JPH0452316A - Permanent ground anchor and its installation method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a permanent ground anchor and its installation method used for anchoring civil engineering architectural structures, securing slopes and other slopes, etc. .

[Prior Art] Permanent ground anchors are sometimes provided for the purpose of anchoring civil engineering construction structures, retaining soil on slopes and other slopes, and the like. Various types of permanent ground anchors have been developed and provided, and a method of fixing the PCM material with an anchor nand is often used for reasons such as less loss of tension during tensioning and ease of work. This method consists of a tension material buried in the soil, a fixing device such as an anchor bolt, an anchor nut, an anchor plate, etc., which fixes the tension material in the ground, and a connection that connects the tension material and the fixing device. It is roughly constructed from the ingredients.

Typical methods for anchoring with anchor nuts include the O8PA method, the BBRV method, and the PZ method.

■05PA construction method The O3PA construction method uses multiple PCs with buttons and buttons.
This is a method in which the steel material is set in a single connector and fixed with an anchor nut.

■BBRV construction method The BBRV construction method is a method in which multiple pieces of PC steel with button heads are set in one connector and connected to an anchor bolt as is.

■pz construction method The PZ construction method consists of an anchor bolt that has a tapered part whose outer diameter gradually increases toward the bottom of the borehole, and an anchor bolt that has a generally cylindrical outer diameter and whose inner diameter gradually decreases toward the axial direction of the cylinder. and a conical sleeve having a fitting portion that fits into the anchor bolt, and the tension member and the anchor bolt are connected by sandwiching the tension member between the anchor bolt and the conical sleeve.

[Problems to be Solved by the Invention] However, the above construction method had the following problems.

In the above construction method, for mechanical reasons, the outer diameter of the connector is larger than the outer diameter of the tendons made of a plurality of prestressed steel materials. In areas where the ground is partially collapsed, a casing pipe is used to drill a hole and a near-hole anchor is inserted. However, in such a case, the casing pipe of the tendon part cannot be removed, so in effect,
Despite the existence of many such grounds, there was a problem in that casing pipes could not be used.

If the diameter of the hole is matched to the outer diameter of the connector, there is no need to change the setup. Moreover, the casing pipe will not become stuck. However, if the diameter of the hole to be drilled is adjusted to match the outer diameter of the connector, much time and labor will be required because the outer diameter of the connector is larger than the outer diameter of the tendon.

The present invention has been made in view of the above-mentioned problems, and its purpose is to make the excavation hole into which the tendon is inserted smaller than that of the prior art, and to create a permanent ground that can be excavated in one step. The object of the present invention is to provide an anchor and its installation method.

[Means for Solving the Problems] The gist of the invention as claimed in claim 1 is to provide a tension member extending in the longitudinal direction of a borehole and having one end reaching the tip of the borehole, and the other end of the tension member being fixed to the ground surface. and a sheath surrounding the tendon at a predetermined interval, the sheath extending from one end of the tendon to the other end of the tendon. , one end of the sheath located on one end side of the tension member has a floating prevention device, and the other end of the sheath is connected to an outer sleeve, the outer sleeve having a diameter larger than that of the sheath. The permanent ground anchor has a diameter and surrounds the fixing device at a required interval.

The gist of the invention according to claim 2 is a permanent ground anchor installation method for fixing the permanent ground anchor according to claim 1 in an excavation hole, which comprises a mouth portion having a diameter larger than the diameter of the excavation hole into which the tendon is inserted. A step of excavating the hole to near the lower end of the position where the fixing tool will be present, a step of inserting a mouth pipe into the mouth portion, and a step of excavating an excavation hole into which the tension material is to be inserted from the bottom of the mouth portion. and inserting the sheath into the excavation hole and grouting between the casing pipe and the sheath, and after the external grout has hardened, an outer sleeve is installed at the outer sleeve mounting position located at the other end of the sheath. a step of attaching a sleeve; a step of cutting the sheath near the upper part of the outer sleeve attachment position; and inserting the tension material and the fixing device into the excavation hole and the mouth;
a step of grouting within the sheath; a step of applying anti-rust oil to the outer sleeve after the internal grout has hardened; and a step of tensioning a permanent ground anchor and fixing it in the ground; and a step of grouting between the outer sleeve and the mouth pipe. The present invention resides in a method for installing a permanent ground anchor characterized by comprising a step of performing the steps.

