JP7240274B2 - Core material for earth retaining wall and installation method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a core material installed in a soil mortar retaining wall (earth retaining wall) and a method for installing the core material.

Earth retaining methods include the TRD (Trench Cutting Re-Mixing Deep Wall) method and the SMW (Soil Mixing Wall) method.

In the TRD method, the ground is excavated by lateral movement of the TRD machine and rotation of the cutter chain, and soil mortar (mixing cement milk and local soil) is created in the trench. Suspend and insert the material (H-shaped steel: H-700 x 300, etc.).

In the SMW construction method, holes are drilled (grooved) in the ground with a 3-axis to 5-axis auger so that they are continuous in a row in plan view, and soil mortar is created in the grooves. Suspend the core material (H-shaped steel: H-700×300, etc.) and insert it.

In the TRD method and the SMW method, for example, 1/200 to 1/250 is the tilt control value (allowable tilt precision).

Here, with reference to FIG. 9, an example of the TRD construction method will be described in more detail regarding the erection (insertion arrangement) of the conventional core material.
In order to make the explanation more specific, the drilling width is 850 mm, the core material is H-700×300, the core material interval is ctc500-900 mm, the groove depth is 40 m, the core material depth is 35 m, and the allowable inclination accuracy is 1/200. The groove depth of 40m is necessary for impermeable walls, and the core material depth of 35m is necessary for stress.

Referring to Fig. 9, a core material 3 made of H-shaped steel (H-700 x 300) is inserted at a predetermined interval (ctc500-900mm) into the soil mortar 2 in the groove 1 cut (850mm wide). and installed.

For each core material, raw material (H-shaped steel) of a unit length is brought in for the required number of pieces, which are connected with splicing plates and bolts on site to be processed into one piece. The unit length that can be carried in is 12 m at maximum for transportation, and if there is a height restriction such as a power line above the earth retainer, it will be about 4 m, for example. Therefore, the H-shaped steel is brought in with a length of about 4m, one is erected, temporarily supported, the second is suspended and connected, lowered, temporarily supported, the third is suspended and connected, etc. becomes.

Patent Document 1 discloses, as a core material used for a soil mortar earth retaining wall, a core material made of H-shaped steel in which the flange width is gradually reduced so as to taper toward the tip. The web width is not reduced in this core.

Japanese Patent No. 5281213

However, in the conventional erection of the core material, the core material may not be inserted. The causes are as follows.

Referring to the image diagram in Fig. 10, when the groove width TW = 850 mm and the core material web width WW = 700 mm, when the core material is placed in the center of the groove, the gap on one side (between the groove wall surface and the flange surface gap) is 75 mm.
When the core material 3 is erected, if the center of the web at the upper end of the core material 3 in the width direction is set as a suspension point, the core material 3 will enter vertically. At this time, if the groove 1 is machined with an inclination of 1/200, it means that the depth is 15m and there is a lateral shift of 75mm. Therefore, when the core material 3 is placed in the center of the width direction of the groove 1 and inserted, one side of the core material 3 comes into contact with the wall surface of the groove and cannot be inserted when the groove is inserted 15 m.

Also, when connecting a short core material, for example, a core material with a length of 4 m, at a core material depth of 35 m, there are nine connections, and even if it is intended to be connected linearly, it may actually be bent and connected. Therefore, even if the slope of the cut groove is 0, if the amount of bending of the core material is large, the tip will come into contact with the wall surface of the groove and will not enter.

Further, when a trench is excavated in the ground containing a gravel layer by the TRD method, the gravel floats in the soil mortar, settles over time, and deposits on the trench bottom. For this reason, if the amount of over-digging exceeds the planned amount of 5m (= 40m - 35m), the core material may not be able to enter. As a countermeasure, the thickness of the gravel layer is increased and the over-digging (gravel pool) is deepened, but this takes time and money.

