Hollow grouting umbrella-shaped centering prestress anchoring device and grouting construction method

Abstract

The invention discloses a hollow grouting umbrella-shaped centering prestress anchoring device and a grouting construction method. The hollow grouting umbrella-shaped centering prestress anchoring device comprises a front guiding mechanism based on a rod body (3) with an external thread, a middle supporting mechanism and a rear anchoring mechanism. The front guide mechanism is provided with a conical anchor head (9); the middle supporting mechanism is an umbrella rib-shaped supporting assembly with the adjustable opening degree. The hollow grouting umbrella-shaped centering prestress anchoring device can provide good support for the anchor rod, the centering effect is good, it is effectively guaranteed that the thickness of a protective layer is uniform and consistent, and stable drilling construction is guaranteed.

Description

Technical Field

[0001] The present invention relates to a hollow grouting umbrella-shaped centering prestressed anchoring device and a grouting construction method. Background Art

[0002] In underground engineering construction, as an effective support means, anchor bolts are widely used in the reinforcement of surrounding rocks of slopes, tunnels or dams. By changing the mechanical state of the surrounding rocks through the anchor bolts inside the surrounding rocks, an integral and stable rock belt is formed around the roadway. By utilizing the combined action of the anchor bolts and the surrounding rocks, the purpose of maintaining the stability of the roadway is achieved. Its main functions include suspension effect, combined beam effect, combined arch effect, span reduction effect, reinforcement effect, etc. In engineering, there are mainly full-length bonded anchor bolts, end-anchored anchor bolts, friction anchor bolts, prestressed anchor bolts, self-drilling anchor bolts and other types.

[0003] Through long-term practice, it is found that the current anchor bolts still have some defects. For example, it is difficult to center the anchor bolts in the drill holes, the grouting is difficult to be full, the end anchoring force is small or even the anchoring components are likely to slip in soft strata, the prestress is small, and it is not convenient for installation.

[0004] Therefore, it is necessary to design a new hollow grouting umbrella-shaped centering prestressed anchoring device. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a hollow grouting umbrella-shaped centering prestressed anchoring device and a grouting construction method. When the hollow grouting umbrella-shaped centering prestressed anchoring device is constructed, the centering effect is good, effectively ensuring the uniform thickness of the protective layer.

[0006] The technical solution of the invention is as follows:

[0007] A hollow grouting umbrella-shaped centering prestressed anchoring device and a grouting construction method, including a front guiding mechanism, a middle supporting mechanism and a rear anchoring mechanism based on a rod body with external threads;

[0008] The front guiding mechanism has a conical anchor head;

[0009] The middle supporting mechanism adopts a ribbed support assembly with adjustable opening degree.

[0010] The front end mechanism includes the front end of the rod body, an exhaust pipe and a conical anchor head;

[0011] The rear end of the conical anchor head is provided with a double-ring sleeve composed of an inner ring and an outer ring; the front end of the exhaust pipe is located in the cavity of the double-ring sleeve;

[0012] The axis lines of the rod body, the conical anchor head, the inner ring and the outer ring coincide.

[0013] The front end mechanism also includes a plurality of connecting rods, the front ends of the connecting rods are connected to the rear ends of the conical anchor heads, and the rear ends of the connecting rods are connected to the front ends of the rod bodies; and the axes of the connecting rods are parallel to the axes of the rod bodies.

[0014] The front end of the connecting rod is located in the inner ring; the connecting rod is equally distributed along the circumference of the rod body.

[0015] There are 4 connecting rods. The exhaust pipe is tied to the rod body by rubber bands. The outer diameter of the outer ring is the same as the cone bottom diameter of the conical anchor head. The conical anchor head is a hollow component.

[0016] The middle support mechanism includes a middle support assembly, and the middle support assembly includes an adjustment ring and an rib-shaped support assembly; when in use, the adjustment ring and the rib-shaped support assembly are both mounted on the anchor rod; the rod body of the anchor rod has an external thread; the adjustment ring is a vertebral body with an internal thread; the rib-shaped support assembly includes a support ring with an internal thread and N support rods hinged to the rear end of the support ring; N is an integer, N≥3; the adjustment ring and the support ring can both engage with the rod body through threads, so that they can rotate on the rod body.

