CN103774648B - A kind of prestressed anchor preventing extracting from anchor hole - Google Patents

Abstract

The invention relates to a prestressed anchor bar which prevents being pulled out from an anchor hole, which comprises an anchor bar body with an expansion plug at the bottom, an expansion tooth bowl, a backing platform, a backing plate and a nut. Both the base platform and the backing plate are provided with anchor holes; the top of the anchor rod body passes through the anchor holes of the base platform and the backing plate in turn and is connected to the nut; The expansion plug is placed in the expansion tooth bowl. The invention has the advantages of simple structure, low cost and convenient construction, and constructs a new type of tension-pressure-embolism composite prestressed anchoring system, which can prevent the bolt and the grouting body from being pulled out from the anchor hole, thereby improving the stability of the rock and soil mass, engineering safety and anchorage durability.

Description

A prestressed anchor rod preventing pulling out from the anchor hole

technical field

The invention relates to rock-soil anchoring technology, in particular to a prestressed anchor rod which prevents pulling out from an anchor hole.

Background technique

Rock-soil anchoring is to tightly interlock the strata through the anchor bolts buried in the formation, relying on the interaction between the anchor bolt-grouting body-hole wall rock-soil physical force to mobilize and improve the rock-soil mass's own strength and natural strength. It is a technology to improve the stress state to ensure the stability of the external rock and soil mass, so as to ensure the safety of the project. The engineering application of geotechnical anchoring technology began at the end of the 19th century. With the development of its theory and technology, it has been extended to mines, water conservancy, hydropower, highways, railways, municipal administration, urban construction, geology, military industry and other departments. It is widely used in slope engineering, underground engineering, and deep foundation pit engineering, and plays a key role in major national economic projects.

Rock and soil anchoring is not only affected by stratum lithology, rock and soil mass structure, geological structure, hydrogeology, topography, etc., but also may be affected by strong earthquakes, all of which pose a threat to the safety of rock and soil anchoring.

During the construction and operation of rock-soil anchorage, the pulling out of the anchor rod together with the grouting body from the anchor hole is the most basic, typical and common form of rock-soil anchorage failure, which will lead to the failure of rock-soil anchorage and endanger the safety of the project. Bring hidden dangers, thereby limiting the anchoring force that the anchor rod can provide. Therefore, when the anchoring force that needs to be provided is large, ordinary bolt anchorage can no longer meet the requirements of the project, which restricts the application and development of rock-soil anchorage technology. How to improve the load transfer mechanism of rock-soil anchorage and overcome the disadvantages of ordinary anchorage has become a It is the fundamental way to increase the anchoring force of the bolt and improve the anchoring effect.

In addition, the grouting body can hardly provide anchoring force at the initial stage of anchoring, so it cannot meet the requirements of immediate support after excavation of weak rock and soil. Although the existing pipe-slit bolts overcome the above-mentioned shortcomings, the anchoring force can be provided immediately after the bolt is installed, which is beneficial to timely control the deformation of the rock and soil mass, but the anchoring force that can be provided is not large; at the same time, due to the weak The rock and soil will be squeezed into the pipe cavity from the pipe seam of the pipe seam anchor, resulting in a decrease in the anchoring force.

Contents of the invention

The technical problem to be solved by the present invention is to provide a prestressed anchor rod that can improve and immediately provide anchoring force, save materials, and is easy to construct and prevent being pulled out from the anchor hole.

In order to solve the above problems, the present invention provides a prestressed anchor rod that prevents it from being pulled out from the anchor hole. plate, nut; the pad and the backing plate are provided with anchor holes; the top of the anchor rod body passes through the anchor holes of the pad and the backing plate in turn and is connected to the nut together; the expansion plug is placed in the expansion tooth bowl.

The expansion plug is in the shape of a truncated cone.

Threads are provided on the top end of the anchor rod body.

The expansion tooth bowl is in the shape of a bowl with a large mouth and a small bottom. The surface conforms to the side of the expansion plug.

A grouting hole is opened on the backing plate.

Compared with the prior art, the present invention has the following advantages:

1. In the present invention, the bowl-shaped expansion tooth bowl with a large mouth and a small bottom is first placed at the bottom of the borehole, the anchor rod body is placed in the borehole and the expansion plug at the bottom end is pushed into the expansion tooth bowl at the bottom of the borehole. The thrust is applied to the round tube sleeved on the anchor rod body, so that the round tube drives the frustum-shaped expansion plug at the bottom of the anchor rod body to the bottom of the expansion tooth bowl, and at the same time pushes the teeth of the expansion tooth bowl to open around and press into the In the rock and soil mass of the borehole wall, when the thrust is stopped on the circular pipe, the expansion plug at the bottom of the bolt body is caught by the inner surface annular platform of the expansion tooth bowl, and the expansion tooth bowl is still kept open to the surroundings to plug in the drill. In the rock and soil mass of the hole wall. After the round pipe is taken out, a backing plate is added to the top of the anchor, that is, the top of the anchor passes through the anchor hole in the center of the backing plate, and the nut is tightened, the body of the anchor applies prestress to the rock and soil mass of the slope.

2. The present invention fills the grouting body in the borehole through the grouting hole on the backing plate, and the consolidated grouting body will be tightly consolidated with the anchor rod body, the expansion plug at the bottom end, and the expansion tooth bowl , when the rock-soil mass of the slope is deformed, the anchoring force is applied to the rock-soil mass of the slope through the anchor rod body.

