JPH10168876A - Anchor construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the reliability of anchor proof stress even in a ground having a large coefficient of permeability by press-fitting a fixing grout material to a highly viscous barrier grout material filled in a hole through a drill pipe, and setting an anchor tendon. SOLUTION: A hole 1 is drilled by use of a drill pipe 3 having a separable tip bit installed thereto. A barrier grout material 2 of shielding material is then pressure-injected and filled therein while pulling out the drill pipe 3. A press-fitted fixing grout material 6 such as cement paste is filled in a pile form while penetrating the drill pipe 3 into the environment of the cylindrical barrier grout material 2. A linear anchor tendon 8 made of PC steel is inserted through the drill pipe 3, and the drill pipe 3 is pulled out while supplying the fixing grout material 6. After the grout material 6 is hardened, the anchor tendon 8 is stretched and fixed. Thus, diffusion and loss of the fixing grout material 6 can be prevented. Accordingly, the construction can be economically performed in a short time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anchoring method for a ground having a high permeability, such as a boulder layer, a gravel layer, or a rock mass having many cracks.

[0002]

2. Description of the Related Art A general anchoring method will be described with reference to FIG. 10. After drilling with a drill pipe b having a lost bit a (FIG. 10A), a drill pipe b
After inserting ancatecaton c therein (B in FIG. 10) and extracting grout pipe d while injecting grouting material d for fixing while leaving uncurtaindon c in the ground (FIG. 1)
0C), after the fixing grout material d is hardened, the uncurtain don c is tension-fixed using the tension jack e installed at the base end of the uncurtain don c (FIG. 10).
D).

[0003]

The above-mentioned conventional anchor technology has the following problems. <A> When the fixing ground has a large permeability coefficient such as a boulder layer or a gravel layer, the fixing grout material d is easily diffused and lost.
For example, in the case where the ground is a cobble layer or a gravel layer, the present situation is that grouting material d for fixing is injected at least five times the normal ground. For this reason, it has been pointed out that installing an anchor on this kind of ground requires a high fixing cost and takes a long time for injection. <B> As described above, the ground having a large water permeability has irregularities in its fixability in spite of injecting a large amount of grout material, and has low reliability with respect to anchor strength.

The present invention has been made in view of the above points, and an object of the present invention is to improve workability and economic efficiency by avoiding loss of grout material even on a ground having a high permeability. It is to provide an anchor method that can be achieved.
It is still another object of the present invention to provide an anchoring method that eliminates variations in grout material fixing and improves reliability with respect to anchor strength.

[0005]

The invention according to claim 1 is
After fixing the uncurtained don through the grout material in the drilled hole, in the anchoring method of tensioning and fixing the base end of the uncurtain don, after filling the barrier grout material into the drilled hole, the barrier grout material An anchoring method, characterized in that a grouting material for fixing is filled in a state in which diffusion is prevented, and then an uncurtain-don is inserted into the grouting material for fixing and tension-fixed. The invention according to claim 2 is a step of drilling through a drill pipe in an anchoring method for fixing and anchoring the base end of the anchor tongue after anchoring the anchor to the drilled hole via a grout material, A step of drawing out the drill pipe while filling the barrier grout material in the hole through the drill pipe; a step of filling the grout material for fixing in the barrier grout material through the drill pipe; and anchoring the grout material for fixing in the drill pipe. An anchor construction method comprising a step of inserting a tendon and a step of extracting a drill pipe and tensioning and fixing an anchor don. The invention according to claim 3 is the anchor method according to claim 1 or 2, wherein the barrier grout material is a non-separable grout material or a highly viscous grout material. . According to a fourth aspect of the present invention, in the anchoring method according to the second or third aspect, when the drill pipe is removed from the inside of the hole, a grout material for fixing is supplied through the drill pipe. It is.

[0006]

Embodiment 1 An example of an embodiment of the present invention will be described below with reference to the drawings.

<A> Drilling In the same manner as in the prior art, drilling is performed using a drill pipe equipped with a separable tip bit at the tip.

<B> Filling of barrier grout material (FIG. 2,
3) While the barrier grout material 2 is being injected into the hole 1 by pressure, the drill pipe 3 used for drilling is pulled out using a drawing jack 4 or the like, and the barrier grout material is extended by about 1 m to 2 m longer than the fixing length. 2 is filled in a pile shape. The barrier grout material 2 is a shielding material for preventing diffusion and loss of a fixing grout material described later, and for example, a non-separable grout material or a high-viscosity grout material can be used.

FIG. 3 shows the distribution of the barrier grout material 2 filled in the holes 1. Since the barrier grout material 2 has a high viscosity, there is no fear that the barrier grout material 2 is diffused and lost over a wide area even on a ground having a high water permeability. In consideration of this point, the filling amount of the barrier grout material 2 is sufficient to be, for example, about twice the content integral of the drill pipe 3.

When the drill pipe 3 is withdrawn, the tip bit 5 is separated from the drill pipe 3 and left in the ground.

