JPS6397718A - Grip-type fixing structure for head of permanent ground anchor - Google Patents

Abstract

PURPOSE:To reduce error in construction work by a method in which at a stage when a tension member is tensed for introducing a given prestress into it, a head bearing plate on anchor plate is screwed into the anchor head in contact with the downside of a solderless grip. CONSTITUTION:A bearing plate is attached to the tip of a tension member 1. At a stage when a prestress is introduced into the tension steel member 1 of a permanent ground anchor, where a load-bearing part is set on the drawing side of the bearing plate, a solderless grip 11 is set on the portion projecting from the anchor plate 13 on the ground's surface. Anchor head 12 with a threaded 12a periphery is set below the grip 11, and the threaded periphery of the anchor head 12 is fixed to the threaded inner surface of the head bearing plate set on the plate 13. The prestress introduced can thus be exactly kept by the anchor head 12 and the bearing plate 14 on the plate 13.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention is applicable to #A
To prevent falls during earthquakes or storms, to prevent surfacing by groundwater when deep underground buildings are constructed in places where the groundwater level is relatively high, or for buildings built on slopes. The present invention relates to a permanent ground anchor used as a countermeasure against uneven earth pressure or sliding, and more specifically, to an anchor head fixing structure that employs a crimp grip that is highly stable and reliable.

2. Description of the Related Art As shown in FIG. 6, a conventional permanent ground anchor has a pressure plate 2 attached to the tip of a tensile steel member 1 through a crimp grip 4, and a tubular support plate 2 attached to the pull-out side of the pressure plate 2. A load-bearing body 3 is installed, and force is transmitted to the surrounding ground 5 through this load-bearing body 3. Each tensile steel member 1 is attached to the bearing pressure plate 2 via a grip 4 by passing it through a hole in the bearing pressure plate 2 in advance, and then inserted and installed into an anchor hole in the ground. To fix the anchor mM, place 11 pieces of the anchor RAD 7 on the anchor plate 6 of JtJ:.

The tensile steel material 1 is inserted into the anchor through a wedge hole in the rod 7 and projected, and is fixed by driving a wedge 8 into the anchor.

Problem to be solved by the present invention (I) In the case of the conventional wedge-type anchoring structure described above, when the tensile steel l is tensed to introduce a prestress of a predetermined amount and anchored, the wedge is completely engaged. However, there is a problem in that a slip of about 3 to 6 mm will inevitably occur, which will disrupt the magnitude of the prestress and, by extension, the performance of the anchor.

(rl) In addition, with permanent anchors, it is necessary to leave the tension steel l in an unbonded state, and it is subject to repeated loads due to earthquakes, etc., so it is necessary to provide extremely high reliability for wedge anchorage. However, there are some points that cannot be said to be completely satisfactory.

(III) In addition, in the case of the above-mentioned wedge-type anchoring structure, considering the case where the tensile steel material l is to be re-tensioned, it is necessary to install the re-tensioning jack upward from the position of the wedge 8 so that the chairman can be at least in position to be re-tensioned. There is a problem in that the space for this entire length must be secured for many years.

Means for Solving the Problems As a means for solving the problems of the prior art described above, the grip-type fixing structure of the permanent ground anchor head according to the present invention is as shown in FIGS. 1 to wrJ5 of the drawings. As shown in the example, a permanent ground is constructed in which a bearing pressure plate 2 is attached to the tip of the tensile steel material 1, a load bearing body 3 is installed on the pull-out side of the bearing pressure plate 2, and force is transmitted to the surrounding ground through the load bearing body 3. In the anchor, a crimp grip 11 is provided in advance on a portion protruding from the anchor plate 13 on the ground when prestress is introduced into the tensile steel l, and a thread 12a is formed on the outer peripheral surface below the crimp grip II. A head support plate 1 with a helad 12 installed and placed on the anchor plate 13
The outer threaded portion 12a of the rod 12 is screwed into the inner threaded portion 14a of the anchor 12 and fixed thereto.