3. The present invention significantly optimizes and improves the load transfer mechanism of rock and soil anchorage, and constructs a new type of composite prestressed anchorage system of tension-pressure-embolism, which can effectively prevent the anchor rod and the grouting body from being pulled out of the anchor hole, that is, the anchor The rod and the grouting body are destroyed along the contact interface with the rock-soil mass, which significantly improves the rock-soil reinforcement effect and better mobilizes the self-stabilization ability of the rock-soil mass, thereby improving the stability of the rock-soil mass and the safety of the project sex.

4. The grouting body of the present invention plays a waterproof, anti-corrosion and anti-rust effect on the anchor rod body wrapped in it, the expansion plug at the bottom end, and the expansion tooth bowl, thereby improving the durability of anchoring.

5. The present invention has simple structure, low cost and convenient construction.

Description of drawings

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Fig. 1 is a structural schematic diagram of the present invention.

Fig. 2 is a structural schematic diagram of the bottom end of the present invention.

Fig. 3 is a schematic diagram of the axial section of the anchor rod body of the present invention.

Fig. 4 is a schematic diagram of the expansion plug at the bottom end of the anchor rod body of the present invention.

Fig. 5 is a schematic cross-sectional view of the shaft of the expansion plug at the bottom end of the anchor rod body of the present invention.

Fig. 6 is a schematic diagram of the expansion tooth bowl of the present invention.

Fig. 7 is a schematic cross-sectional view of the expansion gear bowl shaft of the present invention.

In the figure: 1—rock and soil body 2—grouting body 3—drilling hole 4—bolt rod body 5—pad 6—backing plate 7—nut 8—top 9—expansion plug 10—expansion tooth bowl 11—teeth 12— Hole wall 13—annular platform 14—grouting hole 15—thread.

Detailed ways

As shown in Figures 1 to 7, a prestressed anchor rod that prevents it from being pulled out from the anchor hole includes an anchor rod body 4 with an expansion plug 9 at the bottom, an expansion tooth bowl 10, a pad 5, and a backing plate 6 , Nut 7. Both the base 5 and the base 6 are provided with anchor holes; the top 8 of the anchor body 4 passes through the anchor holes of the base 5 and the base 6 in turn and is connected with the nut 7; the expansion plug 9 is placed on the expansion gear Inside the bowl 10.

Wherein: the expansion plug 9 is in the shape of a truncated cone.

The top end 8 of the anchor rod body 4 is provided with threads 15 .

The expansion tooth bowl 10 is in the shape of a bowl with a large mouth and a small bottom. The inner surface coincides with the side of the expansion plug 9.

A grouting hole 14 is opened on the backing plate 6 .

During use, (1) drill hole 3 to rock and soil body 1 according to design requirements; (2) carry out the construction of pad 5 at hole 3; Place the bowl-shaped expansion tooth bowl 10 with a large mouth and a small bottom in the borehole 3, and the bottom of the bowl-shaped expansion tooth bowl 10 coincides with the bottom of the borehole 3; (4) Put the anchor rod body 4 in the borehole 3 and push the bottom The frustum-shaped expansion plug 9 at the end coincides with the inner surface of the bowl-shaped expansion tooth bowl 10 at the bottom of the borehole 3; Put the round tube on the anchor rod body 4, apply thrust to the round tube, and drive the frustum-shaped expansion plug 9 at the bottom end of the anchor rod body 4 to approach the bottom of the expansion tooth bowl 10 through the round tube, and squeeze the expansion tooth bowl 10 The teeth 11 spread out to the surroundings and are pressed into the rock and soil mass 1 of the wall 12 of the borehole 3; Stop applying thrust to the round pipe and take it out, the expansion plug 9 at the bottom end of the anchor rod body 4 is caught by the inner surface annular platform 13 of the tooth 11, and the tooth 11 is still kept open to the surrounding rock and soil mass plugged in the hole wall 12 1 among; Add the backing plate 6 at the anchor rod top 8, that is, even if the anchor rod top 8 passes through the anchor rod hole in the center of the backing plate 6, and tighten the nut 7, the anchor rod body 4 applies prestress to the slope rock and soil mass 1; The grouting body 2 is filled in the borehole 3 through the grouting hole 14 on the backing plate 6, and the consolidated grouting body 2 will be tightly connected with the anchor rod body 4 and the expansion plug 9 at the bottom end, and the expansion tooth bowl 10. Consolidated in one body, when the rock-soil mass 1 of the slope is deformed, an anchoring force is applied to the rock-soil mass 1 of the slope through the anchor rod body 4 .

Claims (1)

1. prevent the prestressed anchor extracted from anchor hole, it is characterized in that: it comprises bottom with the anchor rod body (4) of expansible stopper (9), expansion tooth bowl (10) and pad (5), backing plate (6), nut (7); Described pad (5) and described backing plate (6) are equipped with bolthole; The top (8) of described anchor rod body (4) connects together with described nut (7) with the bolthole of described backing plate (6) through described pad (5) successively; Described expansible stopper (9) is placed in described expansion tooth bowl (10); Described expansible stopper (9) is in truncated cone-shaped; The top (8) of described anchor rod body (4) is provided with screw thread (15); Described expansion tooth bowl (10) is little bowl-shape in the large end in mouth, its opening upwards, circumference is spacedly distributed and the tooth be connected at the bottom of bowl (11), and the inner surface of this tooth (11) is distributed with multiple annular platform (13), and the side-anastomosis of the inner surface of described tooth (11) and described expansible stopper (9); Described backing plate (6) has an injected hole (14).