In addition, soil mortar begins to harden with the passage of time and its viscosity increases. Especially when the length of the core material is long, it becomes impossible to insert it due to adhesion. As a countermeasure, agitation is again performed by rotating the cutter chain of the TRD machine, and the core material is erected, but this is time-consuming and costly.

Also, if the core material cannot be inserted, the following countermeasures are taken, but these also require a great deal of labor and cost.
・Pull up the core once, then suddenly loosen the wire of the crane to drop it and insert it forcibly.
・Remove the core material, back up the TRD machine, create soil mortar again, correct the slope, and reinsert the core material.
・If the core material is bent at the connecting part, pull out the core material completely, and connect and install while ensuring the straightness of the core material.

In the tapered core material described in Patent Document 1, although the flange width is narrowed, the web width is not narrowed. When the core material is inserted into the groove that serves as the retaining wall, the core material is inserted so that the flange surface of the core material is along the groove wall surface. However, it is inevitable that the core material will not enter.

In view of such a situation, the present invention is intended to prevent difficulty in inserting the core material, which can be inserted along the groove wall surface without biting into the groove wall surface even when the tip portion of the core material comes into contact with the groove wall surface. , a core material for an earth retaining wall, and a method for installing the same.

The core material for the earth retaining wall in the first aspect of the present invention is made of H-shaped steel provided with a pair of flanges and a web connecting the intermediate portions of the flanges ,
The tip of the core material has no flange on one side and is composed of a flange on the other side and a web,
A side end face (width direction end face) of the web of the tip portion on the side without the flange is characterized by being inclined inward toward the front.

The core material for the earth retaining wall in the second aspect of the present invention is made of H-shaped steel provided with a pair of flanges and a web connecting the intermediate portions of the flanges ,
the tip of the core material is free of both flanges and consists only of a web,
Both end faces (both end faces in the width direction) of the webs at the ends without flanges are inclined inward toward the front.
That is, the web width of the leading end portion without both flanges is narrowed so as to be tapered.

The term "H-section steel" as used in the present invention refers to a steel having a pair of flanges and a web connecting the intermediate portions of the flanges. include.

When installing the above-mentioned core material in a groove for constructing an earth retaining wall filled with soil mortar, the flange surface of the above-mentioned core material on the side without a flange at the tip is inclined to the groove. It is characterized by being inserted toward the wall surface.

According to the present invention, even if the tip of the core material touches the wall surface of the groove, it can be inserted along the wall surface of the groove without biting into the groove wall surface. .

The front view, side view and bottom view of the core material showing the first embodiment of the present invention. FIG. 2 is a perspective view of the tip of the core material in the first embodiment; Image diagram of core material insertion in the first embodiment Image diagram of core material insertion when only one side has an inclined part Front view, side view and bottom view of a core material showing a second embodiment of the present invention The perspective view of the core material front-end|tip part in 2nd Embodiment Image diagram of core material insertion in the second embodiment Image diagram of core material insertion when only one side has ridges Top view, front view and side view of soil mortar retaining wall Image diagram showing the problem when inserting the core material

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.
First, a first embodiment will be described with reference to FIGS. 1 to 4. FIG.

FIG. 1 is a front view (A), a side view (B) and a bottom view (C) of a core material showing a first embodiment of the present invention. Here, the front surface is the web surface of the core material when viewed in the extending direction of the groove. FIG. 2 is a perspective view of the tip of the core material in the first embodiment.

The core member 3 is made of H-shaped steel and includes a pair of flanges 11 and 12 and a web 13 connecting the intermediate portions thereof.
The leading end of the core member 3 (the leading end in the direction of insertion and the lower end) does not have the flanges 11 and 12 and is composed only of the web 13 .

Both side end faces (width direction end faces) 13a and 13b of the web 13 at the leading end portion without flanges are inclined inward toward the front. That is, the web width of the web 13 at the leading end without the flange is narrowed so as to taper. In other words, the side end faces 13a and 13b of the web 13 at the leading end form inclined portions (tapered portions), the leading end of the web 13 forms a triangular or trapezoidal shape, and the central portion protrudes.

