a steel hollow shell, an umbrella-shaped grouting device and a central grouting pipe;

[0006] The replaceable pressure transmission device is arranged at the top of the steel hollow shell, and includes a top pressure-bearing plate and a middle pressure-transmitting rod; the top pressure-bearing plate is fixedly connected to one end of the middle pressure-transmitting rod, and is subjected to pressure during the process of anchor bolt drilling; one end of the middle pressure-transmitting rod away from the top pressure-bearing plate extends into the steel hollow shell through the pressure-transmitting rod limiting hole arranged at the top of the steel hollow shell, and is detachably fixedly connected to the umbrella-shaped grouting device;

[0007] The steel hollow shell is cylindrical, and has four external bone exploration reserved holes evenly distributed in the circumferential direction on its side;

[0008] The umbrella-rib type grouting device comprises a pressure transmission and limiting tube, a central bone and an outer probe bone; one end of the pressure transmission and limiting tube is detachably fixedly mounted on one end of the middle pressure transmission rod extending into the hollow steel shell, and the other end is hollowly arranged; the central bone is an integrally formed component, one end of which is fixedly mounted on the top end of the central grouting pipe, and the other end is inserted into the inner cavity of the pressure transmission and limiting tube; the outer probe bones are four and are arranged corresponding to the reserved holes of the outer probe bones, one end of each outer probe bone is rotatably connected to the pressure transmission and limiting tube, and the other end extends into the corresponding reserved hole of the outer probe bone, and the four outer probe bones are evenly spaced along the circumference of the pressure transmission and limiting tube. cloth; a slide rail is arranged on the outer probe bone, an outer probe bone fixing guide joint is fixedly installed in the outer probe bone reserved hole, and the outer probe bone fixing guide joint is embedded in the slide rail, and the two cooperate to limit the movement trajectory of the outer probe bone; an outer probe bone injection tube is arranged on the end of the outer probe bone extending into the outer probe bone reserved hole, and the outer probe bone injection tube is connected with the central slurry delivery tube through a telescopic injection tube; the outer end of the outer probe bone extending into the outer probe bone reserved hole is also wrapped with an outer probe bone blocking liquid sac, and a blocking liquid sac pressurizing port is opened on the outer probe bone injection tube corresponding to the outer probe bone blocking liquid sac;

[0009] The central injection tube is fixedly installed inside the steel hollow shell through a grouting tube fixing column, the top end is fixedly connected to the central bone, the bottom end extends to the bottom of the anchor rod, and is provided with a bottom grouting interface; the end of the central injection tube connected to the central bone is connected to the external bone injection tube through a telescopic injection tube, and after the slurry is input from the bottom grouting interface, it is input into the drill hole through the central injection tube, the telescopic injection tube and the external bone injection tube.

[0010] Preferably, the outer wall of one end of the pressure transmission limiting tube connected to the central bone is fixedly installed with an outer detection tooth of the limiting tube, and a fixed steering knuckle is fixedly installed on the outer detection tooth of the limiting tube, and the outer detection bone is hinged with the outer detection tooth of the limiting tube through the fixed steering knuckle.

[0011] Preferably, one end of the central injection tube connected to the telescopic injection tube is provided with four-outlet slurry delivery interfaces.

[0012] The present invention further discloses a method for grouting reinforcement of the umbrella-shaped grouting anchor rod for broken surrounding rock support, comprising the following steps:

[0013] Step 1: Select the area that needs grouting reinforcement in the underground coal mine tunnel, drill a certain number of holes in the tunnel roof, and use a rock formation detection recorder to observe and record the holes after the holes reach the predetermined depth;

[0014] Step 2: sort and analyze the images of the drilling process, select the broken roof rock layer to be grouting, and determine the grouting height R;

[0015] Step 3: According to the broken roof rock layer and grouting height R found in step 2, take the rock sample at R for physical and mechanical parameter testing to measure the rock's gravity γ and rock's tensile strength σ t , Poisson's ratio of rock ν, grouting hole depth R z , the static lateral pressure coefficient of rock K0;

[0016] Step 4: Calculate according to the splitting grouting theory of rock fissures to obtain the vertical splitting grouting pressure and horizontal splitting grouting pressure required for the grouting of the umbrella-shaped grouting anchor to form a splitting grouting slurry vein network in the top rock layer during the grouting process, and take the larger value of the two as the minimum grouting pressure;

