JP7621879B2 - Earth retaining wall - Google Patents

Description

The present invention relates to an earth retaining wall equipped with parent piles, cross piles and auxiliary piles.

Patent Document 1 describes an earth retaining wall that includes multiple parent piles that are inserted at a predetermined interval into the ground where the earth retaining wall is to be constructed, multiple cross-sheet piles that are installed between adjacent parent piles, and multiple auxiliary piles (inserted piles) that are inserted into the rear ground from the side positions of the parent piles and connected to the parent piles via connecting members. With such an earth retaining wall, the earth pressure of the rear ground acting on the auxiliary piles is converted into a moment in the direction of pressing the parent piles against the rear ground, which has the advantage that the length of the embedded part of the parent piles can be shortened and the cross-sectional dimensions of the parent piles can be reduced.

JP 2017-197950 A

However, in the case of the retaining wall described in Patent Document 1, if the connection between the parent pile and the auxiliary pile is deformed by a moment, the moment is not transmitted from the auxiliary pile to the parent pile, and the retaining function may be reduced.

The present invention has been created in view of the above-mentioned circumstances and with the objective of solving these problems. The invention of claim 1 is an earth-retaining wall comprising a plurality of parent piles inserted at a predetermined interval into a ground for construction of an earth-retaining wall, a plurality of cross sheet piles installed between adjacent parent piles, and a plurality of auxiliary piles inserted from the sides of the parent piles into the rear side ground and connected to the parent piles via connecting members, wherein the parent piles and the auxiliary piles are H-shaped steel integrally having a pair of flanges and a web connecting the pair of flanges, the web being the bottom surface of a groove, and the pair of The connecting member has a pair of grooves with flanges as the groove sides, and is integrally provided with a square pipe material that can be fitted into the grooves of the parent pile and the grooves of the auxiliary pile, a first end plate that covers an opening at one end of the square pipe material, and a second end plate that covers an opening at the other end of the square pipe material , and the parent pile and the connecting member are connected by fastening the web of the parent pile to the first end plate via a plurality of bolts, and the auxiliary pile and the connecting member are connected by fastening the web of the auxiliary pile to the second end plate via a plurality of bolts .
The invention of claim 2 is a retaining wall as described in claim 1, wherein the square pipe material is configured to be fastened to a pair of flanges of the auxiliary pile via a plurality of long bolts that penetrate the pair of flanges of the auxiliary pile and the square pipe material in the vertical direction.
The invention of claim 3 is a retaining wall as described in claim 1 or 2, wherein the connecting member further comprises a reinforcing intermediate plate arranged in parallel between the first end plate and the second end plate and integrally joined to the inner periphery of the square pipe material.
The invention of claim 4 is a retaining wall according to any one of claims 1 to 3 , in which a reinforcing member is provided on the base end side of the auxiliary pile in the insertion direction, the reinforcing member being welded to a pair of the flanges and the web.
The invention of claim 5 is a retaining wall according to claim 4 , wherein the reinforcing member includes a first reinforcing member covering a base end face of the auxiliary pile in the insertion direction.
The invention of claim 6 is a retaining wall as described in claim 4 or 5, wherein the reinforcing member includes a second reinforcing member provided within the groove portion of the pair of groove portions of the auxiliary pile on the side into which the connecting member is not inserted, near the fastening position with the connecting member.

