WO2020151161A1

WO2020151161A1 - Flexible anchor rod

Info

Publication number: WO2020151161A1
Application number: PCT/CN2019/090615
Authority: WO
Inventors: 张农; 魏群; 谢正正
Original assignee: 中国矿业大学
Priority date: 2019-01-25
Filing date: 2019-06-11
Publication date: 2020-07-30
Also published as: CA3156369C; CN109538266A; CA3156369A1; CN109538266B

Abstract

A flexible anchor rod, which is suitable for the field of coal mine tunnel support engineering. The flexible anchor rod comprises a flexible anchor rod body (B), a tray (C), a fixed torque nut (D), an anti-friction washer (E) and an anti-twist self-aligning ball head (F). The flexible anchor rod body (B) comprises a connecting sleeve (B4), a steel strand (B1), a limit cylinder (B3) and a friction-increasing wire spring (B2); the connecting sleeve (B4) is reliably fixed to the steel strand (B1) and the wire spring (B2) by means of an extrusion manner, and the limit cylinder (B3) is sleeved on the connecting sleeve (B4). The described flexible anchor rod is not limited by the height of the tunnel, and effectively enhances the support effect. The unique anti-twist structure solves the problem of the torsion of the rod body when the flexible anchor rod is preloaded, and improves the preloading force. The anchor rod improves construction speed by means of spiral preloading, and the support efficiency is high.

Description

A flexible anchor

Technical field

The invention relates to a flexible anchor rod, and is especially suitable for a flexible anchor rod used in the field of coal mine tunnel support engineering.

Background technique

Nowadays, bolt support technology has been widely used in coal mine roadways in our country. At first, it was first used in rock tunnels with relatively stable surrounding rocks. Later, by improving the stiffness and strength of bolt materials, the bolt support technology can adapt to soft and broken surrounding rocks. Roadways and mines affect roadways with various bad conditions. Bolt support mainly uses bolts to drive into the preset boreholes of the surrounding rock of the roadway, and combine the shallow broken surrounding rock mass with the deep stable rock mass to achieve the purpose of controlling roadway deformation and achieving roadway safety and stability.

The anchor rod is very important in the anchor rod support system, so there are many types of anchor rods. With the complexity of roadway conditions, small-aperture resin anchoring pre-stressed anchor cables have also been developed and applied to coal mine sites. In short, the diversity of anchor rods and cables can adapt to the complex site conditions of coal mines in my country. However, due to the restriction of the height of the roadway, the length of the bolt can only be maintained at about 2m, and the thickness of the bolt anchoring area can only be 2m, which is no longer suitable for the current complicated geological conditions of the roadway. Although the anchor cable can be long enough, the installation process of the anchor cable is relatively complicated compared with the anchor rod. The pump body needs to be tensioned later, which restricts the speed of the coal roadway. At the same time, the longer the anchor cable length, the need The greater the tightening force, the large enough pre-tightening force cannot be applied on site, and the limited pre-tightening force cannot effectively strengthen the anchorage area, and the roadway deformation cannot be better controlled. Therefore, there is an urgent need to develop a bendable and quick installation bolt.

Summary of the invention

Technical problem: In view of the shortcomings of the above technology, a flexible anchor rod can be provided that can be bent to adapt to complex geological environments, does not need to be stretched by the pump body, is installed quickly, and has good supporting effects.

Technical solution: In order to achieve the above technical purpose, the flexible anchor rod of the present invention includes a flexible anchor rod body, a tray, a fixed torque nut, an anti-friction washer, and an anti-twist self-aligning ball head, wherein the tray is arranged at the tail of the flexible anchor rod body, The fixed torque nut fixes the tray, and the anti-friction washer and anti-twist self-aligning ball head are arranged between the tray and the fixed torque nut;

The flexible anchor rod body includes a steel strand, the tail end of the steel strand is arranged in a connecting sleeve, the connecting sleeve includes a tail end and a head end, and the transition section between the tail end and the head end is provided with a ring-shaped boss , The boss is provided with a limit cylinder, the surface of the boss facing the head end is a vertical end surface, the surface of the boss facing the tail end is a tapered surface, the outer cylindrical surface of the tail end has threads, and the end is provided with a symmetrical arrangement along the connecting sleeve shaft The head end of the rectangular groove is provided with an inner cylindrical hole connected with the steel strand. The steel strand is inserted into the cylindrical hole of the connecting sleeve. The bottom of the inner cylindrical hole is provided with an annular groove. A friction-increasing wire spring is arranged in the middle, and the fastening between the steel strand and the connecting sleeve is realized by squeezing the outer cylindrical surface of the connecting sleeve head end.

