JPS6040500A - Anchor bolt - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anchor bolt, such as a rock bolt or an earth anchor, which is fixed to the ground such as a slope surface or an excavated tunnel surface.

BACKGROUND ART Conventionally, a method has been adopted in which an anchor bolt is fixed to a ground such as a slope surface or an excavated surface to prevent the ground from loosening or collapsing. In other words, an anchor bolt is inserted into a hole drilled in the ground, and it is fixed to the ground by tightening with a wedge or by adhesion with mortar, etc., and then attaching it to the head of the anchor bolt exposed on the surface of the ground. A bearing pressure device consisting of a bearing plate and a nut was installed to bear the tension of the anchor bolt on the ground surface and tighten the ground.

However, since conventional anchor bolts use a bearing plate made of steel plate etc. as a bearing device, it is not possible to make them stick tightly to the uneven ground surface. It was difficult to tighten the mountain. Additionally, there is a limit to the size of the bearing plate due to ease of transportation, installation, etc.

For this reason, the area of the ground that can be supported by a single anchor bolt is limited, and it becomes necessary to construct dense anchor bolts, or use shotcrete concrete or double-layer concrete after installing the anchor bolts. processing was required.

This invention was made in view of the above circumstances, and its purpose is to provide close contact with the ground surface, support the ground uniformly over the entire surface, and increase the bearing surface to provide high support for the ground. To propose an anchor bolt with a bearing plate that generates force.

The gist is that a bag-like flexible formwork that can be filled with a hardening fluid and a frame that supports this formwork are attached to the exposed head of an anchor bolt that is fixed in the ground. 7 Lexiple formwork is an anchor bolt characterized by having a hardening fluid press-filled and hardened inside, and forming a bearing plate in close contact with the ground surface.

The flexible formwork referred to in this invention is, for example, synthetic fibers with high tensile strength such as nylon, polyester, polyacrylic, polypropylene, vinylon, polyethylene, etc., chemical fibers such as rayon, cupro, acetate, etc., or cotton, linen, wool, etc. It is highly flexible and is made of woven, knitted, non-woven fabrics, etc. made from natural fibers, etc., and can be formed into the desired shape and size of the plate. It is a bag-shaped bag with a space for filling with fluid.

This anchor bolt is a bearing made by press-fitting a hardening fluid such as mortar into the inside of a bag-shaped flexible formwork. Because it has a grate, it evenly bears the tension of the anchor bolt, tightens the ground more strongly than conventional anchor bolts with bearing plates, and prevents the ground from loosening and collapsing. In addition, the bearing pressure area is increased as needed, and the support area of a single anchor bolt can be expanded. Therefore, it is possible to reduce the construction density of anchor bolts, and it is possible to omit shotcrete and two-duration concrete construction.

The dimensions of the bearing plate of this anchor bolt can be selected from a range of about 10 cR to 100 α in diameter or side length. Usually, a large plate of about 30 to 60 yen is suitable because it is effective in expanding the support area of the anchor bolt and is easy to install. Further, as will be described later, when 91 bearing plates are formed across a plurality of anchor bolts, the size thereof may be several meters.

The illustrated embodiment will be explained below.

In Fig. 1, the anchor bolt 2 is fixed on the slope of the earth 1, the flexible formwork 3 is inserted into the bolt head 2a exposed on the earth surface, and the bolt head 2a is inserted into the insertion hole 3a. The flexible formwork 3 is installed on the outside of the foot.
A frame 4 supporting the bolt is inserted through the bolt head 2a, and a bolt is screwed into the recess and fixed thereto.

7 The lexiple formwork 3 has a disk shape, and has an insertion hole 3a in the center.
, an injection port 3b is provided at the periphery. 'Also, as shown in Fig. 7, a square button-shaped flexible formwork 3'
Furthermore, for example, strings 7 may be attached to the four corners of the rectangular formwork to improve workability when locking the formwork to the frame.

The frame 4 used in this example has a circular dish shape with a spherical curved surface as shown in Fig. 3, and has an insertion hole 4a in the center, a notch 4b on the periphery, and a large number of small through holes 4c). A rectangular washer 5 is integrally fixed to the center of the outer surface. In addition, various frames can be used in the present invention.

For example, as shown in Figure 5, materials such as reinforcing bars or iron pipes may be bent and welded to form a trapezoid with a truncated pyramid shape, or thin reinforcing bars may be formed into a lattice shape as shown in Figure 6. It may be constructed by assembling it, and in short, it can be of any shape and size as long as it can support the 7-lexiple formwork 3 expanded by press-fitting a fluid such as fluid concrete or mortar as described later. It's okay. In addition,
Although the washer 5 is integrally welded to the center of each frame 4 in the above embodiments, a separate washer may be assembled during construction.

The flexible formwork 3 arranged as shown in Fig. 1 has a fourth
As shown in the figure, a hardening fluid such as lutal or concrete 8 is press-fitted and hardened.