[0017] Step 5: Determine the actual grouting pressure P according to the minimum grouting pressure determined in step 4. z , combined with the rock grouting splitting diffusion theory, the granular slurry splitting penetration diffusion radius R is obtained K ;

[0018] Step 6: The splitting penetration diffusion radius of the granular slurry obtained in step 5 is combined with the characteristics of the four-way orthogonal grouting diffusion of the anchor rods to determine the spacing between the anchor rods, so that a dot matrix grouting anchor rod group is formed in a certain broken roof roadway area, and the slurry is injected to form a grid-like diffusion group;

[0019] Step 7: In the area requiring grouting reinforcement, according to the position of the broken roof rock layer determined in step 2, the grouting height R and the spacing between anchors determined in step 6, a plurality of anchor holes with a length of L0 are constructed, and at the same time, a horizontal grouting hole perpendicular to the anchor hole is constructed at the grouting height R in the anchor hole;

[0020] Step 8: Place the anchoring agent above the top pressure plate, and drill the umbrella-shaped grouting anchor into the anchor hole by the anchor drilling machine. When the anchor reaches the head of the anchor hole, pierce the anchoring agent to form an anchoring end.

[0021] Step 9: Continue to apply drilling force to the umbrella-shaped grouting anchor bolt, the top pressure-bearing plate, the middle pressure-transmitting rod and the pressure-transmitting limiting tube remain in position, and the steel hollow shell and the center bone continue to move into the anchor bolt borehole. At this time, the center bone is inserted into the inner cavity of the pressure-transmitting limiting tube, and the outer bones are expanded upward and outward and inserted into the horizontal grouting hole. When the outer bones are expanded to a horizontal state, the center bone is just inserted into the top of the pressure-transmitting limiting tube for mechanical locking, and the drilling action is stopped;

[0022] Step 10: Based on the actual grouting pressure determined in step 5, use a high-pressure grouting pump to perform grouting through the lower grouting interface at the tail end of the umbrella-shaped grouting anchor rod.

[0023] Preferably, in step 4, the calculation method of the vertical splitting grouting pressure and the horizontal splitting grouting pressure required for the grout to form a splitting grouting slurry vein network in the top rock layer during the grouting process of the umbrella-shaped grouting anchor is:

[0024] Vertical Splitting:

[0025]

[0026] Horizontal splitting:

[0027]

[0028] Where:

[0029] P0-grouting pressure, kPa;

[0030] γ-weight of rock, kN / m3;

[0031] R z - Grouting hole depth, m;

[0032] σ t - tensile strength of rock, kPa;

[0033] N-the proportional coefficient of fluid pressure used to expand the hole wall, generally ranging from 0 to 1;

[0034] ν - Poisson's ratio of rock;

[0035] K0-static lateral pressure coefficient of rock.

[0036] Preferably, in step 5, the granular slurry splitting penetration diffusion radius R K The calculation method is:

[0037]

[0038] Where:

[0039] ρ w -Density of water, g / cm 3 ;

[0040] g-gravitational acceleration, cm / s 2 ;

[0041] P z -Actual grouting pressure, kPa;

[0042] r e -Equivalent radius of the pore, cm;

[0043] S-Gel strength of grouting material, dyn / cm 2 ;

[0044] R z - Grouting hole depth, m.

[0045] Compared with the prior art, the advantages of the umbrella-shaped grouting anchor rod and grouting reinforcement method for broken surrounding rock support disclosed in the present invention are:

[0046] (1) The present invention is used for supporting the broken roof in the well. Its umbrella-shaped grouting device can realize mechanical locking and fixing through the cooperation of the pressure-transmitting limit tube and the central bone. Its umbrella-shaped movement shape can ensure that the outer bone can be extended in a smaller space, so that the reserved hole has no squeezing and hindering effect on the outer bone. At the same time, its mechanical locking structure can make the outer bone open at an angle of 90° with the anchor rod body, so as to increase the anchoring force of the anchor rod through the mechanical structure.

[0047] (2) The present invention treats the broken roof through directional grouting, uses an umbrella-shaped grouting device to perform four-way in-hole grouting, forms horizontal directional splitting grouting at the end of the external rib, and forms horizontal grouting diffusion. Compared with the spherical and columnar grouting of traditional grouting equipment, this device does not use the grouting anchor as a grouting unit to perform extremely small-scale grouting, but forms a dot matrix grouting grid through the four-way horizontal diffusion of the slurry, which can effectively prevent the roof from falling and water seepage.