The limit cylinder includes a conical cylinder body of the limit cylinder. The conical cylinder body of the limit cylinder includes two openings, one large and one small. The large opening on the conical cylinder of the limit cylinder is provided with a flange and a small opening. Equipped with a ring bayonet, the inner diameter of the ring bayonet is less than the outer diameter of the boss 0.5 ~ 2mm, the limit cylinder is sleeved by the end of the connecting sleeve, the ring bayonet deforms and crosses the tapered end face of the boss and is clamped in the vertical of the boss On the end surface, the limit cylinder is made of hard plastic material.

The tray includes a tray body and a stop column. The tray body is composed of a round flange and an arch. The center of the arch is provided with a tapered hole, and the large end of the tapered hole faces the top of the arch, and The tapered surface of the tapered hole is provided with multiple grooves evenly distributed along the circumference, the number of grooves is 4-8, and the stop column is fixed to the flanging part by welding or interference connection.

The anti-twist self-aligning ball head includes a curved surface and a flat surface, wherein the curved surface includes a plurality of tapered surfaces, and a protrusion I is arranged between every two tapered surfaces. The radius of the tapered surface is consistent with the tapered hole The radius and the height of the protrusion I are the same as that of the groove. The number of protrusions I is the same as the number of grooves. When the flexible anchor is pre-tightened, the protrusion I is embedded in the groove to ensure the anti-twist ball head and the tray. The circumferential direction is fixed, and the center of the anti-twist self-aligning ball head is provided with a circular hole. The circular hole is provided with a convex II distributed on the opposite side. The cross-section of the convex II is a rectangular structure, and the width of the convex II is 0.5-1mm smaller than the width of the rectangular groove. The height of the protrusion II is 0.5-1mm smaller than the width of the rectangular groove, and the protrusion II is embedded in the rectangular groove to restrict the torsion of the flexible anchor body.

Beneficial effects: Due to the adoption of the above technical solution, the present invention has the following advantages compared with the prior art:

(1) The bolt body composed of steel strands is easy to bend, which solves the problem that the length of the bolt is restricted by the height of the roadway. As the depth of coal continues to increase, it is necessary to build thick anchored rock beams, and high-strength long bolts are needed. To control the deformation of the roadway, the breaking load and length of the flexible bolt are two times higher than that of the ordinary bolt, which can effectively adapt to the complex mine environment;

(2) The flexible anchor rod body is squeezed and connected with the connecting sleeve, and the strength of the connection between the two parts can reach 95% or more of the strength of the rod body, which can meet the requirements of the complex environment on site;

(3) The flexible anchor rod is pre-tightened by a fixed torque nut, without the need for pump body tension. Compared with the steel stranded lock tension installation method, the fixed torque nut type can achieve rapid installation, greatly improving the anchor support speed, and then Improve the advancing speed of the roadway, effectively improve the work efficiency, and at the same time save the manpower for equipment handling without the need to carry the pump body;

(4) The limit tube in the flexible anchor rod can accurately locate the installation position of the anchor rod. Even if the bolt hole is too deep, the limit tube can be used to constrain the outside of the rock mass to ensure the installation length of the flexible anchor rod connecting sleeve. It will lead to failure of the flexible anchor rod, high reliability, and at the same time help to ensure a uniform exposed length of the anchor rod, and realize the quality standardization of coal mine bolt support;

(5) The tray, self-aligning ball head and connecting sleeve of the flexible anchor rod use the structure of groove and boss to solve the thorny problem of the flexible anchor rod following the rotation of the nut when the anchor rod drill is pre-tightened, plus the anti-friction washer. The flexible anchor rod can apply a larger pre-tightening force, realize a greater anchor pre-tightening force, and better restrain the deformation of the roadway.

