JP2001123446A - Construction method for inserting tension member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To insert a high-strength tension member at a low cost. SOLUTION: A rod 13 is inserted into a screen pipe 1 provided with a net part 1a of small knot in insertion of the tension member, a bit 14 having a drilling diameter equal or more to/than an outside diameter of the screen pipe 1 is fitted to a tip of the rod 13, the screen pipe 1 is inserted into a drilled well 15 while drilling the well 15 into a soil A by the bit 14 and a drilled soil is discharged, the rod 13 is separated from the bit 14 to be extracted from the well 15 when a prescribed depth of the well 15 is formed, and then cement milk 16 is injected and the tension member 2 is inserted into the drilled well 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inserting a tensile member.

[0002]

2. Description of the Related Art The above-mentioned tensile material is inserted at a predetermined angle into the ground of a sloped ground in order to stabilize the ground on a sloped ground, to prevent landslides due to uneven earth pressure, and to reinforce a retaining wall. The conventional method of inserting the tensile member was generally as follows.

[0003] That is, using a rod having a bit at the tip, excavated soil is excavated while excavating a hole in the ground, and when the excavation hole of a predetermined depth is formed, the rod is pulled out from the excavation hole. A method of inserting a tensile material with a sheath tube having an anchor at the tip into the excavation hole and injecting cement milk is employed. Then, after the cement milk is hardened, a tension is applied to the tensile material to transmit a compressive force to the ground.

[0004]

However, in the above-mentioned insertion method, the wall of the hole may collapse during the drilling of the ground, and the collapsed soil deteriorates the fixation between the tensile material and the cement milk. In some cases, the strength of the tensile member was reduced.

[0005] In addition, sometimes, there is a problem that it becomes impossible to insert a tensile material and to inject cement milk due to the collapsed soil.

In addition to this, there is a method of inserting a self-drilling rock bolt for injecting cement milk into a drilling hole while leaving a rod provided with a bit in the drilling hole.
Although the problem that the tensile material cannot be inserted does not occur, the problem of the decrease in the strength of the tensile material and the inability to inject the cement milk still remains, and in addition, leaving the rod leads to an increase in cost.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method of inserting a high-strength tensile material that solves the above-mentioned disadvantages.

[0008]

That is, in the tensile material insertion method according to the present invention, a rod is inserted through a screen tube having a small mesh net portion through which cement milk can flow,
At the end of the rod, a bit whose outer diameter is greater than the outer diameter of the screen pipe is attached, and while drilling a hole in the ground with this bit, the screen pipe is inserted into the drill hole and the excavated soil is removed. Then, when a drilling hole of a predetermined depth is formed, the rod is detached from the bit and pulled out from the drilling hole, and the injection of cement milk and the insertion of a tensile material into the drilling hole are performed. There is a feature (claim 1).

According to the above insertion method, the outer diameter of the screen pipe is slightly smaller than the inner diameter of the drill hole, and there is almost no gap between the screen pipe and the drill hole. Even if the hole falls, it is immediately received by the screen tube, so that a large collapse of the hole wall is reliably prevented.

[0010] Further, since only a small mesh portion is formed in the screen tube, the collapsed soil hardly enters the screen tube, and therefore, it is easy to insert the tensile material into the screen tube. In addition, with regard to cement milk, since this is evenly distributed throughout the borehole through the net portion, by applying tension to the tensile material after hardening of the cement milk, and transmitting compressive force to the ground, The tensile material can be inserted into a high-strength structure.

Further, since the rod is collected while the bit is left before the cement milk is injected, a high-strength tensile material can be obtained at a low cost in comparison with the method of inserting a self-drilling lock bolt.

Further, in the tensile material insertion method according to the present invention, a rod is inserted into a screen tube having a small mesh net portion through which cement milk can flow, and an excavation outer diameter is set at the rod tip. A drill bit with a predetermined depth was formed by mounting a bit larger than the outer diameter of the drill bit, drilling a hole in the ground with this bit, inserting a screen tube into the drill hole, and removing the excavated soil. At this time, the bit and the rod may be left in the drill hole to be a tensile material, and cement milk may be injected into the drill hole (claim 2).

[0013] Further, the tension member may be formed by coating a sheath tube.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for inserting a tensile material according to the present invention will be described below with reference to the drawings. When inserting a tensile material, first, as shown in FIGS.
A screen tube 1 having a net portion 1a on its peripheral surface and a tensile member 2 are prepared.