[0048] (3) The dot matrix installation scheme provided by the present invention can apply pressure to the equipment through the minimum horizontal and vertical splitting pressure of the rock, and determine the spacing between the anchor equipment through the slurry diffusion radius. It is used for safe and efficient operations under a large range of broken roofs. Within a certain range, the equipment can be used at intervals to form a grouting grid plate model in a large range of roof fracture zones, which can provide a grid-type water-blocking layer for production activities under the aquifer. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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.

[0050] Figure 1 This is a schematic diagram of the overall device of the umbrella-shaped grouting anchor.

[0051] Figure 2 This is a schematic diagram of the external bone exploration.

[0052] Figure 3 This is a schematic diagram of an umbrella rib type grouting device.

[0053] Figure 4 Expand the top view for the outer exploration bone.

[0054] Figure 5 This is a top view of the center slurry pipe.

[0055] Figure 6 This is the effect diagram of using a single umbrella-rib type grouting anchor.

[0056] Figure 7 Use renderings for anchor groups.

[0057] In the figure: 1-replaceable pressure transmission device; 11-top pressure plate; 12-middle pressure transmission rod; 2-steel hollow shell; 21-pressure transmission rod limit hole; 22-external probe bone reserved hole; 221-external probe bone fixed guide joint; 3-umbrella rib type grouting device; 31-pressure transmission limit tube; 311-external probe tooth of limit tube; 312-fixed steering knuckle; 32-center bone; 33-external probe bone; 331-slide rail; 332-external probe bone injection tube; 333-sealing liquid sac pressure port; 334-external probe bone sealing liquid sac; 335-liquid outlet; 4-center slurry delivery pipe; 41-four-outlet slurry delivery interface; 42-telescopic injection pipe; 43-lower slurry delivery interface; 5-slurry delivery pipe fixing column; 6-high pressure grouting pump. DETAILED DESCRIPTION

[0058] The specific implementation of the present invention is briefly described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] Figure 1-Figure 7 The preferred embodiments of the present invention are shown and analyzed in detail.

[0060] like Figure 1, 2 An umbrella-shaped grouting anchor rod for broken surrounding rock support shown in 4 includes a replaceable pressure transmission device 1, a steel hollow shell 2, an umbrella-shaped grouting device 3 and a central grouting pipe 4.

[0061] The replaceable pressure transmission device 1 is arranged at the top of the steel hollow shell 2, and includes a top pressure plate 11 and a middle pressure transmission rod 12. The top pressure plate 11 is a metal flat plate, and the middle pressure transmission rod 12 is a rigid metal rod. The top pressure plate 11 is fixedly connected to one end of the middle pressure transmission rod 12, and is subjected to pressure during the process of anchor drilling. The end of the middle pressure transmission rod 12 away from the top pressure plate 11 extends into the steel hollow shell 2 through the pressure transmission rod limiting hole 21 set at the top of the steel hollow shell 2 and is threadedly connected to the umbrella-shaped grouting device 3. During the process of anchor drilling into the hole, as the anchor is drilled, the pressure on the top gradually increases, and the top pressure plate 11 directly transmits the pressure downward from the middle pressure transmission rod 12. Since the direction of the force transmitted by the top pressure plate 11 may not be along the drilling direction, the device fails. In order to avoid this situation, a pressure transmission rod limiting hole 21 is provided to constrain the middle pressure transmission rod 12 in the longitudinal force direction.

[0062] The steel hollow shell 2 is a hollow cylinder, and four external bone-probing reserved holes 22 are evenly distributed on its side circumferentially. The diameter of the pressure-transmitting rod limiting hole 21 for the middle pressure-transmitting rod 12 to pass through is slightly larger than the outer diameter of the middle pressure-transmitting rod 12, which limits its horizontal displacement and only ensures its vertical displacement. The top pressure plate 11 is a horizontal metal plate, which is parallel to the upper plane of the steel metal shell.

