阅读说明：本技术 一种新型微预应力损失注浆锚杆及其施工方法 (Novel micro-prestress loss grouting anchor rod and construction method thereof ) 是由 肖衡林 李晨旭 刘永莉 马强 李丽华 熊豪文 郭斌 陈智 陶高梁 于 2020-04-29 设计创作，主要内容包括：本发明提供了一种新型微预应力损失注浆锚杆及其施工方法,上述注浆锚杆包括周壁上开设有渗透孔的隔离套管、由多根钢绞线束缚形成的锚杆、一次注浆管、二次注浆管、钢锚板及锚固螺母,本发明中隔离套管套设于锚杆的自由段上,且锚杆的上端部通过锚固螺母锚固于钢锚板上,一次注浆管的下端部可穿过钢锚板并穿入隔离套管中,二次注浆管的下端部可穿过钢锚板并穿入隔离套管中。本发明中利用开设有渗透孔的隔离套管进行两次注浆作业,这使得注浆浆液可通过渗透孔渗入土体缝隙之中,以增加阻动面的同时还使得锚杆的自由段及锚固段可共同抵抗滑坡体变形,从而有效提高稳固效果。(The invention provides a novel micro-prestress loss grouting anchor rod and a construction method thereof, wherein the grouting anchor rod comprises an isolation sleeve with a penetration hole on the peripheral wall, an anchor rod formed by binding a plurality of steel strands, a primary grouting pipe, a secondary grouting pipe, a steel anchor plate and an anchoring nut, the isolation sleeve is sleeved on the free section of the anchor rod, the upper end part of the anchor rod is anchored on the steel anchor plate through the anchoring nut, the lower end part of the primary grouting pipe can penetrate through the steel anchor plate and penetrate into the isolation sleeve, and the lower end part of the secondary grouting pipe can penetrate through the steel anchor plate and penetrate into the isolation sleeve. In the invention, the isolation sleeve with the penetration hole is used for carrying out two grouting operations, so that grouting slurry can penetrate into a soil body gap through the penetration hole, the resistance surface is increased, and the free section and the anchoring section of the anchor rod can jointly resist the deformation of a landslide body, thereby effectively improving the stabilizing effect.)

1. A novel micro-prestress loss grouting anchor rod is characterized by comprising an anchor rod (1) formed by binding a plurality of steel strands, an isolation sleeve (2), a grouting pipe (3) and an anchor head (4), wherein the isolation sleeve (2) is sleeved on the anchor rod (1), and the peripheral wall of the isolation sleeve (2) is provided with a penetration hole (21), the grouting pipe (3) comprises a primary grouting pipe (31) and a secondary grouting pipe (32), the anchor head (4) comprises a steel anchor plate (41) and an anchor nut (42), the upper end part of the anchor rod (1) can penetrate through the steel anchor plate (41) and is anchored on the steel anchor plate (41) through the anchoring nut (42), the lower end part of the primary grouting pipe (31) can penetrate through the steel anchor plate (41) and penetrate into the isolation sleeve (2), the lower end of the secondary grouting pipe (32) can penetrate through the steel anchor plate (41) and penetrate into the isolation sleeve (2).

2. The novel micro-prestress loss grouting anchor rod according to claim 1, characterized in that a anchor rod hole (411), a primary grouting hole (412) and a secondary grouting hole (413) are formed in the steel anchor plate (41), the anchor rod (1) can pass through the anchor rod hole (411) and be anchored on the steel anchor plate (41) through the anchoring nut (42), the lower end part of the primary grouting pipe (31) can pass through the primary grouting hole (412) and penetrate into the isolation sleeve (2), and the lower end part of the secondary grouting pipe (32) can pass through the secondary grouting hole (413) and penetrate into the isolation sleeve (2).

3. A novel micro pre-stress loss grouting anchor rod according to claim 1 or 2, characterized in that the lower end of the primary grouting pipe (31) extends to the lower end of the anchor rod (1).

4. A novel micro pre-stress loss grouting anchor according to claim 3, characterized in that the lower end of the secondary grouting pipe (32) extends to the lower end of the isolation sleeve (2).

5. The novel micro-prestress loss grouting anchor rod according to claim 4, characterized in that the isolation sleeve (2) is sleeved on the rod body free section (1a) of the anchor rod (1).