[Operations] The diameter of the mouth portion according to the present invention is larger than the diameter of the excavated hole into which the tendon is inserted. Therefore, the present invention:
Even when the diameter of the anchor is larger than the diameter of the borehole, the borehole can be drilled with a smaller diameter than in the prior art.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this example are intended to limit the scope of this invention to only those, unless otherwise specified. It's not, it's just an illustrative example.

First, the permanent ground anchor according to this embodiment will be explained using FIGS. 1(a) to 1(b). FIG. 1(a) is a longitudinal sectional view of the permanent ground anchor, and FIG. 1(b) is a side view of the vicinity of the conical sleeve.

The permanent ground anchor A according to this embodiment is shown in Fig. 1 (a).
As shown in FIGS. 1(b) to 1(b), the tension member IO, a fixing device, and a corrugated sheath 30 are provided.

The tension material 10 is a plurality of pruning PCj! Q line! Consisting of 1,
It extends in the longitudinal direction of the borehole and one end reaches the tip of the borehole. The branched PC steel wire 11 is shown in Figure 1 (A).
As shown in the figure, one end forms a waveform. The number of PC steel wires 11 may be determined based on the design strength, the outer diameter of the tendon 10, etc.

Reference numeral 10a represents a free length portion, and reference numeral 10b represents a fixed length portion.

The fixing device includes an anchor bolt 20 and an anchor nut 21.
and an anchor plate 22, and the other end of the tendon 10 is fixed to the ground surface. The anchor bolt 20 has a tapered portion 20a whose outer diameter gradually increases toward one end, and a male screw at the other end. The anchor nut 21 has a female thread that is engaged with the male thread. The anchor plate 22 is a planar rectangular plate having a through hole for the anchor bolt 20 in the center, and the anchor bolt 20 is inserted into the through hole. Furthermore, the anchor plate 22 according to this embodiment includes:
When the anchor plate 22 is installed, a hole for inserting the secondary grout injection pipe 73 is inserted between the mouth pipe 40 and an outer sleeve 80 (described later).
It is located in a location where there will be The conical sleeve 23 has a substantially cylindrical outer shape and has a fitting portion that fits into the tapered portion 20a and has an inner diameter that gradually decreases in the direction of the cylinder axis. The tension material 10 and the anchor bolt 20 are connected by sandwiching the tension material 10 between them. The corrugated sheath 30 has a cylindrical shape with a corrugated longitudinal section, extends from one end of the tendon material 10 to the other end, and extends from the tendon material 10 to the other end.
One end of the corrugated sheath 30 located on the one end side of the corrugated sheath 30 has a locking device 90 (floating prevention device), and the other end of the corrugated sheath 30 is connected to the outer sleeve 80. As shown in FIGS. 3(a) and 3(b), the locking device 90 consists of an end cap 91 having a substantially semicircular spherical shape and a locking plate 92 attached to the outer periphery of the end cap 91 and capable of rising and falling freely. It is something.

The outer sleeve 80 has a diameter larger than the diameter of the full gate sheath 30, and surrounds the fixing device at a required interval.

Furthermore, in this embodiment, the free length portion 10 of the tendon 10
A is inserted into an oil-proof smooth sheath 110. Further, a center riser 100 is provided on the outside of the corrugated sheath 30.

The center riser 100 consists of two plates 101 located parallel to each other as shown in FIGS. 4(A) to 4(C).
The spacing member 102 is made up of a plurality of spacer members 102 whose ends are respectively fixed to the two plate members 101. Each spacing member 102 is a flexible member having a predetermined distance from each other and having a raised central portion. The center riser 100 is made into a substantially cylindrical shape by curving the spacer 102 and fixing the two plates 101, and is inserted into an excavated hole as shown in FIG. 2()X). .

In addition, the code|symbol 40 is the mouth pipe 40, the code|symbol 50 is a casing pipe, and the code|symbol 71 is an external grout injection pipe.

Next, the installation method of the permanent ground anchor A in the ground that has a part that easily collapses will be explained using Fig. 2 (In to Fig. 4 ()\).
G) is a process diagram of permanent ground anchor A, FIG. 3A is a front view of the locking device 90, and FIG. A side view, FIG. 4(a) is a plan view of the center riser 100, and FIG. 4(b) is a plan view of the center riser 10.
FIG. 4(C) is a side view of the center riser 100. FIG.