[0017] An annular ring is provided at the rear end of the support ring, and the support rod is hinged to the annular ring;

[0018] The conical surface of the adjusting ring is provided with N semicircular grooves for correspondingly accommodating N supporting rods; the semicircular grooves are arranged along the generatrix of the vertebral body; and the N semicircular grooves are equally arranged along the circumference of the vertebral body.

[0019] The rear anchoring mechanism includes a pad, a grout stopper and a nut with an internal thread; when in use, the grout stopper, the pad and the nut are sequentially installed at the rear end of the rod body;

[0020] The slurry stopper is a sleeve with a taper (smaller at the front and larger at the back);

[0021] Both the backing plate and the slurry stopper are provided with exhaust pipe mounting holes for the exhaust pipe to pass through.

[0022] The middle part of the pad is convex backwards so as to form a pot-shaped part in the middle part of the pad (which is beneficial to the stability of the rear end of the slurry stopper).

[0023] A grouting construction method, using the aforementioned hollow grouting umbrella-shaped centering prestressed anchoring device of the grouting anchor rod to perform grouting construction; the steps are:

[0024] Install adjustment rings and rib-shaped support components on the rod body, a total of 3 groups, each group is evenly distributed on the rod body; rotate the whole ring to insert the small head of the cone into the support rod, and through the guiding effect of the semicircular groove, expand the support rod, and the expansion amplitude is 1 to 2 cm larger than the diameter of the drill hole; after all three groups of rib-shaped support components are adjusted to the same amplitude, tie the exhaust pipe to the anchor rod with a rubber band, and the end is deep into the conical anchor head; insert the anchor rod into the drill hole; the construction personnel push the rod body forward, and the rod body drives the conical anchor head to move toward the bottom of the hole;

[0025] After the anchor rod body is successfully inserted into the drill hole, insert the exhaust pipes into the first circular exhaust pipe installation hole of the grout stopper and the second exhaust pipe installation hole of the backing plate respectively. The grout stopper and the backing plate are successively sleeved on the rod body, install the nut, press the backing plate tightly against the rock at the orifice of the drill hole, and the grout stopper is pushed into the drill hole to prevent the cement slurry from flowing out from the orifice during grouting.

[0026] N generally takes a certain value between 4 and 8. Preferably, N = 6.

[0027] There are multiple sets of middle support components; all are arranged on the anchor rod. Generally, there are 2 - 6 sets, depending on the length of the anchor rod.

[0028] In the present invention, 3 sets are selected.

[0029] Beneficial effects:

[0030] The technical advantages of the present invention are reflected in:

[0031] First, the front end of the grouting anchor rod has the following technical advantages:

[0032] 1. The pointed top guides to open the way. The front end of this grouting anchor rod (also known as the front guiding section) adopts a pointed top structure, which can effectively poke open sundries such as sediment and gravel in the hole when inserting the anchor rod into the drill hole, facilitating the insertion of the anchor rod to the bottom of the hole;

[0033] 2. The double - ring protection exhaust pipe. The inner ring 9 - 3 and the outer ring 9 - 2 form a double - ring sleeve structure. The end of the exhaust pipe 5 extends into the gap between the inner ring 9 - 3 and the outer ring 9 - 2. When grouting the rod body 3, the cement slurry emerging from the orifice of the rod body 3 is blocked by the inner ring 9 - 3 and will not enter the exhaust pipe 5, effectively protecting the exhaust pipe from being blocked.

[0034] 3. Judging the pouring situation. When grouting the anchor rod, the cement slurry emerges from the orifice of the rod body 3, sinks under the action of gravity, fills the drill hole densely from bottom to top, and the air in the hole flows upward under the extrusion of the cement slurry and is discharged from the inside of the exhaust pipe 5. After the drill hole is gradually filled with cement slurry, it will finally also flow out of the drill hole from the exhaust hole. When it is seen that the cement slurry flows out from the exhaust pipe outside the drill hole, it can be judged that the drill hole has been filled with cement slurry, ensuring the project quality.

[0035] Second, the advantages of the middle support section:

[0036] The annular ring and the adjusting ring are easy to move, and can adjust the opening amplitude of its support rods according to the size of the drill hole (actual needs), achieving the effect of firm support. The adjusting ring is designed with a semi - circular groove, which is convenient for maintaining the overall shape stability of the entire middle support section and is conducive to its playing a stable supporting role.

