JPH08165648A - Work executing method for anchor, and its device - Google Patents

Abstract

PURPOSE: To reinforce the strength of an anchor by expanding the diameter of the fixing length part of the anchor easily. CONSTITUTION: After an anchor hole 17 is cut to a specific depth by a hole cutting rod 11 having a tube form to insert an anchor pull-out member 18 as well as having an injection nozzle 15 to inject to the square direction to a rod longitudinal direction, near the tip, the anchor pull-out member 18 is inserted in the anchor hole 17. And the anchor cutting rod 11 is pulled up to the height of the anchor fixing length while rotating the hole cutting rod 11, while injecting a high pressure cement milk from the injection nozzle 15 of the hole cutting rod 11, from the position where the anchor pull-out member 18 is left.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anchor construction method and an apparatus for expanding the anchor fixing length to increase the ultimate pulling force.

[0002]

2. Description of the Related Art When constructing a ground anchor, first, an anchor hole is drilled in the ground, an anchor tension material is inserted therein, and cement milk is injected into the outer peripheral portion of the anchor to fix it.

The ultimate pulling force of the anchor fixing long portion is substantially proportional to the strength of the fixing ground and the contact area with the surrounding ground.
Since the above-mentioned anchor hole is not so large in diameter as compared with the outer diameter of the anchor, the contact area with the natural ground is not so large.
Therefore, for example, in a fixing ground having low strength, the anchor fixing length must be increased in order to increase the contact area of the anchor fixing length portion in order to obtain a predetermined tensile strength.

However, lengthening the anchor fixing length naturally causes the lengthening of the anchor and the depth of the anchor drilling hole. However, the length of the anchor can be increased indefinitely together with the regulation of the anchor construction standard. You cannot do it.

Therefore, it has been proposed to expand the diameter of the anchor hole and inject cement milk into the hole to form a hardened cement column having a large diameter in the anchor fixing length portion to enhance the strength. Conventionally, the following procedure has been taken to form a large-diameter cement column in the anchor anchoring long portion. First, the small anchor hole is drilled, and then the injection rod of the injection rod inserted in the anchor hole is used to inject the cement milk at high pressure, and the injection rod is gradually pulled up while rotating the injection rod. Expand the diameter of the part and fill it with cement milk. Next, after the cement milk hardens to form a cement column, the anchor hole is drilled again in the cement column, and finally the anchor tension material is inserted into the anchor hole and cement milk is injected into the outer periphery of the anchor. Anchor tension material is fixed to the cement column.

[0005]

As described above, the conventional method for forming a large-sized cement column in the anchor anchoring long portion is to wait for the injected cement milk to harden, and then to further cut the anchor hole there. Since the holes were drilled and the anchor tension material was inserted into the holes and cement milk was applied thereto, there was a problem that the work procedure was complicated and inefficient, and the device configuration was complicated accordingly.

The present invention is intended to solve the above-mentioned problems, and an object thereof is to provide an anchor construction method and apparatus in which the anchor fixing long portion is easily expanded in diameter to enhance its strength. .

[0007]

A method of constructing an anchor according to the present invention for achieving the above-mentioned object has an injection nozzle for injecting in a direction perpendicular to a rod longitudinal axis in the vicinity of a tip end portion and an anchor tension member. After drilling the anchor hole to a predetermined depth with a cylindrical drilling rod that can be inserted, an anchor tension member is inserted into the drilling rod that is in the state of being inserted into the anchor hole. The method further comprises the step of raising the anchor fixing length while rotating the drilling rod while injecting high-pressure cement milk from the injection nozzle of the drilling rod while leaving the tensile material.

Another method of constructing an anchor according to the present invention is an outer cylinder drilling rod having an injection nozzle for injecting in the vicinity of the tip end in a direction perpendicular to the rod longitudinal axis, and inserting / removing into / from the outer cylinder drilling rod. After the anchor hole is drilled to a predetermined depth with an internally drilled rod that can be freely inserted, the internal drilled rod is pulled out from the outer cylinder drilled rod that is inserted into the anchor hole. Instead, an anchor tension material is inserted into the outer cylinder drilling rod, the anchor tension material is left, and the outer cylinder drilling hole is injected from the injection nozzle of the outer cylinder drilling rod while injecting high-pressure cement milk. The method is characterized by having a step of raising the anchor fixing length while rotating the rod.