First, as shown in Figure 2 (a), the mouth part m is excavated,
The mouth tube 40 is inserted into the mouth part m. The diameter of the mouth portion m is larger than the diameter of the excavated hole into which the tendon 10 is inserted. Moreover, the depth of the mouth part m is excavated to the vicinity of the lower end of the position where the fixing tool will be present.

Next, as shown in FIG. 2(o), an excavation hole into which the tension material 10 is to be inserted is excavated from the bottom of the mouth Km. Such holes are drilled into the inner rod 51 and the casing pipe 50.
This is done using a double tube method using After excavating to the required depth, the slime removal port is removed, and then the inner rod 51 is pulled out. Next, as shown in FIG. It is inserted into the borehole together with the riser 100 and the external grout injection pipe 71, and grouting is performed over the entire length of the borehole between the casing pipe 50 and the corrugated sheath 30 using the external grout injection pipe 7I to form an external grout. . At this time, since water accumulates in the excavation hole, a sunny hose 31 or the like is placed as a weight to prevent the corrugated sheath 30 from floating up.

The sunny hose 31 is a bag, and the inside is filled with water. Furthermore, during grouting, the casing pipe 50 is pulled out. In addition, corrugated sheath 3
As shown in FIG. 2 (/\), a head cap 32 is attached to the other end of the head. In such cases,
Grout can be prevented from entering the inside of the full gate sheath 30. As the grout material, any material suitable for carrying out the present invention may be used. Further, an anti-locking device and a center riser 100 are attached to the corrugated sheath 30 in advance. However, Sunny Horse 31
The insertion of the head cap 32 into the corrugated sheath 30 and the attachment of the head cap 32 to the corrugated sheath 30 can be performed before or after the corrugated sheath 30 is inserted into the borehole.

Next, as shown in FIG. 2(d), after the external grout has hardened, the head cap 32 is removed from the corrugated sheath 30, the sunny hose 31 is removed, and the corrugated sheath 30 is removed.
Attach the outer sleeve 80 to the attachment position of the outer sleeve 80.

Such attachment may be performed using a suitable material for carrying out the present invention, such as glue or adhesive. Additionally, the external grout injection pipe 71 is cut near the attachment position of the outer sleeve 80. Note that the scope of the present invention is not intended to be limited thereto, and in the present invention, the external grout injection pipe 7
! can also be pulled out before the external grout hardens.

Next, as shown in FIG. 2(e), the corrugated sheath 30 is cut near the upper part (the other end side of the corrugated sheath 30) of the attachment position of the outer sleeve 80.

Next, as shown in the figure, the rust-proof oil-filled smooth sheath 1
10 covered tension material 1O1 internal grout 1: entered t72
, the tensile member equipped with the conical sleeve 23 and the fixing device is inserted into the borehole and the mouth m, and the internal grouting pipe 7 is inserted.
2, grouting is performed inside the corrugated sheath 30 to form internal grout. Such grouting is performed up to the lower end of the mouth portion m. In addition, tension material 10. The anchor bolt 20, the conical sleeve 23, and the antirust oil-filled smooth sheath 110 are assembled in advance before being inserted into the excavation hole and the mouth m.

Next, as shown in FIG. 2(f), after the internal grout has hardened, an oil preventive 120 is injected into the outer sleeve 80 from the through hole of the anchor plate 22, and then the permanent ground anchor 8 is tensioned. And anchor plate 22 is used to fix it to the ground. Such tensioning may be performed using a tensioning device suitable for carrying out the present invention, such as a center hole type hydraulic jack/cow. Note that this tensioning work is performed after confirming, using a separately collected specimen, that the internal grout has hardened and the desired texture has been developed. In addition, before installing the anchor plate 22, the internal grout injection pipe 72 was cut at a suitable position (in addition, in this step, the oil preventive 120 was injected into the anchor plate 22 from the through hole of the anchor plate 22. However, the scope of the present invention is not intended to be limited thereto, and the present invention includes, for example, a method of providing an oil-proof injection hole in the anchor plate 22 and injecting the oil-proof 120 from the oil-proof injection hole. This can be done by any suitable method.