[0037] Third, the advantages of the rear anchoring section;

[0038] The grout plug is made of elastic material. After entering the drill hole, it can fit tightly in the drill hole like a cork, preventing the cement slurry from flowing out of the mouth during grouting.

[0039] The innovations of this solution are reflected in:

[0040] First, the centering effect is good. Due to the support of multiple support rods of the umbrella-shaped support component, the anchor rod can be evenly lifted when inserted into the drill hole, and the anchor rod can be completely located at the center of the drill hole, without clinging to the drill hole due to its own gravity, effectively ensuring the uniform thickness of the protective layer.

[0041] Second, the construction safety is high. When installing the anchor rod, due to the support and locking effect of the umbrella-shaped support component on the drill hole, the anchor rod is not easy to slide down under its own gravity after being inserted into the hole, ensuring the safety of personnel and equipment.

[0042] Third, it has a large prestress. Under the top support of the umbrella-shaped support component, the anchor rod is locked after being inserted into the drill hole. By tightening the nut at the mouth, the anchor rod has a tendency to be stretched. Through its own elastic deformation, a large prestress can be applied to the anchor rod, which can effectively reinforce the surrounding rock.

[0043] Fourth, the grouting effect is good. Since the exhaust pipe is inserted into the conical anchor head, it can well protect the exhaust pipe from being blocked by the cement slurry, and the air in the hole can be discharged smoothly through the exhaust pipe, ensuring the dense filling of the cement slurry in the drill hole.

[0044] In summary, the new hollow grouting umbrella-shaped centering prestressed anchor rod of the present invention can solve the problems of the existing technology together, achieving the effects of convenient construction, safety and reliability, and excellent quality. Brief Description of the Drawings

[0045] Figure 1 It is a schematic diagram of the overall structure of the grouting anchor rod;

[0046] Figure 2 It is a schematic diagram of the front end structure of the anchor rod;

[0047] Figure 3 It is a schematic diagram of the positions of the conical anchor head, inner ring, outer ring and connecting rod;

[0048] Figure 4 It is a schematic diagram of the front end structure of the grouting anchor rod during the grouting construction process;

[0049] Figure 5 It is an assembly schematic diagram of the middle support section (mechanism)

[0050] Figure 6 It is a disassembly schematic diagram of the components of the middle support section (mechanism);

[0051] Figure 7Schematic diagram (one) of the decomposition of the components of the rear anchorage section (mechanism);

[0052] Figure 8 Schematic diagram (two) of the decomposition of the components of the rear anchorage section (mechanism);

[0053] Figure 9 Schematic diagram of the positional relationship between the middle support section (mechanism) and the rear anchorage section (mechanism);

[0054] Figure 10 Schematic diagram when the anchoring device is partially inserted into the drill hole;

[0055] Figure 11 Schematic diagram when the anchoring device is fully inserted into the drill hole;

[0056] Figure 12 Schematic diagram when the anchoring device is fully inserted into the drill hole (one of the partial views of the tail);

[0057] Figure 13 Schematic diagram when the anchoring device is fully inserted into the drill hole (two of the partial views of the tail);

[0058] Figure 14 Schematic diagram of the cooperative operation of the grouting machine and the anchoring device (the anchoring device is placed horizontally);

[0059] Figure 15 Schematic diagram of the cooperative operation of the grouting machine and the anchoring device (the anchoring device is placed longitudinally).

[0060] Label description: 1. Nut; 2. Base plate; 3. Rod body; 4. Grout plug; 5. Exhaust pipe; 6. Adjusting ring; 7. Umbrella-shaped support assembly; 8. Support rod; 9. Tapered anchor head. 10. Rock mass; 11. Drill hole; 12. Grout pump; 13. Grout pipe; 14. Grout stop valve; 15. Cement slurry. 16 - Air, 17 - Mud.