6. A construction method of the novel micro-prestress loss grouting anchor rod as claimed in any one of claims 1 to 5, characterized by comprising the following steps:

step one, distributing holes according to the designed drilling intervals, and drilling to obtain anchor rod holes (5);

step two, sleeving and fixing the isolation sleeve (2) on the free section (1a) of the rod body of the anchor rod (1), and then installing the steel anchor plate (41) and the anchor nut (42) on the anchor rod (1);

inserting a primary grouting pipe (31) and a secondary grouting pipe (32) into the isolation sleeve (2), and fixing the primary grouting pipe (31) and the secondary grouting pipe (32) to the anchor rod (1);

inserting the assembled grouting anchor rods into the anchor rod holes (5), and then fixing the steel anchor plates (41) on anchor seats (6) around the anchor rod holes (5);

fifthly, primary grouting is carried out through the primary grouting pipe (31) to form a rod body anchoring section (1 b);

sixthly, after the rod body anchoring section (1b) is formed, tensioning the anchor rod (1) to a designed tonnage, and then anchoring the anchor rod (1) on the corresponding steel anchor plate (41) by utilizing the anchoring nut (42);

seventhly, performing compensation tensioning on the anchor rod (1) at intervals to make up for the loss of prestress;

step eight, immediately carrying out secondary grouting through the secondary grouting pipe (32) until grout flows to the hole opening of the anchor rod hole (5) so as to form grouting reinforcement on the free section (1a) of the rod body;

and step nine, performing concrete anchor sealing construction on the anchor rod head of the anchor rod (1) to finish the anchor rod construction.

7. The construction method according to claim 6, wherein the primary grouting in the third step is low-pressure grouting, the grouting pressure is 0.5-2.0MPa, and the water-cement ratio of the primary grouting slurry is 1: 1.

8. The construction method according to claim 6, wherein in the fourth step, during the second grouting, the grout is injected in a mode of low pressure and high pressure, the low-pressure grouting pressure is 0.5-2MPa, the high-pressure grouting pressure is 2.0-6.0MPa, and the water-cement ratio of the second grouting grout is 0.5.

9. The construction method according to claim 7 or 8, wherein the grouting slurry in the third step and the fourth step is a cement-based-water glass two-fluid slurry.

Technical Field

The invention relates to the technical field of prestressed anchor rod construction, in particular to a novel micro-prestress loss grouting anchor rod and a construction method thereof.

Background

As shown in fig. 1, the conventional anchor rod construction process in geotechnical engineering is as follows: firstly drilling anchor rod hole 5 during construction^*Then to the anchor rod hole 5^*In which an isolation sleeve 2 is arranged^*And then the anchor rod 1 is penetrated^*Then the grouting pipe 3 is put^*Along the insulating sleeve 2^*Internally inserted anchor rod 1^*Then using the anchor head 4^*Anchoring-bolt 1^*Is fixed on the anchor seat 6^*Upper, reuse grouting pipe 3^*Grouting to form rod anchoring section 1b^*Then prestressed tension is carried out, and the tension force is completely transmitted to the rod body anchoring section 1b through isolation measures^*And finally, sealing the anchor. The anchor rod 1 is constructed by the above construction process^*Finally forming the free section 1a of the rod body^*(by means of the spacer sleeve 2^*Sliding surface 7^*The above partial anchor rods are isolated to form a rod body free section 1a^*) And rod anchoring section 1b^*(part of the anchor rod stabilized in the mountain is anchored by grouting to form a rod body anchoring section 1b^*) Two parts.

However, after long-term tracking, the subject group finds that the traditional anchor rod is easy to have the possibility of prestress loss and even failure due to various reasons such as anchor retraction, sliding mass compression deformation in the range of the free section and the like, and once the situation occurs, the slope stability is inevitably reduced, thereby bringing about great potential safety hazard.

Disclosure of Invention

To the above problem, a novel micro-prestress loss grouting anchor rod which is simple to construct and install and easy to popularize is provided.

The specific technical scheme is as follows:

the invention provides a novel micro-prestress loss grouting anchor rod which is characterized by comprising an anchor rod, an isolation sleeve, a grouting pipe and an anchor head, wherein the anchor rod is formed by binding a plurality of steel strands, the isolation sleeve is sleeved on the anchor rod, the peripheral wall of the isolation sleeve is provided with a penetration hole, the grouting pipe comprises a primary grouting pipe and a secondary grouting pipe, the anchor head comprises a steel anchor plate and an anchor nut, the upper end part of the anchor rod can penetrate through the steel anchor plate and is anchored on the steel anchor plate through the anchor nut, the lower end part of the primary grouting pipe can penetrate through the steel anchor plate and penetrate into the isolation sleeve, and the lower end part of the secondary grouting pipe can penetrate through the steel anchor plate and penetrate into the isolation sleeve.

Foretell novel little prestressing force loss slip casting stock still has such characteristic, is equipped with stock pole hole, primary grouting hole and secondary grouting hole on the steel anchor slab, and the stock can pass stock pole hole and pass through anchor nut anchor on the steel anchor slab, and the lower tip of primary grouting pipe can pass primary grouting hole and penetrate the isolation sleeve in, and the lower tip of secondary grouting pipe can pass secondary grouting hole and penetrate the isolation sleeve.