More specifically, the anchor head 12 has a cut groove 12b that can be installed between the plurality of tensile steel members 1 from the lateral direction. This is implemented in a configuration in which the necessary number of the filters are provided in the vertical direction of the filter 2a.

In addition, the anchor head 12 and the head bearing pressure plate 14 shall have a threaded length necessary for re-tensioning the tensile steel material l, and the anchor head 12 shall be capable of screwing the attachment of the re-tensioning jack. Head support plate 14 for length only
It is implemented with a configuration that stands out from the rest.

At the stage when the tensile steel material 1 is tensioned with the jack 10 and a predetermined prestress is introduced, the head bearing plate 14 on the anchor plate 3 is screwed into the anchor head 12 brought into contact with the bottom of the crimp grip 11, and After tightening lightly to prevent loosening, release the tension on the jack 10. By doing this, the introduced prestress is reliably maintained at its size by the anchor head 12 and the head bearing pressure plate 14 on the anchor plate 13, and there is no room for errors in construction.

Since the fixing structure is based on the pressure grip 11,
The stability against repeated loads is increased, resulting in a highly reliable fixing structure.

Furthermore, since retensioning can be performed by connecting the ram attachment of a retensioning jack to the outer circumferential threaded portion 12a of the anchor head 12 as needed, almost no extra length of the tensile steel material 11 is required.

Example Next, the illustrated embodiment will be explained.

First, FIG. 1 shows a crimp grip 11 installed in advance at a predetermined position m on the upper end of a tensile steel material 1 as a factory process, and an anchor head 12 attached to the tensile steel material 1 at a position below the crimp grip 11. It shows the relationship between As illustrated in FIG. 6, the anchor head 12 is constructed by attaching a bearing plate 2 to the tip of a tensile steel member 1, installing a load-bearing body 3 on the pull-out side of the bearing plate 2, and inserting the membrane into a hole in the ground anchor. After that, it is attached to the tensile steel member 1. This is because if the anchor head 12 is attached to the tensile steel member 1 before the load-bearing body 3, the inner diameter of the load-bearing body 3 must be made larger than the outer diameter of the anchor head 12, making it unnecessary to build an anchor body with a large diameter. This is because it would be uneconomical to create new land.

Therefore, in order to make it possible to install the anchor head 12 in the above-mentioned order, the anchor head 12 is installed as shown in FIG.
, as shown in B, a substantially U-shaped cut groove 12 is inserted into and installed from the lateral direction between four (but not limited to four) tensile steel members l... It has a configuration in which it is provided vertically at positions divided into four equal parts in the circumferential direction.

One tensile steel material 1 is placed in each cut groove 12b, and the anchor rod 12 is installed at the center of the four tensile steel materials 1.

A male thread 12a is formed on the outer peripheral surface of this anchor head 12. Further, a through hole 12c is provided in the axial direction of the central portion of the rad 12 to the anchor. This through hole 12c is used to attach the anchor head 12 to the grip 1 for a period of time at the beginning of construction.
This is for temporary fixing to 1.

That is, the presser plate 15 is placed on the crimp grip 11, the fixing bolt 16 passed upward through the through hole 12C of the anchor head 12 is screwed into the nut 17 on the presser plate 15, and the anchor head 12 is placed under the crimp grip 11. It is temporarily fixed (see Figure 2).

Next, FIG. 2 shows a stage in which the tensile steel material 1 having the above-described structure has been inserted into an anchor hole in the ground and is ready for tensioning work using a jack lug.

An anchor plate 13 is installed on the frame 18 on the ground, and a ram chair of Jyatsuki In is placed on the anchor plate 13.
10a is installed.

Ramchair 10a on the same anchor plate 13
Inside the head bearing plate 14 having a nut structure is attached to the tensile steel member 1.
It is installed to surround the outer periphery of... As shown in FIG.
It is formed into a nut shape.

In the preparation stage shown in FIG. 2, the position of the fixing grip 11 of the tensile steel material l is 30 cm to 60 cm lower than the position of the head bearing plate 14 of the frame 18-1, and a prestress of a predetermined size is applied. We expect sales of tensile steel materials to increase until the introduction of the product.