[0061] 2-1. First exhaust pipe installation hole (base plate); 3-1. Grouting hole; 4-1. Second exhaust pipe installation hole (grout plug); 6-1. Semi-circular groove; 7-1. Ring; 7-2. Connecting rod member; 7-3. Support ring; 8. Support rod. 9-1. Sharp tip; 9-2. Outer ring; 9-3. Inner ring; 9-4. Connecting rod; 9-5. Base plate. Detailed implementation mode

[0062] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0063] Embodiment 1:

[0064] As Figure 1, the hollow grouting umbrella-shaped centering prestressed anchor rod mainly consists of three parts: the front guiding section, the middle supporting section, and the rear anchoring section, and mainly includes components such as nut 1, backing plate 2, rod body 3, grout stopper 4, exhaust pipe 5, adjusting ring 6, umbrella bone-shaped support assembly 7, support rod 8, and conical anchor head 9.

[0065] Its structural principle is as follows: The front guiding section is used to punch through debris such as stone chips and soil in the borehole through the front conical anchor head when the anchor rod is inserted into the borehole, facilitating the installation of the anchor rod; the middle supporting section generally has three umbrella bone-shaped support assemblies, evenly distributed on the rod body at intervals. Through the supporting effect of this assembly, the anchor rod is centered and placed in the borehole. At the same time, since the support rod is stuck on the rock wall, the anchor rod is neither easy to slip nor can a certain prestress be applied; the rear anchoring section is used to apply prestress to the anchor rod. After tightening the nut and pressing the backing plate, the rod body of the anchor rod is pulled outwards, the support rod opens outwards and tightens against the rock wall, and prestress is applied to the rod body of the anchor rod (the tighter the nut is screwed, the greater the prestress applied).

[0066] The following will be elaborated in detail in combination with the structural characteristics of each section.

[0067] Such as Figures 1-4 , the front guiding mechanism, that is, the front end of the grouting anchor rod (located at the front end of the anchor rod), includes the front end of the rod body 3, the exhaust pipe 5, and the conical anchor head 9;

[0068] A double-ring sleeve composed of an inner ring 9-3 and an outer ring 9-2 is provided at the rear end of the conical anchor head; the front end of the exhaust pipe is located in the cavity of the double-ring sleeve;

[0069] The axis lines of the rod body, the conical anchor head, the inner ring, and the outer ring coincide.

[0070] It also includes 4 connecting rods 9-4. The front end of the connecting rod is connected to the rear end of the conical anchor head, and the rear end of the connecting rod is connected to the front end of the rod body; the axis of the connecting rod is parallel to the axis of the rod body.

[0071] The front end of the connecting rod is located inside the inner ring. The connecting rods are evenly distributed circumferentially along the rod body.

[0072] The exhaust pipe is tied to the rod body with a rubber band.

[0073] The outer diameter of the outer ring is the same as the bottom diameter of the conical anchor head.

[0074] The conical anchor head is a hollow component, which can save material costs and reduce the driving energy consumption of the equipment on the premise of ensuring the strength of the anchor head.

[0075] The conical anchor head 9 is a steel component with a pointed top at one end and a double-layer steel ring at the other end. The inner ring 9-3 and the outer ring 9-2 form a double-ring sleeve structure, and the bottom is welded to the bottom plate 9-5, which is then welded to the pointed head 9-1; the connecting rod 9-4 is composed of four steel cylinders, one end is welded to the inner side of the inner ring 9-3, and the other end is welded to the end of the rod body 3, playing a role in connecting the inner ring 9-3 and the rod body 3, so that a gap of about 2 cm is formed between the inner ring 9-3 and the rod body 3; the exhaust pipe 5 is laid along the rod body 3, and the end extends into the gap between the inner ring 9-3 and the outer ring 9-2 and is fixed by tying with a rubber band.

[0076] As Figures 5-6 shown, a middle support mechanism of a hollow grouting umbrella-shaped centering prestressed anchor rod includes a middle support assembly, and the middle support assembly includes an adjusting ring 6 and an umbrella-bone-shaped support assembly 7; during use, both the adjusting ring and the umbrella-bone-shaped support assembly are sleeved on the anchor rod;

[0077] The rod body 3 of the anchor rod has an external thread; the adjusting ring is a cone with an internal thread; the umbrella-bone-shaped support assembly 7 is composed of an annular ring 7-1, a connecting rod member 7-2, a support ring 7-3 and support rods 8 (6 pieces);

[0078] Both the adjusting ring and the support ring can be meshed with the rod body through threads, so that they can rotate on the rod body (thus changing the position on the rod body).