[0063] like Figure 3The umbrella-shaped grouting device 3 shown includes a pressure transmission and limiting tube 31, a central bone 32 and an outer probe bone 33. One end of the pressure transmission and limiting tube 31 is threadedly connected to one end of the middle pressure transmission rod 12 extending into the steel hollow shell 2, and the other end is a hollow metal straight tube, the upper end is closed and the lower end is open. The central bone 32 is an integrally formed component, one end of which is welded to the top of the central grouting pipe 4, and the other end is inserted into the internal cavity of the pressure transmission and limiting tube 31. The inner diameter of the pressure transmission and limiting tube 31 is slightly larger than the outer diameter of the central bone 32. There are four outer probe bones 33 corresponding to the outer probe bone reserved holes 22, and the four outer probe bones 33 are evenly distributed along the circumference of the pressure transmission and limiting tube 31. One end of each outer probe bone 33 is rotatably connected to the pressure transmission and limiting tube 31, and the other end extends into the corresponding outer probe bone reserved hole 22. Specifically, four outer detection teeth 311 of the limit tube are fixedly installed on the outer wall of one end of the pressure transmission limit tube 31 connected to the central bone 32. The outer detection teeth 311 of the limit tube are integrally formed components fixed to the tail of the pressure transmission limit tube 31; a fixed steering knuckle 312 is fixedly installed on the outer detection teeth 311 of the limit tube, and the outer detection bone 33 is hinged with the outer detection teeth 311 of the limit tube through the fixed steering knuckle 312. A slide rail 331 is provided on the outer detection bone 33, and an outer detection bone fixed guide joint 221 is fixedly installed in the outer detection bone reserved hole 22. The outer detection bone fixed guide joint 221 is embedded in the slide rail 331, and the two cooperate to limit the movement trajectory of the outer detection bone 33, ensuring that the movement of the outer detection bone 33 is completely carried out within the reserved range of the outer detection bone reserved hole 22. An outer bone injection tube 332 is arranged on one end of the outer bone 33 extending into the outer bone reserved hole 22, and the outer bone injection tube 332 is connected to the central slurry delivery tube 4 through a telescopic injection tube 42, and the other end is a liquid outlet 335. An outer bone plugging liquid capsule 334 is also wrapped on the outer end of the outer bone 33 extending into the outer bone reserved hole 22, and a plugging liquid capsule pressurizing port 333 is opened on the outer bone injection tube 332 corresponding to the outer bone plugging liquid capsule 334. When the slurry in the device is pressurized, the outer bone plugging liquid capsule 334 is pressurized by the plugging liquid capsule pressurizing port 333 to plug the horizontal grouting hole.

[0064] When the outer probe bone 33 is unfolded, the end of the outer probe bone 33 inside the steel hollow shell 2 shows a tendency to move vertically downward by fixing the steering knuckle 312, while the middle part of the outer probe bone 33 is limited by the outer probe bone fixing guide joint 221, so that the end of the outer probe bone 33 outside the steel hollow shell 2, that is, the end of the liquid outlet 335, shows a tendency to move upward and rotate outward. When the central bone 32 reaches the upper wall of the pressure transmission limit tube 31, the outer exploration of the outer probe bone 33 ends, and the angle between the outer probe bone 33 and the outer wall of the steel hollow shell 2 is 90°. At this time, the umbrella-shaped grouting device 3 is fully opened, forming a mechanical lock.

[0065] The central injection pipe is fixedly installed inside the steel hollow shell 2 through the grouting pipe fixing column 5. The top end is welded to the central bone 32, and the bottom end extends to the bottom of the anchor rod, and a bottom grouting interface is provided. The end of the central injection pipe connected to the central bone 32 is provided with four outlet grouting interfaces 41, such as Figure 5 The four-outlet grouting interface 41 is connected to the external bone injection tube 332 through the telescopic injection tube 42. The lower grouting pump presses the grout into the bottom grouting interface, and then the grout reaches the four-outlet grouting interface 41 along the central injection tube, and then enters the horizontal expansion borehole through the telescopic injection tube 42 and the external bone injection tube 332.

[0066] like Figure 6 , 7 As shown, the present invention further discloses a method for grouting reinforcement of the umbrella-shaped grouting anchor rod for broken surrounding rock support, comprising the following steps:

[0067] Step 1: In the underground coal mine tunnel, select the area that needs grouting reinforcement according to the production conditions, and drill a certain number of peep holes just above the tunnel roof, symmetrically above the left and right sides, and on both sides of the tunnel. After the drilling reaches the predetermined depth, place the rock formation detection recorder deep into the peep hole to record important information during the observation process, including cracks, broken zones and rock property changes in the surrounding rock, and take videos or photos.