[0009] In some cases, in the construction method, an injection pipe for supplying cement milk to the tip of the anchor tension member is previously attached to the anchor tension member, and after the cement milk is injected by the injection nozzle, The method further comprises the step of injecting a higher concentration of cement milk from the injection pipe.

Further, the anchor construction device according to the present invention for achieving the above-mentioned object is an injection nozzle for injecting in the direction perpendicular to the longitudinal axis of the rod in the vicinity of the tip and a flow for supplying cement milk to the injection nozzle. With a road,
A cylindrical drilling rod into which the anchor tension member can be inserted, a drive device that gives the drilling rod a drilling motion including at least a rotational movement about the rod longitudinal axis and a forward / backward movement, and via the flow path. And a high-pressure cement milk supply device for supplying high-pressure cement milk to the injection nozzle.

For example, the flow path is a pipe attached to the inner peripheral side of the drilled rod. Alternatively, the drilling rod has a concentric outer pipe and an inner pipe, and the flow path is formed between the outer pipe and the inner pipe.

[0012]

The high-pressure cement milk sprayed from the spraying nozzle of the drilling rod destroys the ground around the anchor hole by the spraying energy and substantially expands the diameter of the anchor hole at that portion, and at the same time, expands it. It fills the diametrical space. The injected cement milk is hardened to form a cement column, and at the same time, the anchored long portion is anchored there.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a sectional view showing a construction process by a construction device according to an embodiment of the present invention, FIG. 2 is a sectional view showing another construction process, and FIG. 3 is a sectional view showing a construction completed state thereof.

The apparatus used in this anchor construction method has a double pipe percussion excavating device. This double pipe percussion excavating device has an outer cylinder drilling rod 11 and an inner drilling rod 12 that is removably inserted into the outer cylinder drilling rod 11. Excavation bits 13 and 14 are attached to the tip ends of the hole rods 12, respectively. The outer cylinder drilling rod 11 and the inner drilling rod 12 can be appropriately moved independently of each other by a well-known driving device such as a striking motion, a rotational motion, and a reciprocating motion for drilling. There is. Here, by using the double pipe percussion excavating device, it is possible to efficiently perform the drilling, and it is possible to easily pull out the internally drilled rod 12 for inserting the anchor tension member.

As a characteristic of the device according to the present invention,
The injection nozzle 15 that injects in the direction perpendicular to the rod longitudinal axis on the outer peripheral surface near the tip of the outer cylinder drilled rod 11 (for example,
(Nozzle diameter 2-3 mm) is provided, and this injection nozzle 15 communicates with a pipe 16 mounted along the inner peripheral side of the outer cylinder drilling rod 11 (outer cylinder drilling rod 11).
4 showing a cross-sectional view of FIG. The base end of the pipe 16 is
It is connected to a known cement milk high-pressure supply device via a swivel device (not shown), and constitutes a flow path for supplying the cement milk to the injection nozzle 15. Therefore, by operating the cement milk high-pressure supply device, the cement milk is jetted from the jet nozzle 15 through the pipe 16, and the outer cylinder drilling rod 11 can be rotated about the longitudinal axis in this state.

In this anchor construction method using such a device, first, as shown in FIG. 2, both the outer cylinder drilling rod 11 and the inner drilling rod 12 are used, for example, a drilling diameter of 200 m.
An anchor hole 17 of about m is excavated to a required depth.

Next, the inner drilling rod 12 is pulled out from the outer cylinder drilling rod 11 inserted in the anchor hole 17. Then, instead of the removed internal drilling rod 12, the anchor tension member 18 is inserted into the external cylinder drilling rod 11. Subsequently, as shown in FIG. 1, while the cement milk is being injected at a high pressure from the injection nozzle 15 through the pipe 16, the anchor tension material 18 is left inside the hole, and the outer cylinder drilling rod 11
While pulling up, gradually pull up. As an example, cement milk has a concentration W / C of 80 to 150%, and is injected at an injection pressure of 200 kgf / cm ² and an injection flow rate of 60 l / min.

The jetted high-pressure cement milk destroys the ground around the anchor hole 17 by the jetting energy to substantially expand the diameter of the anchor hole 17 in that portion, and to the expanded space. Fill up. The range of expanding the diameter is defined by the distance that the outer cylinder drilling rod 11 is pulled up while injecting cement milk at a high pressure, and this distance is the fixing length of the anchor tension member 18.

