JP2004108056A - Grout hose and anchor cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grout hose by which a small caliber drill pipe can be used and an execution cost can be reduced and provide an execution method of an anchor cable and the anchor cable using the hose. <P>SOLUTION: The execution method is provided with a tendon, a sheath 22 covering the outer periphery of the tendon and constituting a free length part, a cutoff part formed in the boundary between the length part and the anchor length part where the tendon is exposed from the sheath 22, and a grout hose 30 bound with the tendon outside the sheath. The sectional shape of the ground hose 30 is made flat. By making the sectional shape of the grout hose 30 flat, the grout hose can be housed into a gap between the drill pipe 10 and the sheath 22. By using a small caliber drill pipe 10, a drilling diameter can be made small and the execution cost can be reduced. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to an anchor cable used for reinforcing a slope and the like, a construction method thereof, and a grout hose used for the anchor cable. In particular, the present invention relates to an anchor cable capable of reducing the construction cost by reducing the diameter.
[0002]
[Prior art]
A general process for installing an anchor on a slope or the like will be described with reference to FIG. 2 (for example, see Patent Document 1).
(1) Drill the ground with a boring machine.
{Circle around (2)} In order to prevent the hole wall from being broken at the time of drilling 100, the drill pipe 10 is pushed into the drilling hole 100 while rotating.
(3) The fixing member side of the tendon is inserted into the polyethylene sheath 22, and a water-stop portion 23 is formed at the end of the sheath, thereby dividing the tendon 21 into a free length portion and a fixing length portion. A spacer 24 and a tip nut 25 are attached to the fixing portion of the tension member 21.
{Circle around (4)} The grout hose 30 is tied along the outer periphery of the tendon material. The grout hose 30 is a hose having a circular cross section.
[0003]
{Circle over (5)} The tension member to which the grout hose 30 is bound is inserted into the drill pipe 10.
{Circle around (6)} In order to replace the drilling water in the drill pipe 10 with the grout, grout is injected from the bottom of the drilling 100 and replaced with the drilling water.
{Circle around (7)} After the grout is replaced and injected, the drill pipe 10 is pulled up to a predetermined position so that the drill pipe 10 is removed from the anchor fixing long part.
{Circle around (8)} A pressure cap (not shown) is attached to the end of the drill pipe 10 on the hole exit side, and grout is pressure-injected into the fixing length portion.
{Circle around (9)} After the grout is hardened, the end of the tendon material 21 exposed from the slope is tensioned and fixed with a fixing tool (not shown).
[0004]
[Patent Document 1]
JP-A-11-71756 [0005]
[Problems to be solved by the invention]
However, in the above-mentioned technology, there is a problem that a drilling hole and a drill pipe having a large diameter are required, and the construction cost is increased.
[0006]
For example, as shown in FIG. 3A, when the sheath outer diameter of the free length portion is 48 mm, a drill pipe having an inner diameter of 69 mm and an outer diameter of 90 mm can be used. However, when a grout hose having an inner diameter of 16.5 mm and an outer diameter of 21.5 mm is arranged outside the sheath, the required inner diameter of the drill pipe becomes 69.5 (48 + 21.5) mm or more, and a 69 mm drill pipe is used. Cannot be performed (FIG. 3B).
[0007]
In general, the size of a drill pipe is standardized step by step, and sizes with outer (inner) diameters of 90 (69), 115 (87), 135 (106), and 146 (123) mm are used. Therefore, if a drill pipe having an inner diameter of 69 mm cannot be used, a drill pipe having an inner diameter of 87 mm must be used at a stroke, and as a result, the inner diameter of the hole must be increased. In anchor work, drilling work for drilling holes in the ground occupies a considerable proportion of the construction cost, and it is desired that the drilling diameter be as small as possible for the sake of cost reduction.
[0008]
On the other hand, when the diameter of the drill pipe becomes large, insert only the grout hose into the drill hole before inserting the anchor cable, perform grout injection first, and insert the anchor cable into the drill hole before the grout hardens. May be. However, it is said that this technique may not produce a sound anchor body.
[0009]
Therefore, a main object of the present invention is to provide a grout hose that can use a small-diameter drill pipe and can reduce the construction cost.
[0010]
Another object of the present invention is to provide an anchor cable and a method for constructing an anchor cable using the grout hose of the present invention.
[0011]
[Means for Solving the Problems]
The present invention achieves the above object by using a flat grout hose.
