JP2824566B2 - Construction method of ground anchor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for constructing a ground anchor.

[0002]

2. Description of the Related Art Conventionally, a ground anchor generally forms a drilled hole 1 by digging a casing as shown in FIG. 9, and then, through a casing 2 into the drilled hole 1 as shown in FIG. As shown in FIG. 11, the injection hose 5 was inserted and installed, and then the casing 2 was removed. After that, grout 6 was injected and filled into the hole 1 through the hose 5 and curing and curing were performed.

The construction of such an anchor is often carried out under water to be pressurized, and it is necessary to seal the opening of the drilled hole 1 in order to press-fill the grout 6 into the drilled hole 1 under pressure. Become. Conventionally, the opening of such a hole 1 has been performed by applying a packer 7 as shown in FIG. 12 and expanding it (see FIG. 13).

[0004]

In such a conventional mouth sealing means, as shown in FIG. 14, PC steel wires 4 and 4 constituting a free length portion of the tendon 3 around an injection hose 5 are provided. Inevitably, the gap 8 is generated, and a part of the grout filled in the borehole 1 leaks from the gap 8, so that the backflow of the groundwater into the borehole 1 and the dilution of the grout are caused.
This makes it impossible to construct an anchor having the strength as set.

[0005] Conventionally, a waterproofing agent is injected into the gap 8 to prevent grout leakage. However, this waterproofing work requires not only a high level of skill and skill but also grouting. In some cases, leakage cannot be sufficiently prevented, and improvement has been desired.

[0006] The present invention has been made to eliminate such a conventional problem.

[0007]

According to the present invention, there are provided a plurality of PC steel wires arranged in parallel, which constitute a free length portion of an uncurtain don inserted and installed in a drilling, and a plurality of substantially parallel PC steel wires in the drilling. By expanding the packer around the grout injection hose inserted and installed at the center of each hole, after sealing the hole of the drill hole, pressurize grout into the drill hole under pressurized water through the hose The construction method of the ground anchor to be filled
And the hose can be inserted through the center from the axial direction.
The first insertion hole and the PC steel wire around the first insertion hole.
A second insertion hole that can be inserted from the outside through the split opening
The second insertion hole has the same number as the number of the PC steel wires.
The waterproof rubber is attached to the hose using the first insertion
Insert by inserting the through hole from the axial direction, and to the PC steel wire
Is installed by inserting through the crack opening from the outside
After the waterproof rubber is attached to the hose and the PC steel wire at a predetermined location, the mouth is sealed by a packer expansion around the waterproof rubber, and then the grout is pressure-filled according to a conventional method. It relates to the construction method of the ground anchor which is the feature.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

In the present invention, as shown in FIG. 1, a water-stop rubber 9 having a disk shape or a similar shape is used as a means for closing the opening of the hole 1.

The waterproof rubber 9 has a first insertion hole 10 for inserting the injection hose 5 at the center and a plurality of, for example, six second insertion holes 11 for inserting the PC steel wire 4 around the center. The insertion holes 11 are preferably arranged on a concentric circle at substantially equal intervals.

The waterproof rubber 9 shown in FIG. 1 can be applied to a construction in which up to six PC steel wires 4 are installed in a vertical cross section. The second insertion hole 11 may be used after being provided with a rubber stopper (not shown). FIGS. 7 and 8 show a waterproof rubber 91 of a type that can insert up to ten PC steel wires 4.

In the method of the present invention, the waterproof rubber 9 is provided as shown in FIG.
As shown in the figure, after the packer 7 is installed at the mouth of the drill hole 1 and before it is expanded, the packer 7 is inserted through the injection hose 5 and the PC steel wire 4 in the first and second insertion holes 10, 11,. It is mounted and fixed at a position coinciding with the packer 7 using rubber elasticity. In this case, in order to facilitate the insertion of the PC steel wire 4 into the second insertion hole 11 from the outer side, the peripheral portion of the waterproofing rubber 9, as shown in FIG. 1, every second insertion hole 11 The opening 12 is formed in the opening.

In the state shown in FIG. 3, as a preliminary operation, grout 6 such as cement milk is injected into the drilled hole 1 through the injection hose 5 to a position near the packer 7 installation position, and replaced with groundwater. This preliminary replacement operation may be omitted in some cases.

Next, as shown in FIG. 4, the packer 7 is expanded, and the mouth portion of the hole 1 is sealed by this expansion.

This sealing state is shown in an enlarged manner in FIGS. 5 and 6, and the gap between the sealing portions is completely eliminated by applying the waterproof rubber 9.

In this state, grout is filled under a predetermined filling pressure into the drilled hole 1 through the injection hose 5 according to a conventional method, so that the grout is filled after the grout is filled and the curing and curing is completed. Meanwhile, grout leakage can be prevented stably and reliably.

[0017]

According to the method of the present invention, the use of a water-stopping rubber makes it possible to stably and reliably perform water-stopping at a drill hole by a simple operation and without requiring a high level of skill and skill. It is possible to easily construct a high quality ground anchor.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a waterproof rubber applied to the construction method of the present invention.

FIG. 2 is a vertical sectional side view of the same.

FIG. 3 is an explanatory view schematically showing the installation state of a packer and a waterproof rubber in the method of the present invention.

FIG. 4 is an explanatory diagram schematically showing a state of closing the mouth due to the expansion of the packer.

FIG. 5 is an enlarged view of the mouth sealing portion of FIG. 4;

6 is a vertical sectional view taken along line 6-6 in FIG.

FIG. 7 is a view corresponding to FIG. 1 and showing another example of the waterproof rubber.

FIG. 8 is a diagram corresponding to FIG.

FIG. 9 is an explanatory view schematically showing a state of a drilling step in a conventional method.

FIG. 10 is an explanatory view schematically showing the situation of the step of inserting and installing an uncurtain don and an injection hose.

FIG. 11 is an explanatory view schematically showing the situation of a grout injection step.

FIG. 12 is an explanatory view schematically showing an installation state of a packer.

FIG. 13 is an explanatory diagram schematically showing an expansion state of the packer.

FIG. 14 is a longitudinal sectional view taken along line 14-14 of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drilling hole 2 Casing 3 Uncurtain don 4 PC steel wire 5 Injection hose 6 Grout 7 Packer 8 Gap 9 Waterproof rubber 10 1st penetration hole 11 2nd penetration hole 12 Split opening

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) E02D 5/80

Claims (1)

(57) [Claims] 1. A plurality of PCs arranged in parallel to form a free-length portion of an uncurtain-don inserted and installed in a borehole.
By expanding the packer around the steel wire and the grouting hose inserted and installed at the approximate center of the drilling hole, after sealing the drilling hole, pressurized water is passed through the hose. This is a method of constructing a ground anchor in which grout is pressurized and filled into the drill hole below, and the above-mentioned hose is
The first insertion hole which can be inserted from the line direction is also inserted into the first insertion hole.
Is the above-mentioned PC steel wire around the hole outward through the crack opening?
A second insertion hole that can be inserted from the PC steel wire.
Using the same number of waterproof rubber as the number of
For mounting on the hose, insert the first insertion hole from the axial direction.
To the PC steel wire, cracks from the outside
After the waterproof rubber is attached to the hose and the predetermined portion of the PC steel wire, the mouth is sealed by expanding the packer around the waterproof rubber, and then grouting is performed according to a conventional method. Construction method of ground anchor characterized by performing pressure filling.