JP7664144B2 - Retaining walls and methods for constructing them - Google Patents

Description

The present invention relates to a retaining wall and a method for constructing a retaining wall.

When forming an access road leading to a tunnel from above ground, an underpass at a grade separation, a waterway, etc., a retaining wall in which a pair of left and right retaining walls and a bottom slab are integrally formed is sometimes adopted. Retaining walls are generally constructed with cast-in-place concrete. However, construction with cast-in-place concrete requires assembling formwork, pouring concrete, curing, etc., on-site, and is therefore time-consuming. In addition, cast-in-place concrete has a larger component thickness than secondary products made of precast concrete. This hinders the reduction of the amount of concrete and the reduction of the amount of excavated soil.
Retaining walls can also be constructed using secondary products. However, when using secondary products such as precast concrete to construct a retaining wall, it takes a lot of time and effort to transport and construct large-scale components. In addition, large-scale precast components are expensive.
Patent Document 1 discloses an earth retaining wall consisting of a plurality of U-shaped frames installed at intervals in the axial direction of a waterway and concrete sheet pile members inserted between the U-shaped frames. The U-shaped frames are made of a pair of side steel members and bottom steel members made of H-shaped steel. The concrete sheet pile members are installed between the front and rear U-shaped frames with their ends inserted between the flanges of the side steel members.
The retaining wall of Patent Document 1 requires the use of a lifting machine such as a crane because it is necessary to insert a concrete sheet pile member from the upper end of the side steel material. In addition, the retaining wall of Patent Document 1 requires high-altitude work at the top of the side steel material, which requires time and cost for the installation of scaffolding and safety management facilities. Since it is expected that there will be cases where it is not possible to secure space to install a lifting machine or there will be restrictions on high-altitude work, a structure with a high degree of freedom in construction is desirable.

JP 2020-133111 A

From this perspective, the present invention aims to propose a retaining wall that can be easily constructed and a method for constructing the retaining wall.

The retaining wall of the present invention for solving the above-mentioned problems is a retaining wall comprising a base plate, a pair of left and right wall bodies erected on the base plate, and struts horizontally extending between the pair of left and right wall bodies, the base plate having a plurality of beam bodies laid at intervals in the front-rear direction, each of the walls being composed of a column body erected on the beam body and a plurality of wall panels leaning between adjacent columns in the front-rear direction. The columns have protruding parts protruding forward and backward and are convex in plan view, the ends of the wall panels are engaged with the protruding parts of the columns, the struts are horizontally extended from the upper parts of the columns on the left and right , the plurality of columns arranged in parallel in the front-rear direction are connected by head connecting members made of plate-shaped members fixed to the outer surfaces of the heads of the columns, and the plurality of beam bodies arranged in parallel in the front-rear direction are connected by bottom connecting members made of plate-shaped members fixed to the upper surfaces of the beam bodies .
Such a retaining wall is easy to construct because the wall is formed by leaning precast wall panels against columns that are convex (T-shaped) in plan view. Since the wall panels do not need to be dropped from above, work at height can be omitted or reduced. Furthermore, if the wall panels are small enough to be carried by hand, they can be installed even in cases where there is no space available for a crane or other lifting equipment.
In addition, the base slab further includes a filler material (e.g., soil and sand generated by excavation or liquefied treated soil) filled between the beams, or a deck slab spanning multiple beams, and is formed so that the upper surface is smooth.
In addition, in the case where a bottom ruler member is provided with a plurality of recesses formed at a predetermined interval in the front-rear direction, the beam body is placed in the recesses. With such a retaining wall, the positioning of the beam body and the column body is completed by placing the beam body on the bottom ruler member, which provides excellent workability.
Furthermore, if the structure further includes a head connecting member that connects the heads of multiple pillars arranged side by side in the front-to-rear direction, tilting and deformation of the pillars can be suppressed, thereby improving construction accuracy.