[0068] Step 2: Organize and analyze the images of the drilling process. In the collected videos, record the distance of the broken roof rock layer that needs to be grouted. Record its distance from the inner wall of the tunnel roof as R, and record the equivalent radius of the pores in the fracture area as r. e , and finally determine the grouting height R.

[0069] Step 3: According to the broken roof rock layer and grouting height R found in step 2, take the rock sample at R for physical and mechanical parameter testing to measure the rock's gravity γ and rock's tensile strength σ t , Poisson's ratio of rock ν, grouting hole depth R z , the static lateral pressure coefficient K0 of rock.

[0070] Step 4: Calculate according to the splitting grouting theory of rock fissures to obtain the vertical splitting grouting pressure and horizontal splitting grouting pressure required for the grouting of the umbrella-shaped grouting anchor to form a splitting grouting slurry vein network in the top rock layer during the grouting process, and take the larger value of the two as the minimum grouting pressure;

[0071] Vertical Splitting:

[0072]

[0073] Horizontal splitting:

[0074]

[0075] Where:

[0076] P0-grouting pressure, kPa;

[0077] γ-weight of rock, kN / m3;

[0078] R z - Grouting hole depth, m;

[0079] σ t - tensile strength of rock, kPa;

[0080] N-the proportional coefficient of fluid pressure used to expand the hole wall, generally ranging from 0 to 1;

[0081] ν - Poisson's ratio of rock;

[0082] K0-static lateral pressure coefficient of rock.

[0083] Step 5: Determine the actual grouting pressure P according to the minimum grouting pressure determined in step 4. z , combined with the rock grouting splitting diffusion theory, the granular slurry splitting penetration diffusion radius R is obtained K ;

[0084] Granular slurry splitting penetration diffusion radius R K The calculation method is:

[0085]

[0086] Where:

[0087] ρ w -Density of water, g / cm 3 ;

[0088] g-gravitational acceleration, cm / s 2 ;

[0089] P z -Actual grouting pressure, kPa;

[0090] r e -Equivalent radius of the pore, cm;

[0091] S-Gel strength of grouting material, dyn / cm 2 ;

[0092] R z - Grouting hole depth, m.

[0093] Step 6. Combine the granular slurry splitting penetration diffusion radius obtained in step 5 with the characteristics of four-way orthogonal grouting diffusion of anchor rods to determine the spacing between anchor rods, so that a dot matrix grouting anchor rod group is formed in a certain broken roof tunnel area, and the slurry is injected to form a grid-like diffusion group.

[0094] Step 7. In the area that needs grouting reinforcement, according to the position of the broken roof rock layer determined in step 2, the grouting height R and the spacing between anchors determined in step 6, multiple anchor holes with a length of L0 are constructed. At the same time, a directional drilling horizontal expansion PDC drill bit is used to construct a horizontal grouting hole perpendicular to the anchor hole at the grouting height R in the anchor hole, so that there are lateral horizontal four-way orthogonal expansion holes in the upper area of ​​the anchor hole. Specifically, the length L0 of the anchor hole is equal to the grouting height R plus the length of the top pressure plate 11, the middle pressure transmission rod 12 and the pressure transmission limit tube 31 of the umbrella-shaped grouting anchor. The diameter of the horizontal grouting hole is determined according to the maximum outer diameter of the outer bone plugging liquid capsule 334 after pressurization, and is required to be no greater than the maximum outer diameter of the outer bone plugging liquid capsule 334 after pressurization to ensure a better sealing effect, while not affecting the deployment of the outer bone 33. The depth of the grouting hole is required to be slightly longer than the length of the outer probe bone 33 to ensure that the outer probe bone 33 can be stretched horizontally.

[0095] Step eight, place the anchoring agent above the top pressure plate 11, drill the umbrella-shaped grouting anchor into the anchor hole by the anchor drilling machine, and pierce the anchoring agent when the anchor reaches the anchor hole head to form an anchoring end.

[0096] Step nine, continue to apply drilling force to the umbrella-shaped grouting anchor rod, the top pressure plate 11, the middle pressure transmission rod 12 and the pressure transmission limit tube 31 remain in position, the steel hollow shell 2 together with the center bone 32 continue to move into the anchor rod borehole, at this time the center bone 32 is inserted into the internal cavity of the pressure transmission limit tube 31, and at the same time the outer bone 33 is expanded upward and outward and inserted into the horizontal grouting hole, when the outer bone 33 is expanded to a horizontal state, the center bone 32 is just inserted into the top of the pressure transmission limit tube 31 for mechanical locking, and the drilling action is stopped.