According to the invention of claim 1, the connecting member has a square cylindrical shape and is integrally composed of a square pipe material that can be fitted into the groove of the parent pile and the groove of the auxiliary pile, a first end plate that covers one end opening of the square pipe material and can be fastened to the web of the parent pile via a plurality of bolts, and a second end plate that covers the other end opening of the square pipe material, and at least one of the square pipe material and the second end plate is configured to be fastened to the auxiliary pile via a plurality of bolts, so that a box-shaped connecting member with excellent strength can be formed.As a result, compared to when the connecting member is constructed from H-shaped steel or the like, deformation of the connecting member can be suppressed and moment can be reliably transmitted from the auxiliary pile to the parent pile.
Furthermore , since the second end plate is configured so as to be fastened to the web of the auxiliary pile via a plurality of bolts, the auxiliary pile and the connecting member can be securely connected to each other.
In addition, according to the invention of claim 2 , the square pipe material is configured to be fastened to a pair of flanges of the auxiliary pile via a plurality of long bolts that penetrate the pair of flanges of the auxiliary pile and the square pipe material in the vertical direction, thereby increasing the number of fastening points between the auxiliary pile and the connecting member and more reliably transmitting moment from the auxiliary pile to the parent pile.
Furthermore, according to the invention of claim 3 , the connecting member further includes a reinforcing intermediate plate arranged in parallel between the first end plate and the second end plate and integrally joined to the inner periphery of the square pipe material, thereby further suppressing deformation of the connecting member.
In addition, according to the invention of claim 4 , a reinforcing member welded to a pair of flanges and the web is provided on the base end side of the auxiliary pile in the insertion direction, thereby suppressing deformation of the auxiliary pile and ensuring the transmission of moment from the auxiliary pile to the parent pile.
According to the invention of claim 5 , since the reinforcing member includes a first reinforcing member covering the base end face of the auxiliary pile in the insertion direction, the auxiliary pile can be reinforced without interfering with the insertion of the auxiliary pile.
In addition, according to the invention of claim 6 , the reinforcing member includes a second reinforcing member that is provided within the groove portion of the pair of grooves of the auxiliary pile into which the connecting member is not inserted, near the fastening position with the connecting member, so that the auxiliary pile can be reinforced without interfering with the insertion of the auxiliary pile.

1 is a perspective view showing the structure of an earth retaining wall according to a first embodiment of the present invention; FIG. 2 is a perspective view showing a state in which the connecting member of the first embodiment is attached to a parent pile. FIG. 2 is a perspective view showing a state in which an auxiliary pile is connected to a parent pile via the connecting member of the first embodiment. FIG. 11 is a perspective view showing a state in which the gripping member has been removed from the auxiliary pile. FIG. 2 is a front view showing a state in which an auxiliary pile is connected to a parent pile via the connecting member of the first embodiment. FIG. 2 is a plan view showing a state in which an auxiliary pile is connected to a parent pile via the connecting member of the first embodiment. FIG. 2 is a side view showing a state in which an auxiliary pile is connected to a parent pile via the connecting member of the first embodiment. 6A is a cross-sectional view taken along line XX in FIG. 5, and FIG. 6B is a cross-sectional view taken along line XX showing a state in which the gripping member has been removed from the auxiliary pile. FIG. 2 is a perspective view of a connecting member according to the first embodiment. An oblique view showing the structure of an earth retaining wall according to a second embodiment of the present invention. FIG. 11 is a perspective view showing a state in which a connecting member of a second embodiment is attached to a parent pile. FIG. 11 is a perspective view showing a state in which an auxiliary pile is connected to a parent pile via a connecting member of a second embodiment. FIG. 11 is a perspective view showing a state in which the gripping member has been removed from the auxiliary pile. FIG. 11 is a front view showing a state in which an auxiliary pile is connected to a parent pile via a connecting member of the second embodiment. FIG. 11 is a plan view showing a state in which an auxiliary pile is connected to a parent pile via a connecting member of the second embodiment. FIG. 11 is a side view showing a state in which an auxiliary pile is connected to a parent pile via a connecting member of the second embodiment. 14A is a cross-sectional view taken along the line YY in FIG. 14, and FIG. 14B is a cross-sectional view taken along the line YY showing a state in which the gripping member has been removed from the auxiliary pile. FIG. 11 is a perspective view of a connecting member according to a second embodiment.

[Structure of earth retaining wall]
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In Fig. 1, reference numeral 1 denotes an earth retaining wall, which comprises a plurality of parent piles 2 inserted at a predetermined interval into the ground on which the earth retaining wall is to be constructed, a plurality of cross sheet piles 3 installed between adjacent parent piles 2, and a plurality of auxiliary piles 4 inserted from the sides of the parent piles 2 into the ground on the rear side and connected to the parent piles 2 via connecting members 5.