The construction method of the retaining wall of the present invention includes a frame installation step of arranging a plurality of U-shaped frames, each of which includes a beam, a pair of left and right columns erected on the beam, and a strut horizontally installed on the upper part of the pair of left and right columns, at intervals in the front-rear direction, a filling step of filling the spaces between the beams with a filler, a beam connection step of fixing bottom connection members made of plate-like members to the upper surfaces of the left and right ends of the beams to connect the plurality of beams, a panel installation step of leaning a wall panel between the columns of the U-shaped frames adjacent in the front-rear direction, a backfilling step of backfilling the backs of the wall panels, and a column connection step of fixing head connection members made of plate-like members to the outer surfaces of the heads of the columns to connect the plurality of columns arranged in the front-rear direction . It is also preferable to repeat the panel installation step and the backfilling step to form a wall of a predetermined height.
According to this method of constructing a retaining wall, the wall is formed by leaning precast wall panels against the pillars, which is easy to construct. In other words, the wall panels can be formed by leaning them from the side, rather than dropping them in from above, so there is no need to work at height, and the wall panels can be installed even when there is no space to install a lifting machine. Furthermore, the use of precast members makes it possible to reduce the amount of concrete and the amount of soil discharged during excavation, which in turn makes it possible to reduce the environmental load. Furthermore, if excavated soil is used as a filler, the amount of soil discharged can be reduced.

The retaining wall and the retaining wall construction method of the present invention make it possible to easily construct the retaining wall.

1 is a perspective view showing a retaining wall according to an embodiment of the present invention. 1A is a plan view of a retaining wall, FIG. 1B is a front view of the wall, and FIG. 1C is a side view of the wall. 1 is a flowchart showing a method for constructing a retaining wall. FIG. FIG. FIG. FIG.

In the embodiment of the present invention, a case where a road is constructed by providing a retaining wall in a trench formed by excavating the ground will be described. Figures 1 and 2 show a retaining wall 1. As shown in Figure 1, the retaining wall 1 includes a base slab 2, a pair of left and right wall bodies 3 erected on both ends of the base slab 2, and struts 4 horizontally disposed between the left and right wall bodies 3.
As shown in Fig. 2(a), the base slab 2 is formed with a plurality of beams 5 laid at intervals in the front-rear direction and a filler material 6 filled between the beams 5 so that the top surface is smooth. The beams 5 are formed to extend in the transverse direction (left-right). In this embodiment, excavated soil (backfill soil) generated by excavating the ground is used as the filler material 6.

As shown in Figures 2(a) to (c), the wall 3 is composed of columns 7 erected at both ends of the beam 5, and a number of wall panels 8 provided between adjacent columns 7 in the front and rear.
As shown in Fig. 2(a), the column 7 has a main body 71 having a rectangular shape in plan view, and protruding parts 72 protruding in front and behind the main body 71, and has a convex shape in plan view. As shown in Fig. 2(b), the main body 71 of the column 7 has a thickness (width in the left-right direction) that increases toward the bottom, and has a trapezoidal shape in front view. The beam 5 and the column 7 are integrally formed to constitute a U-shaped frame 10 that is U-shaped in front view. In this embodiment, a precast U-shaped frame 10 in which the beam 5 and the column 7 are integrally formed is used.
The wall panels 8 are plate-shaped precast concrete members. As shown in Fig. 2(c), a wall 3 of a predetermined height is formed by stacking a plurality of wall panels 8 one above the other. As shown in Figs. 2(a) and 2(c), the length of the wall panel 8 in the front-rear direction is equal to or less than the distance between the end faces of the main body parts 71 of adjacent columns 7 in the front-rear direction, and is greater than the distance between the end faces of the overhanging parts 72 of the columns 7. The wall panels 8 are installed with their ends engaged with the overhanging parts 72 of the columns 7.

As shown in Figures 2(a) and (b), the struts 4 are installed horizontally across the tops of the left and right columns 7, 7, and are spaced apart in the front-to-rear direction. In this embodiment, the struts 4 are installed horizontally at the middle of the height of the column 7. The struts 4 in this embodiment are precast concrete members and are formed integrally with the column 7. In other words, the struts 4 are formed integrally with the upper part of the U-shaped frame 10.