[0079] An annular ring 7-1 is provided at the rear end of the support ring, and the support rods are hinged to the annular ring.

[0080] Six semi-circular grooves (6-1) for correspondingly accommodating 6 support rods are provided on the conical surface of the adjusting ring; the semi-circular grooves are all arranged along the generatrix of the cone.

[0081] The six semi-circular grooves are equally distributed along the circumferential direction of the cone.

[0082] There are 3 sets of middle support assemblies; all are arranged on the anchor rod.

[0083] The adjusting ring 6 is a conical sleeve, with internal threads machined on the inner side, which can be meshed with the rod body 3 and move along the rod body. Eight semi-circular grooves 6-1 are opened on the outer side, and the support rods 8 can slide in the grooves; the support rods 8 are made of high-strength steel (similar to the swallowtail of a clip, with excellent elasticity and stiffness, and the diameter is generally about 5-7 mm). The support rods 8 are sleeved on the annular ring 7-1 through the rings at their ends, and the annular ring 7-1 is welded to the end of the support ring 7-3 through the connecting rod member 7-2, so that the support rods 8 can open or close around the annular ring 7-1 to form an umbrella-bone-shaped support assembly;

[0084] The inner side of the support ring 7-3 is machined with threads, which can be tightly engaged with the external threads of the rod body 3 and move along the rod body; the rod body 3 is a hollow steel pipe with a full-length external thread, and grouting holes 3-1 are opened at intervals of 10 to 15 cm in the middle. The diameter of the grouting holes 3-1 is about 6 to 8 mm, and the cement slurry can emerge from the inside of the steel pipe through the grouting holes 3-1.

[0085] The working principle of the middle support section is as follows: According to the design requirements, drilling depth and diameter, a matching rod body 3 is selected (it is required that the protective layer thickness of the cement slurry is not less than 10 mm, that is, the diameter of the rod body 3 is 20 mm smaller than the drilling diameter); an adjustment ring 6 and an umbrella-shaped support assembly 7 are installed on the rod body 3, with a total of 3 groups, and each group is evenly distributed on the rod body; rotate the integral ring 6 so that the small head of the cone is inserted into the support rod 8, and through the guiding action of the semi-circular groove 6-1, the support rod 8 is opened like an umbrella. The opening amplitude is preferably about 1 to 2 cm larger than the drilling diameter (determined according to the rock hardness, the opening amplitude of hard surrounding rock is slightly smaller, and that of soft surrounding rock can be slightly larger); after all three groups of umbrella-shaped support assemblies 7 are adjusted to the same amplitude, tie the exhaust pipe 5 to the anchor rod with a rubber band, and the end extends into the conical anchor head 9; slowly insert the anchor rod into the drilling hole. Since the support rod 8 has strong stiffness and elasticity and has a good rebound phenomenon after being bent by the drilling hole mouth, after entering the hole, it tightly supports the rock wall under the guiding and supporting action of the semi-circular groove 6-1, and can only go in and cannot go out. The three groups of umbrella-shaped support assemblies 7 are stressed simultaneously, which can firmly fix the rod body 3 of the anchor rod in the drilling hole, without worrying about the anchor rod in the inclined or vertical hole slipping out of the drilling hole due to its own weight, and can also make the rod body placed completely in the middle, effectively ensuring the protective layer thickness of the cement slurry.

[0086] As Figures 6-8 , the rear anchoring section (i.e., the rear anchoring mechanism) mainly consists of a nut 1, a backing plate 2, a rod body 3, a grout plug 4, and an exhaust pipe 5. The internal thread of the nut 1 is tightly engaged with the external thread of the rod body 3. The backing plate 2 is a steel plate with a square outside and a round inside, with a rectangular shape on the outside and a convex pot shape on the inside and a round hole in the middle. The rod body 3 passes through the round hole, and a circular exhaust pipe installation hole (backing plate) 2-1 is opened in the pot-shaped part. The exhaust pipe 5 can pass through this hole; the grout plug 4 is a conical body made of elastic rubber material. The small-diameter end is slightly smaller than the drilling hole, and the large-diameter end is slightly larger than the drilling hole. A round hole is opened in the middle to form a sleeve shape. The rod body 3 passes through the round hole, and a circular exhaust pipe installation hole (grout plug) 4-1 is opened on one side of the grout plug 4. The exhaust pipe 5 can pass through this hole.

