JP7621880B2 - Earth retaining wall and its construction method - Google Patents

Description

The present invention relates to a retaining wall equipped with parent piles, cross piles and auxiliary piles, and a construction method thereof.

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 retaining wall described in Patent Document 1, when the insertion heavy machinery grips the base end of the auxiliary pile in the insertion direction and inserts it into the rear side substrate, the auxiliary pile is not inserted by the amount gripped by the insertion heavy machinery, and the uninserted part needs to be cut off, which not only wastes the material cost of the cut part, but also has the potential to increase construction costs by adding a cutting process.

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 comprises a plurality of parent piles inserted at predetermined intervals into a ground for construction of an earth-retaining wall, a plurality of cross sheet piles installed between adjacent parent piles, a plurality of auxiliary piles inserted into the rear-side ground from side positions of the parent piles, a connecting member connecting the parent piles and the auxiliary piles, and a gripping member that is detachably attached to a base end of the auxiliary pile in the insertion direction, serves as a gripping member for an insertion heavy machine that inserts the auxiliary pile when inserting the auxiliary pile into the rear-side ground, and is detached from the auxiliary pile after insertion. This is an earth retaining wall in which the parent piles and auxiliary piles are constructed from H-shaped steel having a pair of flanges and a web connecting the pair of flanges, and the connecting member comprises a square cylindrical square pipe material, one end of which is fitted between the flanges of the parent pile and fastened to the web, and the other end of which is fitted between the flanges of the auxiliary pile and fastened to the web, thereby connecting the parent pile and the auxiliary pile, and the upper and lower surfaces of the other end of the square pipe material when one end is fastened to the parent pile are fitted between the flanges of the auxiliary pile, thereby acting as an insertion guide for the auxiliary pile to be inserted into the ground behind it .
The invention of claim 2 is a retaining wall as described in claim 1, wherein the auxiliary pile and the gripping member are H-shaped steel having a pair of flanges and a web connecting the pair of flanges, the auxiliary pile covers its base end face in the insertion direction and is provided with an auxiliary pile side joint member that also serves as a reinforcing member for the auxiliary pile, and the gripping member covers its tip face in the insertion direction and is provided with a gripping side joint member that can be fastened to the auxiliary pile side joint member via a plurality of bolts.
The invention of claim 3 is an earth retaining wall comprising a plurality of parent piles inserted at a predetermined interval into the ground for earth retaining wall construction, a plurality of cross sheet piles installed between adjacent parent piles, a plurality of auxiliary piles inserted from side positions of the parent piles into the rear side ground, a connecting member connecting the parent piles and the auxiliary piles, and a gripping member detachably attached to a base end of the auxiliary pile in the insertion direction, which serves as a gripping member for an insertion heavy machine that inserts the auxiliary pile when inserting the auxiliary pile into the rear side ground and which is detached from the auxiliary pile after insertion, wherein the parent piles and the auxiliary piles are constituted by H-shaped steel having a pair of flanges and a web connecting the pair of flanges together, the connecting member comprises a square tube-shaped square pipe material, one end of which is fitted between the flanges of the parent piles and fastened to the web, a step of fastening one end of a square pipe material to the parent pile with one end inserted between the flanges of the parent pile ; a step of attaching a gripping member to the base end of the auxiliary pile in the insertion direction; a step of inserting the auxiliary pile into the rear side ground while gripping the gripping member with an insertion heavy machine with the other end of the square pipe material inserted between the flanges of the auxiliary pile so that the upper and lower surfaces of the other end of the square pipe material serve as insertion guides for the auxiliary pile; a step of fastening the other end of the square pipe material to the auxiliary pile inserted into the rear side ground; and a step of removing the gripping member from the auxiliary pile inserted into the rear side ground .