The retaining wall 1 of this embodiment includes a pair of bottom ruler members 9 on the left and right as shown in Fig. 1. The bottom ruler member 9 is a long member with a rectangular cross section that is placed on the ground in a tilted (lying) state in the front-to-back direction. As shown in Fig. 2(c) , a plurality of recesses 91 are formed at a predetermined interval in the front-to-back direction on the upper surface of the bottom ruler member 9. The recesses 91 are cutouts whose front-to-back length is equal to or greater than the front-to-back width of the beam body 5. The beam body 5 is inserted into the recesses 91 and placed on the bottom ruler member 9, whereby the U-shaped frame body 10 is placed in a predetermined position.
As shown in Fig. 1, the multiple U-shaped frame bodies 10 arranged side by side in the front-rear direction are connected by a head connecting member 11 and a bottom connecting member 12. The head connecting member 11 is fixed to the outer surfaces of the heads of the multiple pillar bodies 7, thereby connecting the pillar bodies 7 to each other. The bottom connecting member 12 connects the multiple beam bodies 5 arranged side by side in the front-rear direction to each other on the upper surfaces of the beam bodies 5 at the corners between the beam bodies 5 and the pillar bodies 7. The head connecting member 11 and the bottom connecting member 12 in this embodiment are made of plate-like members having multiple through holes formed therein, and are fixed to the U-shaped frame body 10 by fastening bolts inserted through the through holes to the U-shaped frame body 10 (beam body 5 or pillar body 7).

Next, the construction method of the retaining wall will be explained. The construction method of the retaining wall is shown in FIG.
As shown in FIG. 3, the construction of the retaining wall 1 includes an excavation process S1, a frame installation process S2, a filling process S3, a panel installation process S4, and a backfilling process S5.
In the excavation step S1, the ground is excavated at the construction site of the trench road. The excavation step is shown in Fig. 4. As shown in Fig. 4, the ground is excavated so that the width of the bottom is larger than the width of the bottom slab 2 of the retaining wall 1, and a slope is formed with a predetermined slope gradient. That is, in the excavation step S1, an excavation trench 13 having an inverted trapezoidal cross section is formed. After the excavation is completed, pebbles or crushed stones are spread evenly on the bottom 14, and then the leveling concrete 15 is poured in to flatten the bottom 14 of the excavation trench 13. At this time, a pair of bottom ruler materials 9 on the left and right are embedded in the leveling concrete 15.

In the frame body installation step S2, a plurality of U-shaped frame bodies 10 are arranged in parallel with intervals in the front-rear direction in the excavation trench 13 formed in the excavation step S1. The frame body installation step S2 is shown in Fig. 5. As shown in Fig. 5, the U-shaped frame bodies 10 are horizontally supported on the left and right bottom ruler members 9. At this time, the beam body 5 is placed in the recessed portion 91, so that the U-shaped frame bodies 10 are arranged at a predetermined interval (see Fig. 2).
In the filling step S3, the filler 6 is filled between the beam bodies 5. In this embodiment, the excavated soil generated by the excavation of the ground in the excavation step S1 is used as the filler 6 to backfill the gaps between the beam bodies 5. The filler 6 is backfilled so that the upper surface of the filler 6 is flush with the upper surface of the beam body 5 (see FIG. 2). After the filler 6 is filled between the beam bodies 5, the bottom connecting members 12 are fixed to the left and right ends of the beam body 5 (the corners between the beam body 5 and the column body 7) to connect the multiple beam bodies 5.

In the panel installation process S4, the wall panel 8 is leaned up between the column bodies 7 of the U-shaped frame bodies 10 adjacent in the front-rear direction. The panel installation process S4 is shown in Fig. 6. As shown in Fig. 6, the wall panel 8 is leaned up from the outside (ground surface side) of the column body 7. The surface of the end of the wall panel 8 is abutted against the outer surface of the overhanging portion 72 of the column body 7. In this embodiment, a worker manually leans the wall panel 8 up between the column bodies 7. It is desirable to interpose a water-stopping material (not shown) between the wall panel 8 and the overhanging portion 72.
In the backfilling step S5, the wall panel 8 leaned against the column body 7 and the back surface of the column body 7 are backfilled. The backfilling step S5 is shown in Fig. 7. The excavated soil 61 generated in the excavation step S1 is used to backfill the back surface of the wall panel 8. Backfilling is performed to a position lower than the top of the wall panel 8, as shown in Fig. 7.
After the wall panels 8 are backfilled to the flat surface, new wall panels 8 are installed on the existing wall panels 8 using the backfill soil as a work floor (panel installation step S4), and the backfilling is performed on the rear surface (backfilling step S5). The panel installation step and backfilling step are repeated in the same manner to form a wall body 3 of a predetermined height. After the wall body 3 of a predetermined height is formed, the column bodies 7 are connected to each other by the head connection members 11.