As shown in Figures 1 to 8, the parent pile 2 is usually inserted (driven) vertically into the ground where the earth retaining wall is to be constructed. The material used is an H-shaped steel, which is generally used for parent pile horizontal sheet pile earth retaining walls. The parent pile 2 made of H-shaped steel has a pair of flanges 2a and a web 2b connecting the pair of flanges 2a together, and has a pair of grooves 2c with the web 2b as the groove bottom and the pair of flanges 2a as the groove side. The web 2b is machined with multiple bolt insertion holes (not shown) for connecting the connecting member 5 via the first bolt B1. The bolt insertion holes may be machined before the parent pile 2 is inserted into the ground, or may be machined at the timing when the connecting member 5 is fastened to the parent pile 2 after the parent pile 2 is inserted into the ground.

The cross-sectional dimensions of the H-shaped rope that makes up the parent pile 2 are selected according to the wall height, but generally sizes between H300 and H500 are used. Furthermore, before excavating the ground where the retaining wall will be constructed, the parent piles 2 are inserted into the ground at a specified interval along the boundary line of the ground to be excavated. The insertion interval is generally about 1.0 to 2.0 m.

The horizontal sheet piles 3 are plates that are fitted between adjacent piles 2 as excavation progresses, to retain the soil. Horizontal sheet piles 3 are usually made of wood such as Japanese larch.

The auxiliary piles 4 are installed in one or more stages in the height direction. Figure 1 shows an example where the auxiliary piles 4 are installed in two stages in the vertical direction. H-shaped steel with a cross section of approximately H200 to H400 is used as the auxiliary piles 4. The auxiliary piles 4 made of H-shaped steel have a pair of flanges 4a and a web 4b that connects the pair of flanges 4a together, and have a pair of grooves 4c with the web 4b as the groove bottom surface and the pair of flanges 4a as the groove side surfaces. The number of stages and insertion depth of the auxiliary piles 4 are determined by design calculations based on the allowable deformation amount of the top end of the parent pile 2, but in normal cases, they are installed in about 2 to 4 stages in the height direction, and the insertion depth is about 2 to 5 m.

As excavation progresses, the auxiliary piles 4 are installed for each parent pile 2 at each predetermined excavation stage. Although it is possible to install only one auxiliary pile 4 per location, it is preferable to install a pair on both sides of the parent pile 2 per location, as shown in the figure, in order to ensure a large moment. The auxiliary piles 4 are inserted from the side of the parent pile 2 in a roughly horizontal direction into the ground on the rear side, and the insertion source side is connected to the parent pile 2 via a connecting member 5. The auxiliary piles 4 are basically inserted horizontally, but may be installed at a slight incline to allow for construction errors.

As shown in Figures 3 to 8, a number of reinforcing members 41, 42 are welded to the pair of flanges 4a and web 4b at the base end of the auxiliary pile 4 in the insertion direction. These reinforcing members 41, 42 suppress deformation at the base end of the auxiliary pile 4 in the insertion direction, and ensure the transmission of moment from the auxiliary pile 4 to the parent pile 2.

The reinforcing members 41, 42 include a pair of first reinforcing members 41 that cover the base end face of the auxiliary pile 4 in the insertion direction. The pair of first reinforcing members 41 are welded to the base end face of the auxiliary pile 4 in the insertion direction so as to cover a pair of grooves 4c of the auxiliary pile 4. The pair of first reinforcing members 41 also have bolt insertion holes 41a machined in them for connecting the gripping members 6 described below.

The reinforcing members 41, 42 also include a second reinforcing member 42 that is provided in the groove 4c of the auxiliary pile 4 on the side into which the connecting member 5 is not inserted, near the fastening position with the connecting member 5.

When inserting the auxiliary pile 4 into the rear ground using an insertion heavy machine (not shown), a gripping space for the insertion heavy machine is required at the base end of the auxiliary pile 4 in the insertion direction. As shown in Figures 3 to 8, the earth retaining wall construction method of this embodiment uses a gripping space member 6 that is detachably attached to the base end of the auxiliary pile 4 in the insertion direction, serves as a gripping space for the insertion heavy machine that inserts the auxiliary pile 4 when inserting the auxiliary pile 4 into the rear ground, and is removed from the auxiliary pile 4 after insertion.