[0097] Step 10: Based on the actual grouting pressure determined in step 5, use a high-pressure grouting pump 6 to perform grouting through the lower grouting interface 43 at the tail end of the umbrella-shaped grouting anchor rod.

[0098] The above description of the disclosed embodiments enables those skilled in the art to implement and use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit and scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest range consistent with the principles and novel features disclosed herein.

Claims

1. An umbrella-shaped grouting anchor for broken surrounding rock support, characterized in that: It comprises a replaceable pressure transmission device (1), a steel hollow shell (2), an umbrella-shaped grouting device (3) and a central grouting pipe (4); The replaceable pressure transmission device (1) is arranged at the top of the steel hollow shell (2), and comprises a top pressure-bearing plate (11) and a middle pressure-transmitting rod (12); the top pressure-bearing plate (11) is fixedly connected to one end of the middle pressure-transmitting rod (12), and is subjected to pressure during the process of anchor bolt drilling; the end of the middle pressure-transmitting rod (12) away from the top pressure-bearing plate (11) extends into the steel hollow shell (2) through a pressure-transmitting rod limiting hole (21) arranged at the top of the steel hollow shell (2), and is detachably fixedly connected to the umbrella-shaped grouting device (3); The steel hollow shell (2) is cylindrical, and has four external bone exploration reserved holes (22) evenly distributed in the circumferential direction on its side surface; The umbrella-shaped grouting device (3) comprises a pressure transmission and limiting tube (31), a central bone (32) and an outer bone (33); one end of the pressure transmission and limiting tube (31) is detachably fixedly mounted on one end of the middle pressure transmission rod (12) extending into the steel hollow shell (2), and the other end is hollowly arranged; the central bone (32) is an integrally formed component, one end of which is fixedly mounted on the top end of the central grouting pipe (4), and the other end is inserted into the inner cavity of the pressure transmission and limiting tube (31); four outer bones (33) are arranged corresponding to the outer bone reserved holes (22), one end of each outer bone (33) is rotatably connected to the pressure transmission and limiting tube (31), and the other end extends into the corresponding outer bone reserved hole (22), and the four outer bones (33) are evenly distributed along the circumference of the pressure transmission and limiting tube (31); the outer bones (33) ) is provided with a slide rail (331), an outer bone fixing guide section (221) is fixedly installed in the outer bone reserved hole (22), and the outer bone fixing guide section (221) is embedded in the slide rail (331), and the two cooperate to limit the movement trajectory of the outer bone (33); an outer bone injection tube (332) is arranged on the end of the outer bone (33) extending into the outer bone reserved hole (22), and the outer bone injection tube (332) is connected with the central slurry delivery tube (4) through a telescopic injection tube (42); the outer end of the outer bone (33) extending into the outer bone reserved hole (22) is also wrapped with an outer bone blocking liquid capsule (334), and a blocking liquid capsule pressurizing port (333) is opened on the outer bone injection tube (332) corresponding to the outer bone blocking liquid capsule (334); The central injection pipe is fixedly installed inside the steel hollow shell (2) through a grouting pipe fixing column (5), the top end is fixedly connected to the central bone (32), the bottom end extends to the bottom of the anchor rod, and is provided with a bottom grouting interface; one end of the central injection pipe connected to the central bone (32) is connected to the external bone injection pipe (332) through a telescopic injection pipe (42), and the slurry is input from the bottom grouting interface and then input into the drill hole through the central injection pipe, the telescopic injection pipe (42) and the external bone injection pipe (332).

2. The umbrella-rib type grouting anchor for broken surrounding rock support according to claim 1, characterized in that: An outer wall of one end of the pressure transmission and limiting tube (31) connected to the central bone (32) is fixedly mounted with an outer detection tooth (311) of the limiting tube, a fixed steering knuckle (312) is fixedly mounted on the outer detection tooth (311) of the limiting tube, and the outer detection bone (33) is hingedly connected to the outer detection tooth (311) of the limiting tube via the fixed steering knuckle (312).