The novel micro-prestress loss grouting anchor rod also has the characteristic that the lower end part of the primary grouting pipe extends to the lower end part of the anchor rod.

The novel micro-prestress loss grouting anchor rod also has the characteristic that the lower end part of the secondary grouting pipe extends to the lower end part of the isolation sleeve.

The novel micro-prestress loss grouting anchor rod is characterized in that the free section of the rod body of the anchor rod is sleeved with the isolation sleeve.

In a second aspect of the invention, there is provided a construction method of the novel micro-prestress loss grouting anchor rod as claimed in the claim, which has the characteristics that the construction method comprises the following steps:

step one, distributing holes according to the designed drilling intervals, and drilling to obtain anchor rod holes;

step two, sleeving and fixing the isolation sleeve on the free section of the rod body of the anchor rod, and then installing the steel anchor plate and the anchor nut on the anchor rod;

inserting the primary grouting pipe and the secondary grouting pipe into the isolation sleeve, and fixing the primary grouting pipe and the secondary grouting pipe to the anchor rod;

inserting the assembled grouting anchor rods into the anchor rod holes, and then fixing the steel anchor plates on the anchor seats around the anchor rod holes;

fifthly, performing primary grouting through a primary grouting pipe and forming a rod body anchoring section;

step six, after the rod body anchoring section is formed, tensioning the anchor rod to the designed tonnage, and then anchoring the anchor rod on the corresponding steel anchor plate by utilizing an anchoring nut;

step seven, compensating and tensioning the anchor rod after a period of time to make up for the loss of prestress;

step eight, immediately carrying out secondary grouting through a secondary grouting pipe until grout flows to an orifice of the anchor rod hole so as to form grouting reinforcement on the free section of the rod body;

and step nine, performing concrete anchor sealing construction on the anchor rod head of the anchor rod to complete anchor rod construction.

The construction method also has the characteristics that the primary grouting in the step three is low-pressure grouting, and the grouting pressure is 0.5-2.0 MPa.

The construction method also has the characteristics that during secondary grouting in the fourth step, the grout is injected in a mode of firstly injecting the low pressure grout and then injecting the high pressure grout, the low pressure grouting pressure is 0.5-2MPa, the high pressure grouting pressure is 2.0-6.0MPa, and the water-cement ratio of the secondary grouting grout is 0.5.

The construction method also has the characteristics that the grouting slurry in the third step and the fourth step is cement-based-water glass double-liquid slurry.

The beneficial effect of above-mentioned scheme is:

1. in the invention, the prestress of the anchor rod is retained in the slurry injected by secondary grouting by utilizing the tensioning operation after primary grouting, so that the prestress loss of the anchor rod is greatly reduced, and the stability of a side slope and a formed hole is effectively improved;

2. in the invention, the isolation sleeve with the penetration hole is used for carrying out two grouting operations, so that grouting slurry can penetrate into a soil body gap through the penetration hole, the resistance surface is increased, and the free section and the anchoring section of the anchor rod can jointly resist the deformation of a landslide body, thereby effectively improving the stabilizing effect.

Drawings

Fig. 1 is a schematic structural view of a conventional anchor rod construction process in the background art;

fig. 2 is a schematic structural diagram (a) of a conventional anchor rod construction process in the background art and a partially enlarged view (B) of the conventional anchor rod construction process at a letter a;

fig. 3 is a schematic structural view of a micro pre-stress loss grouting bolt provided in an embodiment of the present invention;

fig. 4 is a schematic structural diagram (a) of a micro-prestress loss grouting bolt provided in an embodiment of the present invention and a partially enlarged view (B) of the micro-prestress loss grouting bolt at a letter a;

FIG. 5 is a schematic structural view of an isolation bushing provided in an embodiment of the present invention;

FIG. 6 is a schematic structural view of a steel anchor plate provided in an embodiment of the present invention;

FIG. 7 is a schematic structural view of a fifth construction step provided in an embodiment of the present invention;

FIG. 8 is a partial enlarged view of the corresponding portion of FIG. 7 at the letter B;

FIG. 9 is a schematic structural diagram of a construction step eight provided in the embodiment of the present invention;

fig. 10 is a partially enlarged view of a corresponding portion at letter C in fig. 9.

In the drawings: 1. an anchor rod; 1a, a free section of the rod body; 1b, a rod body anchoring section; 1^*An anchor rod; 1a^*A free section of the rod body; 1b^*The rod body anchoring section; 2. an isolation sleeve; 21. a penetration hole; 2^*An isolation sleeve; 3. a grouting pipe; 31. a primary grouting pipe; 32. a secondary grouting pipe; 3^*And a grouting pipe; 4. an anchor head; 41. a steel anchor plate; 411. an anchor rod bore; 412. primary grouting holes; 413. secondary grouting holes; 42. an anchor nut; 4^*An anchor head; 5. an anchor rod hole;5^*an anchor rod hole; 6. an anchor block; 6^*An anchor seat; 7. a sliding surface; 7^*And a sliding surface.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.