Such a tip portion shape may be realized by cutting off two points of the tip portion of the H-section steel (ready-made product) by gas cutting (fusion cutting), or the web tip portion of the H-section steel (ready-made product) Alternatively, a trapezoidal steel plate may be connected to the splice plate by bolts or welding so as to extend the web.

FIG. 3 is an image diagram of core material insertion in the first embodiment.
If the cut groove 1 is inclined, the tip of the core material 3 comes into contact with the wall surface of the groove during insertion. However, the tapered tip shape (13a) makes it possible to avoid catching, and the core material 3 enters along the groove wall surface. Therefore, insertion is not difficult.

Also, even when a combination of short H-shaped steels is bent to a large extent, the lower end of the core material 3 enters along the wall surface of the groove, so insertion is not difficult.
Further, the vertical accuracy of the inserted core material 3 is equal to or higher than the groove accuracy, which satisfies the construction accuracy of the soil mortar wall.

In this embodiment, the front end of the core material 3 has no flanges 11 and 12 and is composed only of the web 13, and the side end surfaces 13a and 13b of the web 13 at the front end without flanges are respectively , sloping inwards towards the front. In other words, the tip has inclined portions (tapered portions) 13a and 13b on both sides.
However, as shown in FIG. 4, one flange 11 side of the tip of the core material 3 has no flange 11 at the tip, and the tip on the one flange 11 side is composed only of the web 13. Alternatively, only the side end face (width direction end face) 13a of the web 13 at the leading end without a flange may be inclined forward. In other words, the configuration may be such that the slanted portion (tapered portion) 13a is provided only on one side of the distal end portion.

In this case, as shown in FIG. 4, the flange surface on the side without the flange at the tip portion bulges inward as the depth increases due to the inclination of the groove in the depth direction of the opposing wall surfaces of the groove 1. Insert it toward the wall surface 1a on the side. As a result, the same effect as in the case of FIG. 3 can be obtained, and there is an advantage that the labor for processing the H-shaped steel is reduced. The direction of inclination (and degree of inclination) of the grooving can be known at the time of grooving.

Next, a second embodiment will be described with reference to FIGS. 5 to 8. FIG.

FIG. 5 is a front view (A), a side view (B) and a bottom view (C) of a core material showing a second embodiment of the present invention. Here, the front surface is the web surface of the core material when viewed in the extending direction of the groove. FIG. 6 is a perspective view of the tip of the core material in the second embodiment.

The core member 3 is made of H-shaped steel and includes a pair of flanges 11 and 12 and a web 13 connecting the intermediate portions thereof.

At the tip portion of the core member 3, the flange surfaces (outer surfaces) of the flanges 11 and 12 have ridges 20a and 20b extending along the edges in the width direction.

The shape of the tip portion having such ridges 20a and 20b can be realized by welding a rectangular steel material or flat steel to the tip portion of the H-section steel (off-the-shelf product).

The ridges 20a and 20b may be appropriately tapered at the leading end and the trailing end in the extending direction thereof. Also, the cross-sectional shape of the ridges 20a and 20b may be a mountain shape, and the corners thereof may be rounded or chamfered.

FIG. 7 is an image diagram of inserting the core material in the second embodiment.
If the cut groove 1 is inclined, the tip of the core material 3 comes into contact with the wall surface of the groove during insertion. However, due to the ridges 20a attached to the tip, the core material 3 is guided along the groove wall surface in line contact, not surface contact, in the insertion direction, and is guided along the groove wall surface. . Therefore, insertion is not difficult.

Also, even when a combination of short H-shaped steels is bent to a large extent, the lower end of the core material 3 enters along the wall surface of the groove, so insertion is not difficult.
Further, the vertical accuracy of the inserted core material 3 is equal to or higher than the groove accuracy, which satisfies the construction accuracy of the soil mortar wall.