According to the invention of claim 1, a gripping member is provided which is removably attached to the base end of the auxiliary pile in the insertion direction, serves as a gripping member for the insertion heavy machinery that inserts the auxiliary pile when the auxiliary pile is inserted into the rear side ground, and is detached from the auxiliary pile after insertion. This makes it unnecessary to cut the uninserted portion of the auxiliary pile, and as a result, not only can the material costs for the cut portion be avoided from being wasted, but the cutting process for the uninserted portion is also unnecessary, thereby reducing construction costs.
In addition, according to the invention of claim 2, the auxiliary pile is provided with an auxiliary pile side joint member that covers the base end face in the insertion direction and also serves as a reinforcing member for the auxiliary pile, and the gripping member is provided with a gripping side joint member that covers the tip face in the insertion direction and can be fastened to the auxiliary pile side joint member via a plurality of bolts.This not only makes it easy to attach and detach the gripping member, but also simplifies the structure and reduces costs by using the auxiliary pile side joint member also as a reinforcing member for the auxiliary pile.
In addition, according to the invention of claim 3, the construction method of the retaining wall includes the steps of attaching a gripping member to the base end of the auxiliary pile in the insertion direction, inserting the auxiliary pile into the rear ground while gripping the gripping member using an insertion heavy machine, and removing the gripping member from the auxiliary pile, thereby eliminating the need to cut the uninserted portion of the auxiliary pile. As a result, not only is it possible to avoid wasting material costs for the cut portion, but the cutting step for the uninserted portion is also unnecessary, thereby reducing construction costs.

1 is an oblique view showing the structure of an earth retaining wall according to one embodiment of the present invention; FIG. 13 is a perspective view showing the state in which a connecting member is attached to a parent pile. FIG. 13 is a perspective view showing a state in which an auxiliary pile is connected to a parent pile via a connecting member. FIG. 11 is a perspective view showing a state in which the gripping member has been removed from the auxiliary pile. FIG. 13 is a front view showing the state in which an auxiliary pile is connected to a parent pile via a connecting member. FIG. 11 is a plan view showing the state in which an auxiliary pile is connected to a parent pile via a connecting member. FIG. 13 is a side view showing the state in which an auxiliary pile is connected to a parent pile via a connecting member. 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.

[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 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 heavy 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 upper and lower surfaces of the portion where the connecting member 5 fits to function as insertion guides, as shown in Figure 5. 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 with a plurality 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 retaining wall 1 comprises a plurality of parent piles 2 inserted at a predetermined interval into the ground where the 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 side positions of the parent piles 2 into the rear side ground and connected to the parent piles 2 via connecting members 5. The auxiliary piles 4 are provided with gripping members 6 that are detachably attached to the base ends in the insertion direction of the auxiliary piles 4 and serve as gripping members for the insertion heavy machinery that inserts the auxiliary piles 4 when the auxiliary piles 4 are inserted into the rear side ground, and are detached from the auxiliary piles 4 after insertion. This eliminates the need to cut the uninserted portions of the auxiliary piles 4, and as a result, not only is it possible to avoid wasting material costs for the cut portions, but the cutting process for the uninserted portions is also unnecessary, thereby reducing construction costs.

The auxiliary pile 4 and the gripping member 6 are H-shaped steel members integrally having a pair of flanges 4a, 6a and webs 4b, 6b that connect the pair of flanges 4a, 6a. The auxiliary pile 4 has an auxiliary pile-side joint member that covers the base end face in the insertion direction and doubles as the reinforcing member 41 of the auxiliary pile 4. The gripping member 6 has a gripping side joint member 61 that covers the tip face in the insertion direction and can be fastened to the auxiliary pile-side joint member via a plurality of third bolts B3. This not only makes it easier to attach and detach the gripping member 6, but also simplifies the structure and reduces costs by using the auxiliary pile-side joint member as the reinforcing member 41 of the auxiliary pile 4.