3. The umbrella-rib type grouting anchor for broken surrounding rock support according to claim 1, characterized in that: One end of the central liquid injection pipe connected to the telescopic liquid injection pipe (42) is provided with a four-outlet slurry delivery interface (41).

4. A method for grouting reinforcement using the umbrella-shaped grouting anchor rod for broken surrounding rock support according to claim 1, characterized in that: The following steps are involved: Step 1: Select the area that needs grouting reinforcement in the underground coal mine tunnel, drill a certain number of holes in the tunnel roof, and use a rock formation detection recorder to observe and record the holes after the holes reach the predetermined depth; Step 2: sort and analyze the images of the drilling process, select the broken roof rock layer to be grouting, and determine the grouting height R; Step 3: According to the broken roof rock layer and grouting height R found in step 2, take the rock sample at R for physical and mechanical parameter testing to measure the rock's gravity γ and rock's tensile strength σ t , Poisson's ratio of rock ν, grouting hole depth R z , the static lateral pressure coefficient of rock K0; Step 4: Calculate according to the splitting grouting theory of rock fissures to obtain the vertical splitting grouting pressure and horizontal splitting grouting pressure required for the grouting of the umbrella-shaped grouting anchor to form a splitting grouting slurry vein network in the top rock layer during the grouting process, and take the larger value of the two as the minimum grouting pressure; Step 5: Determine the actual grouting pressure P according to the minimum grouting pressure determined in step 4. z , combined with the rock grouting splitting diffusion theory, the granular slurry splitting penetration diffusion radius R is obtained K ; Step 6: The splitting penetration diffusion radius of the granular slurry obtained in step 5 is combined with the characteristics of the four-way orthogonal grouting diffusion of the anchor rods to determine the spacing between the anchor rods, so that a dot matrix grouting anchor rod group is formed in a certain broken roof roadway area, and the slurry is injected to form a grid-like diffusion group; Step 7: In the area requiring grouting reinforcement, according to the position of the broken roof rock layer determined in step 2, the grouting height R and the spacing between anchors determined in step 6, a plurality of anchor holes with a length of L0 are constructed, and at the same time, a horizontal grouting hole perpendicular to the anchor hole is constructed at the grouting height R in the anchor hole; Step 8: Place the anchoring agent above the top pressure plate (11), and drill the umbrella-shaped grouting anchor into the anchor hole by using an anchor drilling machine. When the anchor reaches the head of the anchor hole, pierce the anchoring agent to form an anchoring end. Step 9: Continue to apply drilling force to the umbrella-shaped grouting anchor rod, the top pressure-bearing plate (11), the middle pressure-transmitting rod (12) and the pressure-transmitting limiting tube (31) remain in position, and the steel hollow shell (2) together with the center bone (32) continue to move into the anchor rod borehole, at which time the center bone (32) is inserted into the inner cavity of the pressure-transmitting limiting tube (31), and at the same time, the outer bone (33) is expanded upward and outward and inserted into the horizontal grouting hole. When the outer bone (33) is expanded to a horizontal state, the center bone (32) is just inserted into the top of the pressure-transmitting limiting tube (31) for mechanical locking, and the drilling action is stopped; Step 10: Based on the actual grouting pressure determined in step 5, use a high-pressure grouting pump (6) to perform grouting through the lower grouting interface (43) at the tail end of the umbrella-shaped grouting anchor rod.

5. The method according to claim 4, characterized in that In step 4, the calculation method of the vertical splitting grouting pressure and the horizontal splitting grouting pressure required for the grout to form a splitting grouting vein network in the top rock layer during the grouting process of the umbrella-shaped grouting anchor is: Vertical Splitting: Horizontal splitting: Where: P0-grouting pressure, kPa; γ-weight of rock, kN / m 3 ; R z - Grouting hole depth, m; σ t - tensile strength of rock, kPa; N-the proportional coefficient of fluid pressure used to expand the hole wall, generally ranging from 0 to 1; ν - Poisson's ratio of rock; K0-static lateral pressure coefficient of rock.

6. The method according to claim 5, characterized in thatIn step 5, the granular slurry splitting penetration diffusion radius R K The calculation method is: Where: ρ w -Density of water, g / cm 3 ; g-gravitational acceleration, cm / s 2 ; P z -Actual grouting pressure, kPa; r e -Equivalent radius of the pore, cm; S-Gel strength of grouting material, dyn / cm 2 ; R z - Grouting hole depth, m.

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