The gripping member 6 is an H-shaped steel having a pair of flanges 6a and a web 6b that connects the pair of flanges 6a together, and an H-shaped steel with the same cross section as the auxiliary pile 4 is used. A pair of gripping side joint members 61 are welded to the H-shaped steel that constitutes the gripping member 6 so as to cover the tip surface in the insertion direction. The pair of gripping side joint members 61 are machined with a plurality of bolt insertion holes (not shown) for fastening to the first reinforcing member 41 (auxiliary pile side joint member) of the auxiliary pile 4 via a plurality of third bolts B3.

The connecting member 5 is integrally composed of a square pipe material 51 having a rectangular cylindrical shape and a dimension that allows it to be inserted into the groove 2c of the parent pile 2 and the groove 4c of the auxiliary pile 4, a first end plate 52 that closes the opening at one end of the square pipe material 51 and can be fastened to the web 2b of the parent pile 2 via a plurality of first bolts B1, and a second end plate 53 that closes the opening at the other end of the square pipe material 51 and can be fastened to the web 4b of the auxiliary pile 4 via a plurality of second bolts B2. The square pipe material 51, the first end plate 52, and the second end plate 53 are all made of steel and are welded together to form a strong box body.

The first end plate 52 extends vertically beyond the square pipe material 51, and the extended portion has multiple bolt insertion holes 52a for fastening to the web 2b of the parent pile 2 via multiple first bolts B1.

The second end plate 53 has multiple bolt holes 53a for fastening to the web 4b of the auxiliary pile 4 via multiple second bolts B2, and a second nut N2 that screws into the second bolt B2 is welded to the back side of each bolt hole 53a.

The auxiliary pile 4 is inserted into the rear ground with one groove 4c fitted into the connecting member 5, and after insertion, it is fastened to the connecting member 5 by the second bolt B2 and the second nut N2.

[Construction method of earth retaining wall]
Next, the construction procedure of the earth retaining wall 1 will be explained with reference to Figs.

First, using a construction machine such as a pile driver, the parent piles 2 are inserted into the ground at a specified interval along the excavation boundary line.

Next, the area enclosed by the parent piles 2 is excavated using an excavator or other excavating machine. As the excavation progresses, cross sheet piles 3 are placed between the parent piles 2, and the ground is gradually dug down while retaining the soil. Once the excavation has reached the specified depth, i.e., a position slightly deeper than the installation position of the first tier of auxiliary piles 4, the work of installing the first tier of auxiliary piles 4 begins.

Prior to inserting the auxiliary piles 4, first, a pair of connecting members 5 are fixed to the parent pile 2. This is done by positioning the first end plates 52 of the pair of connecting members 5 so as to sandwich the web 2b of the parent pile 2, and fastening the first end plates 52 of the pair of connecting members 5 to the web 2b of the parent pile 2 using a number of first bolts B1 and first nuts N1. In addition, a gripping member 6 is attached to the base end of the auxiliary pile 4 in the insertion direction using a number of third bolts B3 and third nuts N3.

The auxiliary pile 4 is inserted while gripping the web 6b of the gripping member 6 with an insertion machine. During insertion of the auxiliary pile 4, the connecting member 5 fits into one of the grooves 4c of the auxiliary pile 4, allowing the connecting member 5 to function as an insertion guide. Once insertion is complete, the web 4b of the auxiliary pile 4 is fastened to the second end plate 53 of the connecting member 5 by a number of second bolts B2 and second nuts N2. The gripping member 6 is then removed from the auxiliary pile 4.