<C> Injecting grouting material for fixing (FIG. 4)
5) Next, the drill pipe 3 is fed into the hole 1 using a well-known drilling machine 7 while the fixing grout material 6 is press-fitted from the base end of the drill pipe 3. The drill pipe 3 penetrates into the uncured barrier grout material 2 while discharging the fixing grout material 6 from its tip. When the drill pipe 3 penetrates, the barrier grout material 2 is pushed around and the shape changes from a pile shape to a tubular shape. Therefore, the fixing grout material 6 is prevented from being diffused by the cylindrical barrier grout material 2. Filled in piles under environmental conditions.

The grout material 6 for fixing is made of cement paste or cement mortar as in the prior art, and can be reliably filled over the entire range of the fixing length portion only by injecting, for example, the integral amount of the content of the drill pipe 3.

<D> Insertion of an uncurtain don (FIG. 6) When the drill pipe 3 is fed into the hole 1, the uncurtain don 8 is inserted from the base end of the drill pipe 3. Since the fixing grout 6 is present in the drill pipe 3, the uncurtain don 8 is installed in the same state as inserted into the fixing grout 6 as in the related art. The uncurtain-don 8 includes, for example, a known PC steel strand, a PC steel wire, a PC steel rod, a high-strength fiber bundle and the like, and also includes various removable anchors.

<E> Extraction of Pipe (FIG. 7) After the insertion of the uncurtain don 8, the drill pipe 3 is extracted using the extraction jack 4 or the like. When the drill pipe 3 is pulled out, the liquid level of the fixing grout material 6 decreases by the thickness of the drill pipe 3, and there is a possibility that an unfilled space of the grout material is generated in the fixing length portion. Therefore, in parallel with the removal of the drill pipe 3, the fixing grout material 6 is replenished from the base end of the drill pipe 3 without applying pressure. This is repeated until the fixing long portion is pulled out, and the liquid level of the fixing grout material 6 is confirmed.

<F> Tension fixing of uncurtain don (FIGS. 8 and 9) When the drill pipe is pulled out, a tension jack (not shown) is set at the base end of the uncurtain don 8 after the grout material is hardened as in the related art. Get nervous and take root.

FIG. 9 is a cross-sectional view of the fixing length portion. The barrier grout material 2 filled before the hole 1 and the fixing grout material 6 filled thereafter form an integrated structure having an integral structure distributed over the entire length of the fixing portion. The anchor strength is secured by the adhesive force between the grout material and the ground, and the adhesive force between the grout material and the uncurtain dong 8.

[0017]

[Embodiment 2] The case where the fixing range of the uncurtain-don is part of the uncurtain-don has been described above. However, when the fixing range extends over the entire length of the uncurtain-don, that is, the grout material is formed over the entire length of the hole. Of course, it can be applied to the anchoring method for filling.

[0018]

【The invention's effect】

<B> Even if the fixing ground is a boulder layer or a gravel layer with a high permeability, the barrier grout material effectively prevents diffusion and loss of the fixing grout material. Since it is halved compared to the construction method, it is economical and can be performed in a short time. <B> In contrast to the conventional method in which the fixing grout material is directly filled into the holes, the present invention employs a method in which the fixing grout material is filled inside the barrier grout material. Further, according to the present invention, when the drill pipe is removed from the hole, the grout material for fixing is supplied through the drill pipe. Therefore, the grout material can be reliably filled over the entire range of the fixing length portion, and the reliability with respect to anchor strength is improved. <C> Barrier grout is highly viscous and hardly penetrates the ground. Therefore, diffusion and loss of the barrier grout material itself can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is a process explanatory view of an anchor method according to the present invention.

FIG. 2 is an explanatory view of filling work of a barrier grout material

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is an explanatory diagram of a grouting material injection process.

FIG. 5 is a sectional view taken along line VV in FIG. 4;

FIG. 6 is an explanatory view of an insertion work of an uncurtain don.

FIG. 7 is an explanatory view of a drill pipe sampling operation.

Fig. 8 Tension fixing work of Ancurtain Don

FIG. 9 is a sectional view taken along line IX-IX of FIG. 8;

FIG. 10 is a process explanatory view of a conventional anchor method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Hole 2 ... Barrier grout material 3 ... Drill pipe 4 ... Pull-out jack 5 ... Tip bit 6 ... Fixing grout material 7 ... Drilling machine 8 ... Uncurtain don

Claims (4)

[Claims] Claims: 1. An anchor method for fixing an uncurtain-don in a drilled hole via a grout material, and then filling a barrier grout material in the drilled hole in an anchor method for tension-fixing the base end of the uncurtain-don. An anchoring method, characterized in that a fixing grout material is filled in the barrier grout material in a state where diffusion is prevented, and then an uncurtain-don is inserted into the fixing grout material and tension-fixed. 2. An anchoring method for fixing an anchor rod in a drilled hole through a grout material and then tensioning and fixing a base end of the anchor rod, drilling through a drill pipe; Drawing a drill pipe while filling the barrier grout material in the hole through the hole, filling the fixing grout material in the barrier grout material through the drill pipe, and inserting an uncurtain don into the fixing grout material in the drill pipe And a step of extracting a drill pipe and tensioning and fixing an uncurtain don. 3. The anchoring method according to claim 1, wherein the barrier grout is a non-separable underwater grout or a highly viscous grout. 4. An anchoring method according to claim 2, wherein when the drill pipe is extracted from the hole, grouting material for fixing is supplied through the drill pipe.