By hardening the cement milk injected and injected, as shown in FIG. 3, the anchored long portion of the anchor tension member 18 is anchored to the expanded cement column 19. As described above, according to the present method, the cement pillar 19 whose diameter is expanded by the high-pressure injection of cement milk is formed, and at the same time, the anchor tension member 18 is fixed, so that high-strength anchor construction can be easily performed. It will be possible. The cement pillar 19 not only expands the contact area with the ground of the anchor fixing long portion, but also simultaneously improves the surrounding ground.

As shown in FIG. 3, a sheath 20 is attached to the exposed anchor tension member at the upper portion of the formed anchor fixing member to form a free length portion. Sheath and anchor hole 1
During 7th period, the excess cement milk used as ground breaking energy of the injected cement milk and the constituent material of the broken ground become a flow path to the surface of the ground, and finally this part is Filled with substance.

FIG. 5 is a cross-sectional view of an outer cylinder drilling rod according to another example. In the above example, the pipe 16 attached to the inner peripheral side of the outer cylinder drilling rod 11 is used as the flow path of the cement milk to be injected at high pressure, but in the example of FIG. 5, the outer cylinder drilling rod 11 is concentric. The outer pipe 23 and the inner pipe 24 are formed into a double pipe, and the space between the outer pipe 23 and the inner pipe 24 serves as a flow path for cement milk.

Further, in the above embodiment, the injection nozzle 15
However, a plurality of injection nozzles may be provided at equal intervals in the circumferential direction of the rod to cancel the injection reaction force.

FIG. 6 is a sectional view showing a construction process by a construction apparatus according to another embodiment of the present invention. 6, the injection pipe 25 is installed along the anchor tension member 18 in advance, and after the injection of the cement milk by the injection nozzle 15 described above, a higher concentration (for example, the concentration W / C = 50%) cement milk.

In this way, a high-concentration cement milk is distributed around the anchor tension member 18, and this high-concentration cement milk is properly mixed with the surrounding cement milk to form a stronger anchor fixing length portion. It becomes possible.

FIG. 7 is a sectional view showing a construction process by a construction apparatus according to another embodiment of the present invention, and FIG. 8 is a sectional view showing a construction completion state thereof. The embodiment shown in FIG. 7 and FIG. 8 is different from the above-mentioned embodiment in the anchor to be constructed, and the other method and the configuration of the device are the same.

As shown in FIGS. 7 and 8, the anchor tension member 26 has a bearing blade 27 at the tip. Bearing blade 27
2 to 4 are provided, and one end thereof is rotatably attached to the tip of the anchor tension member 26 at equal intervals. Further, a stopper (not shown) is provided on the bearing vane 27 so that the angle formed between the bearing vane 27 and the longitudinal axis of the anchor tension member 26 is less than 90 degrees even when the bearing vane 27 is most opened. Has been done. A compression spring 28, such as a leaf spring or a coil spring, is interposed between each bearing vane 27 and the anchor tension member 26, and exerts a spring force in the direction of expanding each bearing vane 27.

Each bearing vane 27 has its outer shape reduced just like an umbrella is folded by rotating its free end side toward the anchor tension member 26 side against the spring force of the compression spring 28. It can be inserted into the hole rod 11. Further, 29 is a load bearing body.

Such an anchor tension member 26 is inserted in a state in which the bearing vanes 27 are folded against the compression spring 28 in the above-mentioned anchor construction process.
Is pushed in until the tip reaches the bottom of the anchor hole 17. After that, when the outer cylinder drilling rod 11 is slightly raised to expose the pressure bearing blades 27 from the outer cylinder drilling rod 11, the compression springs 28 spread the pressure bearing blades 27, and the outer diameter of the pressure bearing blades 27 is reduced. It is larger than the outer cylinder drilling rod 11. Next, the outer cylinder boring rod 11 is lowered again, and the support blade 27
To further spread the umbrella so that the umbrella tension member 26 is set.

Depending on the ground, the support vanes 27 may expand by themselves due to the spring force of the compression springs 28. In that case, the support vanes 27 are forced by the outer cylinder boring rod 11 as described above. No need to spread Further, it is possible to make the bearing vanes 27 spread by themselves by simply reciprocating the anchor tension member 26 up and down without using the outer cylinder boring rod 11.

After the anchor tension member 26 is set, the height of the anchor fixing length is raised while injecting cement milk from the injection nozzle 15 and rotating the outer cylinder boring rod 11 in the same manner as described above.