According to the retaining wall 1 and the construction method of the retaining wall 1 of the present embodiment, the wall body 3 is formed by leaning the precast wall panel 8 against the column body 7 that is convex (T-shaped) in plan view, and therefore, the construction is excellent. The wall panel 8 does not need to be dropped from above, so no work at height is required. Therefore, the effort and cost required for temporary construction such as scaffolding required for work at height can be omitted.
In addition, since the wall panel 8 is small enough to be carried by hand, a lifting machine such as a crane is not required. This reduces the cost of the lifting machine. Furthermore, the retaining wall 1 can be constructed even in a narrow place where the space for the installation of the lifting machine cannot be secured.
Since excavated soil generated by excavating the ground is used as the filler 6 to fill the gaps between the beam bodies 5, the cost required for disposal of the excavated soil can be reduced.
In addition, by using the bottom ruler material 9 in which multiple recesses 91 are formed at predetermined intervals in the front-rear direction, the positioning of the U-shaped frame body 10 can be completed simply by placing the beam body 5 on the recesses 91, which provides excellent workability. In other words, surveying when positioning the U-shaped frame body 10 can be omitted.

In addition, because the heads of the multiple columns 7 arranged side by side in the front-to-rear direction are connected by the head connecting members 11, the inclination and deformation of the columns are suppressed, and construction accuracy can be improved. In addition, because the multiple beams 5 arranged side by side in the front-to-rear direction are connected by the bottom connecting members 12, deviation of the U-shaped frame body 10 is suppressed. Furthermore, by connecting the U-shaped frame bodies 10 to each other in the longitudinal direction by the head connecting members 11 and the bottom connecting members 12, earthquake resistance is improved.
By using precast concrete members produced in a factory for the U-shaped frame 10 and wall panel 8, the members can be made thinner. As a result, even when constructing a structure the width of a road, the overall width of the retaining wall 1 can be made smaller, which in turn makes it possible to reduce the amount of concrete used and the amount of soil removed during excavation. This also makes it possible to reduce the environmental load, such as reducing CO2 emissions.
In addition, since the struts 4 are provided, deformation of the wall body 3 is suppressed, and the wall body 3 has excellent durability.

Although an embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and each of the above-described components can be appropriately modified without departing from the spirit of the present invention.
In the above embodiment, backfill soil is filled between the beam bodies 5 as the filler 6, but the material constituting the filler 6 is not limited. For example, it may be liquefied treated soil or improved soil. In this case, it is preferable to use excavated soil generated by excavating the ground as the liquefied treated soil or improved soil. In addition, concrete, crushed stone, etc. may be used as the filler 6.
In addition, in the above embodiment, the filler 6 is filled between the beams 5, but the floor slab may be straddled across multiple beams 5 to form a bottom slab 2 with a flat upper surface.
In the above embodiment, the U-shaped frame 10 is a precast concrete member, but the U-shaped frame 10 does not necessarily have to be made of precast concrete. In addition, either the beam 5 or the column 7 may be a precast concrete member, and the other may be constructed of cast-in-place concrete. In addition, the beam 5 and the column 7 constituting the U-shaped frame 10 may be half precast members.