The flexible formwork 3 has its outer surface in contact with and supported by the spherical curved surface of the frame 4, and its inner surface closely contacts the uneven surface of the earth 1 to form a bearing plate.
This anchor bolt consists of:

To install this anchor bolt, as shown in Figure 4,
A transport pipe 10 of a pumping device 9 such as a concrete pump is connected to the injection port 3b of the formwork 3 protruding from the frame notch 4b of the head of the rock bolt 2 fixed on the ground 1, and the fluid concrete 8 is Inject into the flexible formwork 3.

7 As the concrete 8 is placed inside the flexible formwork 3, the air inside the flexible formwork 3 is exhausted through the material, and the flexible formwork 3 is affected by the strength of the material and the restraint by the frame 4. gradually expands within the
The bolt 20 receives reaction force through the frame 4 and comes into close contact with the surface of the ground 1. Furthermore, when the filling pressure of the concrete 8 increases in the 7-flexible formwork 3, the concrete mixing water is squeezed out from the weave of the flexible formwork 3, and when the predetermined injection pressure is finally reached, the water is inserted into the injection port 3b. A suitable automatic shutoff valve (not shown) is activated or the inlet 3b
At the same time, the pipes are tied together with a string or the like and closed, and at the same time, the pressure feeding is stopped and the transport pipe 10 is cut off. When the kneading water is squeezed out from the flexible formwork 3 as described above, the water-cement ratio decreases, hardening is accelerated, and an anchor plate made of high-density, high-strength concrete 8 or the like is formed.

In this embodiment, the material of the flexible formwork 3 is made water permeable so that the kneading water can be squeezed out, but it is not necessarily necessary to make it water permeable. It does not need to be made of breathable material as long as air vent holes are formed. Further, in the above embodiment, the insertion hole 3a is formed in the center of the flexible formwork 3, and the exposed portion 2a of the bolt 2 is inserted through the insertion hole 3a.
It is also possible to omit this step and directly punch through the material of the flexible formwork 3 to make a hole and pass the bolt 2 through. In this case, the fluid such as the concrete 8 that has been pumped into the hole and the bolt 2
In order to prevent water from spewing out from the gap between the two, it is recommended to attach a separate washer just outside the gap. In addition, if the surface of the ground 1 is particularly uneven, 7 of the parts in contact with the ground 1
The material of the lexiple formwork 3 is made of a material that breaks when a fluid such as concrete reaches a predetermined high pressure, or it is made of elastic fiber or woven fabric to give it elasticity, and It is also possible to further improve the adhesion by digging into the hole.

When a stretchable fabric is used as described above, the pressure of the filled concrete, etc. will spread the fabric, allowing concrete to be produced from between and come into direct contact with the ground surface. This has the effect of making it easier to integrate with the ground. In addition, in the above embodiment, the flexible formwork 3
Although it is constructed in the shape of a bag, it can be pulled as long as it has a space that can be filled with a fluid, such as a tube shape.

Further, FIG. 8 shows an example in which reinforcing reinforcing bars 11 and spiral bars 12 are arranged within the flexible formwork a to improve the strength of the bearing plate. In addition, reinforcing fibers or the like may be mixed into the hardened material such as concrete 8 to improve the strength of the bearing plate.

FIG. 9 shows a group of anchor bolts 2 of the invention anchored in a ground 1. In such a case, for example, as shown in Fig. 10, one flexible formwork 3 and frame 4 may be installed across the heads of a group of anchor bolts 2 to provide one continuous bearing plate. You can also do it.

[Brief explanation of drawings]

Figure 1 is a sectional view of the flexible formwork and frame attached to the head of an anchor bolt anchored in the ground, Figure 2 is a plan view of the flexible formwork, Figure 3 is a plan view of the frame, and Figure 4 is a plan view of the frame. The figures show concrete being press-fitted into the flexible formwork and cross-sectional views of the anchor bolts that have hardened to form bearing plates, Figures 5 and 6 (a) and (b).
) are respectively a plan view and @ side view showing another embodiment of the frame, JIZ diagram is a plan view showing another embodiment of the 7 lexiple roof frame, and Fig. 8 is a reinforcing reinforcing bar in the 7 lexiple roof frame. 9 and 10 are cross-sectional views showing other embodiments of the anchor bolt of the present invention, respectively. 1... Earth 2... Anchor bolt 2
a...Bolt head 3.3'...7 Lexiple formwork 3&...
・Through hole 3b...Inlet 4...Frame 4a...Through hole 4b...Notch 4c...Through hole 5... ...Washer 6...
... Nut 7 ... String 8 ... Concrete 9 ... Pressure feeding device 10 ... Transport pipe 11 ... Reinforcement bar U ... ...Spiral muscle

Claims (1)

[Claims] (1) A bag-shaped 7-lexiple formwork that can be filled with a hardening fluid and a frame that supports this formwork are attached to the exposed head of the anchor bolt that is fixed in the ground. An anchor bolt characterized in that the flexible formwork is press-filled with a hardening fluid and a bearing plate is formed in close contact with the ground surface.