In this embodiment, ridges 20a and 20b extending along the edges in the width direction of the flange surfaces of both flanges 11 and 12 at the tip of the core member 3 are provided. In other words, both flanges 11 and 12 are provided with ridges 20a and 20b.
However, as shown in FIG. 8, only the flange surface of one flange 11 at the tip of the core member 3 may be provided with ridges 20a extending along the edges at both ends in the width direction. In other words, only one flange 11 may be provided with the ridge 20a.

In this case, as shown in FIG. 8, the flange surface on the side having the ridge 20a at the tip bulges inward as the depth increases due to the inclination of the groove in the depth direction of the opposed wall surfaces of the groove. Insert it toward the wall surface 1a on the side where it is. As a result, in addition to obtaining the same effect as in the case of FIG. 7, there is an advantage that the labor for processing the H-shaped steel is reduced. The direction of inclination (and degree of inclination) of the grooving can be known at the time of grooving.

It should be noted that the illustrated embodiment is only a schematic illustration of the present invention, and that the present invention, in addition to what is directly indicated by the described embodiment, can also be made by those skilled in the art within the scope of the claims. Needless to say, it includes the improvement and change of

Also, the dimension examples are provided for easy understanding. Needless to say, the present invention is not intended to be limited to this.
The claims as originally filed were as follows.
[Claim 1]
A core material inserted into a soil mortar retaining wall,
Made of H-shaped steel,
At least one flange side of the tip portion has no flange, and the tip portion is composed only of the web,
A core material for an earth retaining wall, characterized in that the lateral end surfaces of the webs at the leading ends without flanges are slanted forward and inward.
[Claim 2]
A core material inserted into a soil mortar retaining wall,
Made of H-shaped steel,
A core material for an earth retaining wall, characterized in that it has ridges extending along the edges in the width direction of at least one flange surface of its tip portion.
[Claim 3]
A method for installing a core material in a groove for constructing a retaining wall filled with soil mortar, comprising:
Using the core material according to claim 1 as the core material,
The flange surface on the side without the flange at the tip is inserted toward the wall surface of the facing wall surface of the groove, which bulges inward as it becomes deeper due to the inclination of the groove in the depth direction. A method for installing a core material for a retaining wall, characterized by:
[Claim 4]
A method for installing a core material in a groove for constructing a retaining wall filled with soil mortar, comprising:
Using the core material according to claim 2 as the core material,
Insert the flange surface on the side having the ridge at the tip toward the wall surface of the opposite wall surface of the groove, which bulges inward as it becomes deeper due to the inclination of the groove in the depth direction. A method for installing a core material for an earth retaining wall, characterized in that:

1 groove 2 soil mortar 3 core material (H-shaped steel)
11, 12 Flanges 13 Webs 13a, 13b Side end surfaces (inclined portions) of webs
20a, 20b ridges

Claims (3)

A core material inserted into a soil mortar retaining wall,
Consists of H-beam steel comprising a pair of flanges and a web connecting the intermediate portions of the flanges ,
The tip of the core material has no flange on one side and is composed of a flange on the other side and a web,
A core material for an earth retaining wall, characterized in that the side end surface of the web at the tip portion where the flange is not present is inclined inward toward the front. A core material inserted into a soil mortar retaining wall,
Consists of H-beam steel comprising a pair of flanges and a web connecting the intermediate portions of the flanges ,
the tip of the core material is free of both flanges and consists only of a web ,
A core material for an earth retaining wall, characterized in that both side end faces of the webs at the ends without flanges are inclined inwardly toward the front. A method for installing a core material in a groove for constructing a retaining wall filled with soil mortar, comprising:
Using the core material according to claim 1 or claim 2 as the core material,
A method for installing a core material for an earth retaining wall, wherein the flange surface of the core material on the side without a flange at the tip thereof is inserted toward the inclined wall surface of the groove.

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