Once the installation work for the first tier of auxiliary piles 4 is complete, excavation begins, and the ground is gradually dug down while the cross-piles 3 are installed in parallel. Once the excavation has been completed to a position slightly deeper than the installation position for the second tier of auxiliary piles 4, installation work for the second tier of auxiliary piles 4 begins. The installation method is the same as for the first tier. Once the installation work for the second tier of auxiliary piles 4 is complete, excavation is continued to the specified depth, and construction of the retaining wall 1 is completed.

[Effects of the embodiment]
According to the present embodiment configured as described above, the earth-retaining wall 1 includes a plurality of parent piles 2 inserted at a predetermined interval into the ground for earth-retaining wall construction, a plurality of cross sheet piles 3 installed between adjacent parent piles 2, and a plurality of auxiliary piles 4 inserted from the side positions of the parent piles 2 into the rear side ground and connected to the parent piles 2 via connecting members 5, the parent piles 2 and the auxiliary piles 4 being H-shaped steel integrally having a pair of flanges 2a, 4a and webs 2b, 4b connecting the pair of flanges 2a, 4a, the webs 2b, 4b being the bottom surfaces of the grooves, and the pair of flanges 2a, 4a being the side surfaces of the grooves, the connecting members 5 being rectangular tubular shapes, Since the connecting member 5 is integrally equipped with a square pipe material 51 that can be fitted into the groove 2c of the pile 2 and the groove 4c of the auxiliary pile 4, a first end plate 52 that covers the opening at one end of the square pipe material 51 and can be fastened to the web 2b of the parent pile 2 via a plurality of first bolts B1, and a second end plate 53 that covers the opening at the other end of the square pipe material 51 and can be fastened to the web 4b of the auxiliary pile 4 via a plurality of second bolts B2, a box-shaped connecting member 5 with excellent strength can be constructed.As a result, compared to when the connecting member 5 is constructed from H-shaped steel or the like, deformation of the connecting member 5 is suppressed and moment can be reliably transmitted from the auxiliary pile 4 to the parent pile 2.

In addition, reinforcing members 41, 42 are provided on the base end side of the auxiliary pile 4 in the insertion direction, which are welded to a pair of flanges 4a and web 4b, thereby suppressing deformation of the auxiliary pile 4 and ensuring the transmission of moment from the auxiliary pile 4 to the parent pile 2.

In addition, the reinforcing members 41, 42 include a first reinforcing member 41 that covers the base end face of the auxiliary pile 4 in the insertion direction, so that the auxiliary pile 4 can be reinforced without interfering with the insertion of the auxiliary pile 4.

The reinforcing members 41, 42 also include a second reinforcing member 42 that is provided in the groove 2c of the auxiliary pile 4 on the side into which the connecting member 5 is not inserted, near the fastening position with the connecting member 5, so that the auxiliary pile 4 can be further reinforced without interfering with the insertion of the auxiliary pile 4.

[Second embodiment]
Next, a second embodiment of the present invention will be described with reference to Figures 10 to 18. However, differences from the above-mentioned embodiment will be described, and the same reference numerals as in the above-mentioned embodiment will be used for configurations common to the above-mentioned embodiment, and the description of the above-mentioned embodiment may be used.

As shown in Figures 10 to 18, the second embodiment of the present invention differs from the above-mentioned embodiment in that the square pipe material 51 of the connecting member 5B is configured to be fastened to a pair of flanges 4a of the auxiliary pile 4B via a plurality of long bolts B4 that vertically penetrate the pair of flanges 4a and the square pipe material 51 of the auxiliary pile 4B. In other words, in the second embodiment, after the auxiliary pile 4B is inserted into the rear side ground, not only is the web 4b fastened to the second end plate of the connecting member 5B via a plurality of second bolts B2 and second nuts N2, but the pair of flanges 4a are fastened to the square pipe material 51 of the connecting member 5B via a plurality of long bolts B4 and fourth nuts N4. This increases the number of fastening points between the auxiliary pile 4B and the connecting member 4B, and more reliably transmits the moment from the auxiliary pile 4B to the parent pile 2. In addition, the square pipe material 51 of the connecting member 5B and the flange 4a of the auxiliary pile 4B have bolt insertion holes 51a through which the long bolts B4 can be inserted, but the bolt insertion holes formed in the flange 4a of the auxiliary pile 4B are not shown in the figure.

