JPH0545667Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a pressurized anchor, and more specifically, it is used for detecting displacement of the ground in civil engineering works, etc., and is fixed by expanding with hydraulic pressure. Regarding the anchor.

[Prior Art] In civil engineering works such as tunnel construction and shield construction, it is necessary to measure the amount of loosening of the ground over time, and it is necessary to use a reference anchor that does not cause displacement.

Conventionally, the method used to install these anchors is to insert reinforcing bars into bored holes and fix them with cement, but because the cement takes time to harden, hydraulic anchors are often used.

FIG. 7 shows a principle diagram of detecting ground displacement using hydraulic anchors in tunnel construction.

In the same figure, 51 is a fixed part, which is inserted into a hole 53 bored underground from the inner wall of a tunnel 52, and then pumps water through a pipe 55 with a check valve 54 interposed in the path. death,
By expanding the fixing part 51, it is fixed in the hole 53. That is, the part where the fixed part 51 is installed is located at a considerably deep position from the inner wall of the tunnel 52, and the ground does not displace even when the tunnel 52 is excavated, and it is possible to establish a fixed standard using the hydraulic anchor. Become.

During measurement, a detection reference rod 56 connected to the fixed part 51 and guided toward the tunnel 52 and a displacement meter 5 attached to the inner wall of the tunnel 52 are used.
By measuring the amount of relative movement of 7 with the displacement meter 57, it is possible to measure how much the ground near the inner wall of the tunnel 52 has displaced.

An enlarged front view of this hydraulic anchor is shown in FIG. 8, in which a brass bag-like band 59 is wrapped around a steel pipe 58, and water is forced into the band 59 through a pipe 55 to make a bag. The expanded bag-like band 59 bites into the inner wall of the hole 53 and fixes the steel pipe 58 to which the detection reference rod 56 is attached. Note that the check valve 54 serves to prevent backflow of water and maintain a fixed state.

[Problem to be solved by the invention] By the way, according to the above-mentioned hydraulic anchor, when water is pumped, the mode of expansion and deformation of the bag-like band 59 is indeterminate, and the diameter of the hole 53 and the fixing part 51 are variable. The relationship with the outer diameter, how to wrap the bag-shaped band 59, and the steel pipe 5
It varies depending on how it is fixed to 8. That is, as shown in FIG. 9, for example, the bag-shaped band 59 expands and deforms into various shapes, and as a result, the center of the steel pipe 58 deviates from the center of the hole 53, and the detection reference rod 56 Problems such as twisting may occur.

Moreover, as is clear from the same figure, the bag-like band 59
In the expanded state, the inner wall of the hole 53 and the steel pipe 58
There is a problem in that the bag-shaped band 59 is pressed against the outer periphery of the belt only at extremely limited locations, and the pressure-welding conditions are not uniform, resulting in an unsafe anchor. Especially in tunnel construction etc.
There are cases where continuous measurement is to be carried out over a long period of time (for example, three years or more), and the above-mentioned conventional hydraulic anchor may become misaligned during long-term use, making accurate measurement impossible.

Therefore, in the present invention, the detection standard rod 5 is
6 does not shift or twist, and by ensuring a uniform and wide area of pressure contact with the hole 53, stable fixing conditions can be obtained, making accurate displacement measurement possible over a long period of time. Created with the purpose of providing an anchor.

[Means for solving the problem] The first idea is made of a flexible material,
The outer tube in which the pleats are formed is fitted onto a highly rigid tube body, and a seal is formed between both ends of the outer tube and the outer peripheral surface of the tube body, and a pressurized liquid injection pipe is connected to the outer tube and the tube. The present invention relates to a pressurized anchor that communicates with a gap between the body and the body, and is characterized in that a detection reference rod is attached to the tubular body.

The second invention relates to one in which a check valve is interposed in the path of the pressurized liquid injection pipe in the pressurized anchor to prevent backflow of the pressurized liquid.

The third idea is to fasten the center of the outer tube with a high-rigidity band in the vicinity of the seal between both ends of the outer tube and the outer peripheral surface of the tube body in each of the above-mentioned pressurized anchors. Accordingly, peeling at the seal portion is prevented.