[0087] The working principle of the rear anchorage section is as follows: After the bolt body is successfully inserted into the drill hole, the exhaust pipes 5 are respectively inserted into the circular exhaust pipe installation holes (grout stop plug) 4-1 of the grout stop plug 4 and the exhaust pipe installation holes (backing plate) 2-1 of the backing plate 2. The grout stop plug 4 and the backing plate 2 are successively sleeved on the bolt body 3, and the installation nut 1 is installed. The backing plate 2 is pressed tightly against the rock at the mouth of the drill hole, and the grout stop plug 4 is pushed into the drill hole. Due to its elasticity, it can fit tightly in the drill hole like a cork after entering, preventing the cement slurry from flowing out from the mouth during grouting.

[0088] See Figures 10-14 , the working principle of the hollow grouting umbrella-shaped centering prestressed bolt is described as follows:

[0089] 1. According to the design requirements, drill the bolt holes on the rock wall in advance. The diameter of the bolt holes should be 20 mm larger than the designed bolt diameter to ensure that the protective layer thickness is not less than 10 mm;

[0090] 2. Select a suitable bolt type (such as the bolt body has various types such as φ22, φ25, φ32, etc.), and install the supporting umbrella-shaped support components 7 supporting the umbrella bone in advance on the bolt body 3. The components at the front end and the rear end are slightly closer to the conical anchor head 9 and the backing plate 2, and the components in the middle are placed in the middle. Rotate the adjustment ring 6 to expand the support rod 8 to a position slightly larger than the bolt hole;

[0091] 3. Arrange the exhaust pipes 5 along the bolt body, and tie them to the bolt body with rubber bands at intervals in the middle to make them not easy to shake and fall off, and the front end extends into the conical anchor head 9.

[0092] 4. Insert the assembled whole bolt into the hole. Since the umbrella-shaped structure composed of the support rods 8 is slightly larger than the drill hole, a relatively large force is required during insertion. After all are inserted into the hole, the conical anchor head 9 reaches the bottom of the drill hole, and the bolt is tightly locked in the hole by the three groups of support rods 8. The whole bolt will not slip out of the drill hole even if it is vertically installed.

[0093] 5. Install the grout stop plug 4 and the backing plate 2 one by one, pass the exhaust pipes 5 through the holes of the grout stop plug 4 and the backing plate 2 respectively, tighten the nut 1, press the backing plate 2 tightly on the rock wall, and the grout stop plug 4 is pushed into the drill hole. Under the tensioning action of the nut 1 on the bolt body 3, the bolt body 3 has a tendency to be stretched, but due to the locking of the support rods 8, the bolt body undergoes elastic deformation in the radial direction, forming a relatively large prestress, which has an excellent reinforcement effect on the surrounding rock.

[0094] 6. Install a grout stop valve 14 on the exposed part of the anchor bolt, connect the grouting pipe 13 and the grouting pump 12, and inject the grout into the anchor bolt body under a certain pressure. The grout flows into the gap between the bolt body and the drill hole from the gap between the side wall of the bolt body and the conical anchor head. If the anchor bolt is installed vertically or obliquely upward, the grout first fills the position near the grout plug under the action of its own weight, and then gradually grows upward. The air in the hole is squeezed by the grout and flows upward, and is discharged out of the hole through the exhaust pipe 5; if the anchor bolt is installed vertically or obliquely downward, the grout flows out from the conical anchor head and starts to fill from the bottom of the hole, gradually rising towards the hole opening. The air in the hole is squeezed by the grout and flows upward, and is discharged from the exhaust pipe installation holes of the grout plug 4 and the backing plate 2 (when the anchor bolt is installed vertically or obliquely downward, the exhaust pipe 5 may not be installed).

[0095] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A hollow grouting umbrella-shaped centering prestressed anchor device and grouting construction method, characterized in that: It comprises a front guide mechanism, a middle support mechanism and a rear anchoring mechanism based on a rod body (3) with external threads; The front guide mechanism has a conical anchor head (9); The middle support mechanism adopts an umbrella-shaped support component with adjustable opening degree.