The connecting member 5B of the second embodiment is provided with a reinforcing intermediate plate 54 that is arranged in parallel between the first end plate 52 and the second end plate 53 and is integrally joined (e.g., welded) to the inner periphery of the square pipe material 51. Such a reinforcing intermediate plate 54 can further suppress deformation of the connecting member 5B.

The auxiliary pile 4B of the second embodiment also includes a third reinforcing member 43 that is welded to the pair of flanges 4a and web 4b. The third reinforcing member 43 is provided in parallel with the inner side of the first reinforcing member 41, and together with the reinforcing members 41 and 42 described above, it suppresses deformation of the base end side of the auxiliary pile 4B in the insertion direction, ensuring the transmission of moment from the auxiliary pile 4 to the parent pile 2.

The present invention is not limited to the above-described embodiment, and various modifications and alterations are possible within the scope of the claims. For example, the retaining wall 1 can be used as a temporary structure, or as a permanent structure. The retaining wall 1 as a permanent structure can be used as a retaining wall for a moat road at an intersection, a bank retaining wall in developed ground, a retaining wall for a belly-up bank, or a leaning retaining wall (see, for example, JP 2017-197950 A). When the retaining wall 1 is used for deep excavation, ground anchors may be used in addition to the auxiliary piles 4.

REFERENCE SIGNS LIST 1 Retaining wall 2 Parent pile 2a Flange 2b Web 2c Groove 3 Cross sheet pile 4, 4B Auxiliary pile 4a Flange 4b Web 4c Groove 41 First reinforcing member 41a Bolt insertion hole 42 Second reinforcing member 43 Third reinforcing member 5, 5B Connecting member 51 Square pipe material 51a Bolt insertion hole 52 First end plate 52a Bolt insertion hole 53 Second end plate 53a Bolt insertion hole 54 Reinforcing intermediate plate 6 Grip member 6a Flange 6b Web 61 Grip side joint member

Claims (6)

A plurality of parent piles are inserted at predetermined intervals into the ground for construction of the earth retaining wall;
A plurality of horizontal sheet piles installed between adjacent parent piles;
A retaining wall including a plurality of auxiliary piles inserted into the backside ground from a side position of the parent pile and connected to the parent pile via a connecting member,
The parent pile and the auxiliary pile are H-shaped steels integrally having a pair of flanges and a web connecting the pair of flanges, and have a pair of grooves with the web as a groove bottom surface and the pair of flanges as groove side surfaces,
The connecting member is
A square pipe material having a square tubular shape and capable of being inserted into the groove of the parent pile and the groove of the auxiliary pile;
A first end plate that closes an opening at one end of the square pipe material;
and a second end plate that closes the opening at the other end of the square pipe material.
The parent pile and the connecting member are connected by fastening the web of the parent pile and the first end plate via a plurality of bolts,
The auxiliary pile and the connecting member are a retaining wall connected by fastening the web of the auxiliary pile to the second end plate via a plurality of bolts . The retaining wall according to claim 1 , wherein the square pipe material is configured to be fastened to a pair of flanges of the auxiliary pile via a plurality of long bolts penetrating the pair of flanges of the auxiliary pile and the square pipe material in the vertical direction. The retaining wall according to claim 1 or 2, wherein the connecting member further comprises a reinforcing intermediate plate arranged in parallel between the first end plate and the second end plate and integrally joined to the inner periphery of the square pipe material. The retaining wall according to any one of claims 1 to 3 , wherein a reinforcing member is provided on a base end side of the auxiliary pile in the insertion direction, the reinforcing member being welded to a pair of the flanges and the web. The retaining wall according to claim 4 , wherein the reinforcing member includes a first reinforcing member covering a base end face of the auxiliary pile in the insertion direction. The retaining wall of claim 4 or 5, wherein the reinforcing member includes a second reinforcing member provided within the groove portion of the pair of groove portions of the auxiliary pile on the side into which the connecting member is not inserted, near the fastening position with the connecting member .

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