Further, in this example, the following steps are performed.

That is, as shown in FIG. 2(G), grouting is performed between the outer sleeve 80 and the mouth pipe 40 using the secondary grout injection pipe 73 to form secondary grout. In addition,
The secondary grout injection pipe 73 is installed by being inserted into the secondary grout hole.

Permanent ground anchor A can be installed in the ground through the above steps.

In the above process, the mouth pipe 40 is fitted into the mouth part m before drilling the borehole, but this is not intended to limit the scope of the present invention. The mouth tube 40 can be fitted into the mouth part m.

Moreover, after attaching the outer sleeve 80 to the corrugated sheath 30, the corrugated sheath 30 was cut.
Without intending to limit the scope of the present invention, in the present invention, the corrugated sheath 30 is attached to the outer sleeve 8.
It is also possible to attach the outer sleeve 80 to the corrugated sheath 30 after cutting at the upper part of the attachment position 0.

Next, the operation of the permanent ground anchor A configured as above will be explained.

The mouth pipe 40 prevents the ground side wall from collapsing at the mouth part m.

The casing pipe 50 prevents the borehole sidewall from collapsing. Therefore, the permanent ground anchor A can be installed even in ground that easily collapses.

Since the corrugated sheath 30 is made of polyethylene, it prevents water from entering.

The sunny hose 3I prevents the corrugated sheath 30 from rising.

The center riser 100 equalizes the distance between the hour sleeve 80 and the borehole side wall.

The head cap 32 prevents soil, water, grout, etc. from entering the corrugated sheath 30.

The end cap 91 prevents grout in the borehole from entering the full gate sheath 30.

When the locking plate 92 is inserted into the casing pipe 50, it lies down, and when the insertion is completed, it is raised by gravity and engages the end of the locking plate 92 or the lower end of the casing pipe 50. Therefore, the locking device 90 is
To prevent a full gate sheath 30 from rising when grouting external grout.

The outer sleeve 80 isolates the ground at the mouth m from the fixing tool and the tension material 10.

The oil-filled smooth sheath 110 prevents the tendon 10 from rusting and facilitates insertion of the tendon 10 into the excavated hole.

Oil protection 120 injected into outer sleeve 80 prevents the anchor from rusting.

The external grout secures the corrugated sheath 30 inside the borehole.

The internal grout fixes the tendon 10 to the ground and prevents the tendon 10 from rusting.

The secondary grout anchors the outer sleeve 80.

Next, the effects of the permanent ground anchor A configured as above will be explained.

In this embodiment, since the diameter of the mouth part m is larger than the diameter of the drilled hole into which the tendon 10 is inserted, even if the diameter of the fixing tool is larger than the diameter of the drilled hole, can be excavated with a smaller diameter and at -degrees compared to the conventional technology. Therefore, according to this embodiment, the labor and expense required for installing the permanent ground anchor A can be reduced and the time required compared to the conventional technology.

The casing pipe 50 prevents the side wall of the excavation hole from collapsing, so it can be used as a permanent ground anchor A even in the ground that is prone to collapsing.
can be installed.

In addition, by first inserting the corrugated sheath 30, which is a corrosion-preventing member for the free length section 10a and the anchor length section Job, and filling its outer periphery with grout, a space in which the tension material 10 can be easily inserted is created in the ground. can be secured. For this reason, anti-corrosion treatment of the anchorage, which has a larger diameter than the drilled hole, is required for the tension material 1.
After inserting 0, it can be performed within the wide space of the mouth m.

Furthermore, since the corrugated sheath 30 has excellent corrosion resistance, it can protect the tendon 10 even if the external grout cracks or breaks.

Further, since the center riser 100 is provided, the thickness of the external grout can be made uniform.

Furthermore, since the locking device 90 is provided, lifting of the corrugated sheath 30 can be prevented.

Nao, in this example, the present invention is applied to the PZ construction method using the conical sleeve 23, but the scope of the present invention is not limited thereto. , BBRV construction method, Dipidag construction method, Leonhard construction method, etc., which are suitable for carrying out the present invention.

Further, although the mouth portion m is circular in plan view, this is not intended to limit the scope of the present invention, and the present invention may have other shapes, such as a quadrilateral, pentagon, or other polygon in plan view.
Any suitable material can be used to carry out the present invention.