The screen tube 1 is formed, for example, by connecting a plurality of rod members 3 having a triangular portion and a semicircular portion to a cylinder 4 on the cement milk injection side and a cylinder 5 on the tip side around a cylinder core. At a predetermined interval and with the triangular portion facing outward, the rod member 6 having a triangular cross section is made to bite into the triangular portion of the rod member 3 so that the rod portion 6 has a triangular cross section. It is provided spirally around the outside of the member 3, and by the rod members 3 and 6,
Small-mesh net part 1 through which cement milk can be distributed
a.

On the other hand, the tension member 2 is slightly longer than the screen tube 1 and is made of, for example, a male screw-shaped reinforcing bar. An anchor 8 buried in cement milk is attached to the distal end thereof by a nut 9 and a long nut 10, and a sheath tube 11 is put on the tension member 2 over a range excluding an attachment portion of the anchor 8, and The interior of the tube 11 is filled with grease b as required, and a spacer 12 for positioning the tension member 2 at the approximate center of the screen tube 1 is provided. The coil spring is fixed to the sheath tube 11 in the vicinity of the anchor 8 by, for example, a tape c.

In the present embodiment, the reinforcing material is used as the tensile material 2. However, the present invention is not limited to this, and it is possible to use a PC steel rod, a PC steel stranded wire, an aramid fiber, a carbon fiber or the like. Is also good.

At the time of inserting the tension member, as shown in FIG. 4A, the screen tube 1 having the above structure is put on the rod 13 driven forward and reverse by the driving rotation means (not shown). At the tip end, a bit 14 for excavating the ground whose excavation outer diameter is slightly larger than the outer diameter of the screen tube 1 is provided.
Is screwed, and the rod 13 is rotated in the screwing direction of the bit 14 to excavate the hole 15 in the ground A and insert the screen tube 1 into the excavation hole 15. The method of attaching the bit 14 to the rod 13 is not limited to screwing, and for example, may be merely inserting the rod 13 into the bit 14. Further, the formation of the excavation hole 15 may be performed not only by rotating the rod 13 and the bit 14 but also by hitting the rod 13 and the bit 14.

Here, when inserting a long tensile material,
The screen tube 1 also becomes long and requires a long working space, and it is difficult to attach the screen tube 1 to the rod 13. In such a case, for example, a screw-type joint is used for the short screen tube 1. When a plurality of the screen tubes 1 are connected to each other while being joined with screws, a long tensile material can be smoothly inserted.

During the above-mentioned excavation, the rod 13 is pulled out from the excavation hole 15 as necessary to remove excavated soil in the hole, and finally when the excavation hole 15 is formed near a predetermined depth, The rod 13 is withdrawn from the drill hole 15 to remove the excavated soil in the hole.

Next, the rod 13 is returned into the drilling hole 15, and the rod 13 is rotated in the reverse direction while the bit 14 is pressed against the bottom of the hole, so that the bit 14 is unscrewed and detached from the rod 13. The rod 13 is pulled out from the excavation hole 15 while leaving it (see FIG. 4 (B)), and the bottom of the hole is slightly excavated by the reverse rotation of the rod 13 at this time, so that the ground A has a predetermined depth. The excavation hole 15 is formed.

The difference between the outer diameters of the screen tube 1 and the bit 14 is desirably as small as possible within a range in which the screen tube 1 can be easily inserted, from the viewpoint of preventing collapse of the hole wall described later. When the screen tube 1 having the outer diameter of 54 to 57 mm is selected, the bit 14 having the outer diameter of 70 to 75 mm is selected.

Next, as shown in FIG. 4 (C), an attachment (not shown) for injecting cement milk is attached to the base side of the screen tube 1, and a predetermined amount of cement milk 16 is placed in the borehole 15. After that, the attachment is removed, the tension member 2 is inserted into the screen tube 1 so that the anchor 8 is positioned at the distal end side of the screen tube 1, and cement milk 16 is additionally injected as necessary, and The pressure receiving plate 17 is provided on the base side of the tension member 2, the sheath tube 11 is peeled off, and the washer 18 and the double nuts 19 and 20 are attached.

Then, after the cement milk 16 is hardened, the nut 19 is tightened to apply a tension to the tension member 2 and the nut 20 is prevented from loosening by the nut 20 to transmit a compressive force to the ground A. By doing so, the insertion of the tension member 2 is completed.