Description of the drawings

Figure 1 is a cross-sectional view of the flexible anchor body of the present invention.

Figure 2 is a partial enlarged cross-sectional view of the flexible anchor body of the present invention.

Figure 3 is a cross-sectional view of the connecting sleeve of the flexible anchor body of the present invention.

Figure 4 is a schematic diagram of the appearance of the connecting sleeve of the flexible anchor body of the present invention.

Figure 5 is a cross-sectional view of the limiting cylinder of the present invention.

Fig. 6 is a schematic diagram of the unpretensioned state of the flexible anchor rod of the present invention.

Figure 7 is a cross-sectional view of the flexible anchor rod of the present invention after pretensioning.

Fig. 8 is a schematic diagram of an anchor hole for rock mass construction according to the present invention.

Figure 9 is a schematic view of the tray of the present invention.

Figure 10 is a schematic diagram of the anti-twist self-aligning ball head of the present invention.

Figure 11 is a schematic diagram of the fixed torque nut of the present invention.

In the figure: A, rock mass; A1, rock mass facing surface; A2, large hole section; A3 small hole section; B, flexible anchor body; B1, steel strand, B2, friction-increasing wire spring, B3, limit Position tube, B3a, flange, B3b, ring bayonet, B3c, limit tube cone body, B4, connecting sleeve, B4a, tail end, B4b, head end, B4c, cylindrical hole, B4d, ring groove, B4e , Boss, B4f, rectangular groove, C, tray, C1, tray body, C1a, tapered hole, C1b, flanging, C1c, arch, C1d, groove, C2, stop post; D, constant torque Nut; D1, nut body, D2, constant torque baffle, E, anti-friction washer, F, anti-twist self-aligning ball head, F1, tapered surface, F2, protrusion I, F3, protrusion II, F4, round hole.

detailed description

The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings:

As shown in Figure 1, Figure 2, Figure 3 and Figure 4, a flexible anchor rod of the present invention includes a flexible anchor rod body B, a tray C, a constant torque nut D, an anti-friction washer E and an anti-twist self-aligning ball Head F, where the tray C is set at the tail of the flexible anchor body B, the fixed torque nut D fixes the tray C, and the anti-friction washer E and the anti-twist self-aligning ball head F are arranged between the tray C and the fixed torque nut D;

The flexible anchor rod body B includes a steel strand B1, the tail end of the steel strand B1 is arranged in a connecting sleeve B4, the connecting sleeve B4 includes a tail end B4a and a head end B4b, and the end between the tail end B4a and the head end B4b The transition section is provided with a ring-shaped boss B4e, the boss B4e is equipped with a limit cylinder B3, the surface of the boss B4e facing the head end B4b is a vertical end surface, and the surface of the boss B4e facing the tail end B4a is a tapered surface. There are threads on the outer cylindrical surface of B4a, the tail end B4a is provided with a symmetrically arranged rectangular groove B4f along the axial direction of the connecting sleeve B4, and the head end B4b is provided with an inner cylindrical hole B4c and an inner cylindrical hole B4c connected with the steel strand B1 The inner wall is provided with threads and the bottom of the hole is provided with an annular groove B4d. The steel strand B1 is inserted into the cylindrical hole B4c of the connecting sleeve B4, and a friction increasing wire spring B2 is arranged between the steel strand B1 and the cylindrical hole B4c, which is connected by extrusion The outer cylindrical surface of the head end B4b of the sleeve B4 realizes the fastening between the steel strand B1 and the connecting sleeve B4.

As shown in Figure 5, the limit cylinder B3 includes a conical conical cylinder body B3c of the confinement cylinder. The conical cylinder body B3c of the confinement cylinder includes two openings, one large and one small. The opening is provided with a flange B3a, and the small opening is provided with an annular bayonet B3b. The inner diameter of the annular bayonet B3b is smaller than the outer diameter of the boss B4e by 0.5-2mm. The limit cylinder B3 is sleeved by the end B4a of the connecting sleeve B4, and has a ring shape. The bayonet B3b deforms and passes over the tapered end surface of the boss B4e to be clamped on the vertical end surface of the boss B4e, and the limiting cylinder B3 is made of hard plastic material.