As shown in fig. 2 to 10, a micro prestress loss bolt provided in an embodiment of the present invention includes: anchor rod 1, isolation sleeve 2, slip casting pipe 3 and anchor head 4 that form are tied up by many steel strands, isolation sleeve 2 cover is located on anchor rod 1, and be equipped with infiltration hole 21 on isolation sleeve 2's the perisporium, slip casting pipe 3 includes primary slip casting pipe 31 and secondary slip casting pipe 32, and anchor head 4 includes steel anchor plate 41 and anchor nut 42, and the upper end of anchor rod 1 can pass steel anchor plate 41 and pass through anchor nut 42 anchor on steel anchor plate 41, and the lower tip of primary slip casting pipe 31 can pass steel anchor plate 41 and penetrate during isolation sleeve 2, and the lower tip of secondary slip casting pipe 32 can pass steel anchor plate 41 and penetrate in isolation sleeve 2.

Specifically, in the invention, the steel anchor plate 41 is provided with an anchor rod hole 411, a primary grouting hole 412 and a secondary grouting hole 413, the anchor rod 1 can pass through the anchor rod hole 411 and is anchored on the steel anchor plate 41 through the anchoring nut 42, the lower end part of the primary grouting pipe 31 can pass through the primary grouting hole 412 and penetrate into the isolation sleeve 2, and the lower end part of the secondary grouting pipe 32 can pass through the secondary grouting hole 413 and penetrate into the isolation sleeve 2.

In the invention, the lower end part of the primary grouting pipe 31 extends to the lower end part of the anchor rod 1, the lower end part of the secondary grouting pipe 32 extends to the lower end part of the isolation sleeve 2, and the isolation sleeve 2 is sleeved on the rod body free section 1a of the anchor rod 1.

The construction of the anchor rod by using the novel micro-prestress loss grouting anchor rod comprises the following steps:

step one, distributing holes according to the designed drilling intervals, and drilling to obtain anchor rod holes 5;

step two, the isolation sleeve 2 is sleeved and fixed on the free section 1a of the rod body of the anchor rod 1, and then the steel anchor plate 41 and the anchor nut 42 are arranged on the anchor rod 1;

inserting the primary grouting pipe 31 and the secondary grouting pipe 32 into the isolation sleeve 2, and fixing the primary grouting pipe 31 and the secondary grouting pipe 32 to the anchor rod 1;

inserting the assembled grouting anchor rods into the anchor rod holes 5, and then fixing the steel anchor plates 41 on the anchor bases 6 around the anchor rod holes 5;

fifthly, performing primary grouting through the primary grouting pipe 31 to form a rod body anchoring section 1b (in the invention, the primary grouting is low-pressure grouting, the grouting pressure is 0.5-2.0MPa, and the water cement ratio of grouting slurry is 1: 1);

step six, after the rod body anchoring section 1b is formed, tensioning the anchor rod 1 to the designed tonnage, and then anchoring the anchor rod 1 on the corresponding steel anchor plate 41 by utilizing the anchoring nut 42;

step seven, compensating and tensioning the anchor rod 1 after a period of time to make up for the loss of prestress;

step eight, immediately carrying out secondary grouting through a secondary grouting pipe 32 until grout flows to the orifice of the anchor rod hole 5 so as to form grouting reinforcement on the free section 1a of the rod body;

and step nine, performing concrete anchor sealing construction on the anchor rod head of the anchor rod 1 to complete anchor rod construction.

Unlike the anchor rod 1 in the background art^*Extends to the insulating sleeve 2^*The lower end part of the invention, the isolation sleeve 2 is only sleeved on the free section 1a of the rod body of the anchor rod 1, so that the rod body anchoring section 1b of the anchor rod 1 can directly penetrate into the anchor rod hole 5, and further, the low-pressure grout injected by primary grouting can adopt permeation groutingThe rod body anchoring section 1b under the sliding surface 7 is bonded with the hard bedrock to form a whole body by the principle.

In the invention, the secondary grouting pipe 32 is used for grouting back pressure on the free section 1a of the anchor rod 1, and during grouting, grout permeates into the peripheral soil body through the permeation holes 21 on the isolation sleeve 2, so that an enlarged concrete anchor rod compression-resistant body is formed to resist the retraction deformation of the anchor sealing end of the anchor rod. Specifically, during secondary grouting, grout is injected in a mode of firstly low pressure and then high pressure, the low-pressure grouting pressure is 0.5-2MPa, the high-pressure grouting pressure is 2.0-6.0MPa, and the water-cement ratio of the secondary grouting grout is 0.5.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.