According to the above-described method of inserting the tension member 2, since there is almost no gap between the screen tube 1 and the excavation hole 15,
Even if the hole wall of the excavation hole 15 collapses until the insertion is completed, the hole wall is immediately received by the screen tube 1, so that the large collapse of the hole wall is reliably prevented.

Further, since the screen tube 1 only forms the net portion 1a of a small mesh, the collapsed soil hardly enters the screen tube 1, and therefore,
Insertion of the tension material 2 into the screen tube 1 is easy, and the cement milk 16 spreads all over the drill hole 15 through the net portion 1a. By applying a tensile force to the ground and transmitting a compressive force to the ground, a high-strength tensile material 2 can be obtained.

The bit 14 is left in the borehole 15,
After the rod 13 is pulled out from the borehole 15, the
The cement milk 16 is poured into the
Although the tension member 2 is inserted into the hole 1, the procedure of injecting the cement milk 16 into the drilling hole 15 after inserting the tension member 2 into the screen tube 1 may be adopted.

In the above embodiment, the rod 13 used for forming the drill hole 15 and the tension member 2 are separately prepared, but the rod 13 is left in the drill hole 15 together with the bit 14. It may be used as a tensile material.

[0029]

As described above, according to the method for inserting a tensile material according to the present invention, the situation in which the tensile material cannot be inserted or the cement milk cannot be injected due to the collapse of the hole wall is reliably eliminated. In addition, since it does not involve the incorporation of collapsed soil, a tensile material can be inserted with high strength. According to the first aspect of the present invention, since the rod is collected while leaving the bit as compared with, for example, a self-drilling lock bolt, a high-strength tensile member can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is an overall view of a partially cut-away screen tube.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a detailed view of a tensile member.

4 (A) is an explanatory diagram of formation of a drill hole, FIG. 4 (B) is an explanatory diagram of a rod withdrawn state, and FIG. 4 (C) is an explanatory diagram of completion of insertion of a tensile member.

[Explanation of symbols]

1 ... screen tube, 1a ... net part of small eyes, 2 ...
Tensile material, 11: sheath tube, 13: rod, 14: bit, 15: drill hole, 16: cement milk, A: ground.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihiro Nakazawa 19, Nakahama-cho, Amagasaki-shi, Hyogo Nichia Steel Industry Co., Ltd. (72) Inventor Kazuhiro Arika 19, Nakahama-cho, Amagasaki-shi, Hyogo Nichia Steel Industry In-company (72) Inventor Mitsue Taniguchi 573-1, Takao, Tsuyama-shi, Okayama Prefecture, Japan Incorporated (72) Inventor Katsuhiro Sugimoto 573-1, Takao, Tsuyama, Okayama, Japan In-vehicle, Inc. (72) Inventor Fujishima Tera, 573-1 Takao, Takao, Tsuyama-shi, Okayama Prefecture, Japan (72) Inventor Tomoyuki Morizono 573-1, Takao, Tsuyama-shi, Okayama, Japan Intra-vegetation, Inc. (72) Inventor Hiroyuki Komasuri Takao, Tsuyama, Okayama Prefecture 573 No. 1 Nippon Vegetation Co., Ltd. F-term (reference) 2D041 GA01 GC07 GC14

Claims (3)

[Claims] Claims: 1. A rod is inserted through a screen tube having a small mesh net portion through which cement milk can flow,
At the end of the rod, a bit whose outer diameter is greater than the outer diameter of the screen pipe is attached, and while drilling a hole in the ground with this bit, the screen pipe is inserted into the drill hole and the excavated soil is removed. Then, at the time when the drilling hole having a predetermined depth is formed, the rod is detached from the bit and pulled out from the drilling hole, and the injection of the cement milk and the insertion of the tensile material are performed for the drilling hole. Characteristic tensile material insertion method. 2. A rod is inserted through a screen tube having a small mesh net portion through which cement milk can flow,
At the end of the rod, a bit whose outer diameter is greater than the outer diameter of the screen pipe is attached, and while drilling a hole in the ground with this bit, the screen pipe is inserted into the drill hole and the excavated soil is removed. And forming a drilling hole having a predetermined depth, leaving the bit and the rod in the drilling hole as a tensile material, and injecting cement milk into the drilling hole. 3. The method for inserting a tensile material according to claim 1, wherein the tensile material comprises a sheath tube.