In addition, the construction method of the earth retaining wall 1 includes a plurality of parent piles 2 inserted at a predetermined interval into the earth retaining wall construction ground, 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 construction method includes the steps of attaching a gripping member 6 to the base end of the auxiliary pile 4 in the insertion direction, inserting the auxiliary pile 4 into the rear side ground while gripping the gripping member 6 with an insertion heavy machine, and removing the gripping member 6 from the auxiliary pile 4. This eliminates the need to cut the uninserted portion of the auxiliary pile 4, which not only avoids the waste of material costs for the cut portion, but also eliminates the need for the cutting process for the uninserted portion, thereby reducing construction costs.

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 Auxiliary pile 4a Flange 4b Web 4c Groove 41 First reinforcing member 41a Bolt insertion hole 42 Second reinforcing member 5 Connecting member 51 Square pipe material 52 First end plate 52a Bolt insertion hole 53 Second end plate 53a Bolt insertion hole 6 Grip member 6a Flange 6b Web 61 Grip side joint member

Claims (3)

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 plurality of auxiliary piles are inserted into the rear side ground from the side positions of the parent piles;
A connecting member that connects the parent pile and the auxiliary pile;
A retaining wall comprising a gripping member that is detachably attached to the base end of the auxiliary pile in the insertion direction, serves as a gripping member for an insertion heavy machine that inserts the auxiliary pile when the auxiliary pile is inserted into the back side ground, and is detached from the auxiliary pile after insertion.
The parent pile and the auxiliary pile are each formed of an H-shaped steel having a pair of flanges and a web connecting the pair of flanges to each other,
The connecting member includes a square pipe material having a rectangular tubular shape, one end of the square pipe material being fitted between the flanges of the parent pile and fastened to the web, and the other end of the square pipe material being fitted between the flanges of the auxiliary pile and fastened to the web, thereby connecting the parent pile and the auxiliary pile,
The upper and lower surfaces of the other end of the square pipe material, one end of which is fastened to the parent pile, are fitted between the flanges of the auxiliary pile, thereby forming a retaining wall that serves as an insertion guide for the auxiliary pile to be inserted into the ground at the rear . The auxiliary pile and the gripping member are H-shaped steel integrally having a pair of flanges and a web connecting the pair of flanges,
The auxiliary pile includes an auxiliary pile-side joint member that covers the base end surface in the insertion direction and is also used as a reinforcing member for the auxiliary pile,
The retaining wall according to claim 1 , wherein the gripping member covers a tip surface in the insertion direction and is provided with a gripping side joint member that can be fastened to the auxiliary pile side joint member via a plurality of bolts. 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 plurality of auxiliary piles are inserted into the rear side ground from the side positions of the parent piles;
A connecting member that connects the parent pile and the auxiliary pile;
A retaining wall comprising a gripping member that is detachably attached to the base end of the auxiliary pile in the insertion direction, serves as a gripping member for an insertion heavy machine that inserts the auxiliary pile when the auxiliary pile is inserted into the back side ground, and is detached from the auxiliary pile after insertion.
The parent pile and the auxiliary pile are each formed of an H-shaped steel having a pair of flanges and a web connecting the pair of flanges to each other,
A method for constructing an earth retaining wall in which the connecting member is provided with a square pipe material having a square tubular shape, one end of the square pipe material being fitted between the flanges of the parent pile and fastened to the web, and the other end of the square pipe material being fitted between the flanges of the auxiliary pile and fastened to the web, thereby connecting the parent pile and the auxiliary pile , the method includes:
A step of fastening one end of the square pipe material to the parent pile in a state where one end of the square pipe material is inserted between the flanges of the parent pile;
A step of attaching a gripping member to a base end portion of the auxiliary pile in the insertion direction;
The other end of the square pipe material is fitted between the flanges of the auxiliary pile, and the upper and lower surfaces of the other end of the square pipe material are used as insertion guides for the auxiliary pile. In this state, the auxiliary pile is inserted into the rear side ground while gripping the gripping member with an insertion heavy machine.
A step of fastening the auxiliary pile inserted into the rear side ground to the other end of the square pipe material;
and removing the gripping member from the auxiliary pile inserted into the rear side ground .

Images