In the above embodiment, the plurality of pillars 7 are connected by the head connecting members 11, but the head connecting members 11 may be provided as necessary. Similarly, the bottom connecting members 12 may be provided as necessary.
In the above embodiment, the U-shaped frame 10 is placed on a pair of bottom ruler members 9, but the number of bottom ruler members 9 is not limited. The bottom ruler members 9 are not limited to rectangular columnar members, and may be, for example, plate-shaped members. The bottom ruler members 9 may be provided as necessary, and may be omitted.
Instead of the bottom ruler material 9, a recess 91 may be formed in the upper surface of the leveling concrete 15 poured into the bottom 14 of the excavation trench 13, and the beam body 5 may be placed in the recess 91.
In the above embodiment, a wall 3 of a predetermined height is formed by repeating the panel installation process and the backfilling process multiple times, but in the panel installation process, the wall panel 8 may be installed to a predetermined height and then the back surface of the wall panel 8 may be filled.
In the excavation step S1, a temporary retaining wall may be provided.

Although a plate-like member is used as the head connecting member 11, the head of the U-shaped frame body 10 (column body 7) may be fixed by coping or capping. The head connecting member 11 may also be a wire or the like.
In addition, the retaining wall 1 does not necessarily have to be formed in an excavation trench. For example, when the retaining wall 1 is to be formed on an embankment, an embankment is laid behind the retaining wall 1.
The mounting position of the strut 4 is not limited, and may be mounted, for example, on the upper end of the column 7. The strut 4 is not limited to a concrete member, and may be, for example, a steel material such as an H-shaped steel. The strut 4 may be provided as necessary. Furthermore, the strut 4 does not necessarily have to be a member formed integrally with the U-shaped frame body 10, and may be hung horizontally on the left and right columns 7, 7 after the U-shaped frame body 10 is installed in a predetermined position. A top plate may be placed on the strut 4.
The thickness of the lower wall panel 8 may be greater than the thickness of the upper wall panel 8, or the thickness of the wall panels 8 may be constant. Also, the lower wall panel 8 may be made of a material having higher strength.

REFERENCE SIGNS LIST 1 retaining wall 10 U-shaped frame body 11 head connecting member 12 bottom connecting member 13 excavation trench 14 bottom 15 leveling concrete 2 bottom slab 3 wall body 4 strut 5 beam body 6 filling material 7 column body 71 main body 72 overhanging portion 8 wall panel 9 bottom ruler material 91 recess

Claims (5)

A retaining wall comprising a base plate, a pair of left and right wall bodies erected on the base plate, and struts horizontally extending between the pair of left and right wall bodies,
The bottom slab has a plurality of beams laid at intervals in the front-rear direction,
Each wall body is composed of a column body erected on the beam body and a plurality of wall panels leaning against each other between adjacent columns in the front and rear direction,
The columnar body has a protruding portion protruding forward and backward and has a convex shape in a plan view,
The end of the wall panel is engaged with the protruding portion of the pillar,
The struts are horizontally supported on the upper portions of the left and right columns ,
The plurality of pillars arranged in parallel in the front-rear direction are connected by a head connecting member made of a plate-like member fixed to the outer surface of the head of each of the pillars,
A retaining wall, characterized in that a plurality of the beams arranged side by side in the front-to-rear direction are connected by bottom connecting members consisting of plate-shaped members fixed to the upper surfaces of the beams . The retaining wall according to claim 1, characterized in that the base slab further comprises a filler material filled between the beams, or a deck slab spanning multiple beams, and has a smooth upper surface. A bottom ruler member is provided with a plurality of recesses formed at predetermined intervals in the front-rear direction,
The retaining wall according to claim 1 or 2, characterized in that the beam is placed in the recess. a frame installation process in which a plurality of U-shaped frames each including a beam body, a pair of left and right columns erected on the beam body, and a strut horizontally disposed on an upper portion of the pair of left and right columns are arranged side by side at intervals in the front-rear direction;
a filling step of filling a filler material between the beam bodies;
a beam body connecting step of connecting a plurality of beam bodies by fixing bottom connecting members made of plate-like members to upper surfaces of the left and right ends of the beam bodies;
A panel installation process of leaning a wall panel between the pillars of the U-shaped frame bodies adjacent to each other in the front-rear direction;
A backfilling step of backfilling the rear surface of the wall panel;
a column connecting step of fixing a head connecting member made of a plate-shaped member to the outer surface of the head of each of the columns to connect a plurality of the columns arranged side by side in the front-rear direction . 5. The method for constructing a retaining wall according to claim 4 , wherein a wall having a predetermined height is formed by repeating the panel installation step and the backfilling step.

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