[0012]
That is, the grout hose of the present invention is characterized in that its cross section is flat.
[0013]
By using a grout hose with a flat cross section, the diameter of the circle circumscribing the sheath and the grout hose can be reduced when the grout hose runs along the outer periphery of the sheath, and a smaller diameter drill pipe is used. Can be. Thereby, a small diameter drilling is sufficient, and the anchor construction cost can be reduced.
[0014]
Here, the flat shape includes any shape in which the width of the grout hose is larger than the thickness. For example, an elliptical shape or a track-like cross-sectional shape in which sides in the width direction are parallel may be used. Further, since the grout hose is arranged along the outer periphery of the sheath constituting the free length portion, it is preferable that the grout hose has a cross-sectional shape curved along the outer shape of the sheath. By making the cross section of the grout hose into a curved shape, the diameter of a circle circumscribing the sheath and the grout hose can be further reduced.
[0015]
Further, the anchor cable of the present invention using the above grout hose includes a tension member, a sheath that covers the outer periphery of the tension member to form a free length portion, a free length portion, and a fixing length portion in which the tension member is exposed from the sheath. And a grout hose having a flat cross section which is bound to a tension member outside the sheath.
[0016]
Also in this anchor cable, by using a grout hose having a flat cross section, the diameter of a drill pipe that can be used can be reduced, and the anchor construction cost can be reduced. As the tension member, a PC steel rod or a PC steel stranded wire is used.
[0017]
Further, the method for installing an anchor cable according to the present invention is characterized by comprising a step of inserting the anchor cable into a hole and a step of injecting grout from the fixing long part side through a grout hose.
[0018]
ADVANTAGE OF THE INVENTION According to the construction method of the anchor cable of this invention, the diameter of the drill pipe which can be used can be made small, and the reduction of an anchor construction cost can be aimed at.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a cross-sectional view showing a state in which the grout hose of the present invention is housed in a drill pipe together with a sheath.
[0020]
FIG. 1A shows a grout hose 30 having an elliptical cross section. In the case of the grout hose 30, when the grout hose 30 is placed along the sheath 22 of polyethylene or the like, the diameter of the circumcircle of both can be reduced, and the drill pipe 10 having a smaller diameter can be used.
[0021]
FIG. 1B shows a grout hose 30 having a track-shaped cross section. The grout hose 30 has a cross-sectional shape in which two sides parallel to the width direction are vertically opposed in a cross section, and these two sides are connected by a semicircular side wall. Also in this grout hose 30, when the grout hose 30 extends along the sheath 22, the diameter of the circumcircle of both can be reduced, and the drill pipe 10 having a smaller diameter can be used.
[0022]
FIG. 1 (C) shows a grout hose having a cross section obtained by bending a hose similar to that shown in FIG. 1 (B). The grout hose 30 extends along the outside of the sheath 22 constituting the free length portion. Therefore, if the grout hose 30 having a curved shape along the outer shape of the sheath 22 is used, the drill pipe 10 having a smaller diameter than in the case of FIG. 1B can be used.
[0023]
Regardless of the cross-sectional shape, the same material as that of the conventional grout hose is used. Examples include polyethylene and vinyl chloride. In order to make the cross section of the hose flat, a flat die is used as the die at the time of extrusion molding. What is necessary is just to water-cool by passing the hose into a mold having a flat inner shape while sending air into the hose so that the hose remains hollow even after extrusion.
[0024]
Further, it is preferable that the cross-sectional area inside the grout hose secures a cross-sectional area equal to or more than that of a circular cross-section hose of φ21.5 mm. By ensuring such a cross-sectional area, grout can be smoothly injected.
[0025]
Since pressure is often applied to the grout hose, the hose may be partially thickened when strength is required. Further, it is also preferable to embed a reinforcing material in the thick part. As the reinforcing material, synthetic fibers or steel wires having excellent tensile strength can be used.
[0026]
Next, the anchor cable and anchor installation method of the present invention will be described with reference to an example in which the grout hose shown in FIG. 1B is used. FIG. 2 is a schematic configuration diagram showing a state where the anchor body is inserted into the borehole.
[0027]
First, the ground is drilled with a boring machine. The drill pipe 10 is pushed into the hole 100 while rotating in order to prevent the hole wall from breaking.