FIG. 3 shows a stage in which the prestress of a predetermined magnitude has been introduced and fixed by tensioning the tensile steel material 1, and the jack IO has been removed.

That is, from the stage shown in FIG. 2, tension is applied by the jack 10, and as the tensile steel material 1 stretches, the fixing grip 11 rises and reaches the position of the head bearing plate 14, and then the head bearing plate 14 is rotated in the forward rotation direction. Turn it to screw-join it to the anchor head 12. Then, when the head bearing plate 14 is lightly tightened at the stage where the prestress of the planned size is introduced, the anchor head 12
The prestress is maintained as it is by the screw connection.

In Figure 4, the holding plate 15, fixing bolt 16, and nut 17 that temporarily fixed the anchor rod 12 to the fixing grip 11 are removed, and the tensile steel material l is cut by cutting the portion above the fixing grip 11 as short as possible. , the head cap 19 is attached, anti-rust grease 20 is filled through the injection vibrator 21, and fixing is completed.

If it becomes necessary to re-tension the tensile steel material 1 later, remove the head cap 19 and remove the outer circumferential screw portion of the exposed anchor rod 12 that protrudes upward from the upper surface of the head bearing plate 14. The ram attachment of the re-tensioning jack is screwed to 12a to perform re-tensioning, so there is no need for the tension steel member l at all. On the other hand, the anchor rod 12 is configured to already protrude from the upper surface of the head bearing pressure plate 14 by a length that allows the ram attachment of the re-tensioning jack to be easily screwed in during the initial tensioning. Furthermore, the length is such that there is still sufficient margin for the amount of screwing between the anchor head 12 and the head bearing pressure plate t4.

The clip-type fixing structure of the permanent ground anchor head according to the present invention has been described in detail in conjunction with the embodiments, and is the first of its kind as a ground anchor that allows grip-type fixation of the head. Because it is tightly secured, there is no slippage during the fixing process unlike with conventional wedge-type fixing, so construction can be performed with stability in terms of precision.

Furthermore, a ground anchor with high stability against repeated loads can be obtained.

Furthermore, since the tensile steel material 1 does not require a chair for re-tensioning, it can be assembled into a car-like structure, contributing to effective use of space.

[Brief explanation of the drawing]

1 to 4 are cross-sectional views showing the important steps of constructing the anchor head grip type fixing structure according to the present invention; FIGS. 5A and 5B are plan and front views of the anchor head; Figure C is a cross-sectional view of the head bearing pressure plate, and Figure 6 is a cross-sectional view of a conventional anchor fixing structure. No. 25!1 151 Zhang Huoqi No. 3 1g1 Body Cloud Seagull Neo

Claims (1)

[Scope of Claims] [1] A bearing plate (2) is attached to the tip of the tensile steel (1), a load-bearing body is installed on the pull-out side of the bearing plate (2), and the surrounding ground is covered through the load-bearing body (3). In a permanent ground anchor configured to transmit force to a ground anchor plate (13), the tensile steel member (1)
A crimp grip (11) is installed on the part that protrudes from the
Installing the anchor head (12) formed with 12a),
An outer threaded portion (12a) of the anchor head (12) is screwed into an inner threaded portion (14a) of a head bearing pressure plate (14) placed on the anchor plate (13). Grip-type anchoring structure for permanent ground anchor head. [2] The anchor head (12) described in claim 1 has a cut groove (12b) that can be inserted between the plurality of tensile steel members (1) from the lateral direction and installed in the outer peripheral thread part. (12a) A grip-type fixing structure for a permanent ground anchor head, characterized in that the necessary number of the structures are provided in the vertical direction. [3] The anchor head (12) and head bearing plate (14) described in claim 1 or 2 have a threaded length necessary for re-tensioning the tensile steel material (1), A permanent ground anchor head grip type fixing structure is characterized in that the anchor head (12) protrudes from the head bearing plate (14) by a length that allows screw connection of a ram attachment of a jack.