In the anchor tension member 26 thus constructed, as shown in FIG. 8, the supporting vanes 27 spread below the formed cement column 19, whereby the anchor tension member 26 is prevented. The upward movement is surely prevented.

In each of the above embodiments, the outer cylinder drilling rod 1
Although the double pipe percussion excavator having the internal drilling rod 1 and the internal drilling rod 12 is used, it is not always necessary to use the double pipe perforating rod in the present invention, and a tubular shape through which the anchor tension member can be inserted is used. It is also possible to construct with only the drilled rods to be presented.

[0033]

As described above in detail with reference to the embodiments, according to the present invention, an anchor hole is drilled to a predetermined depth by a cylindrical drilling rod and then inserted into the anchor hole. Insert the anchor tension material into the drilled rod in the opened state,
Since the anchor tension material was left behind and the high pressure cement milk was injected from the injection nozzle of the drilling rod while it was pulled up while rotating the drilling rod, the formation of expanded cement columns and the cement columns The anchor tension member can be fixed at the same time, the work procedure is simplified and the work can be performed with high efficiency, and the device configuration is also simplified accordingly.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a construction process by a construction device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing another construction process of FIG.

FIG. 3 is a cross-sectional view showing a construction completed state of FIG.

FIG. 4 is a cross-sectional view of an outer cylinder boring rod according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view of an outer cylinder drilling rod according to another embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a construction process by a construction device according to another embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a construction process by a construction device according to another embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a completed state of construction in FIG.

[Explanation of symbols]

 11 Outer Cylinder Drilling Rod 12 Inner Drilling Rod 13, 14 Drilling Bit 15 Injection Nozzle 16 Pipe 17 Anchor Hole 18, 26 Anchor Tensile Material 19 Cement Column 20 Sheath 21 Bearing Plate 22 Anchor Head 23 Outer Tube 24 Inner Tube 25 Injection Pipe 27 Bearing blade 28 Compression spring 29 Load-bearing body

Claims (6)

[Claims] 1. An anchor hole is drilled to a predetermined depth with a drilling rod having a cylindrical shape which has a spraying nozzle for spraying in the direction perpendicular to the rod longitudinal axis in the vicinity of the tip end portion and has a tubular shape through which an anchor tension material can be inserted. After that, an anchor tension material is inserted into the drilling rod in a state of being inserted into the anchor hole, and the anchor tension material is left to inject high-pressure cement milk from the injection nozzle of the drilling rod. A method of constructing an anchor, which comprises the step of raising the anchor fixing length while rotating the drilling rod. 2. An outer cylinder drilling rod having an injection nozzle for injecting in the direction perpendicular to the rod longitudinal axis in the vicinity of the tip portion, and an inner drilling rod insertably inserted into the outer cylinder drilling rod. After drilling the anchor hole to a predetermined depth, pull out the inner drilling rod from the outer cylinder drilling rod inserted into the anchor hole, and instead pull the anchor into the outer cylinder drilling rod. Material is inserted, the anchor tension material is left, and high-pressure cement milk is injected from the injection nozzle of the outer cylinder drilling rod while rotating the outer cylinder drilling rod to raise the anchor fixing length. A method for constructing an anchor, which has a step. 3. An injection pipe for supplying cement milk to the tip of the anchor tension member is attached to the anchor in advance, and after the injection of the cement milk by the injection nozzle, a higher concentration cement is injected from the injection pipe. The anchor construction method according to claim 1, further comprising a step of injecting milk. 4. A cylindrical shape having an injection nozzle for injecting in the direction perpendicular to the longitudinal axis of the rod in the vicinity of the tip and a flow path for supplying cement milk to the injection nozzle, and having an anchor tension member inserted therethrough. A drilling rod to be presented, a driving device that gives the drilling rod a drilling motion including at least a rotational motion about a rod longitudinal axis and a forward / backward motion, and high-pressure cement milk is supplied to the injection nozzle via the flow path. An anchor construction device, comprising: a cement milk high-pressure supply device. 5. The anchor construction device according to claim 4, wherein the flow path is a pipe attached to an inner peripheral side of the drilled rod. 6. The anchor according to claim 4, wherein the drilling rod has a concentric outer pipe and an inner pipe, and the flow path is formed between the outer pipe and the inner pipe. Construction equipment.