[Function] In the pressurized anchor of the present invention, the outer tube in which pleats are formed is fitted onto the highly rigid tube body, and by sealing between both ends of the outer tube and the outer peripheral surface of the tube body, A bag portion is formed in the gap between the outer tube and the tube body.

When this anchor is inserted into the hole and the liquid is pumped into the bag through the pressurized liquid injection pipe, the outer tube is flexible and has pleats, so the liquid pressure is applied to the outer tube. The outer surface of the outer tube expands outward and bites into the inner wall of the hole, fixing the entire anchor in the hole. In other words, the tube body side is highly rigid and will not deform, but the outer tube side has sufficient room for expansion due to the flexibility of its material and the formation of folds, and when liquid is injected, it will not deform. The folds will stretch and bulge outward.

Here, the pressurized liquid will be filled into the bag by injection, but if a check valve is provided in the path of the pressurized liquid injection pipe, the valve will prevent the pressurized liquid from flowing back. The shape of the outer tube after swelling can be maintained.

Therefore, the entire anchor is fixed and maintained by the press-contact relationship between the outer surface of the expanded outer tube and the inner wall of the hole, but since the outer tube expands uniformly outward, the press-contact part is spread over the entire circumferential area. This makes it possible to achieve extremely stable fixing conditions. In addition, due to uniform bulge,
This prevents the center of the tube from shifting from the center of the hole and prevents the tube itself from rotating.

As a result of the above, the detection reference rod will not bend or twist when installing the anchor, and stable fixing conditions will be obtained, allowing the detection reference rod to be displaced relative to the anchor installation position in the hole. This makes it possible to perform extremely stable measurements using a detection standard rod.

However, a force in the direction of separation is directly applied to the sealing portion between the outer tube and the tubular body due to the injection of pressurized liquid, and there is a possibility that liquid leakage may occur due to separation. To solve this problem, by tightening the outer tube at a predetermined position with a high-rigidity band as described above,
It is possible to prevent peeling force from directly acting on the seal portion.

The inner area of the hollow part of the tubular body can be used as an attachment part for a pipe or a detection reference rod, but it can also be used as a through hole for a pipe or a detection reference rod when installing anchors in multiple stages.

[Example] Hereinafter, an example of the present invention will be described using FIGS. 1 to 6.

Figures 1 and 2 respectively show a front view (partially broken) and a cross-sectional view (cross section taken along the arrow A-A) of the pressurized anchor, in which 1 is a copper or brass outer tube, and 2 is a steel outer tube. A pipe body, 3 is a check valve, 4 is a pressurized liquid injection pipe, 5 is a detection reference rod, and 6 is a steel band.

As the outer tube 1, as shown in FIG.
A structure formed into a tubular shape by forming folds 7 on the surface and brazing both ends 1a of the structure, or
As shown in FIG. 4, a tube that is originally formed into a circular tube shape with pleats 7 is used, and the inner diameter of each tube is set so that it fits over the tube body 2.
In addition, in FIGS. 2 to 4, the folds 7 are depicted as being formed gently for convenience, but
It may be in a crushed form.

This outer tube 1 is fitted onto the tube body 2, and in the fitted state, its both ends 1a are brazed to the outer peripheral surface of the end of the tube body 2 over the entire circumference, and both ends 1a are completely sealed. be done.

Further, a hole 8 is formed in the center of the tubular body 2, and by brazing the pipe 4 into the hole 8, the outer tube 1, 4 of the tubular body 2, and the pipe 4 are communicated with each other. Further, a detection reference rod 5 is welded to the inner surface of the tube body 2.

The anchor configured as described above is inserted into the bored hole, and water is pumped through the pipe 4.

Then, water is injected into the gap between the outer tube 1 and the tube body 2, and its pressure presses the inner surface of the outer tube 1, causing the outer tube 1 to expand. That is, since both ends of the outer tube 1 and the tube body 2 are sealed, and since the tube body 2 is a highly rigid body made of steel, the folds 7 of the outer tube 1 are expanded, and as shown in FIGS. As shown in the figure, it bulges outward, and as a result, it comes into pressure contact with the inner wall of the hole 21 and bites into the same wall.