2. The hollow grouting umbrella-shaped centering prestressed anchoring device according to claim 1 is characterized in that: The front end mechanism comprises a front end of a rod body (3), an exhaust pipe (5), and a conical anchor head (9); The rear end of the conical anchor head is provided with a double-ring sleeve composed of an inner ring (9-3) and an outer ring (9-2); the front end of the exhaust pipe is located in the cavity of the double-ring sleeve; The axis lines of the rod body, conical anchor head, inner ring and outer ring coincide.

3. The hollow grouting umbrella-shaped centering prestressed anchoring device of the grouting anchor rod according to claim 2 is characterized in that: The front end mechanism also includes a plurality of connecting rods (9-4), the front ends of the connecting rods are connected to the rear ends of the conical anchor heads, the rear ends of the connecting rods are connected to the front ends of the rod bodies; and the axes of the connecting rods are parallel to the axes of the rod bodies.

4. The hollow grouting umbrella-shaped centering prestressed anchoring device of the grouting anchor rod according to claim 3 is characterized in that: The front end of the connecting rod is located in the inner ring; the connecting rod is equally distributed along the circumference of the rod body.

5. The hollow grouting umbrella-shaped centering prestressed anchoring device of the grouting anchor rod according to claim 1 is characterized in that: The middle support mechanism comprises a middle support assembly, and the middle support assembly comprises an adjustment ring (6) and an rib-shaped support assembly (7); when in use, the adjustment ring and the rib-shaped support assembly are both mounted on the anchor rod; the rod body (3) of the anchor rod has an external thread; the adjustment ring is a vertebral body with an internal thread; the rib-shaped support assembly comprises a support ring (7-3) with an internal thread and N support rods (8) hinged to the rear end of the support ring; N is an integer, N≥3; the adjustment ring and the support ring can both be engaged with the rod body through threads, so that they can rotate on the rod body.

6. The hollow grouting umbrella-shaped centering prestressed anchoring device of the grouting anchor rod according to claim 5 is characterized in that: An annular ring (7-1) is provided at the rear end of the support ring, and the support rod is hinged to the annular ring; The conical surface of the adjustment ring is provided with N semicircular grooves (6-1) for correspondingly accommodating N supporting rods; the semicircular grooves are arranged along the generatrix of the vertebral body; and the N semicircular grooves are equally spaced along the circumference of the vertebral body.

7. The hollow grouting umbrella-shaped centering prestressed anchoring device of the grouting anchor rod according to claim 6 is characterized in that: There are multiple sets of middle support components, all of which are arranged on anchor rods.

8. The hollow grouting umbrella-shaped centering prestressed anchoring device of the grouting anchor rod according to any one of claims 1 to 7, characterized in that: The rear anchoring mechanism comprises a pad (2), a grout stopper (4) and a nut (1) with an internal thread; when in use, the grout stopper, the pad and the nut are sequentially installed at the rear end of the rod body; The slurry stopper is a sleeve with a taper; Both the backing plate and the slurry stopper are provided with exhaust pipe mounting holes for the exhaust pipe to pass through.

9. A grouting construction method, characterized in that: Grouting construction is carried out using a hollow grouting umbrella-shaped centering prestressed anchoring device of a grouting anchor rod according to any one of claims 1 to 8; the steps are: Install adjustment rings and rib-shaped support components on the rod body, a total of 3 groups, each group is evenly distributed on the rod body; rotate the whole ring to insert the small head of the cone into the support rod, and through the guiding effect of the semicircular groove, expand the support rod, and the expansion amplitude is 1 to 2 cm larger than the diameter of the drill hole; after all three groups of rib-shaped support components are adjusted to the same amplitude, tie the exhaust pipe to the anchor rod with a rubber band, and the end is deep into the conical anchor head; insert the anchor rod into the drill hole; the construction personnel push the rod body forward, and the rod body drives the conical anchor head to move toward the bottom of the hole; After the anchor rod body is successfully installed into the drill hole, the exhaust pipe is inserted into the first circular exhaust pipe mounting hole of the grouting plug and the second exhaust pipe mounting hole of the pad respectively. The grouting plug and the pad are sequentially inserted into the rod body, and the nut is installed. The pad is pressed tightly against the rock at the mouth of the drill hole, and the grouting plug is pushed into the drill hole to prevent cement slurry from flowing out of the mouth during grouting.

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