Furthermore, although a plurality of PC steel wires 11 are used as the tension material 1O, this is not intended to limit the scope of the present invention.
In the present invention, other materials suitable for carrying out the present invention may be used, such as glass fiber tendons, aramid fiber tendons, and the like.

Furthermore, although the permanent ground anchor A is not provided with the packer 60 in this embodiment, this is not intended to limit the scope of the present invention, and a packer may be provided in the present invention.

[Effects of the Invention] Since the present invention is configured as described above, it produces the following effects.

In the present invention, since the diameter of the mouth part is larger than the diameter of the drilled hole into which the tendon is inserted, even if the diameter of the fixing device is larger than the diameter of the drilled hole, the diameter of the drilled hole can be improved compared to the conventional technology. It is possible to excavate with a small diameter and in -degrees. Therefore, according to the present invention, the labor and expense required for installing a permanent ground anchor can be reduced and the time required compared to the prior art.

Furthermore, since the mouth part is provided, it is possible to use a casing pipe, so the present invention can be practiced even on ground that is easily collapsed.

In addition, by pushing in the corrugated sheath, which is a corrosion-preventing member for the free length and anchorage length, first and filling its outer periphery with grout, it is possible to secure a space in the ground where the tension material can be easily inserted. can. Therefore, the anticorrosion treatment of the fixing tool, which has a diameter larger than that of the excavated hole, can be carried out within the wide space at the mouth after the tendon is inserted.

[Brief explanation of the drawing]

Figures 1 to 4 (C) show embodiments of the present invention, Figure 1 (A) is an M sectional view of the permanent ground anchor, and Figure 1 (B) is a side view of the vicinity of the conical sleeve. , Figure 2 (
Figures 2) to 2(g) are process diagrams of the permanent ground anchor, Figure 3(a) is a front view of the locking device, and Figure 3(b) is an excavation hole showing the state in which the locking device is engaged with the casing pipe. Figure 4 (a) is a plan view of the center riser, Figure 4 (b) is a front view of the center riser,
FIG. 4(C) is a side view of the center riser. 2... Anchor plate, 23... Conical sleeve, 30... Corrugated sheath, 40...
... Mouth pipe, 50 ... Casing pipe, 517.
... Inner rod, 60 ... Packer 8
0: Outer sleeve, 90: Locking device (levitation prevention device), Applicant: Shimizu Corporation KFC Japan Basic Technology Co., Ltd. A: Perpetual Ground anchor h: Excavation hole, m: Mouth part, Figure 2 (C) Figure 2 (2)

Claims (2)

[Claims] (1) A tension member that extends in the longitudinal direction of the borehole and has one end reaching the tip of the borehole, a fixing device that fixes the other end of the tension member to the ground surface, and a tension member that connects the tension member at a predetermined interval. A permanent ground anchor having a sheath surrounding the tendon, the sheath extending from one end of the tendon to the other end of the tendon, and one end of the sheath located on one end of the tendon floating. a prevention device, the other end of the sheath is connected to an outer sleeve, the outer sleeve has a diameter larger than the diameter of the sheath, and surrounds the fixing device at a required interval. A permanent ground anchor characterized by: (2) A permanent ground anchor installation method for fixing the permanent ground anchor in an excavation hole according to claim 1, wherein the fixing tool has a mouth portion having a diameter larger than the diameter of the excavation hole into which the tendon is inserted. a step of excavating to near the lower end of the position, a step of inserting a mouth tube into the mouth portion, a step of excavating an excavation hole into which the tension material is to be inserted from the bottom of the mouth portion;
Inserting the sheath into the excavation hole and grouting between the casing pipe and the sheath, and after the external grout hardens, attaching the outer sleeve to the outer sleeve attachment position located at the other end of the sheath. a step of cutting the sheath near the upper part of the outer sleeve attachment position; a step of inserting the tension material and the fixing device into the excavation hole and the mouth portion and grouting the inside of the sheath; and a step of grouting the inner grout. It is characterized by comprising the steps of injecting anti-corrosion oil into the outer sleeve after hardening, tensioning the permanent ground anchor and fixing it in the ground, and grouting between the outer sleeve and the mouth pipe. How to install a permanent ground anchor.