When a certain amount of water is pumped, the tube body 2 becomes completely fixed to the inner wall of the hole 21 due to the expansion of the outer tube 1, but the check valve 3 prevents the water from flowing back. Maintain fixed conditions. In this embodiment, the band 6 is attached to the center of both ends 1a with the outer tube 1 tightened, so that the peeling force due to water pressure does not directly act on the brazed seal portion. .

When the anchor is fixed, the hole 21 and the outer tube 1
The pressure contact relationship with the hole 21 is as shown in FIG. 6, and in this state, the folds 7 of the outer tube 1 are expanded, and the outer surface of the outer tube 1 comes into pressure contact with the entire circumferential direction of the hole 21 at an approximately equal contact area. This ensures extremely stable fixing conditions. Therefore, for a displacement meter installed outside the hole 21, for example, a displacement meter fixed to the inner wall in a tunnel, the end of the detection reference rod 5 can be applied as a stable fixed reference detection part. It becomes possible to accurately detect displacement at the location where the displacement meter is installed.

In addition, since the folds 7 are uniformly formed in the outer tube 1, the outer tube 1 expands uniformly outward, and the tube body 2 is not eccentric from the center of the hole 21, and the detection reference rod is 5 can also be prevented from being twisted.

[Effects of the invention] Since the pressurized anchor of the invention bulges out the pleated outer tube that is fitted onto the outside of the tube body,
A large pressure contact area can be secured against the hole, and as a result,
Supports the detection reference rod in an extremely stable state,
Enables accurate measurement of ground displacement, etc.

Furthermore, since the outer tube expands uniformly, eccentricity of the tube body with respect to the hole is eliminated, and problems such as twisting of the detection rod are also eliminated. Furthermore, the fixing part of the anchor of the present invention can have a simple structure consisting of a tube body and an outer tube made of a single plate, making it lighter than conventional anchors and making installation work easier. It also has the advantage of

Furthermore, the anchor of the present invention has the result that when cement milk is used as the liquid when injected, extremely stable fixation conditions can be achieved over a long period of time. That is, in the prior art, when the bag-like strip expands, the bent portion becomes thin, and even if the cement milk hardens inside the bag-like band, the bent portion is thinned by a slight external force. However, in the anchor of the present invention, the cement milk hardens between the tube body and the outer tube, and there is no possibility of cracking after hardening.
Complete fixation conditions can be maintained semi-permanently.

The invention according to claim (2) prevents the pressurized liquid from flowing backward by providing the check valve, thereby making it possible to reliably maintain the shape of the outer tube after swelling.

The invention according to claim (3) prevents the sealing portion between the outer tube and the tube body from peeling off by adding a fastening band, thereby realizing a robust anchor that does not cause liquid leakage.

[Brief explanation of the drawing]

Figure 1 is a front view of the pressurized anchor (partially broken);
Figure 2 is a cross-sectional view of the same anchor (A in Figure 1).
-A arrow view), Figure 3 is a perspective view of the pleated plate material used for the outer tube, Figure 4 is a perspective view of the pleated circular tube material used for the outer tube, and Figure 5 shows the state in which the anchor is fixed in the hole. Fig. 6 is a sectional view (B--B in Fig. 5).
Fig. 7 is a principle diagram for detecting ground displacement using a hydraulic anchor in tunnel construction, Fig. 8 is an enlarged front view of the hydraulic anchor, and Fig. 9 is a diagram showing how the hydraulic anchor detects ground displacement in a hole. FIG. 1... Outer tube, 1a... Both ends, 2... Tube body, 3
...Check valve, 4...Pipe, 5...Detection standard rod, 6...Band, 7...Fold.

Claims (1)

[Claims for Utility Model Registration] (1) A pleated outer tube made of a flexible material is fitted onto a highly rigid tube body, and both ends of the outer tube and the outer periphery of the tube body. 1. A pressurized anchor characterized in that a pressurized liquid injection pipe is communicated with a gap between the outer tube and the tube body, and a detection reference rod is attached to the tube body. (2) The pressurized anchor according to claim (1), wherein a check valve is interposed in the path of the pressurized liquid injection pipe. (3) The pressurized type according to claim (1) or (2), wherein a high-rigidity band is used to fasten the outer tube in the vicinity of the sealing portion between both ends of the outer tube and the outer peripheral surface of the tube body, and near the center of the outer tube. anchor.