[0028]
On the other hand, an anchor cable 20 is prepared. Here, a deformed PC steel rod serving as the tension member 21 is prepared, and a part in the longitudinal direction is covered with a polyethylene sheath 22. The portion covered by the sheath 22 is a free length portion. Further, a water stopping portion 23 is formed at a boundary between the free length portion covered with the sheath 22 and the fixing length portion where the tendon 21 is exposed.
[0029]
A spacer 24 is fitted into the fixing length portion of the tendon 21, and a tip nut 25 is attached to an end portion.
[0030]
Subsequently, the grout hose 30 shown in FIG. 1B is bound to the anchor cable 20. The grout hose 30 is disposed substantially along the entire length of the anchor cable 20, and is integrated with the anchor cable 20 by a binding material (not shown).
[0031]
The anchor cable 20 integrated with the grout hose 30 is inserted into the drill pipe 10. At this time, by using the grout hose 30 having a track-shaped cross section, the circle circumscribing the sheath 22 and the grout hose 30 can be made smaller than in the case of using a grout hose having a circular cross section, and it is necessary to use the drill pipe 10 having a large diameter. There is no.
[0032]
In order to replace the drilling water in the drill pipe 10 with the grout, grout is injected from the bottom of the drilling 100 and replaced with the drilling water. After the grout is replaced and injected, the drill pipe is pulled up to a predetermined position so that the drill pipe 10 is removed from the anchor anchoring portion.
[0033]
Then, a pressure cap (not shown) is attached to the end of the drill pipe 10 on the drilling hole exit side, and grout is pressurized and injected into the fixing length portion. After the grout hardens, although not shown, the ends of the tension members 21 exposed from the slope are tensioned and fixed by a fixing device.
[0034]
Specific dimensions of the above anchor cable are as follows.
When the tendon is a deformed PC steel rod of φ32 mm with no connecting part in the middle and the sheath has an outer diameter of 48 mm, a drill pipe with an outer diameter of 90 mm and an inner diameter of 69 mm was used unless a grout hose was arranged, and the drill pipe was used. A hole will be formed. When a grout hose (wall thickness: 2.5 mm) having a parallel portion height of 16 mm and a semicircular end wall with a radius of 9 mm is placed outside the sheath, the sheath and the grout hose are placed in a 69 mm inside diameter drill pipe. Can be stored.
[0035]
On the other hand, when a grout hose of φ21.5 mm is arranged outside the above-mentioned sheath, the total of the sheath outer diameter and the grout hose outer diameter becomes 69.5 mm, and it is necessary to use a drill pipe having an outer diameter of 115 mm and an inner diameter of 87 mm. There is.
[0036]
【The invention's effect】
As described above, the grout hose of the present invention can be easily stored in the gap between the drill pipe and the sheath by making its cross-sectional shape flat, and the drilling diameter can be reduced by using a small-diameter drill pipe. The size can be reduced, and the construction cost can be reduced.
[0037]
In addition, the anchor cable of the present invention and the method of constructing the anchor cable of the present invention can use a small-diameter drill pipe by combining a grout hose having a flat cross section, thereby reducing the construction cost.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a state in which a grout hose of the present invention is housed in a drill pipe, wherein (A) is an elliptical grout hose, (B) is a truck-like grout hose, and (C) is a curved grout hose. Is shown.
FIG. 2 is a schematic configuration diagram showing a state in which an anchor is being constructed.
FIG. 3 is a sectional view showing a size relationship between a drill pipe, a sheath, and a grout hose. FIG. 3A shows a case where only a sheath is stored in a drill pipe, and FIG. 3B shows a case where a sheath and a grout hose are stored in a drill pipe. Is shown.
[Explanation of symbols]
Reference Signs List 10 drill pipe 20 anchor cable 21 tendon material 22 sheath 23 water stopping part 24 spacer 25 tip nut 30 grout hose 100 drilling

Claims (4)

A grout hose having a flat cross section. The grout hose according to claim 1, wherein the grout hose has a cross-sectional shape curved along the outer shape of the sheath to be bound. With tension material,
A sheath that covers the outer periphery of the tendon and forms a free length portion,
A free length portion, a water blocking portion provided at a boundary between the fixing length portion where the tendon is exposed from the sheath,
An anchor cable comprising a grout hose according to claim 1 tied with a tendon outside the sheath. Inserting the anchor cable according to claim 3 into the hole;
Injecting grout from the fixing length side through a grout hose.

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