As shown in Figure 9, the tray C includes a tray body C1 and a stop column C2. The tray body C1 is composed of a circular flanged portion C1b and an arch C1c. The center of the arch C1c is provided with a tapered hole C1a , The large end of the tapered hole C1a faces the top end of the arch C1c, and the tapered surface of the tapered hole C1c is provided with multiple grooves C1d evenly distributed along the circumference. The number of grooves C1d is 4-8. The movable column C2 is fixed to the flange part C1b by welding or interference connection.

As shown in Figure 10, the anti-twist self-aligning ball head F includes a curved surface and a flat surface. The curved surface includes a plurality of tapered surfaces F1. A protrusion IF2 is provided between each two tapered surfaces F1. The radius of the surface F1 is the same as the radius of the tapered hole C1a, the width and height of the protrusion IF2 are smaller than that of the groove C1d, and the number of the protrusion IF2 is the same as the number of the groove C1d. When the flexible anchor is pre-tensioned, the protrusion IF2 The embedded groove C1d ensures that the anti-twist ball head F and the tray C are fixed in the circumferential direction. The center of the anti-twist self-aligning ball head F is provided with a circular hole F4. The circular hole is provided with a cross-section of the convex II F3 and the convex II F3 distributed on the opposite side. It is a rectangular structure, the width of the protrusion IIF3 is 0.5-1mm smaller than the width of the rectangular groove B4f, and the height of the protrusion IIF3 is 0.5-1mm smaller than the width of the rectangular groove B4f. The protrusion IIF3 is embedded in the rectangular groove B4f to limit the twisting of the flexible anchor body B .

As shown in Figure 11, the constant torque nut D includes a nut body D1 and a constant torque baffle D2

As shown in Figure 6 and Figure 7, a flexible anchor construction method, the steps are as follows:

Step a. Construct stepped bolt holes in rock mass A. The stepped bolt hole near the excavation surface A1 is the large hole section A2, the remaining stepped bolt holes are the small hole section A3, and the diameter of the large hole section A2 is larger than The extruded diameter of the head B4b is 4-10mm, and the depth of the large hole section A2 meets the requirements of the flexible bolt body B being inserted into the bolt hole. The flanging of the limit cylinder B3 closely fits the excavation surface A1;

Step b. Put the anchoring agent into the stepped hole of the anchor rod, press the flexible anchor body B against the anchoring agent, use the front part of the flexible anchor body B to push the anchoring agent into the bottom of the stepped hole of the anchor rod, and use the bolt drill to rotate The fixed torque nut D then drives the flexible bolt body B and the anti-twist aligning ball head F to rotate together, and while rotating, the flexible bolt is pushed by the bolt drill to stir the anchoring agent evenly, rotate and advance until the limit cylinder B3 turns over After the edge is closely attached to the face A1 near the excavation, the bolter will stop rotating and stay for 30 seconds to wait for the anchoring agent to solidify;

Step c: Start the bolting machine to drive the fixed torque nut D to rotate and destroy the fixed torque structure of the fixed torque nut D, so that the fixed torque nut D continues to be screwed in along the connecting sleeve B4 and tighten the anti-friction washer E and anti-twist self-aligning ball head F. Pallet C, so that the stop post C2 on the pallet C is stuck to the excavation surface A1 to prevent the pallet C from rotating. At this time, the protrusion IF2 on the self-aligning ball head F is stuck with the groove C1d on the pallet C, thereby preventing The anti-twist self-aligning ball head F rotates, and the anti-twist self-aligning ball head F restricts the rotation of the connecting sleeve B4 through the protrusion ⅡF3, thereby restricting the rotation of the flexible anchor body B, so that the flexible anchor body is exerted by the anchor drill. B does not rotate, and the pre-tightening force is 60-100kN.

Step d: Withdraw the bolt drill and repeat steps a to c to construct the next flexible bolt.

Claims

A flexible anchor rod, characterized in that it includes a flexible anchor rod body (B), a tray (C), a fixed torque nut (D), an anti-friction washer (E) and an anti-twist self-aligning ball head (F), wherein The tray (C) is set at the tail of the flexible anchor body (B), the fixed torque nut (D) fixes the tray (C), and the anti-friction washer (E) and anti-friction washer (E) and anti-friction washer (E) are arranged between the tray (C) and the fixed torque nut (D). Twist the aligning ball head (F);

The flexible anchor rod body (B) includes a steel strand (B1), the tail end of the steel strand (B1) is arranged in a connecting sleeve (B4), and the connecting sleeve (B4) includes a tail end (B4a) and a head end (B4b), the transition section between the tail end (B4a) and the head end (B4b) is provided with a ring-shaped boss (B4e), and the boss (B4e) is provided with a limit tube (B3) and boss (B4e) The surface facing the head end (B4b) is a vertical end surface, the boss (B4e) facing the tail end (B4a) is a tapered surface, the tail end (B4a) has a thread on the outer cylindrical surface, and the tail end (B4a) is provided with Symmetrically arranged rectangular grooves (B4f) along the axis of the connecting sleeve (B4), the head end (B4b) is provided with an inner cylindrical hole (B4c) connected to the steel strand (B1), and the inner cylindrical hole (B4c) has a hole bottom An annular groove (B4d) is provided, the steel strand (B1) is inserted into the cylindrical hole (B4c) of the connecting sleeve (B4), and a friction-increasing wire spring (B1) is arranged between the steel strand (B1) and the cylindrical hole (B4c). B2), the fastening between the steel strand (B1) and the connecting sleeve (B4) is achieved by squeezing the outer cylindrical surface of the head end (B4b) of the connecting sleeve (B4).
The flexible anchor rod according to claim 1, characterized in that: the limit cylinder (B3) includes a limit cylinder cone (B3c), and the limit cylinder cone (B3c) includes a large and a small Two openings, the large opening on the conical cylinder (B3c) of the limit cylinder is provided with a flange (B3a), and the small opening is provided with a ring bayonet (B3b). The inner diameter of the ring bayonet (B3b) is smaller than the boss The outer diameter of (B4e) is 0.5～2mm, the limit cylinder (B3) is sleeved by the end of the connecting sleeve (B4) (B4a), the annular bayonet (B3b) is deformed and passes over the conical end surface of the boss (B4e) to be stuck in On the vertical end surface of the boss (B4e), the limit cylinder (B3) is made of hard plastic material.
The flexible anchor rod according to claim 1, characterized in that: the tray (C) comprises a tray body (C1) and a stop column (C2), and the tray body (C1) consists of a round flange part ( C1b) and the arch (C1c), the center of the arch (C1c) is provided with a tapered hole (C1a), the large end of the tapered hole (C1a) faces the top of the arch (C1c), and the tapered hole (C1c) The tapered surface of) is provided with multiple grooves (C1d) evenly distributed along the circumference, the number of grooves (C1d) is 4-8, and the stop column (C2) is connected to the flanging part by welding or interference (C1b) Fixed.
The flexible anchor rod according to claim 1, 2 or 3, characterized in that: the anti-twist self-aligning ball head (F) includes a curved surface and a flat surface, wherein the curved surface includes a plurality of tapered surfaces (F1), There is a protrusion I (F2) between every two tapered surfaces (F1), the radius of the tapered surface (F1) is the same as the radius of the tapered hole (C1a), and the width of the protrusion I (F2) And the height is smaller than the groove (C1d), and the number of protrusions I (F2) is the same as the number of grooves (C1d). When the flexible anchor is pre-tensioned, the protrusion I (F2) is embedded in the groove (C1d) to ensure the anti-twist ball The head (F) and the tray (C) are fixed in the circumferential direction. The center of the anti-twist self-aligning ball head (F) is provided with a circular hole (F4). The circular hole is provided with a convex II (F3) distributed on the opposite side. The cross section of Ⅱ(F3) is a rectangular structure, the width of protrusion Ⅱ(F3) is 0.5～1mm smaller than the width of rectangular groove (B4f), and the height of protrusion Ⅱ(F3) is 0.5～1mm smaller than the width of rectangular groove (B4f). , The protrusion II (F3) is embedded in the rectangular groove (B4f) to limit the torsion of the flexible anchor body (B).